Researcher Database

Shoshiro Minobe
Faculty of Science Earth and Planetary Sciences Earth and Planetary Dynamics
Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Science Earth and Planetary Sciences Earth and Planetary Dynamics

Job Title

  • Professor

ORCID ID

Researcher ID

  • E-2997-2010

J-Global ID

Research Interests

  • 同期   栄養塩   地球シミュレーター   最適内挿法   溶存酸素   接地境界層   大気数値モデル   非静水圧3次元数値実験   気候レジームシフト   非線形共鳴   非線形同期   レジーム・シフト   オホーツク海   pH   数値実験   気候力学   降水帯   高解像度   黒潮   メキシコ湾流   データ解析   アリュ-シャン低気圧   50〜70年スケ-ル   親潮   海氷   衛星データー   気候変動   十年スケール変動   北太平洋   大気海洋相互作用   

Research Areas

  • Environmental science/Agricultural science / Environmental dynamics
  • Natural sciences / Atmospheric and hydrospheric science

Academic & Professional Experience

  • 2006 - Today Hokkaido University
  • 2003/06 - 2006/07 Ministry of Education,Culture,Sports,Science and Technology
  • 2003 - 2005 北海道大学 理学(系)研究科(研究院) 助教授
  • 2005 北海道大学 大学院・理学研究科 教授
  • 1998/04 - 2004/03 (独)海洋研究開発機構 地球フロンティア研究システム・国際北極研究センター 研究員
  • 1998 - 2004 北海道大学 大学院・理学研究科 助教授
  • 2004 北海道大学 理学研究科 助教授
  • 1998 - 1999 北海道大学 理学(系)研究科 助教授
  • 1995 - 1996 北海道大学 大学院・理学研究科 助手
  • 1996 北海道大学 理学(系)研究科 助手
  • 1994/06 - 1994/09 ワシントン大学客員研究員
  • 1989 Hokkaido University School of Science

Association Memberships

  • JAPAN GEOSCIENCE UNION   American Meteorological Society   American Geophysical Union   (2) The Meteorological Society of Japan   The Oceanographic Society of Japan   

Research Activities

Published Papers

  • Chorong Lee, Shoshiro Minobe, Yoshi N. Sasaki
    Journal of Oceanography 75 (2) 119 - 137 0916-8370 2019/04 [Refereed][Not invited]
  • Hanna Na, Kwang-Yul Kim, Shoshiro Minobe, Yoshi N. Sasaki
    Journal of Climate 31 (13) 5107 - 5125 0894-8755 2018/07/01 [Refereed][Not invited]
     
    Three-dimensional oceanic thermal structures and variability in the western North Pacific (NP) are examined on the interannual to decadal time scales and their relationship to oceanic and atmospheric variability is discussed by analyzing observation and reanalysis data for 45 years (1964-2008), which is much longer than the satellite-altimetry period. It is shown that the meridional shift of the Kuroshio Extension (KE) and subarctic frontal zone (SAFZ) is associated with the overall cooling/warming over the KE and SAFZ region (KE-SAFZ mode). It appears, however, that changes in KE strength induce different signs of thermal anomalies to the south and north of the KE, not extended to the SAFZ (KE mode), possibly contributing to noncoherent variability between the KE and SAFZ. Thus, the KE and SAFZ are dependent on each other in the context of the KE-SAFZ mode, while the KE is independent of the SAFZ in terms of the KE mode. This intricate relationship is associated with different linkages to atmospheric variability the KE-SAFZ mode exhibits a relatively fast response to the large-scale wind stress curl forcing in the NP, whereas the KE mode is related to a delayed response to the atmospheric forcing via jet-trapped baroclinic Rossby wave propagation. It is suggested that further knowledge of the underlying mechanisms of the two modes would contribute to understanding ocean-atmosphere feedback as well as potential predictability over the western boundary current region in the NP.
  • Mio Terada, Shoshiro Minobe
    Climate Dynamics 50 (11-12) 4767 - 4782 1432-0894 2018/06/01 [Refereed][Not invited]
     
    Future changes in the dynamic sea level (DSL), which is defined as sea-level deviation from the global mean sea level, is investigated over the North Pacific, by analyzing data from the Coupled Model Intercomparison Project Phase 5. The analysis provides more comprehensive descriptions of DSL responses to the global warming in this region than available from previous studies, by using surface and subsurface data until the year 2300 under middle and high greenhouse-gas emission scenarios. The DSL changes in the North Pacific are characterized by a DSL rise in the western North Pacific around the Kuroshio Extension (KE), as also reported by previous studies. Subsurface density analysis indicates that DSL rise around the KE is associated with decrease in density of subtropical mode water (STMW) and with northward KE migration, the former (latter) of which is relatively strong between 2000 and 2100 for both RCP4.5 and RCP8.5 (between 2100 and 2300 for RCP8.5). The STMW density decrease is related to large heat uptake to the south and southeast of Japan, while the northward KE migration is associated with the poleward shift of the wind stress field. These features are commonly found in multi-model ensemble means and the relations among representative quantities produced by different climate models.
  • Matthew Collins, Shoshiro Minobe, Marcelo Barreiro, Simona Bordoni, Yohai Kaspi, Akira Kuwano-Yoshida, Noel Keenlyside, Elisa Manzini, Christopher H. O'Reilly, Rowan Sutton, Shang-Ping Xie, Olga Zolina
    Nature Climate Change 8 (2) 101 - 108 1758-6798 2018/02/01 [Refereed][Not invited]
     
    Dynamical processes in the atmosphere and ocean are central to determining the large-scale drivers of regional climate change, yet their predictive understanding is poor. Here, we identify three frontline challenges in climate dynamics where significant progress can be made to inform adaptation: response of storms, blocks and jet streams to external forcing basin-to-basin and tropical-extratropical teleconnections and the development of non-linear predictive theory. We highlight opportunities and techniques for making immediate progress in these areas, which critically involve the development of high-resolution coupled model simulations, partial coupling or pacemaker experiments, as well as the development and use of dynamical metrics and exploitation of hierarchies of models.
  • Yoshi N. Sasaki, Ryosuke Washizu, Tamaki Yasuda, Shoshiro Minobe
    Journal of Climate 30 (14) 5585 - 5595 0894-8755 2017/07/01 [Refereed][Not invited]
     
    Sea level variability around Japan from 1906 to 2010 is examined using a regional ocean model, along with observational data and the CMIP5 historical simulations. The regional model reproduces observed interdecadal sea level variability, for example, high sea level around 1950, low sea level in the 1970s, and sea level rise during the most recent three decades, along the Japanese coast. Sensitivity runs reveal that the high sea level around 1950 was induced by the wind stress curl changes over the North Pacific, characterized by a weakening of the Aleutian low. In contrast, the recent sea level rise is primarily caused by heat and freshwater flux forcings. That the wind-induced sea level rise along the Japanese coast around 1950 is as large as the recent sea level rise highlights the importance of natural variability in understanding regional sea level change on interdecadal time scales.
  • Shoshiro Minobe, Mio Terada, Bo Qiu, Niklas Schneider
    JOURNAL OF PHYSICAL OCEANOGRAPHY 47 (5) 957 - 977 0022-3670 2017/05 [Refereed][Not invited]
     
    To better understand coastal sea level variability and changes, a theory that predicts sea levels along a curved western boundary using interior ocean sea level information is proposed. The western boundary sea level at a particular latitude is expressed by the sum of contributions from interior sea levels propagating onto the western boundary by long Rossby waves between that latitude and a higher latitude, and from the western boundary sea level at the higher latitude. This theory is examined by using a linear, reduced gravity model. A comparison between the theory and the model shows good agreement. A simple scaling law (or rule of thumb) derived from the theory provides a measure of the higher-latitude sea level and ocean interior sea level contributions. The theory is then tested using data from 34 climate models in phase 5 of the Coupled Model Intercomparison Project (CMIP5) for dynamic sea level changes between the end of the twentieth and twenty-first centuries. The theory captures the nearly uniform sea level rise from the Labrador Sea to New York City (NYC), with a reduction in the increase of sea level farther south toward the equator, qualitatively consistent with the CMIP5 multimodel ensemble, even though the theory underestimates the equatorward reduction rate. Along the South American east coast, the theory successfully reproduced the spatial pattern of the sea level change. The theory suggests a strong link between a sea level rise hot spot along the northeastern coast of North America and the sea level increase in the Labrador Sea, consistent with the result that rates of NYC sea level rise are highly correlated to those in the Labrador Sea in CMIP5 models.
  • Takamitsu Ito, Shoshiro Minobe, Matthew C. Long, Curtis Deutsch
    GEOPHYSICAL RESEARCH LETTERS 44 (9) 4214 - 4223 0094-8276 2017/05 [Refereed][Not invited]
     
    Historic observations of dissolved oxygen (O-2) in the ocean are analyzed to quantify multidecadal trends and variability from 1958 to 2015. Additional quality control is applied, and the resultant oxygen anomaly field is used to quantify upper ocean O-2 trends at global and hemispheric scales. A widespread negative O-2 trend is beginning to emerge from the envelope of interannual variability. Ocean reanalysis data are used to evaluate relationships with changes in ocean heat content (OHC) and oxygen solubility (O-2,O-sat). Global O-2 decline is evident after the 1980s, accompanied by an increase in global OHC. The global upper ocean O-2 inventory (0-1000m) changed at the rate of -243124TmolO(2) per decade. Further, the O-2 inventory is negatively correlated with the OHC (r=-0.86; 0-1000m) and the regression coefficient of O-2 to OHC is approximately -8.20.66nmolO(2)J(-1), on the same order of magnitude as the simulated O-2-heat relationship typically found in ocean climate models. Variability and trends in the observed upper ocean O-2 concentration are dominated by the apparent oxygen utilization component with relatively small contributions from O-2,O-sat. This indicates that changing ocean circulation, mixing, and/or biochemical processes, rather than the direct thermally induced solubility effects, are the primary drivers for the observed O-2 changes. The spatial patterns of the multidecadal trend include regions of enhanced ocean deoxygenation including the subpolar North Pacific, eastern boundary upwelling systems, and tropical oxygen minimum zones. Further studies are warranted to understand and attribute the global O-2 trends and their regional expressions. Plain Language Summary This new paper describes the analysis of the dissolved oxygen in the global ocean using the most recent version of the World Ocean Database for the period of 1955 to 2015. After careful examination of the data, we found that a statistically significant, widespread O-2 decline is emerging beyond the envelope of natural fluctuations. Our study also reveals a tight relationship between O-2 inventories and the ocean heat content. The spatial pattern and magnitude of this relationship are consistent with expectations derived from mechanistic ocean climate models forced under climate warming scenarios. Taken together, the trends we document here are suggestive of the effects of the ocean warming beginning to supersede natural variability and emerge as a recognizable signal. This merits additional scrutiny over the coming years.
  • Akira Kuwano-Yoshida, Shoshiro Minobe
    JOURNAL OF CLIMATE 30 (3) 1081 - 1102 0894-8755 2017/02 [Refereed][Not invited]
     
    The storm-track response to sea surface temperature (SST) fronts in the northwestern Pacific region is investigated using an atmospheric general circulation model with a 50-km horizontal resolution. The following two experiments are conducted: one with 0.25 degrees daily SST data (CNTL) and the other with smoothed SSTs over an area covering SST fronts associated with the Kuroshio, the Kuroshio Extension, the Oyashio, and the subpolar front (SMTHK). The storm track estimated from the local deepening rate of surface pressure (LDR) exhibits a prominent peak in this region in CNTL in January, whereas the storm-track peak weakens and moves eastward in SMTHK. Storm-track differences between CNTL and SMTHK are only found in explosive deepening events with LDR larger than 1 hPa h(-1). A diagnostic equation of LDR suggests that latent heat release associated with large-scale condensation contributes to the storm-track enhancement. The SST fronts also affect the large-scale atmospheric circulation over the northeastern Pacific Ocean. The jet stream in the upper troposphere tends to meander northward, which is associated with positive sea level pressure (SLP) anomalies in CNTL, whereas the jet stream flows zonally in SMTHK. A composite analysis for the northwestern Pacific SLP anomaly suggests that frequent explosive cyclone development in the northwestern Pacific in CNTL causes downstream positive SLP anomalies over the Gulf of Alaska. Cyclones in SMTHK developing over the northeastern Pacific enhance the moisture flux along the west coast of North America, increasing precipitation in that region.
  • Christopher H. O'Reilly, Shoshiro Minobe, Akira Kuwano-Yoshida, Tim Woollings
    QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 143 (702) 173 - 183 0035-9009 2017/01 [Refereed][Not invited]
     
    In this article we investigate the influence of the Gulf Stream sea-surface temperature (SST) front on the North Atlantic eddy-driven jet and its variability, by analysing the NCEP-CFSR dataset and a pair of AGCM simulations forced with realistic and smoothed Gulf Stream SST boundary conditions. The Gulf Stream SST front acts to generate stronger meridional eddy heat flux in the lower troposphere and an eddy-driven jet over the eastern North Atlantic which is located further polewards than in the simulation with smoothed SST. The strong Gulf Stream SST gradient is found to be crucial in more accurately capturing the trimodal distribution of the eddy-driven jet latitude, with the more poleward climatological jet being the result of the jet occupying the northern jet position more frequently in the simulation forced with observed SSTs. The more frequent occurrence of the northern jet location is associated with periods of high eddy heat flux over the Gulf Stream region. Composite analysis of high eddy heat flux events reveals that the significantly higher heat flux is followed by larger and more persistient poleward jet excursions in the simulations with realistic SSTs than in the simulation with smoothed SSTs, with upper-tropospheric eddy momentum fluxes acting to maintain the more poleward eddy-driven jet. Periods of high eddy heat flux over the Gulf Stream region are also shown to be associated with increased blocking frequency over Europe, which are clearly distinct from periods with a northern jet position.
  • Zhao-Jun Liu, Shoshiro Minobe, Yoshi N. Sasaki, Mio Terada
    JOURNAL OF OCEANOGRAPHY 72 (6) 905 - 922 0916-8370 2016/12 [Refereed][Not invited]
     
    The future regional sea level (RSL) rise in the western North Pacific is investigated by dynamical downscaling with the Regional Ocean Modeling System (ROMS) with an eddy-permitting resolution based on three global climate models-MIROC-ESM, CSIRO-Mk3.6.0, and GFDL-CM3-under the highest greenhouse-gas emission scenario. The historical run is forced by the air-sea fluxes calculated from Coordinated Ocean Reference Experiment version 2 (COREv2) data. Three future runs-ROMS-MIROC, ROMS-CSIRO, and ROMS-GFDL-are forced with an atmospheric field constructed by adding the difference between the climate model parameters for the twenty-first and twentieth century to fields in the historical run. In all downscaling, the RSL rise along the eastern coast of Japan is generally half or less of the RSL rise maxima off the eastern coast. The projected regional (total) sea level rises along the Honshu coast during 2081-2100 relative to 1981-2000 are 19-25 (98-104), 6-15 (71-80), and 8-14 (80-86) cm in ROMS-MIROC, ROMS-CSIRO, and ROMS-GFDL, respectively. The discrepancies of the RSL rise along the Honshu coast between the climate models and downscaling are less than 10 cm. The RSL changes in the Kuroshio Extension (KE) region in all downscaling simulations are related to the changes of KE (northward shift or intensification) with climate change.
  • Christopher H. O'Reilly, Shoshiro Minobe, Akira Kuwano-Yoshida
    CLIMATE DYNAMICS 47 (5-6) 1545 - 1567 0930-7575 2016/09 [Refereed][Not invited]
     
    Wintertime blocking is responsible for extended periods of anomalously cold and dry weather over Europe. In this study, the influence of the Gulf Stream sea surface temperature (SST) front on wintertime European blocking is investigated using a reanalysis dataset and a pair of atmospheric general circulation model (AGCM) simulations. The AGCM is forced with realistic and smoothed Gulf Stream SST, and blocking frequency over Europe is found to depend crucially on the Gulf Stream SST front. In the absence of the sharp SST gradient European blocking is significantly reduced and occurs further downstream. The Gulf Stream is found to significantly influence the surface temperature anomalies during blocking periods and the occurrence of associated cold spells. In particular the cold spell peak, located in central Europe, disappears in the absence of the Gulf Stream SST front. The nature of the Gulf Stream influence on European blocking development is then investigated using composite analysis. The presence of the Gulf Stream SST front is important in capturing the observed quasi-stationary development of European blocking. The development is characterised by increased lower-tropospheric meridional eddy heat transport in the Gulf Stream region and increased eddy kinetic energy at upper-levels, which acts to reinforce the quasi-stationary jet. When the Gulf Stream SST is smoothed the storm track activity is weaker, the development is less consistent and European blocking occurs less frequently.
  • Matthew Newman, Michael A. Alexander, Toby R. Ault, Kim M. Cobb, Clara Deser, Emanuele Di Lorenzo, Nathan J. Mantua, Arthur J. Miller, Shoshiro Minobe, Hisashi Nakamura, Niklas Schneider, Daniel J. Vimont, Adam S. Phillips, James D. Scott, Catherine A. Smith
    JOURNAL OF CLIMATE 29 (12) 4399 - 4427 0894-8755 2016/06 [Refereed][Not invited]
     
    The Pacific decadal oscillation (PDO), the dominant year-round pattern of monthly North Pacific sea surface temperature (SST) variability, is an important target of ongoing research within the meteorological and climate dynamics communities and is central to the work of many geologists, ecologists, natural resource managers, and social scientists. Research over the last 15 years has led to an emerging consensus: the PDO is not a single phenomenon, but is instead the result of a combination of different physical processes, including both remote tropical forcing and local North Pacific atmosphere-ocean interactions, which operate on different time scales to drive similar PDO-like SST anomaly patterns. How these processes combine to generate the observed PDO evolution, including apparent regime shifts, is shown using simple autoregressive models of increasing spatial complexity. Simulations of recent climate in coupled GCMs are able to capture many aspects of the PDO, but do so based on a balance of processes often more independent of the tropics than is observed. Finally, it is suggested that the assessment of PDO-related regional climate impacts, reconstruction of PDO-related variability into the past with proxy records, and diagnosis of Pacific variability within coupled GCMs should all account for the effects of these different processes, which only partly represent the direct forcing of the atmosphere by North Pacific Ocean SSTs.
  • Rhys Parfitt, Arnaud Czaja, Shoshiro Minobe, Akira Kuwano-Yoshida
    GEOPHYSICAL RESEARCH LETTERS 43 (5) 2299 - 2306 0094-8276 2016/03 [Refereed][Not invited]
     
    The link between sea surface temperature (SST) gradients and atmospheric fronts is explored in a general circulation model across the Gulf Stream (GS) region from December to February 1981-2000. Two model experiments are analyzed, one with a realistic control SST distribution and one with a spatially smoothed SST distribution. The analysis shows a noticeable change in regional atmospheric frontal frequency between the two experiments (up to 30%), with the distribution of change exhibiting a clear imprint of the GS SST front. Further analysis of the surface sensible heat flux gradient across cold fronts reveals the pattern of change to be mediated by a thermal interaction between the oceanic and atmospheric fronts (thermal damping and strengthening). These results not only emphasize the significance of the GS SST gradient for storm development in the North Atlantic but also highlight the importance of resolution in assessing the role of frontal air-sea interaction in midlatitude climate variability.
  • Kazutoshi Sato, Atsuyoshi Manda, Qoosaku Moteki, Kensuke K. Komatsu, Koto Ogata, Hatsumi Nishikawa, Miki Oshika, Yuriko Otomi, Shiori Kunoki, Hisao Kanehara, Takashi Aoshima, Kenichi Shimizu, Jun Uchida, Masako Shimoda, Mitsuharu Yagi, Shoshiro Minobe, Yoshihiro Tachibana
    MONTHLY WEATHER REVIEW 144 (3) 1017 - 1033 0027-0644 2016/03 [Refereed][Not invited]
     
    Two mesoscale convective events in the baiu frontal zone (BFZ) were documented, based on intensive atmospheric soundings and oceanic castings in the East China Sea during May 2011, in addition to continuous surface meteorological observations, satellite products, and objective analyses. These events occurred while the BFZ was nearly stagnant and a mesolow was deepening in the zone. Near-surface southerlies associated with the low-level jet transported a warm, humid air mass from south of the BFZ. Enhanced evaporation, which was mainly attributable to the high sea surface temperature of the Kuroshio, augmented the moisture content of the air mass and helped maintain a convectively unstable stratification in the lower troposphere around the BFZ.
  • Yoshi N. Sasaki, Shoshiro Minobe
    Hot Spots in the Climate System: New Developments in the Extratropical Ocean-Atmosphere Interaction Research 31 - 41 2016/01/01 [Refereed][Not invited]
     
    This study examines the climatological mean features of oceanic rings shed from the Kuroshio Extension (KE) jet and their interannual to decadal variability using satellite altimeter observations from October 1992 to December 2010. To objectively capture ring shedding from the KE jet, a new method that consists of the detection of the jet length changes and the tracking of a ring is proposed. Spatial distribution of the ring formations in the KE region indicates that cyclonic (cold-core) rings were most frequently formed in the upstream region between 143° and 147°E around the steady meander of the KE jet. In contrast, most of anticyclonic (warm-core) rings were formed in the downstream region west of the Shatsky Rise. These pinched-off rings in both the upstream and downstream regions generally propagated westward, but about two-thirds of the rings were reabsorbed by the jet. Nevertheless, about one-fourth of the meridional eddy heat transport at the latitude of the KE resulted from the rings that are not reabsorbed by the jet. The number of ring formations showed substantial interannual to decadal variability. In the upstream and downstream KE region, decadal and interannual variability was dominant, respectively. These ring formation fluctuations were negatively correlated with the strength of the KE jet. It is also revealed that the ring formation variations play an important role in sea surface temperature changes north of the KE jet.
  • Shoshiro Minobe, Bo Qiu, Masami Nonaka, Hisashi Nakamura
    World Scientific Series on Asia-Pacific Weather and Climate 7 187 - 211 2010-2763 2016 [Refereed][Not invited]
     
    Studies of the ocean-To-Atmosphere feedback in the midlatitudes have developed rapidly in the last decade, especially in association with the western boundary currents (WBCs). In this article, an overview of the nature and variability of the WBCs in the North Pacific, i.e. The Kuroshio, the Kuroshio Extension (KE), the Subarctic (Oyashio) Front, and the Oyashio, is provided. The KE and the Subarctic Front, just apart by 5° in latitude, have different features for their mean structure, the physical mechanisms of temporal variability, and feedbacks to the atmosphere. The KE has a stronger heat release to the atmosphere than the Subarctic Front, mainly due to latent heat fluxes, but the Subarctic Front, accompanied by strong SST gradients, provides a stronger sensible heat gradient to the atmosphere. The atmospheric responses to these fronts may be viewed via two categories the local response and the remote response. Studies of the local response are substantially stimulated by the QuikSCAT satellite with the scale separation strategy. One of the key processes of the remote response is modulations of storm tracks associated with the oceanic fronts. Although large progress has been made in the last decade in understanding the mechanisms of variability of these WBCs and their feedback to the atmosphere, there are substantial uncertainties and questions to be explored.
  • Nakamura H, Isobe A, Minobe S, Mitsudera H, Nonaka M, Suga T
    Hot Spots in the Climate System: New Developments in the Extratropical Ocean-Atmosphere Interaction Research v - xi 2016 [Refereed][Not invited]
  • Yoshi N. Sasaki, Shoshiro Minobe
    JOURNAL OF OCEANOGRAPHY 71 (5) 499 - 509 0916-8370 2015/10 [Refereed][Not invited]
     
    This study examines the climatological mean features of oceanic rings shed from the Kuroshio Extension (KE) jet and their interannual to decadal variability using satellite altimeter observations from October 1992 to December 2010. To objectively capture ring shedding from the KE jet, a new method that consists of the detection of the jet length changes and the tracking of a ring is proposed. Spatial distribution of the ring formations in the KE region indicates that cyclonic (cold-core) rings were most frequently formed in the upstream region between 143A degrees and 147A degrees E around the steady meander of the KE jet. In contrast, most of anticyclonic (warm-core) rings were formed in the downstream region west of the Shatsky Rise. These pinched-off rings in both the upstream and downstream regions generally propagated westward, but about two-thirds of the rings were reabsorbed by the jet. Nevertheless, about one-fourth of the meridional eddy heat transport at the latitude of the KE resulted from the rings that are not reabsorbed by the jet. The number of ring formations showed substantial interannual to decadal variability. In the upstream and downstream KE region, decadal and interannual variability was dominant, respectively. These ring formation fluctuations were negatively correlated with the strength of the KE jet. It is also revealed that the ring formation variations play an important role in sea surface temperature changes north of the KE jet.
  • Hisashi Nakamura, Atsuhiko Isobe, Shoshiro Minobe, Humio Mitsudera, Masami Nonaka, Toshio Suga
    JOURNAL OF OCEANOGRAPHY 71 (5) 463 - 467 0916-8370 2015/10 [Refereed][Not invited]
  • Shoshiro Minobe, Shogo Takebayashi
    CLIMATE DYNAMICS 44 (7-8) 2079 - 2095 0930-7575 2015/04 [Refereed][Not invited]
     
    Recent studies show mid-latitude western boundary currents (WBCs) substantially influence the atmosphere aloft, and an important feature is enhanced rain band over the WBCs in climatological mean field. However, how such long-term, climate phenomena are related to shorter, weather timescale phenomena are generally remained to be explored. In this paper, diurnal precipitation and cloud variations are investigated global mid-latitude oceans with emphasis on air-sea interactions over WBCs using satellite-derived precipitation and outgoing longwave radiation (OLR) datasets. Strong 24-h period components of precipitations are found over the Gulf Stream in summer and over the Kuroshio in the East China Sea in early summer (Baiu-Meiyu season), respectively. Similar diurnal precipitations are not observed in WBCs in the Southern Hemisphere year around. The diurnal precipitation cycles over the Gulf Stream and the Kuroshio exhibit peak phases in the early to late morning for the Gulf Stream and late morning to early afternoon for the Kuroshio, with southeastward phase propagations. High cloud frequency derived from OLR data exhibit consistent diurnal cycles. A substantial difference of diurnal cycles between the Gulf Stream and the Kuroshio regions are associated with the large-scale Baiu-Meiyu rain and cloud bands for the latter region. Diurnal precipitation and high cloud variability is found in the vicinity of the Kuroshio itself, embedded in the Baiu-Meiyu rain and cloud bands distributing in a wider area without a strong diurnal component. The spatial and seasonal distributions of the diurnal variability over these WBCs strongly suggests that the diurnal precipitation and cloud cycles are essential aspects of deep heating mode of atmospheric response recently reported for these WBCs. These results indicate that these WBCs in the Northern Hemisphere play an important role in modulating short-term precipitation variations, and on the other hand diurnal variability can be a substantial agent for the mid-latitude air-sea interaction.
  • Shiori Kunoki, Atsuyoshi Manda, Yasu-Masa Kodama, Satoshi Iizuka, Kazutoshi Sato, Ibnu Fathrio, Taku Mitsui, Hiromu Seko, Qoosaku Moteki, Shoshiro Minobe, Yoshihiro Tachibana
    Journal of Geophysical Research 120 (2) 449 - 463 2156-2202 2015/01/27 [Refereed][Not invited]
     
    A high-resolution transect of atmospheric soundings across the Kuroshio Current in the East China Sea was conducted onboard a ship in June 2012 with the objective of analyzing the influence of the complex sea surface temperature (SST) distribution on the Baiu frontal zone (BFZ). Expendable bathythermograph castings and continuous surface meteorological observations were also examined. Two distinct mesoscale atmospheric fronts, characterized by changes of wind direction in the lower troposphere and surface air temperature, were found in the BFZ. One (northern) atmospheric front was observed around the SST front in relation to a warm water tongue extending from the Kuroshio. A high SST region around the northern atmospheric front enhances unstable near surface stratification and intensifies turbulent heat flux. They help modify the marine atmospheric boundary layer in the BFZ. The other (southern) atmospheric front was at the southern end of the BFZ. Intense evaporation over the Kuroshio and moisture transport by southerly winds were important in forming the conditionally unstable air masses in the lower troposphere of the BFZ.
  • Shiori Kunoki, Atsuyoshi Manda, Yasu-Masa Kodama, Satoshi Iizuka, Kazutoshi Sato, Ibnu Fathrio, Taku Mitsui, Hiromu Seko, Qoosaku Moteki, Shoshiro Minobe, Yoshihiro Tachibana
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 120 (2) 449 - 463 2169-897X 2015/01 [Refereed][Not invited]
     
    A high-resolution transect of atmospheric soundings across the Kuroshio Current in the East China Sea was conducted onboard a ship in June 2012 with the objective of analyzing the influence of the complex sea surface temperature (SST) distribution on the Baiu frontal zone (BFZ). Expendable bathythermograph castings and continuous surface meteorological observations were also examined. Two distinct mesoscale atmospheric fronts, characterized by changes of wind direction in the lower troposphere and surface air temperature, were found in the BFZ. One (northern) atmospheric front was observed around the SST front in relation to a warm water tongue extending from the Kuroshio. A high SST region around the northern atmospheric front enhances unstable near surface stratification and intensifies turbulent heat flux. They help modify the marine atmospheric boundary layer in the BFZ. The other (southern) atmospheric front was at the southern end of the BFZ. Intense evaporation over the Kuroshio and moisture transport by southerly winds were important in forming the conditionally unstable air masses in the lower troposphere of the BFZ.
  • Kohei Takatama, Shoshiro Minobe, Masaru Inatsu, R. Justin Small
    JOURNAL OF CLIMATE 28 (1) 238 - 255 0894-8755 2015/01 [Refereed][Not invited]
     
    The mechanisms acting on near-surface winds over the Gulf Stream are diagnosed using 5-yr outputs of a regional atmospheric model. The diagnostics for the surface-layer momentum vector, its curl, and its convergence are developed with a clear separation of pressure adjustment from downward momentum inputs from aloft in the surface-layer system. The results suggest that the downward momentum mixing mechanism plays a dominant role in contributing to the annual-mean climatological momentum curl, whereas the pressure adjustment mechanism plays a minor role. In contrast, the wind convergence is mainly due to the pressure adjustment mechanism. This can be explained by the orientation of background wind to the sea surface temperature front. The diagnostics also explain the relatively strong seasonal variation in surface-layer momentum convergence and the small seasonal variation in curl. Finally, the surface-layer response to other western boundary currents is examined using a reanalysis dataset.
  • Kenki Kasamo, Atsuhiko Isobe, Shoshiro Minobe, Atsuyoshi Manda, Hirohiko Nakamura, Koto Ogata, Hatsumi Nishikawa, Yoshihiro Tachibana, Shin'ichiro Kako
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 119 (3) 1277 - 1291 2169-897X 2014/02 [Refereed][Not invited]
     
    To confirm whether surface winds strengthen above warm waters around oceanic fronts using in situ data, a field measurement was conducted using both expendable bathythermographs and Global Positioning System sondes released concurrently across the Kuroshio front in the East China Sea in December 2010. In contrast to previous studies mainly based on satellite observations, the finding of the present field survey is the local weakening of surface winds at the northern flank of the Kuroshio front. From the above field observation in conjunction with a regional numerical model experiment, it is suggested that the northwesterly winds crossing the Kuroshio front from the cooler side first weaken at the northern flank of the front because of the onset of upward transfer of the nonslip condition at the sea surface. Thereafter, as the atmospheric mixed layer with warm and humid air mass develops gradually downwind over the Kuroshio region, the surface winds are gradually accelerated by the momentum mixing with strong winds aloft. The surface winds remain strong over the cool East China Sea shelf, and it is thus considered that the surface winds only weaken at the northern flank of the Kuroshio front. However, numerical modeling indicates that this local weakening of the surface winds occurs as a transient state with a short duration and such a structure has thus rarely been detected in the long-term averaged wind fields observed by satellites.
  • Yoshi N. Sasaki, Shoshiro Minobe, Yuji Miura
    JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 119 (1) 266 - 275 2169-9275 2014/01 [Refereed][Not invited]
     
    Decadal sea-level variability along the coast of Japan and its relation to large-scale ocean circulation changes from 1993 to 2010 was investigated using tide-gauge and satellite-derived sea-level data. A singular value decomposition (SVD) analysis is performed between coastal sea levels of Japan and sea levels in the western North Pacific. The first SVD mode reveals that the northward shifts of the Kuroshio Extension (KE) jet and the Kuroshio southeast of Japan accompany the coastal sea-level rise in the early 2000s and 2010, and their southward shifts accompany the coastal sea-level fall in the late 1990s and the late 2000s. The shifts of the KE jet are induced by westward propagating Rossby wave from the eastern North Pacific, which is concentrated along the KE jet axis as jet-trapped Rossby waves. The resulting sea-level changes along the coast of Japan show a strong spatial contrast. The sea-level fluctuation is quite large along the southeastern coast of Japan that is under the direct influence of the jet-trapped Rossby waves, and also large in the western coast of Japan, probably due to coastal waves that are excited by the incoming Rossby waves, but is small north of the KE jet latitude. Hence, the nature of the wave trapped by the KE jet produces an active zone and a shadow zone of coastal sea-level variability of Japan. Our results indicate that the correct representation of western boundary currents is necessary for reliable prediction of future coastal sea-level changes. Key Points <list list-type="bulleted"> Decadal sea level change of the coast of Japan shows strong spatial contrast The nature of the Kuroshio Extension jet produces the strong spatial contrast Understanding of western boundary currents is necessary for sea level prediction
  • Yoshi N. Sasaki, Shoshiro Minobe, Yuji Miura
    Journal of Geophysical Research: Oceans 119 (1) 266 - 275 2169-9291 2014 [Refereed][Not invited]
     
    Decadal sea-level variability along the coast of Japan and its relation to large-scale ocean circulation changes from 1993 to 2010 was investigated using tide-gauge and satellite-derived sea-level data. A singular value decomposition (SVD) analysis is performed between coastal sea levels of Japan and sea levels in the western North Pacific. The first SVD mode reveals that the northward shifts of the Kuroshio Extension (KE) jet and the Kuroshio southeast of Japan accompany the coastal sea-level rise in the early 2000s and 2010, and their southward shifts accompany the coastal sea-level fall in the late 1990s and the late 2000s. The shifts of the KE jet are induced by westward propagating Rossby wave from the eastern North Pacific, which is concentrated along the KE jet axis as jettrapped Rossby waves. The resulting sea-level changes along the coast of Japan show a strong spatial contrast. The sea-level fluctuation is quite large along the southeastern coast of Japan that is under the direct influence of the jet-trapped Rossby waves, and also large in the western coast of Japan, probably due to coastal waves that are excited by the incoming Rossby waves, but is small north of the KE jet latitude. Hence, the nature of the wave trapped by the KE jet produces an "active zone" and a "shadow zone" of coastal sea-level variability of Japan. Our results indicate that the correct representation of western boundary currents is necessary for reliable prediction of future coastal sea-level changes. © 2013. American Geophysical Union. All Rights Reserved.
  • Kunihiro Aoki, Shoshiro Minobe, Youichi Tanimoto, Yoshikazu Sasai
    JOURNAL OF PHYSICAL OCEANOGRAPHY 43 (9) 1899 - 1910 0022-3670 2013/09 [Refereed][Not invited]
     
    The present study investigates meridional heat transport induced by oceanic mesoscale variability in the World Ocean using a degrees global ocean general circulation model (OGCM) running on the Earth Simulator. The results indicate prominent poleward eddy heat transport around the western boundary currents and the Antarctic Circumpolar Current, and equatorward eddy heat transport in the equatorial region, consistent with the previous studies using coarse-resolution OGCMs. Such poleward eddy heat transport in midlatitude oceans suggests that the eddies act to reduce meridional background temperature gradients across the currents, as would be expected based on baroclinic instability. Interestingly, however, along the southern flanks of the eastward jets of the Kuroshio Extension and the Gulf Stream, southward eddy heat transport occurs in subsurface layers. This is likely due to the southward migration of warm water cores originating from southern areas adjacent to these currents. Southward movement of these cores is caused by interactions with unsteady meanders and cold eddies detaching from the meanders. The potential impact on biological production in the subtropical surface layers of these southward-traveling warm water cores is also discussed.
  • Yoshi N. Sasaki, Shoshiro Minobe, Niklas Schneider
    JOURNAL OF PHYSICAL OCEANOGRAPHY 43 (2) 442 - 456 0022-3670 2013/02 [Refereed][Not invited]
     
    This study examines interannual to decadal variability of the Kuroshio Extension (KE) jet using satellite altimeter observations from 1993 to 2010. The leading empirical orthogonal function (EOF) mode of sea level variability in the KE region represents the meridional shift of the KE jet, followed by its strength changes with a few month lag. This shift of the KE jet lags atmospheric fluctuations over the eastern North Pacific by about three years. Broad sea level anomalies (SLAs) emerge in the eastern North Pacific 3-4 years before the upstream KB jet shift, and propagate westward along the KE jet axis. In the course of the propagation, the meridional scale of the SLAs gradually narrows, and their amplitude increases. This westward propagation of SLAs with a speed of about 5 cm s(-1) is attributed to the westward propagation of the meridional shift of the jet, consistent with the thin-jet theory, whose importance has been suggested by previous numerical studies. In addition, the westward-propagating signals tend to conserve their quasigeostrophic potential vorticity anomaly, which may explain the characteristic changes of SLAs during the propagation. After the westward-propagating signals of positive (negative) SLAs reach at the east coast of Japan, the upstream KB jet strengthens (weakens) associated with the strength changes of the northern and southern recirculation gyres. Interestingly, this strength change of the KE jet propagates eastward with a speed of about 6 cm s(-1), suggesting an importance of advection by the current.
  • Hirohiko Nakamura, Ayako Nishina, Shoshiro Minobe
    JOURNAL OF CLIMATE 25 (21) 7772 - 7779 0894-8755 2012/11 [Refereed][Not invited]
     
    A large meridional shift of the sea surface temperature front occurs off the south coast of Japan associated with transitions between the large-meander and straight paths of the Kuroshio. Most extratropical cyclones generated in winter near the Kuroshio in the East China Sea pass through the region where the Kuroshio takes either the meander or the straight path. To examine whether such cyclones change their tracks and intensities according to the two states of the path, a new dataset of winter cyclone tracks derived from surface weather charts from the period 1969/70-2008/09 was produced. The composite analysis of cyclone tracks with respect to the meander and straight path states reveals the following: the cyclone track axis for the meander path state is located away from the south coast of Japan with a dispersive tendency, while that for the straight path state is attached to the south coast with a long extending feature. A difference in track between these two states also occurs to the east of Japan over the North Pacific. In addition, this behavior of the cyclone track is shown to be independent of the wintertime atmospheric circulation anomalies around Japan. The development rate of cyclones is 41% faster for the straight path state than the meander path state. Snowfall in Tokyo caused by south-coast cyclones is more frequent for the meander than the straight path state because the former state can act to decrease air temperature in Tokyo.
  • Yoshi N. Sasaki, S. Minobe, T. Asai, M. Inatsu
    JOURNAL OF CLIMATE 25 (19) 6627 - 6645 0894-8755 2012/10 [Refereed][Not invited]
     
    Influence of the Kuroshio in the East China Sea on the baiu rainband is examined using satellite observations, a reanalysis dataset, and a regional atmospheric model from 2003 to 2008. Satellite observations and reanalysis data reveal that precipitation over the Kuroshio is the highest in early summer (June), when the baiu rainband covers the East China Sea. The high rainfall is collocated with the warm sea surface temperature (SST) tongue of the Kuroshio. This locally enhanced precipitation is embedded in the large-scale baiu rainband, so that the amplitude of precipitation over the Kuroshio is twice as large as that in its surrounding area. The Kuroshio is also accompanied by high surface wind speed, energetic evaporation, and wind convergence. This wind convergence likely results from the SST influence on atmospheric pressure through not only temperature changes, but also humidity changes. Furthermore, the Kuroshio anchors the ascent motion and large diabatic heating with a peak in the midtroposphere, suggesting that the influence of the Kuroshio extends to the upper troposphere. It is also found that the East China Sea in June is the region of the strongest deep atmospheric response to western boundary currents along with the Gulf Stream region in summer. The observational results are well reproduced by the regional atmospheric model. The model indicates that when the SST tongue of the Kuroshio is smoothed, the enhanced precipitation, the energetic evaporation, and the wind convergence over the Kuroshio disappear, although the large-scale structure of the baiu rainband is not essentially changed.
  • Hanna Na, Kwang-Yul Kim, Kyung-Il Chang, Jong Jin Park, Kuh Kim, Shoshiro Minobe
    JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 117 C02017  2169-9275 2012/02 [Refereed][Not invited]
     
    The upper ocean heat content variability in the East/Japan Sea was investigated using a 40 year temperature and salinity data set from 1968 to 2007. Decadal variability was identified as the dominant mode of variability in the upper ocean (0-300 m) aside from the seasonal cycle. The decadal variability is strong to the west of northern Honshu, west of the Tsugaru Strait, and west of southern Hokkaido. Temperature anomalies at 50-125 m exhibit a large contribution to the decadal variability, particularly in the eastern part of the East/Japan Sea. The vertical structure of regressed temperature anomalies and the spatial patterns of regressed 10 degrees C isotherms in the East/Japan Sea suggest that the decadal variability is related to upper ocean circulation in the East/Japan Sea. The decadal variability also exhibits an increasing trend, which indicates that the regions showing large decadal variations experienced warming on decadal time scales. Further analysis shows that the decadal variability in the East/ Japan Sea is not locally isolated but is related to variability in the northwestern Pacific.
  • Kohei Takatama, Shoshiro Minobe, Masaru Inatsu, R. Justin Small
    ATMOSPHERIC SCIENCE LETTERS 13 (1) 16 - 21 1530-261X 2012/01 [Refereed][Not invited]
     
    This study proposes a novel diagnostics for near-surface wind responses to oceanic fronts. By separating two roles of wind stress, i.e. downward momentum input and the surface friction, the diagnostics can express near-surface winds as a sum of terms relating to pressure adjustment, downward momentum mixing, and horizontal advection. The diagnostics are applied to the climatological wind convergence/divergence over the Gulf Stream obtained from a regional atmospheric model. It is found that the pressure adjustment plays a primary role and is mainly responsible for the convergence, while the downward momentum mixing is a secondary contributing factor to the divergence. Copyright (c) 2011 Royal Meteorological Society
  • Hanna Na, Kwang-Yul Kim, Kyung-Il Chang, Jong Jin Park, Kuh Kim, Shoshiro Minobe
    Journal of Geophysical Research: Oceans 117 (2) 2169-9291 2012 [Refereed][Not invited]
     
    The upper ocean heat content variability in the East/Japan Sea was investigated using a 40 year temperature and salinity data set from 1968 to 2007. Decadal variability was identified as the dominant mode of variability in the upper ocean (0-300 m) aside from the seasonal cycle. The decadal variability is strong to the west of northern Honshu, west of the Tsugaru Strait, and west of southern Hokkaido. Temperature anomalies at 50-125 m exhibit a large contribution to the decadal variability, particularly in the eastern part of the East/Japan Sea. The vertical structure of regressed temperature anomalies and the spatial patterns of regressed 10C isotherms in the East/Japan Sea suggest that the decadal variability is related to upper ocean circulation in the East/Japan Sea. The decadal variability also exhibits an increasing trend, which indicates that the regions showing large decadal variations experienced warming on decadal time scales. Further analysis shows that the decadal variability in the East/Japan Sea is not locally isolated but is related to variability in the northwestern Pacific. Copyright 2012 by the American Geophysical Union.
  • Teruhisa Shimada, Shoshiro Minobe
    GEOPHYSICAL RESEARCH LETTERS 38 0094-8276 2011/03 [Refereed][Not invited]
     
    We investigate the signatures of atmospheric pressure adjustment mechanism for surface wind convergence/divergence over major sea surface temperature (SST) frontal regions using global observations of satellite sounding and scatterometer. Lower tropospheric air thickness, which includes a sea-level pressure component modified by air temperature in the marine atmospheric boundary layer, is analyzed, and the relation between the Laplacian of the thickness and wind convergence are examined. Among four SST frontal regions in mid-latitudes, correlation between the thickness Laplacian and wind convergence is the largest over the Gulf Stream followed by those for the Agulhas Return Current and for the Brazil/Malvinas Current, and relatively small but still significant over the Kuroshio-Oyashio Extension. These correlations strongly suggest that the pressure adjustment mechanism ubiquitously plays an important role in air-sea interaction over the global SST frontal regions. Furthermore, air temperatures in the first two regions exhibit SST-relating signatures even in the mid-troposphere. Citation: Shimada, T., and S. Minobe (2011), Global analysis of the pressure adjustment mechanism over sea surface temperature fronts using AIRS/Aqua data, Geophys. Res. Lett., 38, L06704, doi:10.1029/2010GL046625.
  • Tsuyoshi Watanabe, Atsushi Suzuki, Shoshiro Minobe, Tatsunori Kawashima, Koji Kameo, Kayo Minoshima, Yolanda M. Aguilar, Ryoji Wani, Hodaka Kawahata, Kohki Sowa, Takaya Nagai, Tomoki Kase
    NATURE 471 (7337) 209 - 211 0028-0836 2011/03 [Refereed][Not invited]
     
    The El Nino/Southern Oscillation (ENSO) system during the Pliocene warm period (PWP; 3-5 million years ago) may have existed in a permanent El Nino state with a sharply reduced zonal sea surface temperature (SST) gradient in the equatorial Pacific Ocean(1). This suggests that during the PWP, when global mean temperatures and atmospheric carbon dioxide concentrations were similar to those projected for near-term climate change(2), ENSO variability-and related global climate teleconnections-could have been radically different from that today. Yet, owing to a lack of observational evidence on seasonal and interannual SST variability from crucial low-latitude sites, this fundamental climate characteristic of the PWP remains controversial(1,3-10). Here we show that permanent El Nino conditions did not exist during the PWP. Our spectral analysis of the delta(18)O SST and salinity proxy, extracted from two 35-year, monthly resolved PWP Porites corals in the Philippines, reveals variability that is similar to present ENSO variation. Although our fossil corals cannot be directly compared with modern ENSO records, two lines of evidence suggest that Philippine corals are appropriate ENSO proxies. First, delta(18)O anomalies from a nearby live Porites coral are correlated with modern records of ENSO variability. Second, negative-delta(18)O events in the fossil corals closely resemble the decreases in delta(18)O seen in the live coral during El Nino events. Prior research advocating a permanent El Nino state may have been limited by the coarse resolution of many SST proxies, whereas our coral-based analysis identifies climate variability at the temporal scale required to resolve ENSO structure firmly.
  • Alexander L. Bond, Ian L. Jones, William J. Sydeman, Heather L. Major, Shoshiro Minobe, Jeffrey C. Williams, G. Vernon Byrd
    MARINE ECOLOGY PROGRESS SERIES 424 205 - U218 0171-8630 2011 [Refereed][Not invited]
     
    Growing evidence indicates relationships between seabird demography and both large- and small-scale variation in climate and oceanography, yet few studies have examined multiple species and locations simultaneously. As secondary consumers, least, whiskered, and crested auklets (Aethia pusilla, A. pygmaea, and A. cristatella, respectively), congeneric planktivorous seabirds endemic to the Bering and Okhotsk seas, are expected to respond to changes in ocean climate due to their low trophic positioning. From 1990 to 2008, we measured reproductive success (productivity) and breeding phenology (mean hatching date) of auklets on Buldir, Kiska, and Kasatochi, 3 islands spanning 585 km across the Aleutian Islands, Alaska, USA. A model including Island, Species, and Winter Aleutian Low Pressure Index (ALPI) best explained productivity, with reproductive success decreasing among all species with increasing ALPI (beta = -0.273 +/- 0.0263 [SE]), likely through control of water temperature and prey (zooplankton) availability. Auklet productivity also increased with increasing winter sea surface temperature (SST) in the western North Pacific and western Bering Sea (and correspondingly decreased with increasing SST in the Gulf of Alaska), and was correlated negatively with spring sea-level air pressure in the North Pacific. These responses are reflective of positive values of the Aleutian low pressure system. Though our datasets cover only 19 yr or less, we found similar correlations between climate and auklet productivity among all species and islands. Together, our results suggest that ocean climatic conditions and reproductive success of planktivorous auklets are significantly related.
  • Hanna Na, Kwang-Yul Kim, Kyung-Il Chang, Kuh Kim, Jae-Yul Yun, Shoshiro Minobe
    JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 115 C09031  0148-0227 2010/09 [Refereed][Not invited]
     
    A 35 yearlong temperature data set is analyzed to investigate the long-term temperature variability in the Korea Strait and its relationship with the temperature variability in the upper layer of the Sea of Japan (East Sea). The second cyclostationary empirical orthogonal function mode of the vertical temperature section in the Korea Strait describes the interannual variability of the Korea Strait Bottom Cold Water (KSBCW). According to the corresponding principal component time series, the strength of the KSBCW fluctuates yearly with a major spectral peak around 3 years. Multiple regression analysis shows that the interannual KSBCW variability is closely linked with the temperature variability in the southwestern region of the Sea of Japan (East Sea) at about 50-100 m depth. Along 40 degrees N, the source of the KSBCW is traced at about 50 m, extending eastward from the east coast of Korea to about 135 degrees E. At 37 degrees N, the source is traced at a deeper level (about 50-100 m), confined more toward the east coast of Korea with a hint of double core characteristics. The interannual KSBCW variability is also related to the southward wind stress along the east coast of Korea. It appears that strong cooling/warming of upper water temperature induced by the basin-scale wind stress results in the interannual KSBCW variability. This connection is verified by showing a reasonable interannual covariability between the KSBCW and the basin-scale wind stress.
  • Shoshiro Minobe, Masato Miyashita, Akira Kuwano-Yoshida, Hiroki Tokinaga, Shang-Ping Xie
    JOURNAL OF CLIMATE 23 (13) 3699 - 3719 0894-8755 2010/07 [Refereed][Not invited]
     
    The atmospheric response to the Gulf Stream front in sea surface temperature is investigated using high-resolution data from satellite observations and operational analysis and forecast. Two types of atmospheric response are observed with different seasonality and spatial distribution. In winter, surface wind convergence is strong over the Gulf Stream proper between Cape Hatteras and the Great Banks, consistent with atmospheric pressure adjustments to sea surface temperature gradients. The surface convergence is accompanied by enhanced precipitation and the frequent occurrence of midlevel clouds. Local evaporation and precipitation are roughly in balance over the Florida Current and the western Gulf Stream proper. In summer, strong precipitation, enhanced high clouds, and increased lightning flash rate are observed over the Florida Current and the western Gulf Stream proper, without seasonal surface convergence enhancement. For the precipitation maximum over the Florida Current, local evaporation supplies about half of the water vapor, and additional moisture is transported from the south on the west flank of the North Atlantic subtropical high. Atmospheric heating estimated by a Japanese reanalysis reveals distinct seasonal variations. In winter, a shallow-heating mode dominates the Gulf Stream proper, with strong sensible heating in the marine atmospheric boundary layer and latent heating in the lower troposphere. In summer, a deep-heating mode is pronounced over the Florida Current and the western Gulf Stream proper, characterized by latent heating in the middle and upper troposphere due to deep convection. Possible occurrences of these heating modes in other regions are discussed.
  • Akira Kuwano-Yoshida, Shoshiro Minobe, Shang-Ping Xie
    JOURNAL OF CLIMATE 23 (13) 3676 - 3698 0894-8755 2010/07 [Refereed][Not invited]
     
    The precipitation response to sea surface temperature (SST) gradients associated with the Gulf Stream is investigated using an atmospheric general circulation model. Forced by observed SST, the model simulates a narrow band of precipitation, surface convergence, and evaporation that closely follows the Gulf Stream, much like satellite observations. Such a Gulf Stream rainband disappears in the model when the SST front is removed by horizontally smoothing SST. The analysis herein shows that it is convective precipitation that is sensitive to SST gradients. The Gulf Stream anchors a convective rainband by creating surface wind convergence and intensifying surface evaporation on the warmer flank. Deep convection develops near the Gulf Stream in summer when the atmosphere is conditionally unstable. As a result, a narrow band of upward velocity develops above the Gulf Stream throughout the troposphere in summer, while it is limited to the lower troposphere in other seasons.
  • Hiroshi Sumata, Shoshiro Minobe, Tatsuo Motoi, Wing-Le Chan
    DYNAMICS OF ATMOSPHERES AND OCEANS 50 (1) 55 - 77 0377-0265 2010/06 [Refereed][Not invited]
     
    A semi-analytical model of the Panama throughflow is presented. The model expresses the throughflow transport as a function of deep water formation in the North Pacific and in the North Atlantic, and of the Panama Gateway depth. The model is derived from the integral of the momentum equation along a circumpolar path, and can be interpreted from the point of view of the vorticity balance. The important conditions are whether the deep water, whose location is considered to be above the bottom water formed around Antarctica, originates from the North Atlantic or from the North Pacific, and whether the Panama Gateway is shallower than the lower boundary of the deep water. The present model indicates that the barotropic transport through the Panama Gateway is eastward, except for the case where the deep water is formed in the North Pacific and the sill of the Panama Gateway is shallow. The baroclinic structure of the Panama throughflow depends on whether the deep water is formed in the North Pacific or in the North Atlantic. These qualitative implications of the model are consistent with recent numerical studies and proxy-based paleoceanographic studies. Numerical experiments performed in the present study reinforce confidence in the semi-analytical model. (C) 2009 Elsevier B.V. All rights reserved.
  • Lixin Wu, Yan Sun, Jiaxu Zhang, Liping Zhang, Shoshiro Minobe
    JOURNAL OF CLIMATE 23 (7) 1945 - 1954 0894-8755 2010/04 [Refereed][Not invited]
     
    The coupled ocean atmosphere responses to idealized freshwater forcing in the western tropical Pacific are studied using a fully coupled climate model. The model explicitly demonstrates that freshwater forcing in the western tropical Pacific can lead to a basinwide response with the pattern resembling the Pacific decadal oscillation. In the tropics, a negative (positive) freshwater forcing over the western tropical Pacific decreases (increases) sea surface height locally, and sets up a positive (negative) zonal pressure gradient anomaly, which accelerates (decelerates) the meridional overturning circulation and equatorial surface westward flow. This leads to an intensification (reduction) of meridional heat divergence and vertical cold advection, and thus a development of La Nina (El Nino)-like responses in the tropics. The tropical responses are further substantiated by the positive Bjerknes feedback, and subsequently force significant changes in the extratropical North Pacific through atmospheric teleconnection. The local freshwater response also reinforces the imposed Forcing, forming a positive feedback loop. Applications to Pacific climate changes are discussed.
  • Hanna Na, Kwang-Yul Kim, Kyung-Il Chang, Kuh Kim, Jae-Yul Yun, Shoshiro Minobe
    Journal of Geophysical Research: Oceans 115 (9) 2169-9291 2010 [Refereed][Not invited]
     
    A 35 yearlong temperature data set is analyzed to investigate the long-term temperature variability in the Korea Strait and its relationship with the temperature variability in the upper layer of the Sea of Japan (East Sea). The second cyclostationary empirical orthogonal function mode of the vertical temperature section in the Korea Strait describes the interannual variability of the Korea Strait Bottom Cold Water (KSBCW). According to the corresponding principal component time series, the strength of the KSBCW fluctuates yearly with a major spectral peak around 3 years. Multiple regression analysis shows that the interannual KSBCW variability is closely linked with the temperature variability in the southwestern region of the Sea of Japan (East Sea) at about 50-100 m depth. Along 40°N, the source of the KSBCW is traced at about 50 m, extending eastward from the east coast of Korea to about 135°E. At 37°N, the source is traced at a deeper level (about 50-100 m), confined more toward the east coast of Korea with a hint of double core characteristics. The interannual KSBCW variability is also related to the southward wind stress along the east coast of Korea. It appears that strong cooling/warming of upper water temperature induced by the basin-scale wind stress results in the interannual KSBCW variability. This connection is verified by showing a reasonable interannual covariability between the KSBCW and the basin-scale wind stress. Copyright 2010 by the American Geophysical Union.
  • Yutaka Watanuki, Motohiro Ito, Tomohiro Deguchi, Shoshiro Minobe
    MARINE ECOLOGY PROGRESS SERIES 393 259 - 271 0171-8630 2009 [Refereed][Not invited]
     
    Predator-prey relationships are key to understanding complex marine ecosystem dynamics. The match-mismatch hypothesis posits that predators time energy-intensive activities, such as reproduction, to periods of high food availability. However, predators may be constrained by various ecological or physiological processes, leading to mistimed activities relative to prey availability. We investigated inter-annual variation in the timing of breeding for a piscivorous seabird (rhinoceros auklet Cerorhinca monocerata) in relation to availability of a preferred prey item, Japanese anchovy Engraulis japonicus, using data collected over 18 yr between 1984 and 2006 at Teuri Island in the northern Japan Sea. Our primary goals were (1) to identify the climatic factors that affect the seabirds' timing of breeding, proxied by hatching date, and anchovy seasonal availability, and (2) to quantify the fitness effects of predator-prey matches and mismatches relative to climate variability. Hatching date was later in years with lower spring air temperatures. Auklets switched their feeding from sandlance and juvenile greenling to anchovy when it was transported into the birds' foraging range with the seasonal northern expansion of 13 degrees C warm water from the south. The mismatch between hatching date and the period of high anchovy availability was most pronounced when spring air temperatures were warm, and there was a weak Tsushima (warm) Current. Spring air temperature was influenced by spring atmospheric pressure gradients in the Arctic and northern Eurasia, which drive the east Asian winter monsoon, whereas timing of the Tsushima warm water expansion was influenced by winter surface pressures over the western North Pacific. Chick growth rates, mass at fledging, and overall fledging success (fitness) were lower during mismatch years when the auklets fed less on anchovy. The auklets were constrained to adjust hatching date because the seasonal mismatch appeared to be driven by independent and unpredictable surface pressure patterns.
  • G. Vernon Byrd, William J. Sydeman, Heather M. Renner, Shoshiro Minobe
    DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY 55 (16-17) 1856 - 1867 0967-0645 2008/08 [Refereed][Not invited]
     
    Climate variability and change are expected to influence the seasonal cycle in North Pacific sub-arctic marine ecosystems. The hypothesis that timing of nesting and productivity of piscivorous seabirds [kittiwakes (Rissa tridactyla and Rissa brevirostris) and murres (Uria aalge and Uria lomvia)] at the Pribilof Islands are related to variation in ocean climate as indexed by changes in sea-ice concentrations (SICs) and sea-surface temperatures (SSTs) was tested. To test this hypothesis, timing and productivity of the seabirds were correlated with the winter sea-ice extent, defined as area-averaged SICs, and with winter, spring, and summer SST near the Pribilofs over a 32-yr period, 1975-2006. Timing and productivity for the two species of kittiwake were strongly correlated with each other and between the two breeding locations, St. George and St. Paul islands. Similar results were found for the two species of murres, although kittiwakes and murres were not strongly correlated with each other. Kittiwakes bred progressively earlier, advancing their hatching dates by 0.58 to 0.88d/yr over the study period. In contrast, there were no overall trends for murres, with the exception of thick-billed murres at St. Paul that nested progressively later, delaying breeding by 0.47 d/yr. Because of these trends, residuals from quadratic regressions were used to "detrend" the data (including cases where no significant trend was observed) for interannual comparisons with climate variables. Detrended kittiwake timing was inversely correlated with maximum SIC and positively correlated with winter SST. We found no strong relationships between the timing of murre nesting and SIC or SST with either raw or detrended data. Both raw and detrended data revealed a positive relationship between kittiwake productivity and SIC, and an inverse relationship with winter and spring SST. Murre productivity was correlated negatively with summer SST, but unrelated to SST in other seasons and to SIC. Timing and productivity were correlated inversely for murres and kittiwakes at both sites, but were significant only for raw (i.e. non-detrended) murre data and for detrended kittiwake data. Detrending emphasizes high-frequency (interannual) variability by suppressing low-frequency (interdecadal) variability, indicating that low-frequency change in murre timing has an effect on productivity, whereas interannual variation is responsible for the timing-productivity relationship for kittiwakes. These contrasting responses of surface-foraging kittiwakes and deep-diving murres provide insight into how the eastern Bering Sea ecosystem is responding to climate variability and change, and suggest that the food web has changed more substantially in the upper water column than at depth. Published by Elsevier Ltd.
  • R. J. Small, S. P. deSzoeke, S. P. Xie, L. O'Neill, H. Seo, Q. Song, P. Cornillon, M. Spall, S. Minobe
    DYNAMICS OF ATMOSPHERES AND OCEANS 45 (3-4) 274 - 319 0377-0265 2008/08 [Refereed][Not invited]
     
    Air-sea interaction at ocean fronts and eddies exhibits positive correlation between sea surface temperature (SST), wind speed, and heat fluxes out of the ocean, indicating that the ocean is forcing the atmosphere. This contrasts with larger scale climate modes where the negative correlations suggest that the atmosphere is driving the system. This paper examines the physical processes that lie behind the interaction of sharp SST gradients and the overlying marine atmospheric boundary layer and deeper atmosphere, using high resolution satellite data, field data and numerical models. The importance of different physical mechanisms of atmospheric response to SST gradients, such as the effect of surface stability variations on momentum transfer, pressure gradients, secondary circulations and cloud cover will be assessed. The atmospheric response is known to create small-scale wind stress curl and divergence anomalies, and a discussion of the feedback of these features onto the ocean will also be presented. These processes will be compared and contrasted for different regions such as the Equatorial Front in the Eastern Pacific, and oceanic fronts in mid-latitudes such as the Gulf Stream, Kuroshio, and Agulhas Return Current. (C) 2008 Elsevier B.V. All rights reserved.
  • Yoshi N. Sasaki, Shoshiro Minobe, Niklas Schneider, Takashi Kagimoto, Masami Nonaka, Hideharu Sasaki
    JOURNAL OF PHYSICAL OCEANOGRAPHY 38 (8) 1731 - 1747 0022-3670 2008/08 [Refereed][Not invited]
     
    Sea level variability and related oceanic changes in the South Pacific from 1970 to 2003 are investigated using a hindcast simulation of an eddy-resolving ocean general circulation model (OGCM) for the Earth Simulator (OFES), along with sea level data from tide gauges since 1970 and a satellite altimeter since 1992. The first empirical orthogonal function mode of sea level anomalies (SLAs) of OFES exhibits broad positive SLAs over the central and western South Pacific. The corresponding principal component indicates roughly stable high, low, and high SLAs, separated by a rapid sea level fall in the late 1970s and sea level rise in the late 1990s, consistent with tide gauge and satellite observations. These decadal changes are accompanied by circulation changes of the subtropical gyre at 1000-m depth, and changes of upper-ocean zonal current and eddy activity around the Tasman Front. In general agreement with previous related studies, it is found that sea level variations in the Tasman Sea can be explained by propagation of long baroclinic Rossby waves forced by wind stress curl anomalies, if the impact of New Zealand is taken into account. The corresponding atmospheric variations are associated with decadal variability of El Nino-Southern Oscillation (ENSO). Thus, decadal sea level variability in the western and central South Pacific in the past three and half decades and decadal ENSO variability are likely to be connected. The sea level rise in the 1990s, which attracted much attention in relation to the global warming, is likely associated with the decadal cooling in the tropical Pacific.
  • James Overland, Sergei Rodionov, Shoshiro Minobe, Nicholas Bond
    PROGRESS IN OCEANOGRAPHY 77 (2-3) 92 - 102 0079-6611 2008/05 [Refereed][Not invited]
     
    The many recent publications on regimes and shifts highlight the importance of decadal variability in understanding climate and ecosystems and their connectivity. This paper explores several issues in the application of regime concepts. Even the definition of regimes is unclear, as usage by different authors highlight: (1) displacement or shifts in timeseries, (2) underlying mechanisms, and (3) the distinction between external forcing and internal reorganization of ecosystems. Such differences arise, and cannot be easily resolved, because of the relatively short duration of available physical and biological timeseries, and the complexity of multivariate process in marine systems with unknown variables and relationships. Climate indices often show a rather Gaussian distribution of values with a single mean, rather than clearly separated discrete multiple states. These physical indices can be represented by a red noise long memory process, where the index can, in fact, deviate substantially from the long term mean for multiple years. If we consider changes in timeseries themselves, then climate variables for the North Pacific display shifts near 1977,1989 and 1998. Recent variability suggests considerable uncertainty in the current state of the North Pacific. Biological variables often show a broader distribution of shifts over time, which is consistent with different types of responses to climate for different ecosystem elements and the importance of time lags in response to changes in physical forcing. Our current understanding of regime shifts is not a deterministic one, and while one can discuss amplitudes and mean duration of regimes, we cannot predict their precise timing other than to say that they will be a main feature of future climate and ecosystem states. While the authors believe that a single definition for regimes is currently not possible, the concept continues to be useful in moving the discussion of ecosystems away from the assumptions of single species and stationary processes. Published by Elsevier Ltd.
  • Shoshiro Minobe, Akira Kuwano-Yoshida, Nobumasa Komori, Shang-Ping Xie, Richard Justin Small
    NATURE 452 (7184) 206 - U51 0028-0836 2008/03 [Refereed][Not invited]
     
    The Gulf Stream transports large amounts of heat from the tropics to middle and high latitudes, and thereby affects weather phenomena such as cyclogenesis(1,2) and low cloud formation(3). But its climatic influence, on monthly and longer timescales, remains poorly understood. In particular, it is unclear how the warm current affects the free atmosphere above the marine atmospheric boundary layer. Here we consider the Gulf Stream's influence on the troposphere, using a combination of operational weather analyses, satellite observations and an atmospheric general circulation model(4). Our results reveal that the Gulf Stream affects the entire troposphere. In the marine boundary layer, atmospheric pressure adjustments to sharp sea surface temperature gradients lead to surface wind convergence, which anchors a narrow band of precipitation along the Gulf Stream. In this rain band, upward motion and cloud formation extend into the upper troposphere, as corroborated by the frequent occurrence of very low cloud- top temperatures. These mechanisms provide a pathway by which the Gulf Stream can affect the atmosphere locally, and possibly also in remote regions by forcing planetary waves(5,6). The identification of this pathway may have implications for our understanding of the processes involved in climate change, because the Gulf Stream is the upper limb of the Atlantic meridional overturning circulation, which has varied in strength in the past(7) and is predicted to weaken in response to human- induced global warming in the future(8).
  • 北太平洋における気候の数十年スケール変動に関する研究,―2006年度堀内賞受賞記念講演―
    見延庄士郎
    天気 55 (3) 1731 - 1747 2008 [Refereed][Not invited]
  • Yoshi N. Sasaki, Yurika Katagiri, Shoshiro Minobe, Ignatius G. Rigor
    JOURNAL OF OCEANOGRAPHY 63 (2) 255 - 265 0916-8370 2007/04 [Refereed][Not invited]
     
    Relations in year-to-year variability between wintertime Sea-Ice Concentrations (SICs) IN in the Okhotsk Sea and atmospheric anomalies consisting of zonal and meridional 1000-hPa wind speeds and 850-hPa air temperatures are studied using a singular value decomposition analysis. It is revealed that the late autumn (October-Novemher) atmospheric conditions strongly influence sea-ice variability from the same season (late autumn) through late winter (February-March), in which sea-ice extent is at its maximum. The autumn atmospheric conditions for the positive sea-ice anomalies exhibit cold air temperature anomalies over the Okhotsk Sea and wind anomalies blowing into the Okhotsk Sea from Siberia. These atmospheric conditions yield anomalous ocean-to-atmosphere heat fluxes and cold sea surface temperature anomalies in the Okhotsk Sea. Hence, these results suggest that the atmospheric conditions affect the sea-ice through heat anomalies stored in sea-ice and oceanic fields. The late autumn atmosphere conditions are related to large 700-hPa geopotential height anomalies over the Bering Sea and northern Eurasia, which are related to a stationary Rossby wave propagation over the North Pacific and that from the North Atlantic to Eurasia, respectively. In addition, the late autumn atmospheric preconditioning also plays an important role in the decreasing trend in the Okhotsk sea-ice extent observed from 1980 to the mid-1990s. Based on the lagged sea-ice response to the late autumn atmosphere, a simple seasonal prediction scheme is proposed for the February-March sea-ice extent using four-month leading atmospheric conditions. This scheme explains 45% of the variance of the Okhotsk sea-ice extent.
  • Kenji Baba, Shoshiro Minobe, Noriaki Kimura, Masaaki Wakatsuchi
    Journal of Geophysical Research: Oceans 111 (12) 2169-9291 2006/12/08 [Refereed][Not invited]
     
    This study investigated mechanisms for the intraseasonal variability of sea-ice concentration in the Antarctic, using Complex Empirical Orthogonal Function (CEOF) analysis of daily sea-ice concentration data during the period 1992 through 2001 derived from images of the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSM/I). The first CEOF mode clearly showed that the large amplitudes of sea-ice concentration occur in the marginal sea-ice zone of the western Antarctic. The first mode also revealed the existence of eastward propagating phases with a period of 10-20 days in the western Antarctic. Regression analysis of meridional wind velocity onto the temporal coefficient of the first CEOF mode showed that the spatial phase of the meridional wind velocity precedes that of sea-ice concentration by about 90 degrees, indicating that the maximum change of sea-ice concentration occurs at the maximum wind velocity. From data analyses of ice-drifting velocity and simple sea-ice model results, it is suggested that thermodynamical effects such as sea-ice production are likely to contribute dominantly to the intraseasonal variability of sea-ice concentration in the marginal sea-ice zone of the western Antarctic. Copyright 2006 by the American Geophysical Union.
  • Kenji Baba, Shoshiro Minobe, Noriaki Kimura, Masaaki Wakatsuchi
    JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 111 (C12) C12023 doi:10.1029/2005JC003052  2169-9275 2006/12 [Refereed][Not invited]
     
    This study investigated mechanisms for the intraseasonal variability of sea-ice concentration in the Antarctic, using Complex Empirical Orthogonal Function (CEOF) analysis of daily sea-ice concentration data during the period 1992 through 2001 derived from images of the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSM/I). The first CEOF mode clearly showed that the large amplitudes of sea-ice concentration occur in the marginal sea-ice zone of the western Antarctic. The first mode also revealed the existence of eastward propagating phases with a period of 10-20 days in the western Antarctic. Regression analysis of meridional wind velocity onto the temporal coefficient of the first CEOF mode showed that the spatial phase of the meridional wind velocity precedes that of sea-ice concentration by about 90 degrees, indicating that the maximum change of sea-ice concentration occurs at the maximum wind velocity. From data analyses of ice-drifting velocity and simple sea-ice model results, it is suggested that thermodynamical effects such as sea-ice production are likely to contribute dominantly to the intraseasonal variability of sea-ice concentration in the marginal sea- ice zone of the western Antarctic.
  • T Nakanowatari, S Minobe
    JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN 83 (4) 453 - 469 0026-1165 2005/08 [Refereed][Not invited]
     
    Moisture budgets are analyzed using National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data over the North Pacific for a Bi-Decadal Oscillation (BDO) in precipitation that was reported by Minobe and Nakanowatari (2002). BDO in wintertime precipitation is mostly associated with moisture flux convergence, with a minor contribution from evaporation. The moisture convergence is mainly due to anomalies of wind and moisture on time scales longer than a month, except at high-latitudes where transient eddy (time scales shorter than a month) contributions are greater. When the Aleutian low strengthens (weakens), the anomalous moisture flux convergence is due to a cyclonic (anti-cyclonic) wind circulation over 30 degrees-60 degrees N and anti-cyclonic (cyclonic) wind circulation over 0 degrees-30 degrees N. This pair of anomalous circulations is also observed on inter-annual time scales, but they appear independent of El Nino/Southern Oscillation (ENSO). The anomalous circulation over 0 degrees-30 degrees N is associated with sea-level pressure anomalies in the tropics (20 degrees S-20 degrees N) and this result is confirmed with the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) and the NCEP real-time marine data. This low-latitude anomalous circulation plays a dominant role in precipitation variability in Hawaii on the bi-decadal and interannual time scales.
  • S Minobe, A Maeda
    INTERNATIONAL JOURNAL OF CLIMATOLOGY 25 (7) 881 - 894 0899-8418 2005/06 [Refereed][Not invited]
     
    Using surface marine data collected in International Comprehensive Ocean Atmosphere Data Set (ICOADS) release 2.1, a gridded SST dataset on a monthly, 1 degrees x 1 degrees to grid is produced from 1850 to 2002. Some unrealistic features, which are commonly found in the gridded SSTs of ICOADS, are removed by a subjective quality control. Based on the gridded SST data, SST variability associated with the oceanic fronts is investigated for the North Atlantic and North Pacific. Year-to-year SST variability in the North Atlantic is prominent along the climatological Gulf Stream extension (GSE) in winter and spring. This correspondence is captured better in the present SST dataset than in several widely used datasets. GSE mean SST exhibits multidecadal variability similar to the Atlantic multidecadal oscillation represented by mean SSTs over the North Atlantic. Year-to-year SST variability in the North Pacific in winter and spring seasons is strong along the subarctic front (SAF) and also in the subtropical front (STF), with weaker amplitudes in the latter. In particular, just east of Japan, the Kuroshio extension appears to be a core of strong variability. Winter and spring averaged SAF and STF exhibit prominent decadal warmings in the 1940s, i.e. these fronts may be two of the action centres for the 1940s climate regime shift and the previously reported 1970s shift. The warming anomalies around the SAF associated with the 1940s shift are distributed more broadly than those with the 1970s shift, and have maximal amplitudes around Japan. Copyright (c) 2005 Royal Meteorological Society.
  • Yoshi N. Sasaki, Shoshiro Minobe
    Journal of Geophysical Research C: Oceans 110 (5) 1 - 11 0148-0227 2005/05/08 [Refereed][Not invited]
     
    Interannual variability of sea ice in the Bering Sea and its relationship to atmospheric variability is analyzed using a singular value decomposition (SVD) analysis of sea ice concentrations (SICs) an 1000 hPa wind speeds in winter and spring seasons. The statistically significant first and second SVD modes, explaining 76.3% and 17.6% in winter and 54.6% and 29.6% in spring of the squared covariance between the two fields, are identified for SICs both in the winter and spring Seasons with 1 month leading wind speeds. The spatial structures show that the first (second) SVD mode explains the SIC variability in the northeastern (northwestern) Bering Sea, related to the local northwesterly (northerly) wind anomalies for the positive SIC anomalies both in the winter and spring seasons. A comparison of the first SVD modes between the winter and spring seasons suggests that the difference of dominant patterns of wind anomalies results in the difference of SIC anomaly distributions between two seasons. The relationship between sea ice and atmospheric circulation anomalies indicates that one mode of the leading two SVD modes in each season is related to large-scale atmospheric circulation associated with the Aleutian low and the other mode is related to relatively local atmospheric fluctuations related with pressure anomalies over Alaska. Furthermore, a slight difference of 700 hPa geopotential height anomalies results in the substantially different sea ice anomalies. These results suggest that in order to know the interannual sea ice variability in the Bering Sea, a better understanding of the wind anomalies over the Bering Sea are important. Copyright 2005 by the American Geophysical Union.
  • YN Sasaki, S Minobe
    JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 110 (C5) C05011  2169-9275 2005/05 [Refereed][Not invited]
     
    Interannual variability of sea ice in the Bering Sea and its relationship to atmospheric variability is analyzed using a singular value decomposition (SVD) analysis of sea ice concentrations (SICs) and 1000 hPa wind speeds in winter and spring seasons. The statistically significant first and second SVD modes, explaining 76.3% and 17.6% in winter and 54.6% and 29.6% in spring of the squared covariance between the two fields, are identified for SICs both in the winter and spring seasons with 1 month leading wind speeds. The spatial structures show that the first (second) SVD mode explains the SIC variability in the northeastern (northwestern) Bering Sea, related to the local northwesterly (northerly) wind anomalies for the positive SIC anomalies both in the winter and spring seasons. A comparison of the first SVD modes between the winter and spring seasons suggests that the difference of dominant patterns of wind anomalies results in the difference of SIC anomaly distributions between two seasons. The relationship between sea ice and atmospheric circulation anomalies indicates that one mode of the leading two SVD modes in each season is related to large-scale atmospheric circulation associated with the Aleutian low and the other mode is related to relatively local atmospheric fluctuations related with pressure anomalies over Alaska. Furthermore, a slight difference of 700 hPa geopotential height anomalies results in the substantially different sea ice anomalies. These results suggest that in order to know the interannual sea ice variability in the Bering Sea, a better understanding of the wind anomalies over the Bering Sea are important.
  • T Motoi, WL Chan, S Minobe, H Sumata
    GEOPHYSICAL RESEARCH LETTERS 32 (10) L10618, doi:10.1029/2005GL022844  0094-8276 2005/05 [Refereed][Not invited]
     
    The influence of the closure of the Panamanian Gateway during the late Cenozoic on climate in and around the North Pacific is investigated by using a coupled ocean-atmosphere general circulation model with an open and closed gateway. In the case of an open (closed) gateway, deep convection is present ( absent) in the North Pacific. The deep convection is associated with surface saline water transported from the subtropical Atlantic through the open gateway to the North Pacific. On the other hand, with the closed gateway, the lack of saline water transport from the Atlantic induces halocline formation over the subarctic Pacific with cold climate. The deep convection in the North Pacific leads to a vigorous thermohaline circulation with larger meridional heat transport, and causes warmer climate in and around the North Pacific. These results are generally consistent with paleoceanographic and paleoclimatic estimates related to the closure of the Panamanian Gateway.
  • N Okada, M Ikeda, S Minobe
    JOURNAL OF OCEANOGRAPHY 60 (6) 927 - 943 0916-8370 2004/12 [Refereed][Not invited]
     
    The dense water formation process under polynya or lead is examined by numerical experiments using a three-dimensional non-hydrostatic model. Many numerical experiments on isolated convection in an initially homogeneous fluid have been performed for different sets of external parameters, in order to investigate a relationship between the convection process and the external parameters. The main focus is on the situation in which the horizontal length scale of disk-shaped buoyancy forcing (radius R) is comparable with the total water depth (H). The two dynamical regimes described in previous work-the baroclinically unstable convection and the baroclinically stable convection-are confirmed in the experiments. A horizontal shift of a convective chimney is important to a density anomaly in baroclinically stable convection. For the stable range, as R is reduced R/H < 0.7, a new regime is found, called "single-plume convection", in which multiple convective plumes do not fully develop, and the density anomaly scale has nearly no dependency on R. This change of dependency on R is consistent with that derived by scaling analysis. The non-hydrostatic component is more significant than the hydrostatic one in the single-plume convection. The information obtained is useful for parameterizing dense water formation under ice cover in a numerical model with a large grid size; i.e., the newly formed water has a density anomaly independent of the polynya size smaller than the water depth, while the anomaly increases as the size exceeds the depth.
  • S Minobe, A Sako, M Nakamura
    JOURNAL OF PHYSICAL OCEANOGRAPHY 34 (11) 2382 - 2397 0022-3670 2004/11 [Refereed][Not invited]
     
    A new gridded water temperature dataset of upper 400-m depths (0, 50, 100, 200, 300, and 400 m) for the Japan Sea ( or East Sea) is produced by using an optimal interpolation technique from 1930 to 1996, based on oceanographic observations collected in the World Ocean Database 1998. The temperature data are analyzed by a complex empirical orthogonal function (CEOF) with six levels combined using the data for a period from 1957 to 1996, during which most of gridded data are available. Before calculating the CEOFs, low-pass or high-pass filters (cutoff period at 7 yr) are applied to separate interannual and decadal temperature changes, respectively. One interannual and two decadal CEOF modes are identified. The interannual first CEOF mode is characterized by the energetic variability around and south of the subpolar front in the western Japan Sea, accompanied by northward and northeastward phase propagations emanating from the Tsushima Strait. The decadal first CEOF mode exhibits a broad structure prevailing over the whole Japan Sea, but large amplitudes are trapped by the subpolar front, with 60degrees-90degrees phase lags between the northeastern and southwestern Japan Sea. The decadal second CEOF mode has a localized structure with strong correlations in the Yamato Basin. The relation between the atmosphere and ocean is analyzed by a correlation analysis of wintertime sea level pressures (SLPs) onto the temporal coefficients of the CEOF modes. The interannual first CEOF mode is accompanied by the SLP anomalies over the western North Pacific Ocean with steep SLP gradients over the Japan Sea, suggesting that this mode is forced by local wind anomalies associated with the SLP changes over the western North Pacific. The decadal first CEOF mode is likely to be caused by changes of the east Asian winter monsoon due to the SLP variability of the northern part of the Siberian high, which is closely associated with the decadal fluctuations of the Arctic Oscillation and the North Atlantic Oscillation. The second decadal CEOF mode is accompanied by high SLP correlations over the central North Pacific associated with strength changes of Aleutian lows, suggestive of remote forcing from the central North Pacific.
  • S Minobe, FF Jin
    GEOPHYSICAL RESEARCH LETTERS 31 (16) L16206, 10.1029/2004GL019776.*  0094-8276 2004/08 [Refereed][Not invited]
     
    The resonant behavior of delayed oscillators is studied using two simple prototype equations similar to that used by Suarez and Schopf. One prototype equation has a periodic modulation of simultaneous feedback, and the other prototype equation has a periodic external forcing term. The periodic modulation yields even-multiple resonance to the modulation periods, while the periodic forcing results in odd-multiple resonance to the forcing periods. The reason why these two-types of resonance occur in each system is explained. The key mechanism for the resonance is that a positive simultaneous feedback for small amplitudes sets a threshold. Only when the sum of non-simultaneous terms is larger than the threshold, a phase reversal can take place. The implications of El Nino elimination due to annual cycle and potential importance for the decadal variability are discussed.
  • S Minobe, M Nakamura
    JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 109 (C9) C09S05: doi:10.1029/2003JC001916.  2169-9275 2004/07 [Refereed][Not invited]
     
    A new gridded water-temperature data set of upper 200 m depths (0, 50, 100, 200 m depths) for the Okhotsk Sea was produced using an optimal interpolation technique from 1950 to 1996 using oceanographic observations in the World Ocean Database 1998. Temperature variability at 50, 100 and 200 m depths in the southern Okhotsk Sea (south of 52degreesN) in the warm-season (May-October) was investigated by an Empirical Orthogonal Function (EOF) analysis from 1958 to 1994, for which sufficient data exist for an EOF analysis. The first EOF mode has a monopole structure with the maximal amplitude in the Kuril Basin, and the corresponding Principal Component (PC) exhibits prominent quasi-decadal variability. The first EOF mode is closely related with the wintertime (December-February) sea surface temperature anomalies over the subarctic front or Oyashio front in the North Pacific, and with wintertime Sea level Pressure (SLP) differences between northern Eurasia and the northern North Pacific. This suggests that the temperature changes in the Okhotsk Sea are caused by changes in the strength of the Asian winter monsoon, which are associated with the SLP difference. A quasi-decadal oscillation, similar to that of the PC-1, is observed in the SLP difference since the 1960s, and shared by the Polar/Eurasian (POL) pattern, Arctic Oscillation (AO) and North Atlantic Oscillation (NAO). Some hints of the relating variability are observed in coastal sea level difference between Wakkanai and Abashiri, which was used as a proxy for transport in the Soya Warm Current. Also, some features of sea ice extents co-vary with the PC-1.
  • Updated assessments of the 1998/99 climate change over the north Pacific.
    Shoshiro Minobe
    In Neo-Science of Natural History: Integration of Geoscience and Biodiversity Studies, Proc. int. symp. 103 - 106 2004 [Refereed][Not invited]
  • Impact of Panamanian Gateway Opening on the Global Ocean Circulation.
    Sumata, H, S. Minobe, T. Motoi, W.-L. Chan
    Neo-Science of Natural History: Integration of Geoscience and Biodiversity Studies, 93 - 101 2004 [Refereed][Not invited]
  • Year-to-year variability in the Hadley and Walker circulations from NCEP/NCAR reanalysis data
    S Minobe
    Hadley Circulation: Present, Past and Future 21 153 - 171 2004 [Refereed][Not invited]
     
    The year-to-year variability in the local Hadley and Walker circulations is studied by empirical orthogonal function (EOF) analysis of zonal and meridional divergent winds at 200 and 850 hPa in the NCEP/NCAR reanalysis data. The first mode of the EOF analysis for the period since 1979 is closely related to the El Nino/Southern Oscillation (ENSO). The corresponding vertical velocity structure at the middle of the troposphere is characterized by the combination of a horseshoe pattern in the western tropical Pacific and an oval pattern in the central-eastern equatorial Pacific, consistent with satellite-derived precipitation correlations. A streamline analysis for horizontal divergent winds and vertical winds revealed that the dominant local Hadley and Walker circulation anomalies connect the oval and the horseshoe, while the other clusters of the local Hadley circulation anomalies rotating in opposing directions emanate from the Maritime Continent region. The first EOF mode of the data for 1949 through 2002 is characterized by a trend-like increase from the 1960s to the 1980s that is consistent with a previous study by Goswami and Thomas (2000). This mode is accompanied by an increase of downward vertical wind anomalies over Sahel and over the central equatorial Pacific Ocean and by an increase in upward anomalies over the Maritime Continent and the Amazon. A consistent decrease in precipitation is observed over Sahel. Precipitation also decreased over the central Pacific, but the region of the decrease is located to the south of the center of the downward wind anomalies. Precipitation increases consistent with the local upward motions are not observed over the Maritime Continent or over the Amazon.
  • S Minobe
    PROGRESS IN OCEANOGRAPHY 55 (1-2) 45 - 64 0079-6611 2002 [Refereed][Not invited]
     
    Sea-Surface Temperatures (SSTs), upper water Heat Storage (HS), Sea-Level Displacements (SLDs), Sea-Ice Concentration (SICs) in the Bering Seas and associated atmospheric circulations are analyzed to identify dominant interannual to interdecadal variations. As a representative time series of the SST variations, Principal Component (PC) of the first mode of a seasonally combined Empirical Orthogonal Function (EOF) is employed. The corresponding EOF (spatial pattern) exhibits the smallest amplitudes in winter and largest in summer. PC1 is characterized by a warming trend throughout the record (1921-2001) with the warmest year in 1997, which is followed by rapid cooling until 1999. The warming from 1995-1997 and cooling from 1997-1999 are commonly found in HS along the southern rim of the Bering Sea, and also accompanied by SLD rise and fall, respectively. The SIC variability corresponding to SST PC1 is prominent in the eastern Bering Sea in spring with correlations as high as 0.7, but good correlations were mainly observed prior to 1990. The correlations between the SST PC1 and sea-level pressures (SLPs) also suggest that the spring atmospheric circulation anomalies play an important role in the variations of the SST and sea-ice in the Bering Sea. The cooling and SLD fall in the late 1990s in the Bering Sea might be related with a possible major regime shift in 1998/1999, which was discussed by Minobe (2000), Hare and Mantua (2000), and Schwing and Moore (2000). In the 1998/99 change over the North Pacific, SSTs and HS increased abruptly both in the Kuroshio/Oyashio Extension region and the central North Pacific, accompanied by cooling in the eastern North Pacific. At the same time, SLDs rose from Japan to 160 W roughly along Kuroshio Extension path with a tongue-like structure. The tongue-like SLD rise is likely forced by wintertime atmospheric anomalies associated with SLP increase in the eastern North Pacific. (C) 2002 Elsevier Science Ltd. All rights reserved.
  • Global structure of bidecadal precipitation variability in boreal winter.
    Minobe, S, T. Nakanowatari
    Geophysical Research Letters 29 (10) 1396, doi 10.1029/2001GL014447, 22 May 2002.  2002 [Refereed][Not invited]
  • Minobe, S, T. Manabe, A. Shouji
    Journal of Climate 15 (9) 1064 - 1075 2002 [Refereed][Not invited]
  • S Minobe
    PROGRESS IN OCEANOGRAPHY 47 (2-4) 381 - 408 0079-6611 2000 [Refereed][Not invited]
     
    Using a Multi-Taper frequency domain-Singular Value Decomposition (MTM-SVD), a pentadecadal oscillation was detected in the winter-spring sea-level pressure (SLP) field over the North Pacific and surface air-temperature in North America which was significant at the 95% confidence level. The MTM-SVD captured the different SLP and ah-temperature distributions between the winter and spring seasons in a consistent manner. The pentadecadal SLP signature in the spring season is centered nearer the west coast of North America than in the winter season. This zonal displacement is consistent with the prominent springtime pentadecadal air-temperature variability in mid-latitude western North America. A wavelet analysis of the Pacific Decadal Oscillation index (PDOI) showed that the regime shifts in the 1920s, 1940s and 1970s involved simultaneous phase reversals of the bidecadal and pentadecadal variations. The two interdecadal variations are synchronized with one another such that a half period of the pentadecadal oscillation tone epoch of an individual regime) corresponds to one and half periods of the bidecadal oscillation. These results are consistent with the wavelet analysis of the North Pacific Index (NPI). Similar resonance between the bidecadal and pentadecadal variations is evident in air-temperatures over Alaska. The bidecadal and pentadecadal signals have different seasonality in these time series, suggesting that although the two interdecadal variations arise from two different physical mechanisms, they interact with each other. The most distinct seasonal difference was observed in mid-latitude western North America, where the bidecadal variation prevails only in the winter season and the pentadecadal variation only in the spring season. Alaska air-temperatures in the winter and winter-spring of 1999 were the coldest since 1977, as were springtime air-temperatures in mid-latitude western North America, in contrast to the warm anomalies that prevailed in this: region during 1977-98. The NPI and PDOI also exhibited an opposite polarity in 1999 to the respective regime mean polarities. These anomalous conditions in winter and spring seasons of 1999 may signify a major regime shift in 1998-1999. In order to verify whether or not a regime shift did occur in 1998-1999, a careful examination of additional data in coming ten or so years will he necessary. (C) 2000 Elsevier Science Ltd. All rights reserved.
  • Nishino, S, S. Minobe
    Journal of Physical Oceanography 30 2391 - 2403 2000 [Refereed][Not invited]
  • Hare, SR, S Minobe, WS Wooster, S McKinnell
    PROGRESS IN OCEANOGRAPHY 47 (2-4) 99 - 102 0079-6611 2000 [Refereed][Not invited]
  • Plume Structures in Deep Convection of Rotating Fluid.
    Minobe, S, Y. Kanamoto, N. Okada, H. Ozawa, M. Ikeda
    Nagare Multimedia 2000 (internet journal) http://www.nagare.or.jp/mm/2000/minobe/index.htm  2000 [Refereed][Not invited]
  • S Minobe
    GEOPHYSICAL RESEARCH LETTERS 26 (7) 855 - 858 0094-8276 1999/04 [Refereed][Not invited]
     
    The roles of interdecadal oscillations in climatic regime shifts, which are observed as rapid strength changes in the Aleutian low in winter and spring seasons, have been analyzed. A regime shift results from simultaneous phase reversals between pentadecadal and bidecadal variations, which synchronize with one another at a relative period of three. The pentadecadal variation, which is observed in both winter and spring seasons, provides the basic timescale of regime shifts, while the bidecadal variation, which is observed only in winter, characterizes the rapidity of the shifts. A Monte-Carlo simulation has shown that the simultaneous phase reversals or resonance between the pentadecadal and bidecadal variations reflect a physical linkage between them and do not coincide accidentally. The role of this synchronization feature for assessing and predicting regime shifts is discussed.
  • Yasuda, I, H Sugisaki, Y Watanabe, SS Minobe, Y Oozeki
    FISHERIES OCEANOGRAPHY 8 (1) 18 - 24 1054-6006 1999/03 [Refereed][Not invited]
     
    Relations between the long-term variations in numbers of Japanese sardine and in ocean/climate were studied. We examined long-term records of the spring air temperature on the north-western coast of North America (ATNA; 40-50 degrees N, 130-110 degrees W) reconstructed from tree rings, and the sardine catch records inferred from documents dating from 1600 to 1990. High sardine catches occurred eight times in this period, and each high catch continued for 7-45 years. We found a significant difference in mean ATNAs between the abundant and poor catch periods: high (low) catch occurred in periods of high (low) ATNA. ATNA was negatively correlated with spring sea-surface temperature east of Japan (SSTJ; 36-40 degrees N, 150-160 degrees E), where the sardine possibly migrate north-eastward, a relation which was confirmed from 1940 to 1990. In years when the Aleutian Low Pressure System (AL) shifted south-east and intensified, the westerly wind was strong east of Japan along the south-western edge of the AL, resulting in low SSTJ; a warm southwesterly wind blows in the west coast of North America along the south-eastern edge of the AL. If we assume that this relation between ATNA and SSTJ can be extended Lack to the 1600s, high (low) catches occur in the period when SSTJ is low (high). This relation between sardine catch and SSTJ is consistent with previous studies based on data from after 1900. The present results suggest that long-term variations in Japanese sardine are related to interdecadal North Pacific ocean/climate variability.
  • S Minobe, N Mantua
    PROGRESS IN OCEANOGRAPHY 43 (2-4) 163 - 192 0079-6611 1999 [Refereed][Not invited]
     
    The interdecadal modulation of interannual variability of the atmosphere and ocean is examined over the North Pacific by using Wavelet Transform combined with Empirical Orthogonal Function (EOF) or Singular Value Decomposition (SVD) analysis. For the period of record 1899-1997, the interannual variability of the wintertime Aleutian Low, identified by either the North Pacific Index or the leading eigenvector (EOF-1) of North Pacific sea level pressure (SLP) exhibits an interdecadal modulation, Interannual variance in the strength of the Aleutian Low was relatively large from the mid-1920s to mid-1940s and in the mid-1980s, but relatively small in the periods from 1899 to the mid-1920s and from the mid-1940s to the mid-1970s. The periods of high (low) interannual variability roughly coincide with pentadecadal regimes having a time averaged relatively intense tweak) Aleutian Low. Consistent with this SLP variability the interannual variance in the zonal wind stress is strengthened in the central North Pacific after the 1970s. The SLP EOF-2, which is related to the North Pacific Oscillation, exhibited a strengthening trend from the beginning of this century to the mid-1960s. After the 1970s. the interannual variance of SLP EOF-2 is generally smaller than that in the period from 1930 to 1970, Similar interdecadal changes in interannual variance are found in expansion coefficients for the first two EOFs of the Pacific sector 500 hPa height field for the period 1946-1993, EOF-1 of Pacific sector 500 hPa corresponds to the Pacific/North American (PNA) teleconnection pattern, while EOF-2 is related to the Western Pacific (WP) pattern, The relative influence of the atmospheric PNA and WP interannual variability on North Pacific SSTs appears to have varied at pentadecadal time scales. Results from an SVD analysis of winter season (December-February) 500 hPa and North Pacific spring season (March-May) SST fields demonstrate that the PNA-related SST anomaly exhibited larger interannual variance after the 1970s. whereas the interannual variance of the WP related SST anomaly is larger before the 1970s. Correlations between the coastal North Pacific SST records and gridded atmospheric field data also change on interdecadal time scales. Our results suggest that the SST records from both the northwest and northeast Pacific coasts were more closely coupled with the PNA teleconnection pattern during the periods of 1925-1947 and 1977-1997 than in the regime from 1948 to 1976. Teleconnections between ENSO and preferred patterns of atmospheric variability over the North Pacific also appear to vary on interdecadal time scales. However, these variations do not reflect a unique regime-dependent influence. Our results indicate that ENSO is primarily related to the PNA (WP pattern in the first (last) half of the present century. Correlation coefficients between indices for ENSO and PNA-like atmospheric variability are remarkably weak in the period from 1948 to 1976. (C) 1999 Elsevier Science Ltd. All rights reserved.
  • S Minobe
    GEOPHYSICAL RESEARCH LETTERS 24 (6) 683 - 686 0094-8276 1997/03 [Refereed][Not invited]
     
    The chronology of interdecadal climatic regime shifts is examined, using instrumental data over the North Pacific, North America and the tropical oceans, and reconstructed climate records for North America, In the North Pacific and North America, climatic regime shifts around 1890 and in the 1920s with alternating polarities are detected, whose spatial structure is similar to that of the previously-known climatic shifts observed in the 1940s and 1970s. Sea-surface temperatures in the tropical Indian Ocean-maritime continent region exhibit changes corresponding to these four shifts. Spectra obtained by the Multi-Taper-Method suggest that these regime shifts are associated with 50-70 year climate variability over the North Pacific and North America. The leading mode of the empirical orthogonal functions of the air-temperature reconstructed from tree-rings in North America exhibits a spatial distribution that is reminiscent of instrumentally observed air-temperature differences associated with the regime shifts. The temporal evolution of this mode is characterized by a 50-70 year oscillation in the eighteenth and nineteenth centuries. This result, combined with the results of the analyses of the instrumental data, indicates that the 50-70 year oscillation is prevalent from the eighteenth century to the present in North America.
  • S Minobe
    JOURNAL OF CLIMATE 9 (7) 1661 - 1668 0894-8755 1996/07 [Refereed][Not invited]
     
    A westward propagating signal with the annual period is detected in anomalies of the zonally averaged meridional wind component along 8 degrees N across the Pacific Ocean. The propagating signal in the ''eddy'' (defined as the departure from the zonally averaged) meridional wind has approximately the same propagation speed as the well-known propagating signal in the zonal wind component along the equator, and the former has larger amplitude than the latter. The eddy SST gradient between the equator and 10 degrees N exhibits a similar westward propagation and is in phase with the eddy meridional wind; the northward eddy wind is accompanied by the warmer eddy SST to the north. The propagating features in both the eddy meridional wind and the SST gradient are quite regular from year to year, except for El Nino years. In the El Nino periods, the regular features are disturbed in the western Pacific, but the in-phase relationship between these two parameters still holds. These relationships indicate that the boundary-layer mechanism is most likely to be of primary importance in the response of the eddy meridional wind to the SST variations.
  • Minobe, S, K. Takeuchi
    Journal of Geophysical Research 100 (18) 379-18 - 392 1995 [Refereed][Not invited]
  • Analysis of wind forcing contributions to annual period sea-level displacement at the equator.
    Shoshiro Minobe
    TOGA-Notes (USA) 4 7 - 9 1991 [Refereed][Not invited]

Books etc

  • 地球惑星科学入門
    在田 一則, 竹下 徹, 見延庄士郎, 渡部 重十編著 (Joint work)
    北海道大学出版会 2010
  • 気象学と海洋物理学で用いられるデータ解析法, 気象研究ノート
    伊藤 久徳, 見延 庄士郎 (Joint work)
    日本気象学会 2010
  • 理系のためのレポート・論文完全ナビ
    見延庄士郎 (Single work)
    講談社 2008
  • 物理的環境におけるレジーム・シフトと十年スケール変動のメカニズム. レジーム・シフト-気候変動と生物資源管理-
    川崎 健, 谷口 旭, 二平 章, 花輪 公雄, 見延庄士郎 (Joint work45-61)
    成山堂 2007
  • 日本の気候変動と中高緯度の大気・海洋変動,in 海と環境:海が変わると地球が変わる
    見延庄士郎 (Joint work88-98)
    日本海洋学会編, 講談社 2001

Conference Activities & Talks

  • Shoshiro Minobe, Shogo Takebayashi
    Climate implications of frontal scale air-sea interaction  2013/08
  • Shoshiro Minobe, Yutaka Hosoya
    WCRP/CLIVAR Second International Symposium on Boundary Current Dynamics  2013/07
  • Shoshiro Minobe
    CLIVAR/WCRP Workshop on Decadal and Multi-decadal Variability in Pacific and Indian Ocean, First Institute of Oceanography in Qingdao  2012/09
  • Shoshiro Minobe, Yoshi N. Sasaki, Niklas Schneider, Yuji Miura
    International Workshop Development and Application of Regional Climate Models-II  2012/04
  • Shoshiro Minobe, Yutaka Hosoya
    PICES 2011  2011/10
  • Minobe S, M. Miyashita, T. Asai, M. Inatsu, A. Kuwano-Yoshida, H. Tokinaga, S.-P. Xie
    In International Symposium on Boundary Current Dynamics: its connection with open-ocean and coastal processes and responses to global climate change  2010/05
  • Minobe S, M. Miyashita, A Kuwano-Yoshida, H. Tokinaga, S.-P Xie
    Ocean Science Meeting  2010/02
  • Meridional eddy heat transport estimations using satellite data and eddy resolving OGCM.  [Invited]
    Minobe S, K. Aoki, Y. Tanimoto, Y. N. Sasaki, Y. Sasai
    Workshop for “Mesoscale eddies and their roles in North Pacific ecosystems” in PICES annual meeting  2009/10
  • Influence of the Kuroshio in the East China Sea on the atmosphere.  [Invited]
    Minobe, S, T. Asai, M. Miyashita, K. Takatama, M. Inatsu
    The 15th Pacific-Asian Marginal Seas Meeting.  2009/04
  • Influence of the Gulf Stream on the troposphere.  [Invited]
    Shoshiro Minobe
    U.S. CLIVAR Western Boundary Current Workshop.  2009/01
  • Anomalous SST warming over Kuroshio-Oyashio extensions from 1999 to 2001 and its possible ocean to atmosphere influence.  [Not invited]
    Shoshiro Minobe
    Climate Change: Past and Future.  2006/11
  • What is a Regime Shift? Semantics and recent indicators.  [Invited]
    Overland, J, R. Rodionov, N. Bond, S. Minobe
    Climate variability and ecosystem impacts on the North Pacific: A basin-scale synthesis.  2006/04
  • Scale interactions of climate and marine ecosystems.  [Invited]
    Shoshiro Minobe
    PICES/CLIVAR Workshop  2004/10
  • Pacific decadal variability: A review.  [Invited]
    Minobe, S, N. Schneider, C. Deser, Z. Liu, N. Mantua, H. Nakamura, M. Nonaka
    CLIVAR 2004  2004/06
  • Climate regime shift in the North Pacific.  [Invited]
    Shoshiro Minobe
    Historical transition and its future of ocean marine ecosystem.  2003/12
  • Influence of decadal Arctic Oscillation on Japan (East) sea and Okhotsk sea.  [Invited]
    Shoshiro Minobe
    P04 Arctic environment change (IAPSO, IAMAS, IAHS)  2003/07
  • Interannual to interdecadal variations in Hadley and Walker circulations.  [Invited]
    Shoshiro Minobe
    The Hadley Circulation: Present, Past and Future.  2002/11
  • Atmospheric circulation changes in 1998/99 over the North Pacific.  [Invited]
    Shoshiro Minobe
    PICES CCCC - GLOBEC Joint, Coupled biophysical processes, fisheries, and climate variability in coastal and oceanic ecosystems of the North Pacific. North Pacific Marine Science Organization (PICES) 11th Annual meeting,  2002/10
  • Decadal variability and large-scale air-sea interaction.  [Invited]
    Minobe, S, T. Suga, T. Watanabe, Y. Tanimoto, K. Hanawa
    Symposium for “Recent Progress in Physical Oceanography in Japan", Oceanographic Soc.  2002/10
  • Wavelet analysis of Pacific Decadal Oscillation and North Atlantic Osillation.  [Invited]
    Shoshiro Minobe
    workshop Camp-GLOBEC  2002/02
  • Co-variability between the Pacific pentadecadal oscillation and length of day.  [Invited]
    Shoshiro Minobe
    Symposium for Arctic Environmental Changes  2001/03
  • Interdecadal SST and SLP variability in the North Pacific  [Invited]
    Minobe, S, T. Manabe, A. Shouji
    International workshop on “Preparation, processing and use of historical marine meteorological data”  2000/11
  • Pacific pentadecadal oscillation: its nature and impact.  [Invited]
    Shoshiro Minobe
    “Interdecadal/interannual variability in the Pacific Ocean”, American Geophysical Union (AGU)/Western Pacific Geophysical Meeting (WPGM)  2000/06
  • Spatio-temporal structure of the pentadecadal and bidecadal variability over the North Pacific.  [Invited]
    Shoshiro Minobe
    "The nature and impacts of North Pacific climate regime shifts (Science board symposium), North Pacific Marine Science Organization (PICES) 8th Annual meeting,  1999/10
  • “Resonance in bidecadal and pentadecadal climate oscillations over the North Pacific : Role in climatic regime shifts “  [Invited]
    Shoshiro Minobe
    The workshop on “The development of the next-generation climate models.”  1999/03
  • ”Bidecadal and pentadecadal Oscillations over the North Pacific ”,  [Invited]
    Shoshiro Minobe
    TRIANGLE ’98  1998/09
  • Bidecadal and pentadecadal climatic oscillations over the North Pacific and North America.  [Invited]
    Shoshiro Minobe
    Hawaiian Winter Workshop on "Biotic impacts of extratropical climate change in the Pacific",  1998/01
  • Bidecadal and pentadecadal climatic oscillations over the North Pacific and North America.  [Invited]
    Shoshiro Minobe
    IAMAS/IAPSO joint symposium JPM3 "Decadal and interdecadal variations in the Pacific", IAMAS/IAPSO Joint Assembly  1997/07
  • “ Interdecadal Climatic Variability over the North Pacific “  [Invited]
    Shoshiro Minobe
    International Arctic Research Center, Science Plan Symposium  1997
  • A 50-70 year climatic oscillation over the North Pacific and North America.  [Invited]
    Shoshiro Minobe
    Science board symposium, North Pacific Marine Science Organization (PICES), 5th Annual meeting,  1996/10

MISC

Awards & Honors

  • 2016/08 Prime minister of Japan Ninth National Maritime Awards Released
     Study on physical interaction between the ocean and the atmosphere 
    受賞者: Shoshiro Minobe

Research Grants & Projects

  • 文部科学省:科学研究費補助金(基盤研究(B))
    Date (from‐to) : 2014 -2017 
    Author : 見延 庄士郎
  • 文部科学省:科学研究費補助金(挑戦的萌芽研究)
    Date (from‐to) : 2014 -2016 
    Author : 見延 庄士郎
  • 文部科学省:科学研究費補助金(新学術領域研究(研究領域提案型))
    Date (from‐to) : 2010 -2014 
    Author : 見延 庄士郎, 稲津 將, 吉田 聡, 小守 信正
     
    データ解析では,A2-3班と連携し世界に先駆けて,雲の中まで調査することが可能な雲レーダーを搭載するCloudSAT衛星データを用いて大気海洋相互作用にともなう雲構造を同定する研究を開始した.また,北西太平洋のSSTの経年変動が最も大きい、亜熱帯循環と亜寒帯循環の境界のフロント付近において、SSTの変動と衛星データによる大気データ(:海上風、積算雲水量)との関係を調べ,海流変動がSST変動を通して大気場に影響を与えている可能性を示した。数値計算では,地球シミュレータ上の高解像度大気大循環モデルで北太平洋、または北大西洋上の海面水温勾配を平滑化した実験をそれぞれ10年分実施した。また、大気大循環モデル、大気海洋結合モデルでそれぞれ再現された梅雨前線の季節進行について解析を行い、対流圏中層ジェットと海面水温前線の相対位置によって変動する海洋から梅雨前線に供給される水蒸気量が梅雨明けに影響することを明らかにした。地球シミュレータ上の大気海洋結合モデルの出力に基づく大気海洋間の結合係数に関して解析を進め,その季節的・空間的な変動には,海洋フロント近傍での対流圏下層の局所的な安定度に加えて大規模な風系の変動が重要であることを見出した.非静力学領域・全球結合大気モデルにおいて,高解像度SSTによる駆動を可能とする開発を行った。1年分の予備的実験を2002年の海面水温を与えて行い、同モデルが計算機的に正常に終了するだけでなく、その結果が気候学的にも概ね観測と整合的であることを確認した。さらに,大洋規模の海洋フロントがどのように変動するかについて,これまで考えられていた大規模ロスビー波とは異なって,狭いジェットである黒潮続流や湾流に補足されるロスビー波が本質的であることを,高解像度海洋モデル出力結果にthin-jet理論を適用することで明らかにした.
  • 文部科学省:科学研究費補助金(基盤研究(A))
    Date (from‐to) : 2010 -2013 
    Author : 見延 庄士郎, 稲津 將, 吉田 聡, 小守 信正, 磯辺 篤彦, 中村 啓彦, 万田 敦昌
     
    2011年6月に鹿児島大学・かごしま丸で梅雨期の東シナ海の黒潮横断観測を行った.同観測ではADCP(音響ドップラー流向流速計),XBT(投下式水温水深計),GPSゾンデを用い,72時間の観測時間内に黒潮上を3往復した.このように短期間に西岸境界流を3往復(6断面)して,大気応答を調べたのは世界初である.また,2010年12月に実施した東シナ海黒潮前線域における大気海洋観測で発見した従来の知見と異なる前線上における海上風の局所的な低下現象について,領域大気モデルを用いて,この海上風の弱化が,前線横断方向に風が吹き始める時期に限られた,一時的な現象であることを確認した。さらに,衛星風データであるASCATを用いて,上記の解析に使用するべく格子データセットを作成し,国際学術誌にて発表するとともに,インターネットを通してデータを無償配布している。数値計算では,地球シミュレータ上の高解像度大気大循環モデル実験から,東シナ海および日本南岸では海面水温勾配に対して大気下層は収束として応答し,日本東沖の黒潮親潮続流域では発散として応答していることを明らかにした。双方向ネスト大気モデルにおいて,東シナ海における黒潮が作り出す海面水温勾配が全球大気に及ぼす影響を調べる実験の準備を行った.また,梅雨期の黒潮に対する平均的な大気応答が,梅雨降水の黒潮上への集中をもたらすこと,および大気境界層を超え対流圏上層まで及ぶ影響を与えていることを,衛星および再解析データ解析,そして領域気象モデルを総合して明らかにした.この大気応答は,我々が2010年に提案したDeep heating modeと整合的であり,局所応答の強さは夏季のメキシコ湾流上と同程度であるが,大規模梅雨前線帯およびそれにともなう降水が加わることで,中緯度海流上の対流性降水としては世界で最も強いことが明らかとなった.
  • 文部科学省:科学研究費補助金(特定領域研究)
    Date (from‐to) : 2009 -2010 
    Author : 見延 庄士郎
     
    前回の公募研究で作成した栄養塩・溶存酸素についての全球グリッド・データは,その基礎となる海洋観測データについてWorld Ocean Database 2005に収録されているものを用いていた.しかし,2009年に新しいWorld Ocean Database 2009が公開されたので,栄養塩・溶存酸素のグリッド・データをこれを用いて作り直した.また最も観測点数が多く,信頼できると考えられるリン酸について,日本の南方で顕著な減少トレンドとそれに重なっている十年スケールの変動について,水温・塩分場などと合わせて解析を行った.その結果,十年スケール変動は,黒潮大蛇行によって引き起こされていることが判明した.すなわち,大蛇行期には,栄養塩が顕著な増加を見せる.このような関係は,特に1960年代初め,そして1970年代後半の長期間持続した大蛇行に伴う栄養塩増加として表れていた.一方,大蛇行期間を除いてトレンドの有意性検定を行っても有意な減少トレンドが見られることから,リン酸塩の減少トレンドは黒潮大蛇行とは基本的に無関係であると結論でき,地球温暖化など他の要因の影響が考えられる.この減少トレンドは,その振幅極大が水深100m付近に見られ,地球温暖化と関係して表層の栄養塩減少メカニズムとして広く受け入れられている仮説である,成層強化による上下混合の抑制では説明し難い.もし,混合抑制であれば100mに減少トレンドの極大が生じるのではなく,それよりも浅い層でより強い栄養塩の減少が見られるはずである.この栄養塩の減少トレンドのメカニズムを理解することは,日本付近の栄養塩分布がそしてそれが影響する海洋生態系が今後どのように変化していくかを議論する上で非常に重要であろう.
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2007 -2009 
    Author : Shoshiro MINOBE, Nobumasa KOMORI, Akira KUWANOーYOSHIDA, Tomohiro NAKAMURA
     
    We reported in a cover article of Nature (13 Mar. 2008) that the Gulf Stream causes a series of atmospheric responses, not limited to the atmospheric boundary layer, but penetrate to the free troposphere. Also, we found two different atmospheric modes, i.e., the shallow heating mode prominent in winter and the deep heating mode in summer. The difference of the summer and winter atmospheric responses is associated with the atmospheric stability between the two seasons. A long-term numerical integration of an Atmosphere-Ocean Coupled General Circulation model realistically reproduces major features of the recent satellite surface-wind observations. Furthermore, the first observational evidence of wave breaking, which is expected to cause low sea-surface temperatures, associated with ocean tide is obtained.
  • 文部科学省:科学研究費補助金(特定領域研究)
    Date (from‐to) : 2007 -2008 
    Author : 見延 庄士郎
     
    栄養塩・溶存酸素についての全球グリッドデータを作成した. 格子間隔は水平1度で深度1000mまでの18層, 時間解像度は月毎であり, 1930年より現在までの期間をカバーしている-グリッド化の手法はガウス関数によるスムージングである. このグリッドデータセットは栄養塩については初めての, また溶存酸素についても先行研究以上の範囲をカバーするものであり, このデータセット作成の意義は大きいと言えよう. 本データセットは, 観測がない場合は欠損として扱っているが, 日本付近は世界でも最も欠損が少ない領域となり, 本データセットは世界で最も充実している日本付近の栄養塩・溶存酸素観測を, 簡単に解析することを可能とするものである. このデータセットを用いて, 地球温暖化によって生ずる可能性があるトレンド成分を同定したところ, 日本の付近に顕著な栄養塩の減少トレンドが生じていることが見出された.またpHについては, 元データとして用いているWorld Ocean Database 05のデータの信頼性が不十分であることが明らかになった. すなわち, 同データベースにはpH測定に関するスケール情報と, 基準水温情報がほとんど示されていない. 測定スケールの大部分はNBSスケールであることが期待されるが, 基準水温については現場水温か25Cあるいは他の水温であるかでpHの値が大きく異なり, この基準を統一する形でWorld Ocean Database 05のデータを解析することは不可能である. そこで, JODCで公開されている気象庁のpHデータを解析した. その結果, 一般に予想されているpH低下と, 大きな矛盾のない結果が得られた.
  • 文部科学省:科学研究費補助金(萌芽研究)
    Date (from‐to) : 2007 -2007 
    Author : 見延 庄士郎
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(C))
    Date (from‐to) : 2003 -2006 
    Author : Shoshiro MINOBE
     
    A number of studies are conducted for a climate change over the North Pacific around 1998/99, as well as climate studies which may be a basis of understanding of such a rapid climate change. Here, some major results are described.The principal investigator of this research proposed previously that climatic regime shifts over the North Pacific appeared to be caused as synchronization between a 20-year oscillation and 50-70-year oscillation. In order to understand some basic mechanism of such resonance, a simple delayed oscillator model with periodic modulation of nonlinear feedback and that with periodic forcing are investigated. The basic mechanism of the nonlinear resonance associated with a concept of threshold has been clarified.It was found that substantial changes of sea-ice occurred around 1998/99 in marginal seas around the North Pacific. In the Bering Sea, spring sea-ice reduced around 1999 in the eastern Bering Sea. This change was likely to be caused by a low-pressure anomaly over Alaska. In the Okhotsk Sea, although long-term trend of sea-ice reduction continued until the mid-1990s, in the late 1990s and the early 2000s, sea-ice areas were larger than usual. It was found that for this long-term fluctuation of sea-ice, atmospheric conditions in autumn, not in winter previous studies focused, are important.For large-scale oceanic frontal zones, SST changes including those associated with 1998/99 change were investigated using a newly gridded high-resolution SST data (The dataset is available through the internet. You can find via google with "Minobe Maeda 1dg SST"). It was found that the subtropical front exhibited a large change in 1998/99, but not in the subpolar front. This is in contrast to the 1970s climatic regime shift, when a signal is more prominent in the subpolar front.Also, it is found that the winter strength of the Aleutian Low, which is a major atmospheric circulation changes associated with the regime shifts, exhibits bimodality after removal of a linear trend. This suggests that the nonlinear feedback is important in the climate feedback underlying the regime shifts.
  • 文部科学省:科学研究費補助金(奨励研究(A))
    Date (from‐to) : 1998 -1999 
    Author : 見延 庄士郎
     
    北太平洋西部の戦前において、観測手法の変遷によるバイアスが無視できないバケツまたはエンジン採水による従来の海面水温のグリッドデータの精度を、そのようなバイアスが無い採水ビンおよびBTデータに基づく海面水温のグリッドデータを作成して評価した。従来のグリッドデータの解像度は緯度経度5度であり、今回作成したデータは実効解像度が2〜3度(グリッドの間隔は0.5×0.5)である。この新たなデータによって、日本を中心とする1940年代のSSTの温度上昇の従来の推定は、過大評価であることが強く示唆された。このことは北太平洋の気候レジームシフトおよび温暖化研究において大きな意味を持ち、今後従来提案されているSSTの観測データの補正方法よりも高精度の補正方法を開発する上でその道を開くものである。また、既存データの解析から、北太平洋のレジームシフトは位相同期する50年変動と20年変動とが同期していることを明らかにした(Minobe 1999)。これらの50年変動と20年変動との同期は、北太平洋上の気圧とSSTおよびアラスカの地上気温に顕著に見られる。また50年変動は北太平洋および北極海上の冬季の経年変動の振幅変調をもたらしていることを報告した(Minobe and Mantua 1999)。数値実験ではわが国で初めてマイアミ大学等密度面座標海洋モデルを用いた研究を行い、1/3度の水平解像度で気候値に対する海洋応答を調査し、観測された風応力を与えて40年間の長期積分を行った。気候値に対する応答では、年周期のロスビー波がシャツキーライズ・ヘスライズなどの海嶺と相互作用し振幅が強化される様子を、初めて北太平洋の海洋大循環数値モデルで再現した。
  • 文部科学省:科学研究費補助金(奨励研究(A))
    Date (from‐to) : 1996 -1996 
    Author : 見延 庄士郎
     
    本研究は、50年から70年の周期を持つ変動が北太平洋および北米に存在することを、世界で初めて明らかにした。この長期変動は冬季・春季のアリューシャン低気圧の強化・弱化を伴い、アリューシャン低気圧が強い場合には、日本沿岸では親潮が通常よりも南下し、北米西部の春季気温は高いことが示された。これらの変動は、今世紀では1920年代・1940年代の気候シフトで特徴づけられるとともに、50-70年周期に統計的に有意なスペクトルピークを持つことが示された。このスペクトルの統計的な有意水準検定は、比較的あらたな手法であるMulti-Taper Methodを用いた。さらに、北米上で樹木年輪より推定される過去の気温データを解析することにより、50年〜70年スケールの変動は18世紀半ば以降継続していることが示された。この50〜70年スケール変動は親潮については顕著であるが、黒潮にはさほど影響が見られない。しかしながら、黒潮続流にも興味深い十年スケール変動が存在する。本研究では、1957年〜1992年の期間について黒潮続流の位置を144°E〜150°Eの区間で経度の関数として同定した。この区間の黒潮続流の平均緯度は1981年〜1987年の期間にその前後と比べて顕著な南下を示す。水温場の相関解析より黒潮続流の平均的な緯度の変動は、上流の黒潮流露および親潮第二分枝の勢力の強弱と関連することが示された。風応力分布との関連を解析した結果、黒潮続流の平均緯度は北太平洋上の風のcurlと弱い負の相関を持つことが判明した。一方、2つの定常蛇行の北向きの峰に当たる144°Eと150°Eの黒潮続流緯度の差は、本州東方の東西風応力と比較的高い相関を示す。黒潮続流の平均緯度と144°Eと150°Eの続流緯度の差が、異なる風応力分布パターンとの間で相関を持つことは、黒潮続流に関わるこれら二つの変動が異なるメカニズムによって定まることを示唆するものである。
  • 文部科学省:科学研究費補助金(奨励研究(A))
    Date (from‐to) : 1995 -1995 
    Author : 見延 庄士郎, 身延 庄士郎
     
    日本海における深層水温の変動は、深層水の形成量の変動によって生じていると考えられる。そこで深層水形成の長期変動をGCMで再現する第一歩として、非静水圧3次元数値モデルを開発し、密度の圧力依存性およびコリオリ項の水平成分が、深層水形成にどのような役割を果たすのかを検討した。モデル領域は水平32km×32km・鉛直に2000mとし、水平方向には周期境界条件を適用した。モデルのグリッド幅は水平250m・鉛直100mである。初期値には0℃で一様な水温分布と2000mで0.01PSUの塩分差のある塩分成層を与え、半径800mの円内で800W/m2の熱フラックスで、海洋表面から200m深まで一様に冷却した。コリオリパラメータには緯度45°Nにおける値を設定した。この条件下で、コリオリ項の水平成分および密度の圧力依存性の各々を組み込む場合組込まない場合の、計4通りのケースについて96時間の積分を行った。その結果、1)密度の圧力依存性を考慮する場合のみ深層水が形成される。2)密度の圧力依存性とコリオリ項の水平成分を考慮する場合には、78時間で海底に達する強い対流が生ずる。3)密度の圧力依存性を考慮してもコリオリ項の水平成分を含めない場合には、強い対流が生ずる時間が(2)に比べて約6時間早くなり、また36時間で弱い対流が生ずる、という結果が得られた。これらの結果から日本海の深層水形成過程に関して、密度の圧力依存性が非常に重要であり、またコリオリ項の水平成分の有無は有意な差を与えると結論される。

Educational Activities

Teaching Experience

  • Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : 地球生命史, 生物進化, 地球環境変化, 気候変動, 生物大量絶滅, 生物多様性, 古生物科学, 地質年代
  • Physics for Ocean Climate
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 気候変動・変化,海洋,循環,波動,大気海洋相互作用

Campus Position History

  • 2017年4月1日 
    2019年3月31日 
    研究戦略室室員
  • 2017年4月1日 
    2019年3月31日 
    総長補佐
  • 2019年4月1日 
    Present 
    研究戦略室室員
  • 2019年4月1日 
    Present 
    総長補佐

Position History

  • 2017年4月1日 
    2019年3月31日 
    研究戦略室室員
  • 2017年4月1日 
    2019年3月31日 
    総長補佐
  • 2019年4月1日 
    Present 
    研究戦略室室員
  • 2019年4月1日 
    Present 
    総長補佐

Social Contribution

Social Contribution

Media Coverage

  • ”気候変化と変動”
    Date : 2014/02/01
    Program, newspaper magazine: 環境・自然を考える会
  • “空に映る海流:海洋から大気へのフィードバック”
    Date : 2012/11/20
    Publisher, broadcasting station: 札幌新川高校
  • Date : 2010/08/05
    Publisher, broadcasting station: (独)科学技術振興機構・サイエンス・パートナーシップ・プロジェクト事業,秋田県立横手高校, 秋田・札幌
  • Date : 2009/08/06
    Publisher, broadcasting station: (独)科学技術振興機構・サイエンス・パートナーシップ・プロジェクト事業,秋田県立横手高校, 秋田・札幌
  • “空に映る海流:海洋から大気へのフィードバック”
    Date : 2008/11/07
    Program, newspaper magazine: 第17回先端科学移動大学2008
  • “山の中での海洋物理学講座”
    Date : 2008/08/05
    Publisher, broadcasting station: (独)科学技術振興機構・サイエンス・パートナーシップ・プロジェクト事業,秋田県立横手高校, 秋田・札幌
  • “気候変動の科学 エルニーニョ”
    Date : 2004/09
    Program, newspaper magazine: スーパーサイエンスハイスクール・札幌北校出前授業
  • “十年から百年スケールの気候変動”
    Date : 2004/04
    Publisher, broadcasting station: 21世紀COE「新・自然史科学創成」総合博物館・市民セミナー
  • “気候変動と海 -太平洋で起こっていること:エルニーニョやその他の現象について-”
    Date : 2003/07
    Program, newspaper magazine: 2003進学わくわくライブ札幌
  • “気候変動と海 ―太平洋はなにをしているか―”
    Date : 2002/10
    Program, newspaper magazine: リクルート進学ナビ
  • “気候の長期変動と水産資源への影響”
    Date : 2002/07/19
    Program, newspaper magazine: 水産油脂協会年次講演会


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