Researcher Database

Yoshi N Sasaki
Faculty of Science Earth and Planetary Sciences Earth and Planetary Dynamics
Associate Professor

Researcher Profile and Settings

Affiliation

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

Job Title

  • Associate Professor

Degree

  • PhD (Science)(Hokkaido University)

URL

Research funding number

  • 50604815

J-Global ID

Research Interests

  • Baiu front   Kuroshio Extension   Kuroshio   North Pacific   Sea Level Rise   Air-Sea Interaction   Physical Oceanography   

Research Areas

  • Natural sciences / Atmospheric and hydrospheric science

Academic & Professional Experience

  • 2018/02 - Today Hokkaido University Faculty of Science Associate Professor
  • 2013/04 - 2018/01 Hokkaido University Faculty of Science Lecturer
  • 2011/04 - 2013/03 Hokkaido University
  • 2010/12 - 2011/03 Hokkaido University
  • 2008/04 - 2010/11 University of Hawaii

Association Memberships

  • The American Geophysical Union   the Meteorological Society of Japan   THE OCEANOGRAPHIC SOCIETY OF JAPAN   

Research Activities

Published Papers

  • Philip L. Woodworth, Angélique Melet, Marta Marcos, Richard D. Ray, Guy Wöppelmann, Yoshi N. Sasaki, Mauro Cirano, Angela Hibbert, John M. Huthnance, Sebastià Monserrat, Mark A. Merrifield
    Surveys in Geophysics 40 (6) 1351 - 1397 0169-3298 2019/11 [Refereed]
  • 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.
  • Yoshi N. Sasaki, Yuko Yamada
    Climate Dynamics 1 - 14 1432-0894 2017/11/28 [Refereed][Not invited]
     
    The atmospheric response, especially the response of the meiyu-baiu rainband, to interannual variability of the sea surface temperature (SST) front associated with the Kuroshio in the East China Sea in early summer is examined by using reanalysis, satellite, and rain-gauge datasets from 1982 to 2010. It is revealed that the strong (weak) SST front in the East China Sea is accompanied by the heavy (weak) precipitation over the central East China Sea and the southern Japan. Because the strong SST front largely results from the negative SST anomaly over the continental shelf, the local evaporation change in the East China Sea is not balanced by this enhanced precipitation. The moisture for this enhanced precipitation is supplied by interannual variability of horizontal wind convergence over the central East China Sea. In addition to the precipitation change, the strong SST front is also accompanied by the intensification of weather disturbances in the lower troposphere over the East China Sea. This is probably because the negative SST anomaly over the continental shelf enhances the baroclinicity in the lower troposphere. This intensification of the weather disturbances over the East China Sea can explain the enhanced precipitation over the central East China Sea in response to the interannual variability of the SST front. Because the SST anomaly over the continental shelf, which primarily determines the interannual variability of the SST front, persists for a couple of months, these results imply the predictability of the precipitation associated with the meiyu-baiu rainband.
  • Yoshi N. Sasaki, Ryosuke Washizu, Tamaki Yasuda, Shoshiro Minobe
    JOURNAL OF CLIMATE 30 (14) 5585 - 5595 0894-8755 2017/07 [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 inter-decadal 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.
  • 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.
  • 西岸境界流およびその続流の変動に関する理論的・解析的研究
    佐々木 克徳
    海の研究 25 (1) 1 - 16 2016 [Refereed][Invited]
  • Shinichiro Kida, Humio Mitsudera, Shigeru Aoki, Xinyu Guo, Shin-ichi Ito, Fumiaki Kobashi, Nobumasa Komori, Atsushi Kubokawa, Toru Miyama, Ryosuke Morie, Hisashi Nakamura, Tomohiro Nakamura, Hideyuki Nakano, Hajime Nishigaki, Masami Nonaka, Hideharu Sasaki, Yoshi N. Sasaki, Toshio Suga, Shusaku Sugimoto, Bunmei Taguchi, Koutarou Takaya, Tomoki Tozuka, Hiroyuki Tsujino, Norihisa Usui
    JOURNAL OF OCEANOGRAPHY 71 (5) 469 - 497 0916-8370 2015/10 [Refereed][Not invited]
     
    This article reviews progress in our understanding of oceanic fronts around Japan and their roles in air-sea interaction. Fronts associated with the Kuroshio and its extension, fronts within the area of the Kuroshio-Oyashio confluence, and the subtropical fronts are described with particular emphasis on their structure, variability, and role in air-sea interaction. The discussion also extends to the fronts in the coastal and marginal seas, the Seto Inland Sea and Japan Sea. Studies on oceanic fronts have progressed significantly during the past decade, but many of these studies focus on processes at individual fronts and do not provide a comprehensive view. Hence, one of the goals of this article is to review the oceanic fronts around Japan by describing the processes based on common metrics. These metrics focus primarily on surface properties to obtain insights into air-sea interactions that occur along oceanic fronts. The basic characteristics derived for each front (i.e., metrics) are then presented as a table. We envision that many of the coupled ocean-atmosphere global circulation models in the coming decade will represent oceanic fronts reasonably well, and it is hoped that this review along with the table of metrics will provide a useful benchmark for evaluating these models.
  • 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.
  • 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, 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.
  • 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.
  • Yoshi N. Sasaki, Niklas Schneider
    JOURNAL OF PHYSICAL OCEANOGRAPHY 41 (5) 979 - 993 0022-3670 2011/05 [Refereed][Not invited]
     
    Meridional shifts of the Kuroshio Extension (KE) jet on decadal time scales are examined using a 1960 2004 hindcast simulation of an eddy-resolving ocean general circulation model for the Earth Simulator (OFES). The leading mode of the simulated KE represents the meridional shifts of the jet on decadal time scales with the largest southward shift in the early 1980s associated with the climate regime shift in 1976/77, a result confirmed with subsurface temperature observations. The meridional shifts originate east of the date line and propagate westward along the mean jet axis, a trajectory inconsistent with the traditionally used linear lone Rossby waves linearized in Cartesian coordinates, although the phase speed is comparable to that in the traditional framework. The zonal scale of these westward propagation signals is about 4000 km and much lamer than their meridional scale. To understand the mechanism for the westward propagation of the KE jet shifts, the authors consider the limit of a thin jet. This dynamic framework describes the temporal evolution of the location of a sharp potential vorticity front under the assumption that variations along the jet are small compared to variations normal to the jet in natural coordinates and is well suited to the strong jet and potential vorticity gradients of the K E. For scaling appropriate to the decadal adjustments in the KE, the thin-jet model successfully reproduces the westward propagations and decadal shifts of the jet latitude simulated in OFES. These results give a physical basis for the prediction of decadal variability in the K E.
  • Yoshi N. Sasaki, Niklas Schneider
    OCEAN MODELLING 39 (3-4) 209 - 219 1463-5003 2011 [Refereed][Not invited]
     
    Meridional shifts of the Gulf Stream (GS) jet on interannual to decadal timescales and the corresponding oceanic changes around the GS are investigated using a near global eddy-resolving ocean model hindcast from 1960 to 2003. The simulated variability in the shifts of the GS jet axis shows good agreement with observations, and lags atmospheric fluctuations characterized by the North Atlantic Oscillation by about 2 years. This lagged response of the GS jet to the atmospheric variations is attributed to the westward propagation of the undulation of the jet axis from 45 degrees W to 75 degrees W, which has a wavelength of about 4000 km and a displacement of 0.5 degrees. The propagation direction and phase speed of about 2.8 cm s(-1) are consistent with the thin-jet theory. The shifts of the jet axis in the downstream region are likely induced by wind fluctuations through Ekman convergence over the central North Atlantic. Associated with the northward (southward) shift of the jet axis, sea surface temperature is warming (cooling) around and north of the jet, and the former warming has a deep and meridionally narrow subsurface structure, consistent with the northward shift of the jet. The meridional shifts of the jet accompany coherent meridional shifts of energetic eddy activity regions around the GS. Our numerical results suggest that the GS jet brings the atmospheric signals from the central to the western North Atlantic, and the resultant meridional shift of the jet induces the notable oceanic changes around the GS. (C) 2011 Elsevier Ltd. All rights reserved.
  • Ju Chen, Tangdong Qu, Yoshi N. Sasaki, Niklas Schneider
    GEOPHYSICAL RESEARCH LETTERS 37 0094-8276 2010/12 [Refereed][Not invited]
     
    Analysis of results from an eddy-resolving ocean general circulation model has revealed the existence of an anti-correlated variability in subduction rate of the western and eastern North Pacific Oceans, consistent with the leading mode of Pacific Decadal Oscillation (PDO). A composite analysis shows that during the positive phase of PDO, the winter mixed layer depth (MLD) generally gets deeper in the west and shallower in the east, being closely related to the variability in surface heat flux stemming from an enhanced Aleutian Low, and the situation during the negative phase of PDO is reversed. Changes in MLD are primarily responsible for the anti-correlated variability in subduction rate, though changes in subtropical gyre circulation also play a role. The result also provides useful evidence for the interior and western boundary pathways, through which variability in eastern subtropical mode water can be conveyed into the equatorial region. Citation: Chen, J., T. Qu, Y. N. Sasaki, and N. Schneider (2010), Anti-correlated variability in subduction rate of the western and eastern North Pacific Oceans identified by an eddy-resolving ocean GCM, Geophys. Res. Lett., 37, L23608, doi:10.1029/2010GL045239.
  • Yoshi N. Sasaki, Niklas Schneider, Nikolai Maximenko, Konstantin Lebedev
    GEOPHYSICAL RESEARCH LETTERS 37 0094-8276 2010/04 [Refereed][Not invited]
     
    The propagation of density-compensated (warm/salty or cool/fresh) spiciness anomalies in the North Pacific thermocline is investigated using Argo profiles for the period 2001-2008. A cool/fresh spiciness anomaly on 25 < sigma(theta) < 25.5 kg m(-3) isopycnals appears in the eastern subtropical North Pacific at 120 degrees W-150 degrees W in 2003-2004 with a salinity anomaly of about -0.15 PSS-78. This spiciness anomaly migrates southwestward, and arrives in the western tropical North Pacific at 145 degrees E-175 degrees W in 2008 with the salinity anomaly decreasing to about -0.043 PSS-78. Two warm/salty anomalies are observed to propagate along the same path from 2003 to 2005, and after 2005. The propagation path and speed of the anomalies are in good agreement with advection by the mean geostrophic current. In the course of propagation, the anomalies are diffused and are subject to high frequency injection of spiciness anomalies, especially in the eastern subtropical North Pacific. Citation: Sasaki, Y. N., N. Schneider, N. Maximenko, and K. Lebedev (2010), Observational evidence for propagation of decadal spiciness anomalies in the North Pacific, Geophys. Res. Lett., 37, L07708, doi:10.1029/2010GL042716.
  • 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.
  • 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.
  • YN Sasaki, S Minobe
    JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 110 (C5) 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.

MISC

  • MORI NOBUYUKI, MINOBE SHOSHIRO, NAKAMURA HIROHIKO, SASAKI YOSHINORI, NISHINA AYAKO, IWASAKI SHINSUKE, ISOBE ATSUHIKO  日本海洋学会大会講演要旨集  2014-  27  2014/03/10  [Not refereed][Not invited]
  • 2012: Ocean Science Meeting 2012報告
    見延庄士郎, 須賀利雄, 佐々木克徳, 安藤健太郎, 渡邉英嗣, 蒲生俊敬, 齊藤宏明, 池田元美, 鈴木亨  JOS News Letter  2-  (1)  3  -6  2012/05  [Not refereed][Not invited]
  • 佐々木 克徳, 見延 庄士郎  低温科学  65-  21  -30  2007/03/23  [Not refereed][Not invited]
     
    オホーツク海の海氷と上層水温の十年変動についての時空間構造と、その大気との関係について解析を行った。冬季の海氷の十年変動はオホーツク海北部で大きい振幅を持ち、1980年代の初めから1990年代中頃までは減少傾向、それ以降は海氷増加の傾向を示す。この海氷変動は秋季の大気変動に強く影響されている。一方、オホーツク海南部の夏期(5-10月)の上層水温の十年変動はクリル海盆付近で大きい振幅を持ち、概ね十年毎に温暖のピークを持つ準十年変動を示す。この上層水温の十年変動はその前の冬季の大気変動に強く影響されている。

Awards & Honors

  • 2017 Advances in Atmospheric Sciences Editor's Award
     
    受賞者: 佐々木 克徳
  • 2015 日本海洋学会 日本海洋学会岡田賞
     
    受賞者: 佐々木 克徳
  • 2012 PICES POC Committee Best Oral Presentation Awards
     
    受賞者: 佐々木 克徳
  • 2008 Ocean Sciences Meeting Outstanding Student Poster Awards
     
    受賞者: 佐々木 克徳

Educational Activities

Teaching Experience

  • 自然史科学論文講読1
    開講年度 : 2019
    課程区分 : 修士課程
    開講学部 : 理学院
  • 自然史科学特別研究1
    開講年度 : 2019
    課程区分 : 修士課程
    開講学部 : 理学院


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