研究者情報

マスター

アカウント（マスター）

• 氏名

  阿部　泰人(アベ　ヒロト), アベ　ヒロト

所属（マスター）

• 水産科学研究院　海洋生物資源科学部門　海洋計測学分野

所属（マスター）

• 水産科学研究院　海洋生物資源科学部門　海洋計測学分野

独自項目

syllabus

• 2021, 衛星海洋学, Satellite Oceanography, 学士課程, 水産学部, 地球観測衛星、リモートセンシング、海洋環境、海面水温、海面高度、海上風、海面塩分、海氷、海洋光学、クロロフィルa濃度、基礎生産、植物プランクトン
• 2021, 海洋学入門, Introduction to Oceanography, 学士課程, 水産学部, 海底地形、海洋大循環、熱/物質循環、プランクトン、海底資源、海洋観測、海洋法、海洋生物資源の保全
• 2021, 海洋資源科学実験Ⅲ, Laboratory Work on Marine Resources Ⅲ, 学士課程, 水産学部, 行動生態計測、衛星データ解析－マイクロ波リモートセンシング、海洋観測データ解析、魚類遊泳力学，魚類行動計測、水産海洋工学、数値流体解析
• 2021, 水産科学英語Ⅱ, English for Fisheries Sciences II, 学士課程, 水産学部, 論文講読，プレゼンテーション，海洋資源科学
• 2021, 海洋計測学, Marine Metrology, 学士課程, 水産学部, 電磁波，測位，電波測位，衛星測位，衛星リモートセンシング，CTD，音波，測深，音響測深，魚群探知機，ソナー，ドップラー流向流速計

researchmap

プロフィール情報

所属

• 北海道大学, 大学院水産科学研究院 海洋生物資源科学部門, 准教授

学位

• 博士（理学）（東北大学）

プロフィール情報

• 姓

  阿部

• 名

  泰人

• ID各種

  201301071803528670

対象リソース

http://odyssey.fish.hokudai.ac.jp/

所属

• 北海道大学, 大学院水産科学研究院 海洋生物資源科学部門, 准教授

業績リスト

研究分野

• 自然科学一般 / 大気水圏科学

経歴

• 2023年04月 - 現在 北海道大学 大学院水産科学研究院 准教授
• 2023年04月 - 2024年03月 海洋研究開発機構 むつ研究所 招聘主任研究員
• 2018年04月 - 2023年03月 海洋研究開発機構 むつ研究所 招聘研究員
• 2016年11月 - 2023年03月 北海道大学 大学院水産科学研究院 助教
• 2016年04月 - 2016年10月 東京大学 大気海洋研究所 特任研究員
• 2014年04月 - 2016年03月 北海道大学 低温科学研究所 非常勤研究員
• 2011年07月 - 2014年03月 北海道大学 低温科学研究所 博士研究員

学歴

• 2008年04月 - 2011年03月   東北大学   大学院理学研究科   地球物理学専攻博士課程
• 2006年04月 - 2008年03月   東北大学   大学院理学研究科   地球物理学専攻修士課程
• 2002年04月 - 2006年03月   東北大学   理学部物理系（宇宙地球物理学科）

委員歴

• 2019年 - 現在   PICES   Member of MONITOR Committee

受賞

• 2021年09月 日本海洋学会 日高論文賞
   

  受賞者: 阿部泰人
• 2018年11月 PICES ベストポスター賞
   

  受賞者: 阿部泰人
• 2015年03月 日本海洋学会 奨励論文賞
   

  受賞者: 阿部泰人

論文

• Classification of optical water groups in the subarctic Pacific and adjacent seas using satellite-derived light absorption spectra of chromophoric dissolved organic matter

  Joji Oida, Toru Hirawake, Youhei Yamashita, Hiroto Abe, Jun Nishioka, Hisatomo Waga, Daiki Nomura, Shigeho Kakehi

  Deep Sea Research Part I: Oceanographic Research Papers 104313 - 104313 2024年04月 [招待有り]
  
• Protist dynamics in the eastern Tsugaru Strait, Japan from 2010 to 2018: Implications for the relationship between decadal climatology and aquaculture production

  Koji Sugie, Masahide Wakita, Shoko Tatamisashi, Makoto Takada, Takashi Yusa, Ken-ichi Sasaki, Hiroto Abe, Takahiro Tanaka

  Environmental Research 115691 - 115691 2023年05月 [査読有り]
  
• Significant nutrient consumption in the dark subsurface layer during a diatom bloom: a case study on Funka Bay, Hokkaido, Japan

  Sachi Umezawa, Manami Tozawa, Yuichi Nosaka, Daiki Nomura, Hiroji Onishi, Hiroto Abe, Tetsuya Takatsu, Atsushi Ooki

  Biogeosciences 20 2 421 - 438 2023年01月27日 [査読有り]
   

  Abstract. We conducted repetitive observations in Funka Bay,Hokkaido, Japan, on 15 February, 4 and 15 March, and 14 April 2019. Thediatom spring bloom peaked on 4 March and started declining on 15 March.Funka Bay winter water remained below 30 m depth, which was below thesurface mixed-layer and dark-layer depth (0.1 % of the surface photosynthetically active radiation, PAR, depth) on 4and 15 March. In the subsurface layer at depths of 30–50 m, concentrationsof NO3-, PO43-, and Si(OH)4 decreased by halfbetween these dates, even in the dark. Incubation experiments using thediatom Thalassiosira nordenskioeldii showed that this diatom could consume added nutrients in the dark atsubstantial rates after pre-culturing to deplete nutrients. Incubationexperiments using natural seawater collected in the growing phase of the bloom on 8 March 2022 also showed that nutrient-depleted phytoplankton could consumeadded nutrients in the dark. We excluded three physicalprocess – water mixing, diffusive transport, and subduction – as possible mainreasons for the decrease in nutrients in the subsurface layer. We concludethat the nutrient reduction in the subsurface layer (30–50 m) between 4 and15 March 2019 could be explained by nutrient consumption by diatoms in the dark in thatlayer.
• Intrusion of Coastal Oyashio water to Funka Bay and Tsugaru Strait occasionally disturbed by Kuroshio-originating warm core ring

  H. Abe, Y. Yahiro, T. Hasegawa, T. Hirawake, H. Onishi, A. Ooki, T. Takatsu, K. Sasaki, M. Wakita, H. Kaneko, S. Watanabe, T. Tanaka, T. Okunishi, S. Ohno, S. Hashizume

  Journal of Oceanography 2023年01月09日 [査読有り]
  
• Data assimilation using high-frequency radar for tsunami early warning: A case study of the 2022 Tonga volcanic tsunami

  Yuchen Wang, Kentaro Imai, Iyan E. Mulia, Keisuke Ariyoshi, Narumi Takahashi, Kenichi Sasaki, Hitoshi Kaneko, Hiroto Abe, Yoshiaki Sato

  Journal of Geophysical Research: Solid Earth 2023年01月 [査読有り]
  
• Subinertial frequency variations in the axis of the Tsugaru Warm Current east of the Tsugaru Strait

  Hitoshi Kaneko, Takahiro Tanaka, Hiroto Abe, Masahide Wakita, Ken’ichi Sasaki, Yasumasa Miyazawa, Takeshi Okunishi, Shuichi Watanabe, Shoko Tatamisashi, Yoshiaki Sato

  Progress in Earth and Planetary Science 9 1 2022年10月15日 [査読有り][通常論文]
   

  Abstract The eastern part of the Tsugaru Strait (located at ~ 41.5° N) is a remarkable region of the coastal flow system around Japan due to the Tsugaru Warm Current (TgWC), an intensive eastward current that flows over its complex topography and exhibits marked tidal variation. The TgWC has a jetlike structure and demonstrates drastic seasonal changes in its path and vertical current structure. Using a high-resolution dataset obtained from a high-frequency radar system (HFR) and a coastal data assimilation experiment (JCOPE-T DA), we focused on the frontal variation, which is shorter than the seasonal timescale, along the axis of the TgWC in relation to the meanders of the jet. We found variations in the axis with multiple timescales between 1 and 14 days, especially in summer and autumn. The ~ 14-day variation, a remarkable occurrence on the west side of the eastern Tsugaru Strait, was consistent with the tidal variation in the strait. The zonal scale of the axis meander estimated by the HFR matched a scale several times larger than the internal deformation radius, especially in summer and autumn. JCOPE-T DA outputs showed that the crest of such a meander at greater depths progresses in relation to that at the surface. The outputs also suggested instabilities, indicating potential and kinetic energy conversion from the mean to the eddy field. The propagation speed of the several-day variation in the axis estimated from the HFR data was consistent with that of the two-layer baroclinic instability. The several-day variation also showed relatively high coherence with wind variation from summer to autumn, during which time the seasonal wind over the strait switched from easterly to westerly. These variations with multiple timescales imply an effect on north–south water mass mixing in the eastern part of the strait, including rapid acidification in the strait and intensification of stratification.
• Isoprene production in the water column and sediment in Funka Bay, Hokkaido, Japan

  Atsushi Ooki, Naoya Miyashita, Sachi Umezawa, Manami Tozawa, Yuichi Nosaka, Daiki Nomura, Hiroji Onishi, Hiroto Abe, Tetsuya Takatsu

  GEOCHEMICAL JOURNAL 56 5 142 - 150 2022年08月 [査読有り]
  
• Projected future changes in the contribution of Indo-Pacific sea surface height variability to the Indonesian throughflow

  Vivek Shilimkar, Hiroto Abe, Mathew Koll Roxy, Youichi Tanimoto

  Journal of Oceanography 2022年05月14日 [査読有り]
   

  Abstract The Indonesian throughflow (ITF) transports a significant amount of warm freshwater from the Pacific to the Indian Ocean, making it critical to the global climate system. This study examines decadal ITF variations using ocean reanalysis data as well as climate model simulations from the Coupled Model Inter-comparison Project Phase 5 (CMIP5). While the observed annual cycle of ITF transport is known to be correlated with the annual cycle of sea surface height (SSH) difference between the Pacific and Indian Oceans, ocean reanalysis data (1959–2015) show that the Pacific Ocean SSH variability controls more than 85% of ITF variation on decadal timescales. In contrast, the Indian Ocean SSH variability contributes less than 15%. While those observed contributions are mostly reproduced in the CMIP5 historical simulations, an analysis of future climate projections shows a 25–30% increase in the Indian Ocean SSH variability to decadal ITF variations and a corresponding decrease in the Pacific contribution. These projected changes in the Indian Ocean SSH variability are associated with a 23% increase in the amplitudes of negative zonal wind stress anomalies over the equatorial Indian Ocean, along with a 12º eastward shift in the center of action in these anomalies. This combined effect of the increased amplitude and eastward shift in the zonal wind stress increases the SSHA variance over the Indian Ocean, increasing its contribution to the ITF variation. The decadal ITF changes discussed in this study will be crucial in understanding the future global climate variability, strongly coupled to Indo-Pacific interactions.
• Seasonal pathways of the Tsugaru Warm Current revealed by high-frequency ocean radars

  Tomomi Yasui, Hiroto Abe, Toru Hirawake, Ken’ichi Sasaki, Masahide Wakita

  Journal of Oceanography 78 2 103 - 119 2022年02月08日 [査読有り][通常論文]
   

  Seasonal pathway of the Tsugaru Warm Current (TWC), coastal boundary current flowing eastward from the Sea of Japan to the North Pacific Ocean, is investigated using data of surface currents measured by high-frequency ocean radars for the period 2014–2020. The TWC takes a pathway along the center of Tsugaru strait during summer season (41.64ºN), while during winter season the TWC moves to south to flow along the southern coast (41.55ºN). These pathways are associated with seasonal outflow modes known as “Gyre mode” and “Coastal mode,” respectively. Seasonal changes in current velocity, characterized by intensified flow in summer and autumn seasons and weakened flow in winter season, are well correlated with seasonal changes of sea level difference between Fukaura and Hakodate. However, this clear relationship is not seen at the eastern exit of the strait (141.5ºE). There is a shallow sill that extends northward from the southern coast. HFR further reveals that Coastal mode is locally intensified and widened when passing through this sill. These TWC’s responses are qualitatively explained by mass conservation for barotropic flow that flows in a horizontal two-dimensional channel with sea floor depth change. These responses over the sill are not seen during Gyre mode because the northward shift keeps the pathway away from the sill. During the Coastal mode, there are some cases in which the TWC does not ride on the sill but takes a pathway around the sill. Such patterns are seen when the TWC is weak, thus a weak Coastal mode.
• Primary productivity and phytoplankton community structure in surface waters of the western subarctic Pacific and the Bering Sea during summer with reference to bloom stages

  Hisatomo Waga, Amane Fujiwara, Toru Hirawake, Koji Suzuki, Kazuhiro Yoshida, Hiroto Abe, Daiki Nomura

  Progress in Oceanography 201 102738 - 102738 2022年02月 [査読有り][通常論文]
   

  The western subarctic Pacific and adjacent Bering Sea are recognized as one of the most productive regions supported by spring diatom bloom among the world's oceans. Yet, phytoplankton growth and photosynthesis are often suppressed during summer. Little is known about factors controlling the summer primary productivity and phytoplankton community structure in the western subarctic Pacific and the Bering Sea, especially along the Russian coast extending from the Kuril Islands to the Gulf of Anadyr. A total of 24 stations belonging to two cruises conducted in June 2014 and August 2018 was categorized into three groups using hierarchical cluster analysis for physical properties such as seawater temperature, salinity, and mixed layer depth. Based on the biogeochemical characteristics of each cluster, we defined clusters 1, 2, and 3 as bloom, post-bloom, and pre-bloom conditions, respectively. Cluster 1, observed near the Kuril Islands and the Kamchatka Peninsula, was characterized by nutrient-rich cold water that supported the predominance of diatoms. Nutrient-depleted warm waters associated with shallow mixed-layer and small diatom populations were grouped into cluster 2, distributed in the Gulf of Anadyr and near the Kamchatka Peninsula. The deepest mixed layer depth was found in cluster 3, accompanied by the low proportions of diatoms. The spatial distribution of cluster 3 showed broad geographical coverages extending from the Kuril Islands to the Aleutian Basin. Thus, this study identified the relationships between summer primary productivity, phytoplankton community composition, and environmental variables in surface waters of the subarctic Pacific along the Russian coast. Overall, the present study addressed the shortcoming of in situ data in phytoplankton communities and environmental variables in the western subarctic Pacific and the Bering Sea.
• Nutrient consumption by diatoms in the dark subsurface layer of Funka Bay, Hokkaido, Japan

  Sachi Umezawa, Manami Tozawa, Yuichi Nosaka, Daiki Nomura, Hiroji Onishi, Hiroto Abe, Tetsuya Takatsu, Atsushi Ooki

  2022年01月06日 [査読有り]
   

  Abstract. We conducted time-series observations in Funka Bay, Hokkaido, Japan, from 15 February to 14 April 2019. The diatom spring bloom peaked on 4 March and started declining on 15 March. Funka Bay winter water remained below 30-m depth, which was below the surface mixed-layer and dark-zone depths on both dates. At depths of 30–50 m, concentrations of NO3–, PO43–, and Si(OH)4 decreased by half between these dates even in darkness. Incubation experiments using the diatom Thalassiosira nordenskioeldii showed that this diatom could consume nutrients in darkness at substantial rates. We conclude that the nutrient reduction in the subsurface layer (30–50 m) could be explained by dark consumption by diatoms that had been growing in the surface waters and then sank to the subsurface layer. We believe that this is the first study to present observational evidence for the consumption of the main nutrients by diatoms in the dark subsurface layer during the spring bloom. Nutrient consumption in this layer might have a substantial influence on the primary production during and after the spring bloom.
• The Role of an Intense Jet in the Tsugaru Strait in the Formation of the Outflow Gyre Revealed Using High‐Frequency Radar Data

  H. Kaneko, K. Sasaki, H. Abe, T. Tanaka, M. Wakita, S. Watanabe, T. Okunishi, Y. Sato, S. Tatamisashi

  Geophysical Research Letters 48 21 2021年11月16日 [査読有り]
  
• Salinity regime of the northwestern Bering Sea shelf

  Hiroto Abe, Daiki Nomura, Toru Hirawake

  Progress in Oceanography 2021年09月 [査読有り]
  
• Water mass distribution in the northern Bering and southern Chukchi seas using light absorption of chromophoric dissolved organic matter

  Toru Hirawake, Joji Oida, Youhei Yamashita, Hisatomo Waga, Hiroto Abe, Jun Nishioka, Daiki Nomura, Hiromichi Ueno, Atsushi Ooki

  Progress in Oceanography 197 102641 - 102641 2021年09月 [査読有り]
  
• Rapid Reduction of pH and CaCO 3 Saturation State in the Tsugaru Strait by the Intensified Tsugaru Warm Current During 2012–2019

  M. Wakita, K. Sasaki, A. Nagano, H. Abe, T. Tanaka, K. Nagano, K. Sugie, H. Kaneko, K. Kimoto, T. Okunishi, M. Takada, J. Yoshino, S. Watanabe

  Geophysical Research Letters 48 10 2021年05月28日 [査読有り]
  
• Formation of dense shelf water associated with sea ice freezing in the Gulf of Anadyr estimated with oxygen isotopic ratios

  Daiki Nomura, Hiroto Abe, Toru Hirawake, Atsushi Ooki, Youhei Yamashita, Aiko Murayama, Kazuya Ono, Jun Nishioka

  Progress in Oceanography 196 102595 - 102595 2021年05月 [査読有り]
  
• Distinctive spring phytoplankton bloom in the Bering Strait in 2018: A year of historically minimum sea ice extent

  Gennosuke Kikuchi, Hiroto Abe, Toru Hirawake, Makoto Sampei

  Deep-Sea Research Part II: Topical Studies in Oceanography 181-182 2020年11月 [査読有り]
   

  © 2020 Under climate change, the Bering–Chukchi continental shelves have experienced drastic sea ice loss, breaking the minimum sea ice extent record in 2018. In this paper, we report a distinctive spring phytoplankton bloom in the Bering Strait based on year-round mooring observations during 2016–2018. A near-bottom fluorescence sensor mounted on a mooring and satellite observations indicate that, despite the early sea ice retreat in spring of 2018 (mid-April), the spring phytoplankton bloom was not observed for more than 20 days after sea ice retreat. In contrast, in 2017 when sea ice retreat did not occur as early as it did in 2018 (early May), the bloom and sea ice retreat occurred in tighter synchrony. Mooring (2016–2018) and satellite observations (2003–2011, 2013–2018) suggest that an open-water bloom rather than an ice-edge bloom occurred in the Bering Strait in the spring of 2018. Early sea ice retreat apparently provided unfavorable conditions for an ice-edge bloom due to weak sunlight and winter-like weather. Mid-winter sea ice loss was promoted by unusual southerly winds, bringing in warm water from the south. For the Bering Strait, the end of April is a reference date for sea ice retreat that distinguishes between an open-water bloom and an ice-edge bloom, which is approximately one month later than that in the southeastern Bering Sea.
• Observation of Tsugaru warm current by High Frequency Radar and preliminary result for its prediction

  Abe, H, K. Sasaki, T. Yasui, M. Wakita

  Kaiyo Monthly 52 7 312 - 316 2020年07月 [査読無し][通常論文]
  
• Response of Arctic biodiversity and ecosystem to environmental changes: Findings from the ArCS project

  Toru Hirawake, Masaki Uchida, Hiroto Abe, Irene D. Alabia, Tamotsu Hoshino, Shota Masumoto, Akira S. Mori, Jun Nishioka, Bungo Nishizawa, Atsushi Ooki, Akinori Takahashi, Yukiko Tanabe, Motoaki Tojo, Masaharu Tsuji, Hiromichi Ueno, Hisatomo Waga, Yuuki Y. Watanabe, Atsushi Yamaguchi, Youhei Yamashita

  Polar Science 2020年 [査読有り]
   

  © 2020 Elsevier B.V. and NIPR Arctic ecosystems are altered profoundly by climate changes. However, the responses of Arctic marine and terrestrial ecosystems as well as their biodiversity to global warming remain largely unknown. This article provides comprehensive insights into the results and major findings from the Arctic Challenge for Sustainability (ArCS) Project – an Arctic region research program initiated in Japan, which aims to address and advance our understanding of these uncertainties. Marine ecosystem studies have identified several biogeochemical processes that are associated with sea ice decline and northward transport and shift of marine species across multiple trophic levels over the Bering and Chukchi Sea shelves. Studies of the terrestrial ecosystem have identified factors that are important for the understanding of terrestrial biodiversity and ecosystems, including Arctic lakes, under the presence of global warming. Novel fungal species from the Arctic terrestrial ecosystem have also been isolated and described. Overall, these results could contribute to the conservation and sustainable management of the Arctic ecosystem services.
• Sea Ice Observation with Oceanographic HF Radar

  Wei Zhang, Naoto Ebuchi, Yasushi Fukamachi, Feng Cheng, Kay I. Ohshima, Brian M. Emery, Takenobu Toyota, Hiroto Abe, Kunio Shirasawa

  IEEE Transactions on Geoscience and Remote Sensing 58 1 378 - 390 2020年01月 [査読有り]
   

  © 1980-2012 IEEE. High-frequency (HF) ocean radar has the potential to observe sea ice, but this application has not been thoroughly investigated. In this article, we explore sea ice observation with HF radar (HFR) and develop a corresponding signal processing procedure. We derived sea ice radial velocities from raw HFR data and determined angular positions using the MUltiple SIgnal Classification (MUSIC) algorithm. Sea ice velocities were evaluated by comparison with measurements from moored acoustic Doppler current profilers (ADCPs) and a drifting buoy. The root-mean-square (rms) differences between the sea ice velocities obtained by HFR and the ADCPs decreased with increasing radar signal-to-noise ratio (SNR), implying that a high SNR was associated with accurate measurement of sea ice velocity. These results agree with previous validations of HFR ocean current observations. The sea ice pattern mapped by HFR is consistent with the simultaneous C-band microwave radar observations. In particular, the HFR captured the approach of the sea ice edge toward the coast. Sharp attenuation of the HF signal over high concentration sea ice resulted in missing and/or low-SNR data at ranges beyond the front edge of pack ice, in qualitative agreement with model estimates of attenuation.
• Stratification in the northern Bering Sea in early summer of 2017 and 2018

  Hiromichi Ueno, Mizuki Komatsu, Zhaoqianyi Ji, Ryo Dobashi, Miaki Muramatsu, Hiroto Abe, Keiri Imai, Atushi Ooki, Toru Hirawake

  Deep-Sea Research Part II: Topical Studies in Oceanography 181-182 2020年 [査読有り]
   

  © 2020 Elsevier Ltd We investigated spatial and interannual variation in the physical environment in the northern Bering Sea focusing on stratification, which is one factor affecting biological production in Arctic/subarctic regions. In particular, we analyzed in situ data obtained onboard the training ship Oshoro Maru in early summer in 2017 and 2018. We found that stratification in the areas just north of St. Lawrence Island (around 64.5°N and west of 168.5°W) and south/southwest of St. Lawrence Island was significantly weaker in 2018 than in 2017. These results are consistent with the extremely low sea-ice extent present in the winter of 2017/2018, which would have resulted in less freshwater being supplied to the surface layers and a warmer and less saline bottom water. Conversely, stratification was as strong in 2018 as in 2017 in the area close to the Alaska mainland, including the Bering Strait area, suggesting that the Alaskan Coastal Water dominates stratification in this area in early summer. Moreover, we found that the weakly stratified water column in the Bering Strait area stratified quickly shortly after the occurrence of strong northerly winds, likely because of the Ekman transport of warm and low-salinity Alaskan Coastal Water from the east.
• Sediment-Associated Phytoplankton Release From the Seafloor in Response to Wind-Induced Barotropic Currents in the Bering Strait

  Abe, Hiroto, Sampei, Makoto, Hirawake, Toru, Waga, Hisatomo, Nishino, Shigeto, Ooki, Atsushi

  FRONTIERS IN MARINE SCIENCE 6 97 2019年03月 [査読有り][通常論文]
   

  Bering Strait is the single gateway between the Arctic and Pacific Oceans, and has localized strong currents, which can exceed 100 cm s(-1). Although massive spring phytoplankton blooms and the subsequent production of particulate organic matter that sinks to the seafloor are observed in the surrounding regions of the Bering Strait, the impact of the locally strong current on the horizontal and vertical transport of the particles remains unclear. Therefore, we conducted year-round mooring measurements from 2016 to 2017 by focusing on near-bottom processes associated with ocean currents. Our time-series analysis showed that high-turbidity events, triggered by strong barotropic currents, occurred near the seafloor in all seasons. Consequently, the fluorescence sensor detected highly concentrated chlorophyll a in the resuspended sediment; however, the amount of chlorophyll a release was seasonal, with large and small amounts being released during the warm and cold seasons, respectively. The small amounts of chlorophyll a may be attributed to small amounts of phytoplankton in the sediment owing to less input of fresh phytoplankton from the overlaying water column and organic matter decomposition in the sediments under no-light conditions. The barotropic currents were modulated by surface winds associated with an intercontinental atmospheric pattern having a 5000-km spatial scale on a timescale of 6 days. The locally strong ocean current in the Bering Strait, driving the upward transport of sediment and the subsequent horizontal transport, may play a vital role in supplying particulate organic matter/phytoplankton/nutrients to the downstream region of the southern Chukchi Sea where the formation of biological hotspots is reported.
• Aquarius reveals eddy stirring after a heavy precipitation event in the subtropical North Pacific

  Hiroto Abe, Naoto Ebuchi, Hiromichi Ueno, Hiromu Ishiyama, Yoshimasa Matsumura

  JOURNAL OF OCEANOGRAPHY 75 1 37 - 50 2019年02月 [査読有り][通常論文]
   

  This research presents a case study that examines an upper-ocean salinity response to intense rainfall using 4years of observed salinity data from the Aquarius and Argo floats. The Aquarius sea surface salinity (SSS) in the subtropical region of the North Pacific reveals a notable event in which SSS is locally freshened by intense rainfall. Although the SSS pattern shortly after the rainfall reflects the atmospheric pattern, its final form reflects the ocean's dynamic structure; low-salinity water distributes in the shape of an anticyclonic eddy. Observations using Argo profiling floats confirm that low-salinity water dominates the entire water column of the eddy above 70m. We found that an eddy stirring effect would play an important role in forming the eddy-shaped low-salinity water. As a precondition, intense rainfall on the tropical side enhances the meridional gradient of background SSS with freshened low-salinity water to the south and saline water to the north. The anticyclonic eddy located at the enhanced SSS front stirs the water in a clockwise direction. Specifically, northward flow in the western side of the eddy transports fresh water, whereas southward flow in the eastern side transports saline water. As this northward-southward flow moves the eddy to the west where the transported fresh water is dominant as a baroclinic Rossby wave, this dynamic process would form the eddy-shaped low-salinity water. This clear view of such eddy stirring is due to the inherent nature of the subtropical region that is characterized by less frequent precipitation.
• Oceanic Rossby Waves over Eastern Tropical Pacific of Both Hemispheres Forced by Anomalous Surface Winds after Mature Phase of ENSO

  Hiroto Abe, Youichi Tanimoto, Takuya Hasegawa, Naoto Ebuchi

  JOURNAL OF PHYSICAL OCEANOGRAPHY 46 11 3397 - 3414 2016年11月 [査読有り][通常論文]
   

  The present study examined ENSO-related wind forcing contribution to off-equatorial Rossby wave formations in the eastern tropical regions of the North and South Pacific using satellite altimeter data and atmospheric reanalysis data during the period of 1993-2013. After mature phases of ENSO events, the sea surface height anomaly fields showed that off-equatorial Rossby waves propagated westward along 118N and 88S from the eastern Pacific. Starting longitudes of the westward propagation were distant from the eastern coast, especially for weak El Nino events in the 2000s, in contrast to the strong 1997/98 El Nino event in which the propagations started from the coast. Based on observational data, it was hypothesized that the Rossby waves could be formed by off-equatorial zonal belts of wind stress curl anomalies (WSCAs) in 1358-908W rather than by wave emissions from the eastern coast. A numerical model forced only by WSCAs, that is, without wave emissions from the coast, successfully reproduced observed features of the Rossby waves in 1808-1208W, supporting the study's hypothesis. During mature phases of El Nino events, equatorially symmetric negative sea level pressure anomalies (SLPAs) resulting from hydrostatic adjustment to the underlying warm sea surface temperature anomalies dominated over the eastern tropical Pacific. Anomalous surface easterlies blowing around the negative SLPA area as geostrophic winds were a major contributor in forming the anticyclonic WSCAs. The polarity of the anomalies is reversed during La Nina events. Therefore, spatial patterns of the SLPAs associated with the ENSO events are necessary to understand the Rossby wave formations.
• Sea ice observation by high frequency ocean radar in the southern Sea of Okhotsk.

  Zhang, W, H. Abe, N. Ebuchi, Y. Fukamachi, B. Emery, F. Cheng, Y. Xiao, K. Shirasawa

  Proceedings of Third Ocean Radar Conference for Asia 37 - 44 2016年04月 [査読無し][通常論文]
  
• Improvements to a global ocean data assimilation system through the incorporation of Aquarius surface salinity data

  Takahiro Toyoda, Yosuke Fujii, Tsurane Kuragano, John P. Matthews, Hiroto Abe, Naoto Ebuchi, Norihisa Usui, Koji Ogawa, Masafumi Kamachi

  QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 141 692 2750 - 2759 2015年10月 [査読有り][通常論文]
   

  The impact of using sea surface salinity (SSS) data derived from the Aquarius satellite within a global ocean data assimilation system is investigated. In the central-eastern North Pacific, the more realistic SSS structures introduced by the Aquarius data also influence the salinity, temperature and potential vorticity fields obtained in the subsurface layer via enhanced mode-water formation. Around the Indonesian maritime continent, the Aquarius data assimilation leads to salinity distributions which are closer to buoy observations, while in the region of the Amazon River plume, subsurface temperatures are improved following a better reproduction of the low-salinity plume in the surface layer. The SSS model biases are also reduced in the eastern equatorial Pacific and in the Arctic Ocean, although our data are limited in number and accuracy at high latitudes. These results indicate the importance of Aquarius data in deriving improved representations of the global ocean from dynamical models.
• Drift ice detection by HF ocean radar off Mombetsu

  Zhang Wei, Naoto Ebuchi, Brian Emery, Hiroto Abe

  Proceedings of 30th International Symposium on Okhotsk Sea and Sea Ice 95 - 98 2015年 [査読無し][通常論文]
  
• Improvements of the surface layer in the North Pacific reproduced by an ocean data assimilation system through the incorporation of Aquarius surface salinity data

  Takahiro Toyoda, Yosuke Fujii, Tsurane Kuragano, John, P. Matthews, Hiroto Abe, Naoto Ebuchi, Norihisa Usui, Koji Ogawa, Masafumi Kamachi

  Kaiyo Monthly 47 4 172 - 180 2015年 [査読無し][通常論文]
  
• Evaluation of sea-surface salinity observed by Aquarius

  Hiroto Abe, Naoto Ebuchi

  JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 119 11 8109 - 8121 2014年11月 [査読有り][通常論文]
   

  Sea-surface salinity (SSS) observed by Aquarius was compared with global observations from Argo floats and offshore moored buoys to evaluate the quality of satellite SSS data and to assess error structures. Aquarius products retrieved by different algorithms (Aquarius Official Release version 3.0 [V3.0], Combined Active-Passive [CAP] algorithm version 3.0, and Remote Sensing Systems test bed algorithm version 3) were compared. The Aquarius SSS was in good agreement with in situ salinity measurements for all three products. Root-mean-square (rms) differences of the salinity residual, with respect to Argo salinity, ranged from 0.41 to 0.52 psu. These three Aquarius products exhibit high SSS deviation from Argo salinity under lower sea-surface temperature conditions (<10 degrees C) due to lower sensitivity of microwave emissivity to SSS. The CAP product deviates under strong wind conditions (>10 m s(-1)), probably due to model bias and uncertainty associated with sea-surface roughness. Furthermore, significant SSS differences between ascending (south-to-north) and descending (north-to-south) paths were detected. The monthly averaged Aquarius SSS (1 degrees x 1 degrees grid) was also compared with outputs from the ocean data optimal interpolation (OI) system operated by the Japan Agency for Marine-Earth Science Technology (JAMSTEC) and the ocean data assimilation system used by the Meteorological Research Institute, Japan Meteorological Agency (MRI/JMA). Negative bias, attributed to near-surface salinity stratification by precipitation, was detected in tropical regions. For 40 degrees S-40 degrees N, rms difference, with respect to JAMSTEC OI, is 0.27 psu for the V3.0, while the CAP product rms difference is only 0.22 psu, which is close to the Aquarius mission goal. Key Points <list id="jgrc20976-list-0001" list-type="bulleted"> <list-item id="jgrc20976-li-0001">Sea-surface salinity (SSS) observed by Aquarius was evaluated using in situ data <list-item id="jgrc20976-li-0002">SSS retrieved by three different algorithms were compared with each other <list-item id="jgrc20976-li-0003">Error structure of the retrieved SSS was characterized by residual analyses
• Oceanic Rossby waves induced by the meridional shift of the ITCZ in association with ENSO events

  Hiroto Abe, Youichi Tanimoto, Takuya Hasegawa, Naoto Ebuchi, Kimio Hanawa

  JOURNAL OF OCEANOGRAPHY 70 2 165 - 174 2014年04月 [査読有り][通常論文]
   

  This study investigated the eastern Pacific Intertropical Convergence Zone (ITCZ) as an atmospheric forcing to the ocean by using various observed and reanalysis data sets over 29 years. Climatologically, a zonal band of positive wind stress curl (WSC) with a 10 degrees meridional width was exhibited along the ITCZ. A southward shift of the positive WSC band during the El Nino phase induced a negative (positive) WSC anomaly along the northern (southern) portion of the ITCZ, and vice versa during the La Nina phase. This meridional dipole accounted for more than 25 % of interannual variances of the WSC anomalies (WSCAs), based on analysis of the period 1993-2008. The negative (positive) WSCA in the northern portion of the ITCZ during the El Nino (La Nina) phase was collocated with a positive (negative) sea surface height anomaly (SSHA) that propagated westward as a Rossby wave all the way to the western North Pacific. This finding indicates that this off-equatorial Rossby wave is induced by the WSCA around the ITCZ. Our analysis of a 1.5-layer reduced gravity model revealed that the Rossby waves are mostly explained by wind stress forcing, rather than by reflection of an equatorial Kelvin wave on the eastern coastal boundary. The off-equatorial Rossby wave had the same SSHA polarity as the equatorial Kelvin wave, and generation of a phase-preserving Rossby wave without the Kelvin wave reflection was explained by meridional movement of the ITCZ. Thus, the ITCZ acts as an atmospheric bridge that connects the equatorial and off-equatorial oceanic waves.
• EVALUATION OF SEA SURFACE SALINITY OBSERVED BY AQUARIUS

  Naoto Ebuchi, Hiroto Abe

  2014 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS) 5767 - 5769 2014年 [査読無し][通常論文]
   

  Sea surface salinity (SSS) data derived from the Aquarius mission were compared with global observation by Argo floats to evaluate the quality of the SSS and assess the error structure. The Aquarius SSSs agreed well with the Argo near-surface salinity with a root-mean-square (rms) difference of 0.42 psu (version 2.10.1 standard product). The residual of the salinity observation showed a significant correlation with the sea surface temperature (SST) and wind speed. SSS bias caused by inaccurate corrections for the galactic radiation was also discernible. Similar results were obtained for the Aquarius SSSs retrieved by the different algorithms. Aquarius monthly SSS averaged over 1 degrees x 1 degrees was also compared with outputs from a global ocean optimal interpolation system. The rms difference, calculated over 40 degrees S - 40 degrees N, was 0.27 psu (version 2.10.1 standard product). The rms difference was reduced to 0.21 psu, which is very close to the goal of the Aquarius mission, for the product retrieved by an alternative algorithm (CAP version 25.1)
• Interannual variations in the Hawaiian Lee Countercurrent

  Hiroto Abe, Kimio Hanawa, Naoto Ebuchi

  JOURNAL OF OCEANOGRAPHY 69 2 191 - 202 2013年04月 [査読有り][通常論文]
   

  The Hawaiian Lee Countercurrent (HLCC) is an eastward surface current flowing against the broad westward flow of the North Pacific subtropical circulation. Analyses of satellite altimeter data over 16 years revealed that the HLCC is characterized by strong interannual variations. The strength and meridional location of the HLCC axis varied significantly year by year. The eastward velocity of the HLCC was higher when the location of the axis was stable. Mechanisms for the interannual variations were explored by analyses of the altimeter data and results from a simple baroclinic model. The interannual variations in the strength of the HLCC did not correlate with those of the wind stress curl (WSC) dipole formed on the leeward side of the Hawaii Islands, although the WSC dipole has been recognized as the generation mechanism of the HLCC. Meridional gradients of the sea surface height anomaly (SSHA) across the HLCC generated by baroclinic Rossby waves propagating westward from the east of the Hawaii Islands were suggested as a possible mechanism for the interannual variations in the HLCC. The spatial patterns in the observed SSHAs were reproduced by a linear baroclinic Rossby wave model forced by wind fields from a numerical weather prediction model. Further analysis of the wind data suggested that positive and negative anomalies of WSC associated with changes in the trade winds in the area east of the Hawaii Islands are a major forcing for generating SSHAs that lead to the HLCC variations with a time lag of about 1 year.
• EVALUATION OF SEA SURFACE SALINITY OBSERVED BY AQUARIUS AND SMOS

  Naoto Ebuchi, Hiroto Abe

  2013 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS) 656 - 659 2013年 [査読無し][通常論文]
   

  Sea surface salinity data derived from Aquarius and Soil Moisture and Ocean Salinity (SMOS) missions were compared with observations by Argo floats in the global oceans and outputs from a global ocean data assimilation system to evaluate the quality of the salinity measurements and assess the error structure in the data. Under the condition of sea surface temperature (SST) higher than 5 degrees C and wind speed lower than 15 ms(-1), salinity observed by Aquarius agreed well with the Argo data with an rms difference of 0.6 psu. If we applied spatial and temporal averages over 1 degrees x 1 degrees and one month, the rms difference was reduced to 0.3 psu. The residual of the salinity observation depended significantly on the SST and wind speed, as expected from the principle of salinity measurement. Also bias caused by inaccurate corrections for the galactic radiation and radio frequency interference were considered to contribute largely to differences with in-situ observations.
• EVALUATION OF SEA SURFACE SALINITY OBSERVED BY AQUARIUS

  Naoto Ebuchi, Hiroto Abe

  2012 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS) 5767 - 5769 2012年 [査読無し][通常論文]
   

  Sea surface salinity data derived from Aquarius on the SAC-D satellite were compared with observations by Argo floats in the global oceans to evaluate the quality of the Aquarius salinity measurement and assess the error structure in the data. In tropical and mid latitudes, salinity observed by Aquarius agreed well the Argo data with an rms difference of 0.6 psu. In high latitudes where the sea surface temperature is low, a large scatter of data with a deviation up to 2 psu was discernible. The residual of the salinity observation depended significantly on the sea surface temperature, wind speed and relative wind direction, as expected from the principle of salinity measurement.
• Evaluation of sea surface salinity observed by Aquarius on SAC-D

  Naoto Ebuchi, Hiroto Abe

  REMOTE SENSING OF THE MARINE ENVIRONMENT II 8525 2012年 [査読無し][通常論文]
   

  A passive and active L-band microwave sensor, Aquarius, developed by NASA to observe the global sea surface salinity (SSS) distribution, was launched on 10 June 2011. The SSS observed by Aquarius (v. 1.3) was evaluated by comparison with in-situ salinity data from various sources. The Aquarius SSS generally agreed well with salinity measurements by Argo floats in moderate to high sea surface temperature (SST) regions. However, the Aquarius SSS highly deviated in low SST and high wind regions. Typical root-mean-squared difference between the Aquarius and in situ SSS observations under a condition of sea surface temperature higher than 5 degrees C were 0.7 psu for snapshot observations and 0.35 similar to 0.4 psu for monthly 1 degrees x 1 degrees averages.
• Mean sea surface height in the world ocean using Argo float and altimetry

  Hiroto Abe, Kimio Hanawa

  Proceedings of OceanObs'09 2010年 [査読無し][通常論文]
  

MISC

• 近年の津軽暖流の強化による津軽海峡東部のpHと炭酸カルシウム飽和度の急速な低下

  脇田昌英, 佐々木建一, 永野憲, 阿部泰人, 阿部泰人, 田中雄大, 長野晃輔, 杉江恒二, 金子仁, 木元克典, 奥西武, 高田信, 吉野順, 渡邉修一 日本海洋学会大会講演要旨集 2021 2021年
• 有色溶存有機物(CDOM)から見る西部北太平洋及び北部ベーリング海の水塊構造と栄養塩分布

  大井田穣示, 平譯享, 山下洋平, 阿部泰人, 西岡純, 和賀久朋, 野村大樹 日本地球惑星科学連合大会予稿集(Web) 2020 2020年
• 2017・2018年北部ベーリング海における成層強度の時空間変動とその要因

  上野洋路, 小松瑞紀, 吉兆千一, 土橋稜, 村松美幌, 村松美幌, 阿部泰人, 今井圭理, 大木淳之, 平譯享 日本海洋学会大会講演要旨集 2020 2020年
• 有色溶存有機物(CDOM)の光学的特性から見る西部北太平洋及び北部ベーリング海の水塊構造と栄養塩分布

  大井田穣示, 平譯享, 平譯享, 山下洋平, 阿部泰人, 西岡純, 西岡純, 和賀久朋, 和賀久朋, 野村大樹, 野村大樹 日本海洋学会大会講演要旨集 2020 2020年
• アナディール湾における水塊の経年変動:Dense Shelf Waterと太平洋起源水の影響

  阿部泰人, 野村大樹, 野村大樹, 野村大樹, 平譯享, 平譯享 日本海洋学会大会講演要旨集 2020 2020年
• 有色溶存有機物(CDOM)の光吸収係数により分類したベーリング海北部およびチュクチ海南部の水塊の分布

  平譯享, 平譯享, 大井田穣示, 和賀久朋, 和賀久朋, 山下洋平, 阿部泰人, 西岡純, 西岡純 日本海洋学会大会講演要旨集 2020 2020年
• 酸素安定同位体比を用いたベーリング海北部アナディール湾における高密度陸棚水形成の評価

  野村大樹, 野村大樹, 野村大樹, 阿部泰人, 平譯享, 平譯享, 大木淳之, 大木淳之, 山下洋平, 村山愛子, 小野数也, 西岡純, 西岡純 日本海洋学会大会講演要旨集 2020 2020年
• ロシア船を用いた西部ベーリング海の観測研究-航海の概要-

  西岡純, 西岡純, 安田一郎, 平譯享, 平譯享, 小野数也, 村山愛子, 山下洋平, 李勃豊, 森雄太郎, 野村大樹, 野村大樹, 阿部泰人, 和賀久朋, 和賀久朋, 和賀久朋, 田副博文, 藤尾伸三, 柳本大吾, 川口悠介, 李根淙, 木村詩乃, 宋智暎, 島崎智広, 野口真希, 林央之, 宗林留美, 近藤拓斗, 三好友子, 三好友子, 岡崎裕典, CHEUNG Shun Yan, LIU Kailin, SCHERBININ A., LIU Hongbin, 近藤能子, 角皆潤, 長尾誠也, 井上睦夫, 原田尚美, 小川浩史, 小畑元, 乙坂重嘉, 乙坂重嘉, 鈴木崇史, 鈴木光次, 渡辺豊, 亀山宗彦, 関宰, 深町康, 江淵直人, 大島慶一郎, 大島慶一郎, 三寺史夫, 若土正暁, VOLKOV Y. N. 日本海洋学会大会講演要旨集 2020 2020年
• 観測史上最小の海氷面積を記録した2018年のベーリング海峡で見られた特異な春季ブルームについて

  菊池玄之介, 阿部泰人, 三瓶真, 平譯享 日本海洋学会大会講演要旨集 2019 2019年
• Aquariusが捉えた降水後のeddy stirring

  阿部泰人, 阿部泰人, 阿部泰人, 江淵直人, 上野洋路, 石山宙夢, 松村義正, 松村義正 日本海洋学会大会講演要旨集 2017 146 2017年09月 [査読無し][通常論文]
  
• 南北両半球で同時発生する熱帯太平洋東部域の海洋ロスビー波

  阿部泰人, 谷本陽一, 谷本陽一, 長谷川拓也, 江淵直人 日本海洋学会大会講演要旨集 2016 63 2016年03月 [査読無し][通常論文]
  
• Aquarius 衛星海面塩分データの海洋再解析における太平洋表層へのインパクト

  豊田隆寛, 藤井陽介, 倉賀野連, J, P. Matthews, 阿部泰人, 江淵直人, 碓氷典久, 小川浩司, 蒲地政文 月刊海洋 47 172 -180 2015年02月 [査読無し][通常論文]
  
• 熱帯収束帯の南北変位により励起された海洋ロスビー波

  阿部泰人, 谷本陽一, 長谷川拓也, 江淵直人, 花輪公雄 日本海洋学会大会講演要旨集 2014 99 2014年03月10日 [査読無し][通常論文]
  

担当経験のある科目（授業）

海洋学入門北海道大学
海洋計測学特論北海道大学
水産科学英語北海道大学
衛星海洋学北海道大学
海洋計測学北海道大学
海洋資源科学実験北海道大学

共同研究・競争的資金等の研究課題

• 黒潮大蛇行がカツオ漁場形成に及ぼす影響の評価と漁場推定精度の向上

  日本学術振興会：科学研究費助成事業

  研究期間 : 2024年04月 -2027年03月 

  代表者 : 五十嵐 弘道, 阿部 泰人, 齊藤 誠一
• 噴火湾における新たな海洋像の発掘

  日本学術振興会：科学研究費助成事業

  研究期間 : 2023年04月 -2026年03月 

  代表者 : 阿部 泰人
• 海洋の暖水渦が沿岸域の海面水温上昇を介して陸域気象に与える影響の解明

  日本学術振興会：科学研究費助成事業

  研究期間 : 2022年04月 -2026年03月 

  代表者 : 長谷川 拓也, 阿部 泰人
• リアルタイム漁船位置データを活用したカツオ漁場推定精度の向上

  日本学術振興会：科学研究費助成事業

  研究期間 : 2021年04月 -2024年03月 

  代表者 : 五十嵐 弘道, 阿部 泰人, 齊藤 誠一

   

  本研究では、日本のカツオ漁船を対象として、AIS(Automatic Identification System:船舶自動識別装置)から得られる漁船の位置データを活用して操業状態を推定し漁場位置を推定する仕組みを構築し、そのデータを即時的に導入するハビタットモデルを構築して漁場推定精度を向上させることを目的としているが、実施初年度となるR3年度は、AISからリアルタイムで得られる日本のカツオ漁船の位置データから漁船の「状態」を推定する手法を開発して漁場位置データを試作し、その推定精度についての評価を行った。 まず、カツオ漁船について、漁業法第36条に基づく大臣許可を受けた日本のカツオ・マグロ漁船（釣り・全海域）のうちの20隻について、2015-2017年の3年間においてAISで受信された漁船の位置データを入手し、漁船行動解析のための整備を行った。さらにこのデータに対して隠れマルコフモデル(Hidden Markov Model: HMM)を適用して、各時刻の漁船の状態（航行・探索・操業）を推定し、過去の知見として得られている漁船行動解析の結果と比較することで状態推定の精度検証を行った。得らえた結果として、AISに記録されている各漁船の位置情報の密度には大きな偏りがあり、漁船行動を10分程度の間隔で捕捉できる漁船についてはHMMにより推定した「操業状態」が過去の知見とよく一致することが確認できる一方で、AISによる記録が少ない漁船についてはHMMによる推定が困難であることがわかった。漁船によりデータ密度に差が生じる原因は不明であるが、20隻のうち14隻が高密度でデータが得られることを確認できたため、本研究でR4年度に実施する漁場推定モデル構築に必要な漁場位置データをAISデータから入手するための仕組みが整備できた。
• L-バンドマイクロ波センサを使った高風速・強降雨域の海上風速推定

  日本学術振興会：科学研究費助成事業

  研究期間 : 2018年04月 -2023年03月 

  代表者 : 江淵 直人, 阿部 泰人

   

  本研究は，近年入手が可能になった衛星搭載 L-バンドマイクロ波センサ（放射計，散乱計，合成開口レーダ）のデータを利用し，熱帯低気圧中心部などの高風速・強降雨域の海上風速を高精度で推定する手法を開発することを目的とする．これまで，衛星観測による高風速域の海上風速は，基準となる正確な現場観測データを得る手法がないため，主に，中風速域で求めた係数等を高風速域に外挿することで推定されており，精度の評価も難しい状況であった．これに対し，本研究では，降雨の影響が少ない L-バンドマイクロ波センサの観測データを利用し，最近の国際ワークショップで推奨された校正済みの航空機搭載マイクロ波放射計のデータを基準風速とする手法を適用して，高風速（20 m/s 以上）・強降雨域の海上風速を高精度（± 7 m/s 以内）で推定するアルゴリズムを開発し，台風・ハリケーン・サイクロンなどの熱帯低気圧周辺の高風速域のデータセットを作成する． 今年度は，昨年度までに引き続き，米国海洋大気庁の研究協力者から入手したドロップゾンデデータで校正済みの航空機搭載 Stepped-Frequency Microwave Radiometer (SFMR) の最新版データに空間平滑化を施すことによって作成した衛星センサの空間分解能（30～60 km） に対応する基準データを使用して，Aquarius 衛星および SMAP 衛星に搭載されたL-バンドマイクロ波放射計用の風速算出アルゴリズムを作成した．このアルゴリズムで算出したハリケーン周辺の高風速・強降雨域の海上風速データは，残差の標準偏差 3.8 m/s 程度で基準データとよく一致することが示された．このアルゴリズムを使用して，2011年~2020年の北太平洋・北大西洋の台風・ハリケーン周辺の海上風のデータセットを作成した．
• 海面塩分場に見られる中規模渦活動とそのグローバルマップの作成

  日本学術振興会：科学研究費助成事業

  研究期間 : 2019年04月 -2022年03月 

  代表者 : 阿部 泰人

   

  本研究では，近年入手が可能となった人工衛星による海面塩分データを用いて，海面塩分場にみられる中規模渦の活動度を全球海洋において評価した。太平洋，大西洋，インド洋のいずれの海域でも，中規模渦の回転流に伴う塩分輸送を捉えることができた。この中規模渦による塩分輸送は，従来から知られている降水や蒸発，エントレインメント（下層からの水塊取り込み）等と比べても，無視できないほどのインパクトを持つことが明らかになった。
• 機械学習を用いたハビタットモデルによる魚種間関係の解明と漁場予測精度の向上

  日本学術振興会：科学研究費助成事業

  研究期間 : 2018年04月 -2021年03月 

  代表者 : 五十嵐 弘道, 阿部 泰人, 齊藤 誠一

   

  本研究では、黒潮親潮移行域におけるカツオ・アカイカ・サンマ3魚種を扱う統合ハビタットモデルを構築して漁場形成要因としての魚種間の捕食・被食関係を定量的に評価し、3つの魚種間の漁場形成に相互関係が見られることを統計的に明らかにした。さらに統合モデルとして、顕著な関連が見られたサンマとカツオの魚種間関係を考慮したハビタットモデルを構築し、サンマの推定分布を活用することでカツオの漁場推定が高精度化する漁場推定モデルを構築して、実利用に耐えうる高い推定精度を有することを示した。