深層水形成に着目した全球規模海洋熱塩循環のマルチスケールモデリング

• Project/Area Number: 17684025
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Meteorology/Physical oceanography/Hydrology
• Research Institution: The University of Tokyo
• Principal Investigator: 羽角 博康 The University of Tokyo, 気候システム研究センター, 准教授 (40311641)
• Project Period (FY): 2005 – 2007
• Project Status: Completed (Fiscal Year 2007)
• Budget Amount: ¥26,780,000 (Direct Cost: ¥20,600,000、Indirect Cost: ¥6,180,000); Fiscal Year 2007: ¥7,670,000 (Direct Cost: ¥5,900,000、Indirect Cost: ¥1,770,000); Fiscal Year 2006: ¥7,280,000 (Direct Cost: ¥5,600,000、Indirect Cost: ¥1,680,000); Fiscal Year 2005: ¥11,830,000 (Direct Cost: ¥9,100,000、Indirect Cost: ¥2,730,000)
• Keywords: 熱塩循環 / 深層水形成 / 南大洋 / ラブラドル海 / ウェッデル海 / 南極 / LES / 海面境界条件

Research Abstract

全球規模モデリングでは、南大洋における渦解像モデリングを実施し、中規模渦やさらにスケールの小さい渦が深層水塊形成・分布に果たす役割について調べた。特に南極中層水の大西洋への貫入について、渦活動に伴うサブダクション過程を定量的に見積もり、それが本質的に重要であることを指摘した。また、渦解像モデリングの結果を使用し、南大洋における熱塩循環の2種類の経路(cold water routeおよびwarm water route)を定量的に見積もるためのトレーサー実験を行った。領域規模モデリングでは、前年度から引き続き行っているラブラドル海の深層水形成領域シミュレーションに関して、中規模渦による淡水輸送が深層水形成を抑制する過程に関する解像度依存性を調べるための実験・解析を行った。また、南極周囲およびオホーツク海という深層水形成領域について、特に海氷生成の影響を定量化するためのシミュレーションを実施した。両海域とも海氷生産量に関しては高い再現性が得られ、深層水塊の起源となる高塩分水の性質・形成量に関して定量的な評価を行うことができた。微小プロセス規模モデリングでは、昨年度までに開発された非静水圧海洋モデルを用い、ウェッデル海における高密度水の流出・混合過程に関するシミュレーションを行った。特に、地形による制約によって、大陸斜面に沿う流出経路ばかりではなく、渦運動生成とそれに伴う大陸斜面からの高密度水切離過程、さらにそれに引き続く混合過程が大きく影響されることがわかった。

Research Products

• [Journal Article] A nonhydrostatic ocean model with an effective Poisson solver (2008)
  • Author(s): Matsumura, Y., and H. Hasumi
  • Journal Title: Ocean Modelling 印刷中(掲載確定)
  • Peer Reviewed
• [Journal Article] Injection of Antarctic Intermediate Water into the Atlantic subtropical gyre in an eddy resolving ocean model (2008)
  • Author(s): Tanaka, Y., and H. Hasumi
  • Journal Title: Geophysical Research Letters 印刷中(掲載確定)
  • Peer Reviewed
• [Journal Article] Resolution dependence of eddy fluxes (2008)
  • Author(s): Tanaka, Y., and H. Hasumi
  • Journal Title: Ocean Modeling in an Eddying Regime 印刷中(掲載確定)
  • Peer Reviewed
• [Journal Article] Pacific upper ocean response to global warming-climate modeling in an eddying regime (2008)
  • Author(s): Sakamoto, T. T., and H. Hasumi
  • Journal Title: Ocean Modeling in an Eddying Regime 印刷中(掲載確定)
  • Peer Reviewed
• [Journal Article] Brine-driven eddies under sea ice leads and their impact on the Arctic Ocean mixed layer (2008)
  • Author(s): Matsumura, Y., and H. Hasumi
  • Journal Title: Journal of Physical Oceanography 38 Pages: 146-163
  • Peer Reviewed
• [Journal Article] Effects of variability of sea ice transport through the Fram Strait on the intensity of the Atlantic deep circulation (2007)
  • Author(s): Komuro, Y., and H. Hasumi
  • Journal Title: Climate Dynamics 29 Pages: 455-467
  • Peer Reviewed
• [Journal Article] Brine-driven eddies under sea ice leads and their impact on the Arctic Ocean mixed layer (2007)
  • Author(s): Y.Matsumura, H.Hasumi
  • Journal Title: Journal of Physical Oceanography (印刷中)
• [Journal Article] Effects of variability of sea ice transport through the Fram Strait on the intensity of the Atlantic deep circulation (2007)
  • Author(s): Y.Komuro, H.Hasumi
  • Journal Title: Climate Dynamics (印刷中)
• [Journal Article] Different transient climate responses of two versions of an atmosphere-ocean coupled general circulation model (2007)
  • Author(s): T.Yokohata et al.
  • Journal Title: Geophysical Research Letters 34(2)
• [Journal Article] Arctic dipole anomaly and its contribution to sea ice export from the Arctic Ocean in the 20th century (2006)
  • Author(s): E.Watanabe et al.
  • Journal Title: Geophysical Research Letters 33(23)
• [Journal Article] Deep convection seesaw controlled by sea ice transport through the Denmark Strait (2006)
  • Author(s): A.Oka et al.
  • Journal Title: Ocean Modelling 15(3-4) Pages: 157-176
• [Journal Article] Effects of model resolution on salt transport through northern high-latitude passages and Atlantic meridional overturning circulation (2006)
  • Author(s): A.Oka, H.Hasumi
  • Journal Title: Ocean Modelling 13(2) Pages: 126-147
• [Journal Article] Investigating the causes of the response of the thermohaline circulation to past and future climate changes (2006)
  • Author(s): R.J.Stouffer et al.(著者23名中10番にH.Hasumi)
  • Journal Title: Journal of Climate (In press)
• [Journal Article] Role of salinity transport through northern high-latitude narrow passages in the formation of the Atlantic deep circulation (2006)
  • Author(s): A.Oka, H.Hasumi
  • Journal Title: Ocean Modelling (In press)
• [Journal Article] A series of zonal jets embedded in the broad zonal flows in the Pacific obtained in eddy-resolving ocean general circulation models (2005)
  • Author(s): H.Nakano, H.Hasumi
  • Journal Title: Journal of Physical Oceanography 35(4) Pages: 474-488
• [Journal Article] Intensification of the Atlantic deep circulation by the Canadian Archipelago throughflow (2005)
  • Author(s): Y.Komuro, H.Hasumi
  • Journal Title: Journal of Physical Oceanography 35(5) Pages: 775-789
• [Journal Article] Arctic sea ice response to wind stress variations (2005)
  • Author(s): E.Watanabe, H.Hasumi
  • Journal Title: Journal of Geophysical Research 110(C11)
• [Journal Article] A model intercomparison of changes in the Atlantic thermohaline circulation in response to increasing atmospheric CO2 concentration (2005)
  • Author(s): J.M.Gregory et al.(著者18名中8番目にH.Hasumi)
  • Journal Title: Geophysical Research Letters 32(12)
• [Journal Article] Responses of the Kuroshio and the Kuroshio Extension to global warming in a high-resolution climate model (2005)
  • Author(s): T.T.Sakamoto, H.Hasumi 他5名
  • Journal Title: Geophysical Research Letters 32(14)
• [Journal Article] Seasonal cycle of the Mindanao dome in the CCSR/NIES/FRCGC atmosphere ocean model (2005)
  • Author(s): T.Suzuki et al.(著者7名中H.Hasumiが最終著者)
  • Journal Title: Geophysical Research Letters 32(17)
• [Journal Article] Future projection of sea level and its variability in a high-resolution climate model (2005)
  • Author(s): T.Suzuki, H.Hasumi 他7名
  • Journal Title: Geophysical Research Letters 32(19)
• [Presentation] An overview of global scale ocean modeling from low to high resolution (2007)
  • Author(s): Hasumi, H
  • Organizer: GEOTRACES Data-Model Synergy
  • Place of Presentation: Delmenhorst, Germany
  • Year and Date: 2007-09-08
• [Presentation] Pacific bidecadal variability induced by tidal mixing along the Kuril Islands (2007)
  • Author(s): Hasumi, H
  • Organizer: IUGG General Assembly
  • Place of Presentation: Perugia, Italy
  • Year and Date: 2007-07-04