11:00 〜 11:15
[MIS08-08] 観測モデル融合研究から理解する南大洋
キーワード：南大洋、海洋モデル、データ同化
Along the West Antarctic coast, modified Circumpolar Deep Water (mCDW) intrudes into West Antarctic ice shelf cavities, causing high ice shelf melting. On the other side, recent studies are pointing out that the East Antarctic ice shelves may be beginning to shrink. Our goal is to understand the past, present, and future state of the Southern Ocean and identify triggers of ocean warming and Antarctic ice loss on various time scales.
We take two approaches to tackle this question. First, to study the circum-Antarctic scale ocean, we evaluate existing ocean reanalysis. We choose Massachusetts Institute of Technology general circulation model (MITgcm) based ocean reanalysis products (ECCOv4r5, ECCO LLC270, SOSE, and GECCO3) and investigate large-scale ocean processes modulating cross-shelf exchange and thus possibly impacting ice shelf melting. Second, we develop regional ocean simulations by downscaling these ocean reanalysis simulations. This way, we achieve much closer agreement with observations by simulating on-shelf hydrography and circulation in fine grid spacing. We further apply optimization techniques (Green’s functions and adjoint methods) to improve the model-data agreement. Our recent work, for example, employs the adjoint-model estimation method for the first time with explicit representation of sub-ice shelf cavities to develop an ocean state estimate for the Amundsen and Bellingshausen Seas.
In this presentation, we report our recent progress on the MITgcm-based ocean reanalysis evaluation (ECCOv4r5, ECCO LLC270, SOSE, and GECCO3) in the Southern Ocean. We show our new ECCO LLC270 analysis on the Antarctic Slope Current (ASC) and discuss the interannual variability of the ASC. Next, we summarize our ongoing development of the Antarctic regional simulations (e.g., Amundsen, Bellingshausen, Weddell, and Ross Seas and along the East Antarctic coast) that achieve a good match with observations. We give an overview of key findings and provide examples on how to access model outputs available online and plot fundamental variables. We further introduce our recent model development towards ice-ocean-biogeochemistry coupled and paleo-ocean simulations.
We take two approaches to tackle this question. First, to study the circum-Antarctic scale ocean, we evaluate existing ocean reanalysis. We choose Massachusetts Institute of Technology general circulation model (MITgcm) based ocean reanalysis products (ECCOv4r5, ECCO LLC270, SOSE, and GECCO3) and investigate large-scale ocean processes modulating cross-shelf exchange and thus possibly impacting ice shelf melting. Second, we develop regional ocean simulations by downscaling these ocean reanalysis simulations. This way, we achieve much closer agreement with observations by simulating on-shelf hydrography and circulation in fine grid spacing. We further apply optimization techniques (Green’s functions and adjoint methods) to improve the model-data agreement. Our recent work, for example, employs the adjoint-model estimation method for the first time with explicit representation of sub-ice shelf cavities to develop an ocean state estimate for the Amundsen and Bellingshausen Seas.
In this presentation, we report our recent progress on the MITgcm-based ocean reanalysis evaluation (ECCOv4r5, ECCO LLC270, SOSE, and GECCO3) in the Southern Ocean. We show our new ECCO LLC270 analysis on the Antarctic Slope Current (ASC) and discuss the interannual variability of the ASC. Next, we summarize our ongoing development of the Antarctic regional simulations (e.g., Amundsen, Bellingshausen, Weddell, and Ross Seas and along the East Antarctic coast) that achieve a good match with observations. We give an overview of key findings and provide examples on how to access model outputs available online and plot fundamental variables. We further introduce our recent model development towards ice-ocean-biogeochemistry coupled and paleo-ocean simulations.