ROMSへの3次元変分法の導入 Application of a 3D-var data assimilation scheme to ROMS

本研究は北西太平洋海域における主要魚種の漁場形成や加入量変動と、海洋環境との間を関係を調査するため、欠測のない3次元の物理環境を構築することを目的とする。ここでは三次元変分法スキームをROMS（Regional Ocean Modeling System）に導入し、精緻な海洋構造に再現することを目指す。

A three-dimensional variational (3D-var) data assimilation scheme has been developed and applied to Regional Ocean Modeling System (ROMS). Our final goal is for studying fisheries resource/recruitment variation and managing the proper marine/fisheries environment on the basis of the reanalysis or the forecast products. As the first step, we apply this scheme to the ocean model covering the whole of the Western-North Pacific. Satellite SSH/SSTs and in situ temperature-salinity data from GTSPP and WOD2009 are assimilated into the model. It is found that the 3D-var scheme works well and significantly improves simulated results. That is, the reanalysis data is in better agreement with some observed data than the simulation without the data assimilation. For example, eddy activities west of the date-line in the mid-latitude are well reproduced in the reanalysis data.