日本地球惑星科学連合2018年大会

講演情報

[EE] ポスター発表

セッション記号 A (大気水圏科学) » A-OS 海洋科学・海洋環境

[A-OS08] 季節から十年規模の気候変動と予測可能性

2018年5月20日(日) 10:45 〜 12:15 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:望月 崇(国立研究開発法人海洋研究開発機構)、V Ramaswamy(NOAA GFDL)、森岡 優志(海洋研究開発機構)

[AOS08-P06] Multiyear climate prediction using 4D-Var coupled data assimilation system

*望月 崇1増田 周平1石川 洋一1 (1.国立研究開発法人海洋研究開発機構)

キーワード:十年規模予測、四次元変分法、結合データ同化

An initialization relevant to interannual-to-decadal climate prediction has usually used a simple restoring approach for oceanic variables. Here, we demonstrate the potential use of four-dimensional variational (4D-Var) coupled data assimilation on the leading edge of initialization approach particularly in multi-year (5-year-long) climate prediction. We perform full-field initialization rather than anomaly initialization and assimilate the atmosphere states together with the ocean states to an atmosphere-ocean coupled climate model. In particular, it is noteworthy that ensembles of multi-year hindcasts using our assimilation results as initial conditions exhibit an improved skill in hindcasting the multi-year changes of the upper ocean-heat-content (OHC) over the central North Pacific. The 4D-Var approach enables us to directly assimilate a time trajectory of slow changes of the Aleutian Low that are compatible with the sea-surface-height and the OHC. Consequently, we can estimate a coupled climate state suitable for hindcasting dynamical changes over the extratropical North Pacific as observed.