JpGU-AGU Joint Meeting 2020

講演情報

[E] 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-OS17] 季節内から十年規模の気候変動と予測可能性

コンビーナ:望月 崇(九州大学 大学院理学研究院)、V Ramaswamy(NOAA GFDL)、森岡 優志(海洋研究開発機構)

[AOS17-P04] Forecast of summer precipitation in the Yangtze River Valley based on South China Sea springtime sea surface salinity

*LILI ZENG1Raymond W. Schmitt2Laifang Li3Qiang Wang1 (1.State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences、2.Physical Oceanography Department, Woods Hole Oceanographic Instituti、3.Earth and Ocean Sciences, Nicholas School of the Environment, Duke University)

キーワード:Yangtze River Valley, South China Sea, sea surface salinity, summer precipitation

As a major moisture source, the South China Sea (SCS) has a significant impact on the summer precipitation over China. The ocean-to-land moisture transport generates sea surface salinity (SSS) anomalies that can be used to predict summer precipitation on land. This study illustrates a high correlation between springtime SSS in the central SCS and summer precipitation over the middle and lower Yangtze River Valley (the YRV region). The linkage between spring SSS in the central SCS and summer YRV precipitation is established by ocean-to-land moisture transport by atmospheric processes and land–atmosphere soil moisture feedback. In spring, oceanic moisture evaporated from the sea surface generates high SSS in the central SCS and directly feeds the precipitation over southern China and the YRV region. The resulting soil moisture anomalies last for about 3 months triggering land–atmosphere soil moisture feedback and modulating the tropospheric moisture content and circulation in the subsequent summer. Evaluation of the atmospheric moisture balance suggests both a dynamic contribution (stronger northward meridional winds) and a local thermodynamic contribution (higher tropospheric moisture content) enhance the summer moisture supply over the YRV, generating excessive summer precipitation. Thus, spring SSS in the SCS can be utilized as an indicator of subsequent summer precipitation over the YRV region, providing value for operational climate prediction and disaster early warning systems in China.