Forecast of summer precipitation in the Yangtze River Valley based on South China Sea springtime sea surface salinity
Forecast of summer precipitation in the Yangtze River Valley based on South China Sea springtime sea surface salinity
复制标题
基于南海春季海表盐度的长江流域夏季降水预测
DOI：
10.1007/s00382-019-04878-y
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发表时间：
2019
期刊：
影响因子：
4.6
通讯作者：
Wang Dongxiao
中科院分区：
文献类型：
--
作者：
Zeng Lili;Schmitt Raymond W.;Li Laifang;Wang Qiang;Wang Dongxiao
南海是我国夏季降水的主要水汽源地，对我国夏季降水有着重要的影响。海洋-陆地水汽输送产生的海表盐度异常可用于陆地夏季降水的预测。研究表明，南海中部春季SSS与长江中下游地区夏季降水有很高的相关性。南海中部春季SSS与夏季YRV降水之间的联系是通过大气过程的海陆水汽输送和陆-气土壤水分反馈建立的。春季，海洋水汽在南海中部产生高的SSS，并直接供给华南和长江中下游地区的降水。由此产生的土壤湿度异常持续约3个月，触发陆-气土壤湿度反馈，并调制对流层的水分含量和环流在随后的夏季。大气水分平衡的评估表明，一个动态的贡献（较强的北向纬向风）和当地的热力学贡献（较高的对流层水分含量），提高夏季水分供应的YRV，产生过多的夏季降水。因此，南海春季SSS可以作为YRV地区夏季降水的指示因子，为中国的业务气候预测和灾害预警系统提供参考价值。
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.