回顾了对南印度洋副热带海气相互作用的研究,总结了南印度洋偶极子事件背景下的气候变化。印度洋海表温度的方差表明南印度洋是整个印度洋海温变率最强的区域,年际海温变化最显著的特征就是海温呈现西南东北向的偶极子型分布,被称为南印度洋偶极子(Southern Indian Ocean Dipole, SIOD)。南印度洋海温偶极子的形成主要是受大尺度大气环流调整的影响。南印度洋副热带反气旋环流异常引起了印度洋热带东风异常和副热带西风异常的变化,影响了潜热通量、上升流和Ekman热输送,进而引起了海温变化。SIOD对热带和热带外大气环流也有影响,尤其会影响亚洲夏季风降水异常,例如我国的降水异常和南印度洋偶极子海温异常具有显著相关关系。此外,SIOD模态所引起的经向环流异常与南海、菲律宾地区的反气旋环流异常也有紧密联系。
This paper reviews the studies on the southern Indian Ocean (SIO) air-sea interaction and summarizes the climate variability in the SIO at the inter-annual time scale. Variance and correlation analysis of the Indian Ocean sea surface temperature (SST) indicates that a strong dipole oscillation occurs in the SIO, the so-called Southern Indian Ocean Dipole (SIOD). Large-scale atmospheric circulation in the midlatitude of the Southern Hemisphere plays a role in the formation of SIOD. A subtropical anticyclonic anomaly contributes to the tropical easterly anomalies and midlatitude westerly anomalies; this results in anomalies in latent heat flux, upwelling, and Ekman heat transport, and then changes the SST. Through changing the heat distribution in the atmosphere in the South Asia and tropical Pacific, the SIOD has an impact on tropical atmospheric circulation. In particular, it remotely influences the Asian summer monsoon rainfall; for example, a close relationship is found between SIOD and rainfall over China. In addition, the anomaly induced by the SIOD can result in anticyclonic atmosphere anomalies over the South China Sea and Philippine Islands.
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