Impacts of the anomalous southwest tropical Indian Ocean SST warming on Indo-Pacific climate from April to June based on the CESM model
The thermocline depth in the southwest tropical Indian Ocean(TIO)is shallow,and thermocline variations are closely related to the sea surface temperature,making southwest TIO feature a unique ocean-atmosphere interaction.Based on the observation and model data,this study analyzed the climatic effects of the southwest TIO SST warming on the tropical Indo-Western Pacific from April to June.The results show that the local convective activities are enhanced by the warming of the southwest TIO from April to June,and the precipitation in the southwest TIO increases.In the lower troposphere of the tropical Indian Ocean,a"C-shaped"wind anomaly pattern appears with abnormal northeast winds north of the equator and abnormal northwest winds south of the equator.From May to June,abnormal north-easterly winds in the North Indian Ocean can weaken the Asian summer monsoon,reduce the latent heat release of the North Indian Ocean,and warm the North Indian Ocean.The climatic effect of the southwest TIO SST warming is not limited to the tropical Indian Ocean region.The warming can heat the tropospheric atmosphere and stimulate the eastward atmospheric Kelvin wave,and the easterly wind response in the lower troposphere of the tropical northwest Pacific Ocean can also trigger local positive ocean-atmosphere feedback under the background of trade winds.Both are conducive to the maintenance of anticyclonic wind anomaly at the lower troposphere of the tropical northwest Pacific.The anticyclonic wind anomaly can enhance the monsoon water vapor transport in May and June,which makes the rainfall increase significantly over the Yangtze River Valley in China.This study reveals that the heating anomaly in the southwest TIO could cause ocean-atmosphere interaction across the north Indian Ocean and tropical western North Pacific Ocean,which would provide a useful reference for the summer precipitation forecast in eastern China.
万方数据
维普
