The Characteristic Of Winter And Spring Atmospheric Heat Source Over The East China Sea Kuroshio And Western North Pacific Subtropics And Its Impact On Precipitation In Eastern China

A suite of reanalysis and in-situ precipitation data are analyzed to investigate the heat source over the East China Sea Kuroshio in spring and winter and the western North Pacific subtropics in spring, including their interannual variability and the impact on atmospheric circulation and precipitation. The main conclusions are as follows.(1) Marked heat sources occur over the Kuroshio in East China Sea in spring and winter and the western North Pacific subtropics in spring, with obvious interannual variability. Latent heating is the primary heating of the heat sources over the East China Sea Kuroshio and western North Pacific subtropics in spring, and one of the key factors that lead to the interannual anomalies of the sources may be the intensity changes of the SST front. The dominant heating of the heat source over the East China Sea Kuroshio in winter is sensible heating near surface and its interannual anomalies are mainly related to the variation in the heat source in the middle and lower troposphere.(2) On the seasonal and inter-annual time scales, southerly wind anomalies in the lower troposphere with the cyclonic circulation to the west and the anticyclonic circulation to the east is associated with an enhanced atmospheric heat source.Circulation anomalies caused by heat enhancement of the East China Sea Kuroshio in spring are conducive to the enhancement and the westward extension of the subtropical high, which result in the increase of the precipitation in the South of the middle and lower reaches of the Yangtze river region in spring and the middle and lower reaches of the Yangtze river region in summer, and vice versa. Accompanied by the heat enhancement of the East China Sea Kuroshio in winter, circulation anomalies are beneficial to the transportation of the warm moisture flow and the enhancement of the convection over southern region of China, which result in the increase of the precipitation, and vice versa.precipitation decreases in the eastern of Yangtze and Huaihe River Basin and the middle lower of Yangtze River in China because of the effect of a weak anticyclonic circulation anomaly, the block of the strengthen and westward extension of the subtropical high and the decrease of the warm moisture flow to China caused by the enhancement of the heat source over the western North Pacific subtropics in spring. At the same time, affected by the cyclonic circulation and south wind anomaly, precipitation in western North Pacific subtropics increases, and vice versa.(3) In contrast with the seasonal and inter-annual time scales, an enhanced atmospheric heat source over the East China Sea Kuroshio can excite an anomaly cyclonic circulation in the lower troposphere on the synoptic time scale and its short-term variation is closely related to an eastward-moving anomaly cyclonic circulation at the lower troposphere. This eastward-moving anomaly cyclonic circulation in turn affects the precipitation over the eastern China.