The spring atmospheric heat source over the East China Sea Kuroshio area and its impact on precipitation in Eastern China

In this paper, the impact of atmospheric heat source over the East China Sea Kuroshio area in spring on the atmospheric circulation and precipitation at the different time scales are investigated in terms of the ERA-interim daily reanalysis and in-situ precipitation. Observations show that there is a marked heat source over the Kuroshio area in the East China Sea, to which the atmospheric responses differ at the different time scales.On the seasonal and inter-annual time scales, southerly wind anomalies in the lower troposphere is associated with an enhanced atmospheric heat source over the Kuroshio in the East China Sea. At the same time, the northwestern Pacific subtropical high is also abnormally enhanced with its position extending westward during the spring and the late summer. In this situation the northwestern Pacific subtropical regions are mainly dominated by an anomaly anticyclonic circulation and precipitation abnormally increases over the southern China south of the middle-lower reaches of the Yangtze River, and vice versa. In contrast with the seasonal and inter-annual time scales, an enhanced atmospheric heat source over the East China Sea Kuroshio area 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 and associated with abnormal precipitation over eastern China.