Abstract: Maximum covariance analysis is utilized to study the impacts of Tibetan Plateau (TP) snow cover on precipitation in China. The results show a significant correlation between early autumn (ASO) Chinese precipitation and the preceding TP snow cover. A strong pattern with lead positive mode snow cover anomalies over the western TP signifies enhanced ASO rainfall over Yangtze River basin and southern China and reduced rainfall over the southeast coastline of the country.
Maximum response estimation and diagnostic analyses are also utilized to investigate the impacts of TP snow cover on Chinese precipitation and its possible mechanism. The results indicate that positive early spring snow cover anomalies in TP can persist until summer and can modify the surface thermal conditions, which results in a weak South Asian high with the disturbance propagating downstream along the westerly jet through Mongolia to Japan. An additional wave train propagates along the lower southwesterly airflow through the Bay of Bengal to the South China Sea, which leads to low-level anti-cyclonic circulation over Taiwan. The southerly flow to the west of the anti-cyclonic anomalous circulation strengthens abundant moisture transport from the South China Sea to southern China. Moreover, the northerly flow to the northwest of the upper-level cyclonic anomalous circulation over Japan contributes to southward movement of synoptic disturbances from the north. Both conditions lead to increased rainfall in central and southern China. The calculated stationary wave number reveals that as waveguides, the high-level westerly jet and the low-level southwesterly monsoon flow can contribute to the eastward propagation of disturbances over the TP. The positive anomalies of geopotential height over the eastern coastline accompanied by the low-level anti-cyclonic anomalous circulation suppresses the rainfall along southeast coast.