Abstract: Based on the OAFlux3, the NCEP/NCAR reanalysis data for the period of 1985-2008 and the daily data of summer precipitation at 108 observational stations of eastern China, the relationship between the inter-annual variations of summer precipitation in eastern China and the latent heat flux anomalies in the East China Sea (ECS) are analyzed by using the composite and the linear regression analysis methods. The mechanism of summer precipitation anomalies in eastern China caused by the latent heat flux in ECS is also further analyzed from the perspective of atmospheric zonal and meridional circulation and water vapor transport in East Asian area. In order to focus on the inter-annual timescles, the long-term trend in the variations of laten heat flux in ECS, summer precipitation in eastern China and atmospheric circulation over East Asia have been removed in this study. The analyzed results show that the latent heat flux displays strong inter-annual variations signal in ECS and is closely related to summer precipitation in eastern China. When the latent heat flux in ECS is above (below) normal in summer, an anomalous anticyclonic (cyclonic) circulation appears over the northwest Pacific and the northeasterly (southwesterly) anomalies appear over eastern China, which are unfavorable (favorable) for the northward transportation of water vapor and result in more (less) water vapor in South China and less (more) water vapor in the middle and lower reaches of the Changjiang River and north areas. Furthermore, the atmospheric zonal and meridional circulations will be manifested as a downward (upward) motion with a divergence (convergence) in low level and a convergence (divergence) in upper level can appear over the middle and lower reaches of the Changjiang River, which may result in less (more) summer rainfall. While in South China, the atmospheric zonal and meridional circulations will be manifested as upward (downward) anomaly and convergence (divergence) at low levels,which may result in more (less) summer rainfall. The variations of atmospheric zonal and meridional circulation and water vapor transportation over East Asia caused by the latent heat flux anomalies in ECS could lead to the precipitation anomalies in the above mentioned area. It is suggested that the abnormal change of the latent heat flux in ECS may be one of the most important factors for the abnormal of summer rainfall in East China on the inter-annual timescales.

Key words: latent heat flux, atmospheric circulation, summer precipitation, East China Sea