The characteristics of the summer atmospheric water cycle over China and comparison of ERA-Interim and MERRA reanalysis

Abstract

Atmospheric water cycle process includes precipitation, evaporation, water vapor transport and other links. The temporal and spatial characteristics of the atmospheric water cycle over China in summer are investigated by using the ERA-Interim and MERRA reanalysis from 1979 to 2012. Comparison and performance analyses of these two reanalysis data are given. The obtained results are as follows. 1) the spatial distributions of precipitation, evaporation and precipitable water are highly similar to each other, and all gradually decrease from southeast coast to northwest inland regions. Because the differences in physical condition, precipitation and evaporation among different underlying surfaces, mutually promot or mutually restrict each other, the interactions among them have positive and negative feedback mechanisms. Precipitable water mainly concentrates in the ground to the 700 hPa height, accounts for about 75% of the total quantity. 2) All of the atmospheric water cycle elements have obvious characteristics of climate change, especially in these areas like Northwest China, Tibet and Northeast China. The zonal flux of water vapor transport significantly decreases in most parts of the northern, while the meridional flux of water vapor transport significantly increases in the northern region of Northwest China. 3)The reproduction ability to change characteristics of precipitation is better than that of evaporation based on these reanalyses. The temporal and spatial distribution characteristics of moisture transport situation and the various levels of atmospheric water vapor content are highly consistent with each other. The simulations of flux climate change trend of precipitation and water vapor transport are more accurate and more reliable. 4) Interim reanalysis is applicable to the study of the southwest, Southeast and northeast regional atmospheric water balance, water cycle elements can maintain balance well, while MERRA reanalysis is more reasonable in Southwest and northwest.