Characteristics of Heat Sources and Clouds over Eastern China and the Tibetan Plateau in Boreal Summer

Abstract

n this study, the summer clouds and precipitation over eastern China and the Tibetan Plateau (TP) are examined by analyzing the satellite observations and the apparent heat source Q1 and moisture sink Q2 computed from the NCEP?NCAR reanalysis. The vertically integrated [Q1] and [Q2] and precipitation have similar interannual variations in eastern China, revealing the important contribution from the condensation process. This relationship is weakened in east TP (ETP) because of the contribution of the surface sensible heat flux. In west TP (WTP), [Q1] is negatively correlated with precipitation because the surface sensible heat flux can be sharply weakened by the decrease of ground?air temperature difference due to rainfall. High clouds and deep convection are closely related with [Q1] and [Q2] over eastern China and ETP, while middle clouds and nimbostratus are responsible for the condensation over WTP. During the rainy summer, more convective rains and stronger upward motion appear in eastern China. Greater Q1 and Q2 and stronger upward motion present over ETP, while weaker Q1 and upward motion are observed over WTP in the rainy summer when compared to the dry summer. The cloud-water path over eastern China positively correlates with [Q1] and [Q2] over ETP. The deep convection over eastern China also positively correlates with the convection over ETP. These correlations suggest that moisture due to the evaporation of cloud water in anvil clouds detrained from the deep convection over ETP can be transported downstream and benefit the development of convection over eastern China.