Large‐Scale Circulation Environment and Microphysical Characteristics of the Cloud Systems Over the Tibetan Plateau in Boreal Summer

Abstract

AbstractThe Tibetan Plateau (TP) experiences a particular dynamical and thermal environment due to its unique topography, which could affect the generation and development of its cloud and precipitation. Statistical results of 52‐year daily precipitation (1961 to 2012) show that the most frequent daily precipitation is about 3 mm day−1 over the eastern TP (ETP) in the warm season while it is less than 1 mm day−1 over the western TP (WTP). Circulation patterns for rainy and rainless conditions over both the ETP and WTP are investigated. The results show that the rainy weather over the TP is usually related to the moisture transported from the warm ocean by the southerly flow. Moreover, rainy weather in WTP can only appear when the strong southerly flow prevails over the Indian subcontinent. When the south flow is weak, the rainy weather can still develop in ETP under favorable conditions due to the local madid environment. CloudSat observations show that the strong convective system can extend to a level as high as 16 km above the sea level with a favorable dynamical and thermal environment. However, the depth of most precipitating convective clouds over the TP is in a range of 6–9 km. Due to the wetter condition, the precipitating convective cloud holds a lower cloud base in August in ETP than WTP. Compared with other regions, the precipitating convective clouds in both the ETP and WTP are thinner in cloud depth, smaller in cloud particles and weaker in precipitation capacity.