Study On The Thermal Characteristics Of Basins Around The Qinghai-Tibet Plateau And Their Regional Influence

This article is completed under the significance project of the National Natural Science Foundation of China "Research about the mechanism of how do heat source and weather systems over the Qinghai-Tibetan Plateau affect the disastrous weather in China"(No.91337215).Based on the ERA-interim monthly mean reanalysis data from 1983 to 2016 provided by ECMWF(European Centre for Medium-Range Weather Forecasts),the overall distribution of atmospheric heat source and moisture sink over the four basins around the Qinghai-Tibetan plateau and their vertical distribution characteristics in different regions are analyzed in detail.In addition,their interannual variation and interdecadal variation are also analyzed.The results show that,the four major basins around the Qinghai-Tibetan plateau in summer are all heat sources.The heat source intensity of Junggar Basin is the weakest(the central part of the basin is even a heat sink),but that of Sichuan Basin is the strongest.There is no significant difference in the heat source intensity between Tarim Basin and Qaidam Basin,their heat source intensity range from Junggar Basin’s to Sichuan Basin’s.The moisture sink intensity over Sichuan Basin is the strongest,followed by the Tarim Basin.The moisture sink intensity over the Qaidam Basin is the weakest.Except for the Qaidam Basin,the distribution characteristics of the moisture sink over the other three basins are similar to their distribution characteristics of heat sources.Except for the Sichuan Basin,the moisture sink intensity over the other three basins are all weaker than their atmospheric heat source intensity.In summer,the spatial distribution of the atmospheric heat source over the four basins are mainly composed of the first five local types.But Tarim Basin’local characteristics is significant and the spatial distribution is relatively complicated.The heat source anomalies in different regions have much obviously difference over the four basins in summer.The intensity of heat source,interannual variation and interdecadal variation are all different in the first five regions of the basin.The interannual variation is dominant in different regions of all basins,the interdecadal variation is not obvious;Vertical variation of atmospheric heat source and moisture sink is also very distinc in summer.The height of heat source extreme value and moisture sink extreme value over different regions are different.Vertical variation of heat source and moisture sink over different regions is significant.The thermal term which plays a major role in atmospheric heat source(Q1)is also different.Local temperature variation of each basin in summer is generally small and it’s almost zero,so it can be ignored.What determine the intensity of atmospheric heat source(Q1)is the interaction of the temperature advection term and the vertical heating term.Each There is a strong cold advection effect in the upper troposphere to impair the vertical heating effect of each basin,which makes the intensity of the atmospheric heat source extremely weak or even a cold source.The variation of Q1 and its two sub-items with height in the middle and lower troposphere is relatively complex.