Thermal Characteristics Over The Tibetan Plateau And Surrounding Areas And Its Abnormal Impacts On Precipitation In East Asia

Based on the latest high resolution daily ERA-interim reanalysis data from1979to2012which is fairly objective over the Tibetan Plateau (TP), and adopting the"reverse computation" method, atmospheric heat source and moist sink over the TPand its vicinity are calculated, meanwhile its climatic characteristics and linear trendsare discussed. Then the TP and its vicinity are divided into five key areas throughREOF analysis, and the local characteristics of the heat source over each key area andits relationship with the precipitation in East Asia are compared. Finally, three areasare selected to discuss their abnormal heating impacts on the atmospheric circulation,and initially proposed the possible causes of the precipitation anomalies in East Asia.The main conclusions are as follows:(1)The TP acts as a heat source in summer when the heating in the near groundlevel is strongest and act as a heat sink in winter when the heating is exuberant in theupper troposphere. Each heating term has obvious seasonal variations. The local termis strongest in spring and weakest in autumn; advection term is strongest in winter andweakest in Summer; vertical transport term behave the same changes with the totalheat source which is strongest in summer and weakest in winter. Moreover, thediurnal variations of heat source over the TP are significant, especially in spring andsummer, where the Northern India, Tarim Basin and the southeast side of TP are themost prominent regions.(2) Heat source over the TP at06UTC and12UTC have the most significantlinear trends, which present an overall increasing at06UTC and a general decreasingat12UTC. However, in the last few years, both of them show the weakening trends.In addition, the changing trends of the heat source over the TP and its vicinity displaystrong regional differences and seasonal variations, especially in winter. （3）The local characteristics of the heat source over TP and its vicinity areremarkable, and the heat source anomalies of different key areas have distinct impactson the precipitation in East Asia. The heat source anomalies of northwest side of TPand northeastern TP have lag influences on the precipitation in East Asia, while theheat source anomalies of southwest side of TP and southeastern TP primarilyinfluence the contemporaneous precipitation. Both the contemporaneous and lagcorrelations between the heat source anomalies over the Central TP and precipitationin East Asia are significant; however, the correlated regions are slightly different.（4）The heat source anomalies in various areas over the TP and its vicinitycan stimulate different atmospheric circulation anomalies, which will lead to differentimpacts on the distribution of precipitation in East Asia. The heat source of northwestside of TP and northeastern TP in spring are closely related with the precipitation ofMongolian in the following summer, however, they have the opposite effect. Insummer, the local thermal characteristics of the southwest side of TP are notable, butit basically affects the contemporaneous precipitation over the native region, which ismainly affected by the vertical transport heating term, and is not able to influence thelarge areas precipitation in East Asia. The heat source anomalies of the southeasternTP are positive correlated with the precipitation of Yangtze valley. And the heatsource anomalies of the Central TP are positive correlated with the precipitation ofSouth China.