Study On The Relationship Between Frozen-thaw Process Over Qinghai-Tibet Plateau And East Asian Summer Monsoon

In this work, annualy anomaly feature of interaction between the seasonal frozen-thaw process over QinghaiTibet Plateau and climate of QinghaiTibet Plateau, seasonal Frozen-thaw process over Qinghai_Tibet Plateau and Asian summer monsoon are analyzed by using the GAME-Tibet, NCEP and the observation data, relationship of connected mechanism of the seasonal frozen-thaw process over QinghaiJ_Tibet Plateau and the dry-wet season over Qinghai_Tibet Plateau also studied by observation data, the possible relationship between the seasonal frozen-thaw process over QinghaiTibet Plateau and summer monsoon activity are sutdied.As a case, the Tuotuohe station (located at Northern QinghaiTibet Plateau ) are analyzed. Firstly, we analyzed the relationship between the moisture-heat flux transport characters of the seasonal frozen-thaw process over Qinghai_Tibet Plateau in transfer period that from winter to summer, analyzing the QinghaiTibet Plateau thermodynamic effects. Secondly, the possible relationship between the soil Frozen-thaw process and the transfer period that from dry season to wet season over Qinghai_Tibet Plateau, the precipitation in wet season are studied. Lastly, focus to impacts of the soil frozen-thaw process in the east Asian summer monsoon.1, In the area of Northern Qinghai_Tibet Plateau (Tuotuohe), although the increasing of soil temperature is slower than the decreasing, the thaw process is faster than the frozen process. The change of soil moisture and heat is same as time when weather process above the depth of 60cm. The amount of soil moisture connect with the thaw process over Qinghai_Tibet Plateau is more (less) in the transitional season from winter to summer, the transportation of latent heat flux from surface to atmosphere is stronger(weaker), and the thermodynamic effect of QinghaiTibet Plateau is stronger(weaker).2, The start of soil moisture increase from the frozen soil to the thaw soil isearlier than the onset of precipitation over QinghaiJTibet Plateau. From the spring end to the summer begin, the soil moisture increasing from soil Frozen-thaw process over Qinghaijfibet Plateau contribute to atmospheric humidity increase in the local scale water circulation in whole of the wet season of QinghaiTibet Plateau. In wet season, the soil moisture change is mainly caused by the precipitation in wet season of Qinghaijfibet plateau. So the soil moisture change relate to the frozen-thaw process can not be neglected in the moisture circulation process during the transitional period from dry season to wet season in Qinghai-Qinghai_Tibet Plateau.3> As the soil seasonal frozen-thaw process, the exchange of latent heat flux between surface and atmosphere changed follow to the season change of. The thermodynamic effect change over Qinghaijfibet Plateau plays an important role on the local and East Asian atmospheric circulation, and it affects the onset and the intensity of East Asian monsoon. If the frozen-thaw process is stronger(weaker), the exchange of latent heat is stronger(weaker), the thermodynamic effect is stronger(weaker), the onset of East Asian monsoon is earlier(later), and the intensity of East Asian monsoon is stronger(weaker). All in all, the frozen-thaw process of Qinghai_Tibet Plateau is an important factor in the onset of East Asian summer monsoon.