The Uneven Distribution Of Surface Temperature On The Qinghai-Tibet Plateau Affects The Plateau Vortex And Anomalous Precipitation Downstream

Tibetan Plateau Vortex(TPV)is a unique weather system in Tibetan Plateau,which affects the precipitation of its local region and the other parts of China.The altitude and area of Tibetan Plateau is quite high and large,and its surface temperature has an important influence to the atmosphere.Analyzing the climate characteristics of TPV,and the influence caused by the inhomogeneous distribution of surface temperature to TPV and the abnormal precipitation caused by TPV,is helpful to the Tibetan Plateau meteorology.The climate changes of surface temperature,TPV and the abnormal precipitation caused by TPV are discussed by using the TPV data from the yearbook of TPV and TSL,the surface temperature data form ERA-Interim and the precipitation data,and the influence caused by the inhomogeneous distribution of surface temperature to them is also discussed.The conclusions are showed as follows:1.In the past 18 years,the sum of TPV is 769.The time series of TPV's numbers exist an increasing trend.The frequency of TPV in summer half years is significantly higher than that in winter half years.TPVs are active during April to August in each year.TPVs' main source located in Amdo-Tanggula – Wenquan.The activity of TPV will cause abnormal precipitation in the lower reaches of the plateau.The Tibetan Plateau Vortex,which caused abnormal precipitation in the lower reaches of the plateau,can be abbreviated as APTPV.During 1998 to 2015,the sum of APTPV is 228.The frequency of APTPV is decreasing.APTPVs are more active in May to August.The main source of APTPV located in Westward of Gyaring Lake-North of Qumarleb.Abbreviate the TPV which move out of Tibetan Plateau as MTPV.MTPV is an important part of APTPV.In the past 18 years,the sum of MTPV is 175,and the frequency of MTPV has an increasing trend.MTPVs' frequent season is 4-8 months in each year.The main source of MTPV is located in the West Gyaring Lake area.2.Area located in(90°E-104°E,28°N-38°N)are used as the key area for the analysis of surface temperature.In the 1998-2015 years,the average temperature of the key area is-1.09° C,showing a downward trend,and the surface average temperature of the key area during the frequent season is 6.85 °C.The spatial distribution of surface temperature on the Tibetan Plateau is bounded by 34°N.The distribution of surface temperature in the southern part of the plateau is mainly presented as zonal distribution,in the north is mainly distributed in blocks.The warm center is located in the Qaidam Basin,and the cold center is located in the area nearby Qinghai Lake.The analysis of EOF shows that the spatial distribution of surface temperature is dominated by meridional difference and the zonal difference is the second.The source which located in Gyaring Lake-Qumarleb-Zadoi sit in the area between cold and warm place,the source located in Westward of Ya'an sit in the area where the temperature gradient is large.The other sources do not show obvious characteristics.Those sources are mainly distributed in the are where surface temperature climate tendency rate is smaller.3.The surface temperature in the key area has little influence on TPVs,its high and low distribution and change trend do not affect the frequency of TPVs,as well as its sources' location.The surface temperature in the key area is negatively correlated with APTPVs' frequency,and mainly effects the central strength of APTPV's source.The central strength of the source which located in Westward of Ya'an is maximum in warm years,meanwhile the central strength of the sources which located in the upper reaches of the Yalong River,Zadoi – Zhidoi and Westward of Gyaring Lake-North of Qumarleb is increasing in cold years.In addition,there is a new source appeared in Baima in cold years.The influence of surface temperature in key area shows different characteristics to the frequency of MTPV.When the surface temperature in key area in whole year is relatively higher,the frequency of MTPV is less,the variation trend shows the same tendency in whole year.While in the frequent season,when the temperature is higher,the frequency of MTPV is more,and vice versa.4.According to the activity characteristics and position of source of APTPV and MTPV,in the warm years,APTPVs and MTPVs are tending to effect Sichuan Basin,Yunnan,Guizhou,Guangxi Province and the other parts of Eastern China,while in the cold years,Gansu,Shanxi,Ningxia Province are more effected.