Impact of the Anomaly of Surface Sensible Heat in Qinghai-Xizang Plateau and Its Surrounding Areas on Summertime Precipitation in Northern Xinjiang

As well known,the surface thermal anomaly(STA)in the Qinghai-Xizang Plateau(QXP)have important influences on the climate in China.Previous studies were focused on the effects of the STA on the weather and climate in eastern monsoon regions,less attention was paid to the connection between the STA and the precipitation in arid regions,especially in Xinjiang.In this paper,the preliminary results of the relationship between the STA in QXP and summer rainfall in northern Xinjiang were given.Using the NCEP/NCAR reanalysis monthly mean data and precipitation data at 43stations in northern Xinjiang,the relationships between the anomaly of surface sensible heat(SH)in QXP and its surrounding areas and the summer precipitation in northern Xinjiang were analyzed.The results showed the effects of the SH in the QXP,eastern QXP and western QXP(divided along 90°E)on the summer time precipitation are different and the SH in eastern QXP have the most closed relation with summer precipitation.When the SH weakened in QXP and strengthened on the northwest side of the QXP,the South Asia High has two positive centers,which is one of the most important circulation patterns for occurring more summer rainfall in northern Xinjiang,and there are an anomalous cyclone over central Asia and an anomalous anticyclone over the Baikal Lake,respectively,which results in the anomalous south wind prevailing and is favorable to the warm-wet air move from the low latitude regions.In addition,the transportation of water vapor by Somalia jet is unusually strong,passing over the Equator,and at the same time the Arabian Sea is controlled by anomalous anticyclone circulation,driving the water vapor to be transferred continuously to the central Asia and Xinjiang,so the south water vapor channel which impacted Xinjiang is strengthened significantly.Above all are contributed to the occurrence of more summer precipitation in northern Xinjiang,and vice versa.