The Impact of Tibetan Plateau Snow Cover on the Summer Temperature in Central Asia

The current work examines the impact of the snow cover extent(SCE) of the Tibetan Plateau(TP) on the interannual variation in the summer(June-July-August) surface air temperature(SAT) over Central Asia(CA)(SATCA) during the1979-2019 period. The leading mode of the summer SATCA features a same-sign temperature anomalies in CA and explains 62% of the total variance in SATCA. The atmospheric circulation associated with a warming SATCA is characterized by a pronounced high-pressure system dominating CA. The high-pressure system is accompanied by warm advection as well as descending motion over CA, favoring the warming of the SATCA. Analysis shows that the interannual variation in the summer SATCA is significantly positively correlated with the April SCE over the centraleastern TP. In April, higher than normal SCE over the central-eastern TP has a pronounced cooling effect on the column of the atmosphere above the TP and can persist until the following early summer. Negative and positive height anomalies appear above and to the west of the TP. In the following months, the perturbation forcing generated by the TP SCE anomalies lies near the western center of the Asian subtropical westerly jet(SWJ), which promotes atmospheric waves in the zonal direction guided by the Asian SWJ. Associated with this atmospheric wave, in the following summer, a significant high-pressure system dominates CA, which is a favorable condition for a warm summer SATCA.