Influences of Summer Thermal Anomalies over the Tibetan Plateau and the Tropical Indian Ocean on Summer Rainfall in the Tarim Basin

Based on the reanalysis data of the global atmospheric numerical forecast (ECMWF) from 1979 to 2017, the latent heat data and reanalysis data of atmospheric circulation provided by the ERA-interim, the global monthly sea surface temperature grid data provided by the Hadley Center, and the monthly precipitation data of 26 stations in the Tarim Basin provided by the Xinjiang Meteorological Information Center, the influence of the Tibetan Plateau and tropical Indian Ocean thermal anomalies on the summer precipitation in the Tarim Basin is studied. Results show that when the latent heat in the north of the plateau is strong (weak), and the sea surface temperature in the tropical Indian Ocean is warm (cold), the 200-hPa zonal wind shows the characteristics of "north negative (positive) south positive (negative)". In addition, there are abnormal cyclones (anticyclones) and abnormal anticyclones (cyclones) over Central Asia and Baikal Lake, respectively. Under the joint action of the two, the south (north) wind prevails over the Tarim Basin and over the Indian peninsula. The anticyclone (anticyclone) is advantageous (disadvantageous) to transport the water vapor in a low latitude toward the north, and it is advantageous (disadvantageous) to enter the Xinjiang area in combination with the abnormal cyclone (anticyclone) over Central Asia, corresponding to more (less) summer precipitation in the Tarim Basin. At the same time, the summer precipitation in the Tarim Basin is found to be closely related to the temperature anomaly in the middle and upper troposphere of Central Asia, while a significant negative correlation between the middle-upper troposphere temperature index (MUTTI) and the latent heat of the plateau and the sea temperature of the Indian Ocean is observed. In summer, when the latent heat of the plateau is strong, the monsoon of the plateau is strong. Meanwhile, if the sea temperature of the Indian Ocean is strong, the monsoon of South Asia is weak, resulting in the low temperature of the middle and upper troposphere of Central Asia.. The summer precipitation in the Tarim Basin is further influenced by the zonal wind of 200 hPa, the circulation of 500 hPa, and the water vapor transportation in the whole layer.