In situ observation of warm atmospheric layer and the heat contribution of suspended dust over the Tarim Basin

Abstract

Based on radiosonde observations from the spring and summer of 2016-2017, we verified the existence of an anomalously warm atmospheric layer and quantified the heat contribution of suspended dust over the Tarim Basin (TB) in northwest China. The atmospheric layer was identified between 300 and 500ghPa over the TB, with 2.53 and 1.39gK average intensities in spring and summer, respectively. The Taklimakan Desert (TD), i.e., the world's second-largest moving desert, is contained in the TB and emits large amounts of dust particles, which remain suspended over the TB. Using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data, we found that dust can be lifted as high as the upper atmospheric layer, i.e., between 3.0 and 5.5gkm above mean sea level, over the TB. Consequently, suspended dust can exert a maximum heating effect of approximately +0.45 and +0.25gK in spring and summer, respectively. The heat contributions of dust to the anomalously warm atmospheric layer over the TB in spring and summer were 13.77g% and 10.25g%, respectively. With regard to topographical feature, the TB is adjacent to the Tibetan Plateau (TP), which acts as an elevated heat source in spring and summer. The warm atmospheric layer over the TB seems a northward extension of Tibet heat source, the concept of which is proposed in this study. Such a northward "extension"of the elevated heating by the Tibetan Plateau may be a controlling factor of the regional climate, especially in the western section of the Silk Road Economic Belt, and therefore requires further investigations.