Influence of Tibetan Plateau snow cover on East Asian atmospheric circulation at medium-range time scales

Wenkai Li,Yongkang Xue,Bo Qiu,Pang-Chi Hsu,Weidong Guo,Jiangfeng Wei

doi:10.1038/s41467-018-06762-5

Abstract

The responses of atmospheric variability to Tibetan Plateau (TP) snow cover (TPSC) at seasonal, interannual and decadal time scales have been extensively investigated. However, the atmospheric response to faster subseasonal variability of TPSC has been largely ignored. Here, we show that the subseasonal variability of TPSC, as revealed by daily data, is closely related to the subsequent East Asian atmospheric circulation at medium-range time scales (approximately 3–8 days later) during wintertime. TPSC acts as an elevated cooling source in the middle troposphere during wintertime and rapidly modulates the land surface thermal conditions over the TP. When TPSC is high, the upper-level geopotential height is lower, and the East Asia upper-level westerly jet stream is stronger. This finding improves our understanding of the influence of TPSC at multiple time scales. Furthermore, our work highlights the need to understand how atmospheric variability is rapidly modulated by fast snow cover changes.

Highlights

The responses of atmospheric variability to Tibetan Plateau (TP) snow cover (TPSC) at seasonal, interannual and decadal time scales have been extensively investigated
A better understanding of the atmospheric effects of TP snow cover (TPSC) at multiple time scales, including shorter time scales, allows us to understand all aspects of atmospheric variability
We further investigate the atmospheric effects caused by such fast subseasonal variability of TPSC

Summary

Introduction

The responses of atmospheric variability to Tibetan Plateau (TP) snow cover (TPSC) at seasonal, interannual and decadal time scales have been extensively investigated. The faster subseasonal variability of TPSC revealed by daily snow cover data and its effects on the atmosphere have largely been ignored. We analyzed the subseasonal variation of TPSC during wintertime by using daily snow cover data (Fig. 1a). The overall responses of surface energy to the increased/decreased TPSC lead to anomalous cooling/heating effects, due to the snow-albedo effect and snowthermodynamic effect.

Results

Conclusion