Impacts of Spatiotemporal Anomalies of Tibetan Plateau Snow Cover on Summer Precipitation in Eastern China

Abstract

Tibetan Plateau (TP) snow cover undergoes significant temporal and spatial variations during the winter and spring months. This study investigates the relationship between the spatiotemporal distribution of winter–spring snow cover (SC) over the TP and summer precipitation in eastern China (EC) using the singular value decomposition (SVD) method. Four simulation experiments are designed to validate the results of SVD analysis. Both observations and simulations show that heavier snow cover in the southern TP leads to more rainfall in the Yangtze River basin and northeastern China, and less precipitation in southern China, whereas heavier snow cover in the northern TP results in enhanced rainfall in southeastern and northern China and weakened precipitation in the Yangtze River basin. The linkage is attributed to anomalous westerly winds in the upper troposphere at around 200 hPa and to changes of the southern branch of westerlies at 500 hPa on the south side of the TP, which are caused by lasting diabatic heat anomalies over the TP. The shifts in position of the westerly jet at the exit region and negative anomalies of geopotential height at 500 hPa further result in anomalous anticyclone over the East China Sea and the corresponding 850-hPa water vapor convergence and influence the anomalous summer precipitation belt in EC.

Seasonal persistence of soil moisture anomalies related to freeze–thaw over the Tibetan Plateau and prediction signal of summer precipitation in eastern China

“…The atmosphere component is the Community Atmosphere Model Version 4, and the land component is the Community Land Model Version 4 (CLM4). CESM has been widely used in other studies (e.g., Hurrell et al 2013) and can effectively simulate general circulation and climate characteristics over the TP and surrounding regions (Wang et al 2017). Studies have also suggested that CLM4 has good performance for land surface processes (Lawrence et al 2011) and can well describe soil moisture characteristics in FT processes .…”

“…Sea surface temperature anomalies as currently the most significant signal (e.g., the El Niño/La Niña phenomena) widely used for climate prediction (e.g., Ropelewski and Halpert 1987;Wang and Eltahir 1999;Wang et al 2000;Zhang et al 1999;Dai and Wigley 2000). Other factors such as soil moisture (e.g., Fischer et al 2007;Koster et al 2003Koster et al , 2004Seneviratne et al 2006;Conil et al 2007;May et al 2017;Ardilouze et al 2018) and snow cover/depth (e.g., Blanford 1884;Chen 1997;Wu and Qian 2003;Ding et al 2010;Wang et al 2017;Yang et al 2017;, have received much attentions. Studies suggested that sea surface temperature has a much smaller effect than soil moisture on predicting precipitation over mid-latitude land (Koster and Suarez 1995;Conil et al 2007;Yang et al 2016).…”

“…The FT process over the TP shows a significant connection with atmospheric circulation anomalies in East Asia (Wang et al 2003(Wang et al , 2008a. Additionally, spring soil moisture anomalies induced by thawing of frozen soils and melting of snow affect summer precipitation in EC (Wang et al 2003(Wang et al , 2017Chow et al 2008). Spring serves as a transition from winter to summer, and because the atmosphere is mainly influenced by land and ocean diabatic heating, seasonal climate prediction has a well-known spring disorder.…”

Influence of Western Tibetan Plateau Summer Snow Cover on East Asian Summer Rainfall

“…The Tibetan Plateau has a large snow cover area in the cold seasons (Pu et al, ; Z. Wang et al, ). Numerous studies have demonstrated impacts of the cold season Tibetan Plateau snow change on Indian and East Asian climate (e.g., Chen & Wu, ; Dey & Kumar, ; Ding et al, ; Fasullo, ; Hahn & Shukla, ; Kripalani et al, ; Ose, ; Si & Ding, ; C. Wang et al, ; Wu & Kirtman, ; Wu et al, ; Xiao & Duan, ; Zhang et al, ; Zhao et al, ; Zuo et al, ; Zhu et al, ). However, due to the lack of station observations at the high‐elevation region (You et al, ) and the small snow cover area in summer (Z. Wang et al, ), few studies have been conducted on the summer snow variations over the Tibetan Plateau and their impacts on the climate variability.…”

“…Wang et al, 2017). Numerous studies have demonstrated impacts of the cold season Tibetan Plateau snow change on Indian and East Asian climate (e.g., Chen & Wu, 2000;Dey & Kumar, 1983;Ding et al, 2009;Fasullo, 2004;Hahn & Shukla, 1976;Kripalani et al, 2003;Ose, 1996;Si & Ding, 2013;C. Wang et al, 2017;Wu & Kirtman, 2007;Wu et al, 2010;Xiao & Duan, 2016;Zhang et al, 2004;Zhao et al, 2007;Zuo et al, 2012;Zhu et al, 2015).…”