Influence of Tibetan Plateau autumn snow cover on interannual variations in spring precipitation over southern China
- PDF / 5,946,643 Bytes
- 16 Pages / 595.276 x 790.866 pts Page_size
- 32 Downloads / 214 Views
Influence of Tibetan Plateau autumn snow cover on interannual variations in spring precipitation over southern China XiaoJing Jia1 · Chao Zhang1,2 · Renguang Wu1 · QiFeng Qian1 Received: 13 June 2020 / Accepted: 9 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Using observational data from 1979–2015 and a linear baroclinic model (LBM), the present study examined the impact of autumn snow cover (ASC) over the western Tibetan Plateau (WTP) on the subsequent spring precipitation over southern China (SPSC). Focus was placed on the interannual time scale of the snow-precipitation relationship. The ASC over the WTP is positively correlated with the SPSC, and this snow-precipitation relationship is independent of sea surface temperature anomalies over the tropical Indo-Pacific regions. When the ASC over the WTP is more extensive than normal, in the following spring, anomalous southerly winds over eastern China occur and transport water vapor northward from the tropical ocean to the interior of the continent, which is favorable for more SPSC. Further analysis of the energy budget shows that the anomalous ASC over the WTP persists to the following spring because of local positive snow-air feedback. Higherthan-normal ASC over the WTP can cool the above atmosphere and is associated with pronounced negative geopotential height anomalies that dominate in the East Asian-western North Pacific region. These negative height anomalies lead to a weakened and northward-shifted spring East Asian subtropical jet (EASJ). The changes in the spring EASJ lead to divergent anomalies at the upper level over the upstream as well as the central areas of the EASJ; therefore, anomalous low-level convergence and ascent motion dominate over coastal East Asia and in nearby regions, providing a favorable environment for positive SPSC anomalies. Keywords Autumn snow cover · Tibetan plateau · Southern china · Spring precipitation
1 Introduction Southern China is an important economic region and the most densely populated region in China. Flooding and drought exert strong influences on the daily lives of millions of people as well as on the economic growth of this region. Numerous works have been devoted to investigating the mechanisms and predictability of summer precipitation over southern China, as compared to other seasons, the summer has more precipitation in this region (e.g., Lau and Li 1984; Chang et al. 2000; Wu et al. 2003; Chen et al. 2013, * XiaoJing Jia [email protected] 1
Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province, School of Earth Sciences, ZheJiang University, HangZhou, Zhejiang, China
Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences, Fudan University, Shanghai, China
2
You and Jia 2018; Jia et al. 2019). As determined by previous work, the climatological mean spring precipitation can account for more than 30% of the annual total precipitation over southern China (e.g., Feng and Li 2011). Anomalous spring precipita
Data Loading...
