Interdecadal Change in the Effect of Tibetan Plateau Snow Cover on Spring Precipitation over Eastern China around the Early 1990s

Abstract

Previous works extensively investigated the influences of the winter-spring Tibetan Plateau snow cover (TP, TPSC) on climate variability over the East Asia. The present work documents an interdecadal-changed impacts of different spring TPSC anomaly (TPSCA) patterns on spring precipitation over eastern China (SPEC) around the early 1990s. It is found that the correlation of eastern and western TPSCA shifts from negative to positive around 1990. The empirical orthogonal function (EOF) analysis applying onto the spring TPSCA during 1970–1989 (P1) and during 1991–2017 (P2) adds additional support for such interdecadal change in the relationship between the eastern and western TPSCA. Specifically, the leading EOF (EOF1) mode in P1 shows an out-of-phase pattern with opposite signals lying over the eastern and western TP, while the counterpart in P2 is characterized by an in-phase pattern over the entire TP. Corresponding to more (less) snow cover in the eastern (western) TP in P1, a significant TP cold cyclone (TPCC) and a downstream anticyclone over the western North Pacific are observed. Anomalous southerly flow prevailing east to TPCC could bring the warm-wet air from tropics to the coast of East Asian, which largely enhances the spring precipitation south to Yangtze River Valley (YRV). By contrast, regarding more snow cover both in the eastern and western TP in P2, a relatively northward-displaced and wider TPCC sweeps over the entire TP compared with the TPSC-induced TPCC in P1. Moreover, there are significant sinking anomalies observed in the downstream YRV-HRV region, which leads to suppressed spring precipitation over there via the dry-cold advection process. Hence, these discrepancies of local and downstream atmospheric circulation induced by the out-of-phase and in-phase TPSCA patterns in two epochs play an important role in resulting in the interdecadal shift of the SPEC anomaly pattern around 1990.

The Seasonal Evolution of the Tibetan Plateau Snow Cover Related Moisture During Spring‐to‐Summer

“…Previous studies revealed that snow cover can be modulated by the above anomalous atmospheric circulation, which could impact snow variation by modulating upward/downward motion as well as water vapor transport (e.g., Jia et al., 2021; Qian et al., 2019; Zhang, Guo & Wen, 2021; Zhang, Jia & Wen, 2021). However, in the current work, we want to emphasize that snow cover could also play a role in the above atmosphere.…”

Impact of Tibetan Plateau vertical heating on the Asian summer monsoon on the interdecadal scale

“…More specifically, it has been found that a warm TP leads to above‐normal summer rainfall in the middle and lower reaches of the Yangtze River valley (Ding et al, 2009; Wang et al, 2008; Xu et al, 2013; Zhang et al, 2004). Since the late 1990s, the TP has shown a notable warming trend, which has intensified the East ASM, thus causing a northward migration of the summer rainfall belt in East Asia (Si & Ding, 2013; Zhang et al, 2021). Moreover, several studies have also indicated that the heat source over the TP can cause significant climate fluctuations in other regions in the northern Hemisphere, such as South Asia (Sun et al, 2021; Wu & Zhang, 1998; Zhang et al, 2017).…”

Changes in the Dominant Mode of Summer Precipitation Over the Central‐Eastern Tibetan Plateau Around the Mid‐1990s

“…For instance, it has been reported that the spring and summer relationship of the precipitation over the southeast China experienced an out‐of‐phase decadal changes in 1990s, which is mainly driven by the warming SST over the Indian Ocean (Ren et al., 2017; Z. Zhu et al., 2014). In the TP regions, an interdecadal shift of the TP snow cover has been found and its impact on the precipitation over the eastern China is increased after the 1990s (C. Zhang et al., 2022; Jia et al., 2021). Meanwhile, C. Zhou et al.…”