Variations in Spring Atmospheric Circulation on the Southwestern Tibetan Plateau During Holocene Linked to High‐ and Low‐Latitude Forcing

Abstract

Reconstructing paleo-atmospheric circulations can improve our understanding of climate change and its driving mechanisms, and serve as the reference for predicting the future climate change (Jiang & Guo, 2013). The Tibetan Plateau (TP) and its surroundings, commonly referred to as the "Third Pole," has a sensitive response to global change, where climate change and its relations to atmospheric circulations at different time scales have attracted much attention (Yao et al., 2013;Zhu et al., 2015). Observations and simulations of the precipitation stable isotope revealed that the Indian summer monsoon (ISM) mainly affected the southern and southeastern TP in summer, and the Westerlies controlled the most portions of the TP in winter (Yao et al., 2013). From a seasonal perspective, previous proxy-based reconstructions and model simulations mainly focus on summer and/or winter changes in the atmospheric circulation (Ramisch et al., 2016;Wang et al., 2018), but rarely address the variations in the transitional seasons (spring/autumn).The springtime atmospheric circulation over the TP and its surroundings is now characterized by a transition pattern from winter-type to summer-type (Schiemann et al., 2009). This pattern involves a shift of the Westerlies from the south of the TP to the north, and a shift of the meridional circulation between the TP and low latitudes changes from the Hadley circulation to the monsoon circulation. Influenced by the variations in the atmospheric circulations, the current spring precipitation of the TP increased significantly but showed regional differences (Shen et al., 2015), which altered the starting date of the vegetation growing season (Shen et al., 2015) and mediated the shift rates of the alpine tree lines (Sigdel et al., 2018). Therefore, reconstructing the variations in the spring atmospheric circulation of the TP can improve our understanding of changes in climate and ecology.

Study on the Vertical Distribution and Transport of Aerosols in the Joint Observation of Satellite and Ground-Based LiDAR

“…[36]. ERA5 reanalysis data and the HYSPLIT_4 (Hybrid Single-Particle In-tegrated Trajectory) model were used to analyze the weather patterns and air particle trajectories favored in aerosol formation [37].…”