Impact of upstream westerly jet stream on tropospheric dust over the Tibetan Plateau in boreal spring

Abstract

Upstream westerly jet stream including the Middle East jet stream (MEJS) and the polar front jet stream (PFJS) play important roles in influencing tropospheric dust over the Tibetan Plateau (TP). However, few studies have clarified their combined effects on variation in tropospheric dust over the TP. This study analyzed the relationship between upstream westerly jet stream and dust over the TP from 2000 to 2019 during spring by using a singular value decomposition analysis (SVD). Results show that there were three modes between westerly jet stream and tropospheric dust over the TP, i.e., MEJS dominant type, PFJS dominant type and MEJS-PFJS type. MEJS dominant type represents the northerly position of the MEJS when the intensity of the jet stream increases, and vice versa. PFJS dominant type represents the distribution feature of the PFJS intensity increase and the northerly position of the PFJS. These two types of jet stream are more likely to lead to the transport of dust from the Taklimakan Desert in the northern dust source area of TP, and affect the dust content over TP. MEJS-PFJS type represents the southerly distribution of PFJS when MEJS intensifies, where the dust content over TP is more closely related to the local dust emission of TP.