Sun, Fang, Zhou, Shunwu, Yang, Cheng, Ma, Xulin, Wang, Meirong, Sun, Yang, and Zhou, Shu
The Tibetan Plateau Vortex (TPV) is mainly divided into east moving (E-TPV), northeast moving (NE-TPV) and so on according to its moving path after moving off the Tibetan Plateau (TP). Based on the database of TPV from 1979 to 2018, this paper mainly makes statistical analysis on the NE-TPV in summer. According to its moving-off position, NE-TPV is subdivided into westward vortex (denoted as NE I -TPV) and eastward vortex (denoted as NE II -TPV). In terms of source, structure, circulation, moving speed, life history and influence on precipitation, the characteristics of two types of NE-TPVs were analyzed and compared with E-TPV to reveal the activity characteristics of the NE-TPVs and the similarities and differences between them. The results show that: (1) The NE I -TPV is mainly generated in the northwest of the TP, while the NE II -TPV and E-TPV are generated in the whole TP. There are mainly three centers of vortex sources: west, middle and east. The eastern sources of TPV with different paths differ greatly in north-south location and concentration. The eastern source of NE I -TPV is northward and concentrated, while the E-TPV is southward and dispersed, and NE II -TPV is between the former two. (2) The intensity of NE II -TPV is stronger than that of NE I -TPV before moving off, and the ascending motion of these two is located near the vortex center. After moving off, the relative vorticity and vertical velocity of both of them weakened significantly, and the maximum upward movement of NE I -TPV moved to the northeast of the vortex, while the NE II -TPV is similar to E-TPV, and its rising region is located in the southeast of the vortex. (3) The moving direction before moving off and moving-off position of TPV is mainly affected by the 200 hPa westerly fluctuations, while after moving off, the moving direction is mainly affected by 500 hPa troughs and ridges. Among them, the Hetao High-Pressure Ridge is particularly important in blocking NE-TPV. (4) Besides the influence of altitude difference, the moving speed of TPV is closely related to its moving direction, so the TPV moving eastward move faster. (5) NE II -TPV and E-TPV have longer mean life history than NE I -TPV, meanwhile, they often result in a wider range of precipitation and a higher proportion of rainstorms. The precipitation of NE I -TPV is mainly located in the Hexi Corridor. While the precipitation of NE II -TPV is mainly located in the eastern part of Northwest China. • According to its moving-off position, the northeast moving Tibetan Plateau Vortex (NE-TPV) is subdivided into westward vortex (denoted as NE I -TPV) and eastward vortex (denoted as NE II -TPV). • It is found that TPV mainly has three sources, which are located in the west, the middle and the east of the TP. The eastern source of TPVs with different paths is quite different. • After moving off the TP, the maximum ascending motion of NE I -TPV is located in the northeast side of the vortex, while that of NE II -TPV is located in the southeast side of the vortex, just like the E-TPV. • On the one hand, the moving speed of TPV is affected by the altitude difference. On the other hand, it is also related to the moving direction. [ABSTRACT FROM AUTHOR]