A dynamical and numerical study of the effects of the topography of the Tibetan Plateau and westerly wind speed on the East Asian Trough. (10th June 2021)

• Record Type: Journal Article
• Authors: Liang, Zhaoming; Xu, Pengcheng; Gao, Shouting; Zuo, Qunjie
• Is Part Of: International journal of climatology. Volume 42:Number 1(2022)
• Page Start: 17
• Page End: 31
• Publication Date: 2021-06-10
• Subjects: dynamical analysis -- East Asian Trough -- Tibetan Plateau -- topography -- westerly wind speed; Climatology -- Periodicals; Climat -- Périodiques; Climatologie -- Périodiques; 551.605
• DOI: 10.1002/joc.7229
• Languages: English
• ISSNs: 0899-8418

Abstract

Abstract: The effects of the topography of the Tibetan Plateau (TP) and westerly wind speed on the East Asian Trough (EAT) is discussed with analysis using a dynamical model, and verified with numerical experiments based on real cases. The dynamical model utilizes a complex terrain function to approximate the TP topography, and derives a stream function generated by the TP terrain. The numerical experiments used for the verification consider the influence of different TP terrain heights and westerly wind speeds. The results show that the topography of the TP has a prominent contribution to the intensity of the EAT, but little effect on its position. The topography of the TP in the westerly winds causes a low‐pressure trough to its east, which promotes a deepening of the EAT to the east side of the TP. In contrast, in the context of the TP, westerly wind speed has an important influence on the position of the EAT, but a minor impact on the deepening of the EAT. A larger westerly wind speed causes a more eastern position of the EAT. These findings indicate that the combination of large‐scale topography and westerly wind speed plays a key role in the evolution of the EAT, in the terms of intensity and position. Abstract : In the westerly winds, the Tibetan Plateau (TP) has a prominent contribution to the southward deepening of the East Asian Trough (EAT), but a minor contribution to its position. In contrast, in the context of TP, westerly wind speed possesses a major impact on the EAT position, but a minor impact on its intensity. These findings can be shown from the stream functions (black stream lines) associated with different plateau heights (colour shaded; a: 1000 m; b: 3000 m; c, e–h: 5000 m; d: 7000 m) in the mean wind speed of 25 m⋅s –1 and different mean wind speeds (e: 21 m⋅s –1 ; f: 23 m⋅s –1 ; a–d, g: 25 m⋅s –1 ; h: 27 m⋅s –1 ) in the context of TP, in which the dashed lines indicate trough lines.