Height Variation in the Summer Quasi-Zero Wind Layer over Dunhuang, Northwest China: A Diagnostic Study

作     者：Yi YUAN Yi LIU Lingkun RAN Hua ZHANG Yi YUAN;Yi LIU;Lingkun RAN;Hua ZHANG

作者机构：School of Environmental StudiesChina University of GeosciencesWuhan 430074 Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 State Key Laboratory of Severe WeatherChinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 

出 版 物：《Journal of Meteorological Research》 (气象学报（英文版）)

年 卷 期：2022年第36卷第4期

页      面：618-630页

核心收录：

学科分类：07[理学] 0706[理学-大气科学] 

基　　金：Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA17010105) Science and Technology Development Plan Project of Jilin Province(20180201035SF) Flexible Talents Introducing Project of Xinjiang(2019) National Key Scientific and Technological Infrastructure Project“Earth System Numerical Simulation Facility”(EarthLab). 

主　　题：stratospheric quasi-zero wind layer stratospheric airships South Asian high 

摘      要：This study investigates the variation in the stratospheric quasi-zero wind layer(QZWL)over Dunhuang,Gansu Province,China,on 9 August 2020 using sounding observations from the Dunhuang national reference station and the fifth generation of ECMWF atmospheric reanalysis data(ERA5).The QZWL over Dunhuang was located between 18.6 and 20.4 km on 9 August 2020.The South Asian high(SAH)and subtropical westerly jet jointly affected the QZWL.As the SAH retreated westward,the upper-level westerly jet over Dunhuang strengthened,and the jet axis height increased.As a result,the zonal westerly wind was lifted to a higher altitude,and the wind speed of 100–70 hPa increased,raising the QZWL.In addition,the east–west oscillation of the SAH occurred earlier than the adjustment of the QZWL altitude,which can be used as a forecasting indicator for the QZWL.To further explore the mechanism responsible for the QZWL adjustment,the forcing terms in the equations for zonal wind,kinetic energy,and vertical wind shear were analyzed.The results showed that the upper-level geopotential gradient was the basic physical factor forcing the local change in zonal wind and kinetic energy.The change in zonal wind and kinetic energy led to the uplift of the QZWL.The results revealed that the vertical shear of horizontal wind could adequately indicate the stratospheric QZWL location.