Dynamic Impact of the Vertical Shear of Gradient Wind on the Tropical Cyclone Boundary Layer Wind Field  

作　　者：蔡凝昊 徐昕 宋丽莉 白莉娜 明杰 王元 

机构地区：[1]Key Laboratory of Mesoscale Severe Weather of Ministry of Education,School of Atmospheric Sciences,Nanjing University [2]Public Meteorological Service Center,China Meteorological Administration [3]Shanghai Typhoon Institute of China Meteorological Administration [4]Key Laboratory of Meteorological Disaster of Ministry of Education,Nanjing University of InformationScience & Technology

出　　处：《Journal of Meteorological Research》2014年第1期127-138,共12页气象学报（英文版）

基　　金：Supported by the National Nature Science Foundation of China(41275057,91215302);Research Fund of the Key Laboratory of Meteorological Disaster of Ministry of Education,Nanjing University of Information Science&Technology(KLME1103)

摘　　要：This work studies the impact of the vertical shear of gradient wind （VSGW） in the free atmosphere on the tropical cyclone boundary layer （TCBL）. A new TCBL model is established, which relies on five- force balance including the pressure gradient force, Coriolis force, centrifugal force, turbulent friction, and inertial deviation force. This model is then employed to idealize tropical cyclones （TCs） produced by DeMaria＇s model, under different VSGW conditions （non-VSGW, positive VSGW, negative VSGW, and VSGW increase/decrease along the radial direction）. The results show that the free-atmosphere VSGW is particularly important to the intensity of TC. For negative VSGW, the total horizontal velocity in the TCBL is somewhat suppressed. However, with the maximum radial inflow displaced upward and outward, the radial velocity notably intensifies. Consequently, the convergence is enhanced throughout the TCBL, giving rise to a stronger vertical pumping at the TCBL top. In contrast, for positive VSGW, the radial inflow is significantly suppressed, even with divergent outflow in the middle-upper TCBL. For varying VSGW along the radial direction, the results indicate that the sign and value of VSGW is more important than its radial distribution, and the negative VSGW induces stronger convergence and Ekman pumping in the TCBL. which favors the formation and intensification of TC.This work studies the impact of the vertical shear of gradient wind （VSGW） in the free atmosphere on the tropical cyclone boundary layer （TCBL）. A new TCBL model is established, which relies on five- force balance including the pressure gradient force, Coriolis force, centrifugal force, turbulent friction, and inertial deviation force. This model is then employed to idealize tropical cyclones （TCs） produced by DeMaria＇s model, under different VSGW conditions （non-VSGW, positive VSGW, negative VSGW, and VSGW increase/decrease along the radial direction）. The results show that the free-atmosphere VSGW is particularly important to the intensity of TC. For negative VSGW, the total horizontal velocity in the TCBL is somewhat suppressed. However, with the maximum radial inflow displaced upward and outward, the radial velocity notably intensifies. Consequently, the convergence is enhanced throughout the TCBL, giving rise to a stronger vertical pumping at the TCBL top. In contrast, for positive VSGW, the radial inflow is significantly suppressed, even with divergent outflow in the middle-upper TCBL. For varying VSGW along the radial direction, the results indicate that the sign and value of VSGW is more important than its radial distribution, and the negative VSGW induces stronger convergence and Ekman pumping in the TCBL. which favors the formation and intensification of TC.

关 键 词：tropical cyclone vertical shear gradient wind boundary layer 

分 类 号：P444[天文地球—大气科学及气象学] P433