Effect of the Vertical Diffusion of Moisture in the Planetary Boundary Layer on an Idealized Tropical Cyclone  

作　　者：Hongxiong XU Dajun ZHAO 

机构地区：[1]State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,China Meteorological Administration,Beijing 100081,China

出　　处：《Advances in Atmospheric Sciences》2021年第11期1889-1904,共16页大气科学进展（英文版）

基　　金：This study was supported in part by the National Natural Science Foundation of China under Grant Nos.41905095,41730960 and 61827901;in part by the National Key R&D Program of China under Grant No.2017YFC1501602.

摘　　要：Previous numerical studies have focused on the combined effect of momentum and scalar eddy diffusivity on the intensity and structure of tropical cyclones.The separate impact of eddy diffusivity estimated by planetary boundary layer(PBL)parameterization on the tropical cyclones has not yet been systematically examined.We have examined the impacts of eddy diffusion of moisture on idealized tropical cyclones using the Advanced Research Weather Research and Forecasting model with the Yonsei University PBL scheme.Our results show nonlinear effects of moisture eddy diffusivity on the simulation of idealized tropical cyclones.Increasing the eddy diffusion of moisture increases the moisture content of the PBL,with three different effects on tropical cyclones:(1)an decrease in the depth of the PBL;(2)an increase in convection in the inner rain band and eyewall;and(3)drying of the lowest region of the PBL and then increasing the surface latent heat flux.These three processes have different effects on the intensity and structure of the tropical cyclone through various physical mechanisms.The increased surface latent heat flux is mainly responsible for the decrease in pressure.Results show that moisture eddy diffusivity has clear effects on the pressure in tropical cyclones,but contributes little to the intensity of wind.This largely influences the wind-pressure relationship,which is crucial in tropical cyclones simulation.These results improve our understanding of moisture eddy diffusivity in the PBL and its influence on tropical cyclones,and provides guidance for interpreting the variation of moisture in the PBL for tropical cyclone simulations.

关 键 词：TROPICAL CYCLONES MOISTURE EDDY DIFFUSIVITY boundary layer wind-pressure relationship 

分 类 号：P461[天文地球—大气科学及气象学]