An Idealized Numerical Study of the Effects of Uniform Zonal Winds on Tropical Cyclogenesis  

作　　者：CAO Xi 

机构地区：[1]Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences

出　　处：《Atmospheric and Oceanic Science Letters》2015年第6期345-351,共7页大气和海洋科学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.41505048,41461164005,41275001,41230527,and 41475074)

摘　　要：The effect of uniform zonal winds on tropical cyclone(TC)genesis is examined on a beta plane using an idealized mesoscale model.The simulation results show that uniform easterly and westerly flows are both favorable for TC genesis.However,uniform easterly flows result in a faster TC genesis rate compared with uniform westerly flows.It is found that faster TC genesis is associated with greater surface heat fluxes and convection during the early stage.The superposition of uniform easterly flows and the beta effect results in greater surface heat fluxes and convection around the TC center compared with uniform westerly flows.Meanwhile,TC genesis is closely associated with the size and intensity of a mid-level circulation.The joint greater convection induced by the easterly flows and beta effect results in enhancement of the vertical temperature gradient,which is associated with the intensification of mid-level circulation.The strong and compact mid-level circulation is more favorable for efficient conversion of latent heat energy to the kinetic energy of the lower-level cyclonic winds.Thus,uniform easterly flows are more favorable for TC genesis than uniform westerly flows.The effect of uniform zonal winds on tropical cyclone(TC)genesis is examined on a beta plane using an idealized mesoscale model.The simulation results show that uniform easterly and westerly flows are both favorable for TC genesis.However,uniform easterly flows result in a faster TC genesis rate compared with uniform westerly flows.It is found that faster TC genesis is associated with greater surface heat fluxes and convection during the early stage.The superposition of uniform easterly flows and the beta effect results in greater surface heat fluxes and convection around the TC center compared with uniform westerly flows.Meanwhile,TC genesis is closely associated with the size and intensity of a mid-level circulation.The joint greater convection induced by the easterly flows and beta effect results in enhancement of the vertical temperature gradient,which is associated with the intensification of mid-level circulation.The strong and compact mid-level circulation is more favorable for efficient conversion of latent heat energy to the kinetic energy of the lower-level cyclonic winds.Thus,uniform easterly flows are more favorable for TC genesis than uniform westerly flows.

关 键 词：UNIFORM ZONAL winds TROPICAL CYCLOGENESIS idealize 

分 类 号：P444[天文地球—大气科学及气象学]