Comparison of Controlling Parameters for Near-Equatorial Tropical Cyclone Formation between Western North Pacific and North Atlantic  

作　　者：Changhao LU Xuyang GE Melinda PENG 

机构地区：[1]Key Laboratory of Meteorological Disaster of Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science&Technology,Nanjing 210044,China [2]University of Colorado,Colorado Spring,Colorado 80918,USA

出　　处：《Journal of Meteorological Research》2021年第4期623-634,共12页气象学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(42088101)。

摘　　要：In this study,the differences in spatial distribution and controlling parameters for the formation of near-equatorial tropical cyclones(NETCs)between the western North Pacific(WNP)and the North Atlantic(NA)are investigated.NETCs exhibit distinctive spatial variabilities in different basins.Over the past few decades,the majority of NETCs took place in WNP while none was observed in NA.The mechanism behind such a distinguishing spatial distribution difference is analyzed by using statistical methods.It is noted that the dynamical variables such as low-level relative vorticity and vertical wind shear(VWS)are likely the primary controlling parameters.Compared with NA,larger low-level vorticity and smaller VWS appear over WNP.The increase of vorticity attributes a lot to the turning of northeast trade wind.NETCs in WNP tend to occur in the areas with VWS less than 9 m s^(-1),while the VWS in NA generally exceeds 10 m s^(-1).On the other hand,the sea surface temperature in the near-equatorial region of both of the two oceans exceeds 26.5℃and the difference of mid-level moisture is not significant;thus,thermal factors have little contribution to the distinction of NETC activities between WNP and NA.Intraseasonal oscillation(ISO)and synoptic-scale disturbances in WNP are also shown to be more favorable for NETC genesis.More NETCs were generated in ISO active phase.Synoptic-scale disturbances in WNP obtain more energy from the mean flows through the barotropic energy conversion process.The overall unfavorable thermal and dynamic conditions lead to the absence of NETCs in NA.

关 键 词：near-equatorial tropical cyclone(NETC) CYCLOGENESIS genesis potential index(GPI) 

分 类 号：P444[天文地球—大气科学及气象学]