Observational Occurrence of Tropical Cyclone Ducts from GPS Dropsonde Data
- 作者：丁菊丽费建芳黄小刚程小平胡晓华
- 会议时间：2013-10-23
- 母体文献：第30届中国气象学会年会论文集
- 会议名称：第30届中国气象学会年会
- 会议地点：南京
- 主办单位：中国气象学会
- 语种：chi
摘要
Based on the global position system (GPS) dropsonde data,the Japan Meteorology Agency (JMA) Regional Spectral Model (RSM) analysis data,National Centers for Environmental Prediction (NCEP) reanalysis data,the satellite products from Naval Research Lab (NRL),and the best track tropical cyclone (TC) data sets from the Shanghai Typhoon Institute (STI),the statistical characteristics of the ducts induced by TCs (TC-Ducts) over the Western North Pacific (WNP) were analyzed for the period of September 2003 to September 2006,and two typical strong duct cases with remarkable differences in formation cause were analyzed and compared.There are 212 cases in the total of 357 dropsondes showing ducting conditions,with the occurrence percentage of about 59%.Of the total 212 TC-Duct events,profiles with multiple ducting layers make up nearly a half,with the main type of ducts being elevated ducts; besides,weak ducts make up over a half,resulting in a weak median duct strength and thickness.However,ducts formed in the transition zone,especially on the left side of TC tracks,tend to be much stronger and thicker than those formed inside TCs.The former is induced by the interaction between TCs and their surrounding systems,such as the inrush of dry and cold air from the north on the left side of TC tracks.The latter is associated with the successive subsidence in the spiral cloud band gaps.Besides,with the increase of TC intensities,the associated ducts inside TCs tend to be much stronger and thicker and to appear at higher altitudes.