大理地区对流层至低平流层大气垂直结构的特征分析

Vertical Structure Characteristic from Troposphere to Low Stratosphere in Dali Region over the Southeastern Margin of Qinghai-Xizang Plateau

利用JICA计划中日合作"2008年季风过程与暴雨天气上游关键区综合气象观测试验"期间在大理站的GPS探空资料,分析了季风3个加密观测阶段该地区对流层至低平流层大气垂直结构特征。结果表明,观测期间对流层顶以第二(副热带)对流层顶为主,平均高度为14.8 km,对流层平均温度递减率为6.4℃·km^(-1);对流层顶高度与气温、气压和风速均呈显著的负相关;季风爆发前(后)水汽主要集中在6.6(8.3)km以下对流层;季风爆发前对流层至低平流层被西风带控制;季风爆发阶段对流层至低平流层风速减小,低平流层风向由西风转成东风;季风强盛阶段低平流层东风逐渐下传,对流层高层至低平流层风速增大,风向基本转成偏东风。

Based on the air sounding data at Dali station from JICA project of China-Japan cooperation on the planned integrated meteorological observation experiment about monsoon process and heavy rain over the key upper-stream areas in 2008,the vertical structure characteristic from troposphere to low stratosphere in Dali region over the southeastern margin of the Qinghai-Xizang Plateau were analyzed during pre-onset,onset and maintenance of monsoon.The results show that the second tropopause（subtropics type） was the main local tropopause with its average height being 14.8 km.The average temperature declining rate of the troposphere was 6.4 ℃ · km^-1.The heights of the tropopause had obvious negative correlation with its temperature,pressure and wind speed.The water vapor existed mainly below 6.6 km height before monsoon onset,while did below 8.3 km height after monsoon burst.The west wind predominated from troposphere to low stratosphere before monsoon onset.During the onset period of monsoon,the wind speed decreased and the west wind in low stratosphere turned to east wind from troposphere to low stratosphere.During the powerful and prosperous period of monsoon,the wind speed increased and the wind was east wind by and large from the higher level of the troposphere to low stratosphere.