Observational Analysis of Troposphere and Low Stratosphere at Minfeng Station on North Side of Qinghai-Xizang Plateau in July 2011
In order to meet the third Tibetan Plateau Experiment of Atmospheric Sciences,the Urumqi Institute of Desert Meteorology of China Meteorological Administration carried out an atmospheric scientific experiment on the detection of troposphere and low stratosphere using a radiosonde at Minfeng station on the north side the Qinghai-Xizang Plateau in July 2011.By analyzing the intensive radiosonde data obtained at Minfeng sounding station from 1 to 31 July 2011,the results show that:(1) Because of the thermal influence of plateau terrain,the height of troposphere may reach more than 16 000 m in summer at Minfeng station,its absolute height is approximately same with the absolute height of troposphere at Everest region.(2) Summer subtropical westerly jet on the north side of the Qinghai-Xizang Plateau behaves strongly,showing the east-west direction distribution,and thickness is about 12 000 m.With the maximum wind speed center located in 10 700 to 11 400 m heights,the maximum wind speed can reach 45 m·s-1.(3) Affected by the subtropical westerly jet in the bottom of the west and southwest winds,the water vapor over the northwest of the Qinghai-Xizang Plateau will be transported to the south of Tarim basin in summer.There have a high relative humidity value layer from 3 000 to 7 500 m heights at Ruoqiang,Minfeng and Hetian stations.The average relative humidity is about 60% to 70%,maximum humidity 85%,below the height of 3 000 m and a height of 8 000 m above the atmosphere with low humidity.(4) The convective boundary layer in daytime can be up to 3 200 m heights and the stable boundary layer in nighttime is about 1 200 heights,which is far higher than the observations of the Mount Everest region,but lower than the boundary layer height in Dunhuang region.