The Characteristics of Profiles for Wind, Temperature, and Humidity in the Baroclinic Convective Boundary Layer on Xizang Plateau

The characteristics of profiles for wind, temperature and humidity in the baroclinic convective boundary layer on Xizang Plateau were analyzed and discussed based on the observational data of Damxung boundary layer station and the radiosounding data at Lhasa, Gerze and Wuhan during the second field experiment of atmospheric sciences on Qinghai-Xizang Plateau. The results of studies illustrate that the convective boundary layer at daytime on the plateau could develop strongly, with a height of 2 200m which is distinctly higher than that over plain and ocean in middle latitude. The temperature profile in the plateau convective boundary layer has the well mixed characteristics and the maximum value of humidity sometimes appears at certain level in the humidity profile. The budget analyses of heat and water vapour in the plateau convective boundary layer show that the horizontal advection has important effect on the structures of boundary layer. There exists the wind shear phenomenon in the vertical distribution of the average wind speed in the convective boundary layer and the baroclinity formed by the horizontal temperature gradient is the main reason for the formation of the wind shear.