资源环境科技发展态势分析平台

By using 90 radiosonde stations with high vertical resolution data during the period 1998-2011, the latitudinal variation of the tropopause inversion layer (TIL) in different seasons and the interactions with the inertial gravity wave (IGW) activities in the region covering the Northern Hemispheric latitudes from 5 degrees to 75 degrees are studied. For the midlatitudes, the TIL features show obviously seasonal variations. In the Arctic region, TIL is strong and thick. The averaged Arctic TIL intensity peaks in summer. The intense interaction between the TIL and IGW is found in the region of 5 degrees N to 75 degrees N. The TIL could inhibit the upward propagation of IGWs from similar to 2 km below the tropopause in a larger region (40-75 degrees N). It is found that for the middle-latitude regions, the enhanced wind shear layer just above the tropopause could lead to instability and finally result in IGW breaking and intensive turbulence, which then leads to strong wave energy dissipation and a downward heat flux. The IGW-induced cooling around the tropopause, which resulted from the downward heat flux, then makes a colder and sharper tropopause and finally form the TIL. The IGW-associated strong downward heat flux is also found around the Arctic tropopause. However, there is no corresponding wind shear enhancement above the tropopause. This indicates that this strong heat flux may result from some other processes and then form the strong TIL in the Arctic.