Recent Advances in the Study of Atmospheric Vertical Structures in Upper Troposphere and Lower Stratosphere

The issues in the atmospheric tropopause structure and its variation are crucial in the study of stratosphere-troposphere exchange and the balance of atmospheric tracers in the upper troposphere and lower stratosphere,and the change of global tropopause height is a significant indicator in the climate change caused by human activity.Therefore,the study of tropopause,particularly the finer structure and key processes,arouses the attention in the world.In this paper,recent advances in the study of a few basic scientific problems on the definitions of tropopause(such as thermal,dynamical,and chemical definitions,and relationships among them),tropopause being a interface or a layer and the role of mixing in the transition between troposphere and stratosphere,and the distribution feature of tropopause inversion layer and its formation,are reviewed,and current problems among them are given some comments.