[A-AS08] Stratosphere-troposphere interaction

[AAS08-11] The Coupling between the Troposphere and Stratosphere at Middle and High Latitudes

★Invited Papers

*Wenshou Tian¹, Jinlong Huang¹, Ruhua Zhang¹, Jiankai Zhang¹, Shiyan Zhang¹ (1. College of Atmospheric Sciences, Lanzhou University,China)

Keywords:stratosphere-troposphere coupling, planetary waves, polar vortex, BD circulation

The stratosphere and the troposphere coupling is a hot topic in recent years while the stratospheric polar vortex plays a critical role in this coupling at middle and high latitudes. Up to date, the underlying mechanisms and key processes involved in this coupling are still under wide debate. In this work, the connections of tropospheric blockings, eddy driven jet, planetary waves with the stratospheric polar vortex strength and position are investigated. In addition, the role of the large scale BD circulation played in the stratosphere troposphere dynamical coupling at middle and high latitudes is also discussed. The analysis reveals that the blocking frequency has a close relationship with the stratospheric polar vortex strength and position. The connections between blockings and the polar vortex are controlled by the linear and nonlinear wave interference effects while the BD circulation induced airmass transport can significantly modulate stratosphere troposphere coupling at high latitudes at relatively longer time scales. The thermal-dynamical anomalies in the polar stratosphere can get into the polar troposphere under favorable conditions and we found that it is the duration of upward propagation of planetary waves in mid-high latitude upper troposphere, rather than the wave strength that controls the downward extension of the stratospheric anomalies.