Abstract
Abstract. Using multiple reanalysis datasets and modeling simulations, the trends of Antarctic stratospheric planetary wave activities in early austral spring since the early 2000s are investigated in this study. We find that the stratospheric planetary wave activities in September have weakened significantly since the year 2000, which is mainly related to the weakening of the tropospheric wave sources in the extratropical Southern Hemisphere. As the Antarctic ozone also shows clear shift around the year 2000, the impact of ozone recovery on Antarctic planetary wave activity is also examined through numerical simulations. Significant ozone recovery in the lower stratosphere changes the atmospheric state for wave propagation to some extent, inducing a slight decrease in the vertical wave flux in upper troposphere and lower stratosphere (UTLS). However, the changes in the wave propagation environment in the middle and upper stratosphere over the subpolar region are not significant. The ozone recovery has a minor contribution to the significant weakening of stratospheric planetary wave activity in September. Further analysis indicates that the trend of September sea surface temperature (SST) over 20∘ N–70∘ S is well linked to the weakening of stratospheric planetary wave activities. The model simulations reveal that the SST trend in the extratropical Southern Hemisphere (20–70∘ S) and the tropics (20–20∘ S) induce a weakening of the wave 1 component of tropospheric geopotential height in the extratropical Southern Hemisphere, which subsequently leads to a decrease in stratospheric wave flux. In addition, both reanalysis data and numerical simulations indicate that the Brewer–Dobson circulation (BDC) related to wave activities in the stratosphere has also been weakening in early austral spring since the year 2000 due to the trend of September SST in the tropics and extratropical Southern Hemisphere.
Highlights
This study has analyzed the trend of Antarctic stratospheric planetary wave activities in early austral spring since the early 2000s, based on various reanalysis datasets and model simulations
Using the change point method, we find that the Antarctic stratospheric wave activities in September have been weakening significantly since the year 2000, which means the intensified trend of wave activities noted in previous research (Hu and Fu, 2009; Lin et al, 2009) are reversed after the year 2000 in early austral spring
Further analysis suggests that the weakening of stratospheric wave activities is related to the weakening of tropospheric wave sources in extratropical Southern Hemisphere, which is mainly contributed by the wave 1 component
Summary
Stratospheric planetary wave activities have important influences on stratospheric temperature (e.g., Hu and Fu, 2009; Lin et al, 2009; Li and Tian, 2017; Li et al, 2018), the polar vortex (e.g., Kim et al, 2014; Zhang et al, 2016; Hu et al, 2018), and the distribution of chemical substances (e.g., Gabriel et al, 2011; Ialongo et al, 2012; Kravchenko et al, 2012; J. Zhang et al, 2019). Banerjee et al (2020) analyzed the observations and reanalysis datasets They found that, following the ozone recovery after the year 2000, the increase in the SAM index and the poleward shifting of tropospheric jet position and the Hadley cell edge all experienced a pause. Their results suggest that ozone depletion and recovery have made important contributions to the climate shift that occurred around the year 2000 in the Southern Hemisphere.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
