A meteor radar network study on the polar-to-tropical mesospheric
coupling during the 2018 Sudden Stratosphere Warming
Abstract
Using advanced meteor radar network observations along with ERA5 data,
we report observational evidence of polar to tropical mesospheric
teleconnections during the 2018 major sudden stratosphere warming (SSW)
event in the northern hemisphere. A peak SSW on February 14, 2018,
characterized by a ~ 45 K rise in polar stratosphere
temperature and a zonal wind reversal of ~ (–25) m/s at
60°N and 10 hPa, is observed. In the tropical lower mesosphere, a
maximum zonal wind reversal (–24 m/s) compared with that identified in
the extra-tropical regions was observed. Moreover, a time delay in the
wind reversal between the tropical/polar stations and the mid-latitudes
was detected. The wind reversal in the mesosphere is due to the
propagation of dominant intra-seasonal oscillations (ISOs) of
30–60-days and the presence and superposition of 8-day period planetary
waves (PWs). The ISOs phase propagation is observed from the high- to
low-latitudes (60°N to 20°N) in
contrast to 8-day PWs phase propagation, indicating the change in the
meridional propagation of winds during SSW. However, the superposition
of dominant ISOs and weak 8-day PWs could be responsible for the delay
of the wind reversal in the tropical mesosphere. Therefore, this study
has strong implications for understanding the reversed (polar to
tropical) mesospheric meridional circulation during SSW.