Do minor sudden stratospheric warmings in the Southern Hemisphere (SH) impact coupling between stratosphere and mesosphere\u2013lower thermosphere (MLT) like major warmings?

S Eswaraiah,Huixin Liu,Jaewook Lee,M Venkat Ratnam,Yong Ha Kim

doi:10.1186/s40623-017-0704-5

Abstract

We have investigated the coupling between the stratosphere and mesosphere–lower thermosphere (MLT) in the Southern Hemisphere (SH) during 2010 minor sudden stratospheric warmings (SSWs). Three episodic SSWs were noticed in 2010. Mesospheric zonal winds between 82 and 92 km obtained from King Sejong Station (62.22°S, 58.78°W) meteor radar showed the significant difference from usual trend. The zonal wind reversal in the mesosphere is noticed a week before the associated SSW similar to 2002 major SSW. The mesosphere wind reversal is also noticed in “Specified Dynamics” version of Whole Atmosphere Community Climate Model (SD-WACCM) and Ground-to-topside model of Atmosphere and Ionosphere for Aeronomy (GAIA) simulations. The similar zonal wind weakening/reversal in the lower thermosphere between 100 and 140 km is simulated by GAIA. Further, we observed the mesospheric cooling in consistency with SSWs using Microwave Limb Sounder data. However, the GAIA simulations showed warming between 130 and 140 km after few days of SSW. Thus, the observation and model simulation indicate for the first time that the 2010 minor SSW also affects dynamics of the MLT region over SH in a manner similar to 2002 major SSW.Graphical abstract.

Highlights

The study on sudden stratospheric warmings (SSWs) has recently drawn more attention due to its role in altering the Earth’s atmosphere at greater scales
In our earlier study (Eswaraiah et al 2016), we have shown the evidence of 2010 Southern Hemisphere (SH) minor SSW signatures in the mesosphere and investigated the variability of mesosphere dynamics affected by planetary wave (PW) that were associated with SSW
Stratosphere and MLT coupling: zonal wind variations we present the SSW effects on the mesosphere and lower thermosphere zonal winds obtained by King Sejong Station (KSS) meteor radar (MR) and computed by SD-WACCM and GAIA simulations

Summary

Introduction

The study on sudden stratospheric warmings (SSWs) has recently drawn more attention due to its role in altering the Earth’s atmosphere at greater scales. Stratosphere and MLT coupling: zonal wind variations we present the SSW effects on the mesosphere and lower thermosphere zonal winds obtained by KSS MR and computed by SD-WACCM and GAIA simulations.

Results

Conclusion