The Observation and SD‐WACCM Simulation of Planetary Wave Activity in the Middle Atmosphere During the 2019 Southern Hemispheric Sudden Stratospheric Warming. Issue 6 (24th May 2021)

• Record Type: Journal Article
• Authors: Lee, Wonseok; Song, In‐Sun; Kim, Jeong‐Han; Kim, Yong Ha; Jeong, Se‐Heon; Eswaraiah, S.; Murphy, D. J.
• Is Part Of: Journal of geophysical research. Volume 126:Issue 6(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-24
• Subjects: lower thermosphere -- mesosphere -- meteor radar -- planetary waves -- SD‐WACCM -- sudden stratospheric warming; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2020JA029094
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: A sudden stratospheric warming (SSW) is an extremely rare event in the Southern Hemisphere (SH), but occurred in early September 2019. From the Antarctic meteor radar (MR) stations, Davis (68.6˚S, 77.9˚E) and King Sejong Station (62.2˚S, 58.8˚W), quasi 10‐day oscillations were clearly observed in the zonal mesospheric winds before the central date (DOY 253) of the SSW. From the northern low‐latitude Tirupati (13.6˚N, 79.4˚E) MR, a strong wave activity with a period of ∼6 days was detected in the zonal winds right after the central date. This oscillation is also seen in the geopotential height measurements from the Microwave Limb Sounder (MLS) on board the Aura satellite near the Tirupati region. To elucidate the possible source of the quasi 6‐day wave (Q6DW), we use a specified dynamics version of the Whole Atmosphere Community Climate Model (SD‐WACCM) constrained by the reanalysis data from the surface to 50 km. The simulation results show that the amplitude of the westward and equatorward propagating Q6DW was enhanced after the SSW central date in the MLT region, and the Q6DW can be attributed to the baroclinic/barotropic instability in the SH high‐latitude mesosphere where the divergence of Eliassen‐Palm flux occurred. Thus, we suggest that the Q6DW activity observed by the Tirupati MR and MLS originated from the SH high‐latitude mesospheric region. Both the observation and the simulation results clearly demonstrate that the 2019 SH SSW affected not only the high‐latitude MLT region but also the low‐latitude MLT region. Plain Language Summary: A sudden stratospheric warming (SSW) is an extremely rare event in the Southern Hemisphere (SH) but occurred in early September 2019. We report the planetary wave activity (∼10‐day and ∼6‐day periods) in the mesospheric winds measured by Antarctica and tropical meteor radars during the SSW. The 6‐day wave has also been reported in the equatorial electrojet measurements by satellites. The observed planetary wave activity was successfully simulated by a theoretical global circulation model constrained by reanalysis data only up to the stratospheric altitude. The simulation identifies the source of the waves at the high latitude of the Southern Hemisphere and the propagation to the tropical region during the SSW. Key Points: Quasi 10‐day and quasi 6‐day waves (Q6DW) were observed in the mesospheric winds from the Antarctic and tropical meteor radars during the 2019 Southern Hemisphere (SH) sudden stratospheric warming (SSW) The Q6DW were also detected in the geopotential height measurements from the Microwave Limb Sounder over the northern tropical station The Whole Atmosphere Community Climate Model simulation constrained only up to 60 km illucidates that the Q6DW originated from the high‐latitude mesosphere in SH during SSW