Interhemispheric Meridional Circulation During Sudden Stratospheric Warming. Issue 8 (14th August 2019)

• Record Type: Journal Article
• Authors: Laskar, Fazlul I.; McCormack, John P.; Chau, Jorge L.; Pallamraju, Duggirala; Hoffmann, Peter; Singh, Ravindra P.
• Is Part Of: Journal of geophysical research. Volume 124:Issue 8(2019)
• Page Start: 7112
• Page End: 7122
• Publication Date: 2019-08-14
• Subjects: sudden stratospheric warming -- middle atmospheric dynamics -- interhemispheric circulation -- meteor radar wind -- data assimilation -- equatorial ionosphere; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2018JA026424
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Although sudden stratospheric warming (SSW) is mainly a northern high‐latitude phenomena, there are several reports of a concomitant global dynamical response throughout the mesosphere and lower thermosphere. Published reports based on model simulations so far attributed such variabilities to changes in global circulation; however, there is no clear explanation of how all these regions are physically connected during SSW events. The present investigation uses wind observations from two ground‐based specular meteor radars over northern high latitudes and midlatitudes and global winds from a high‐altitude meteorological analysis system to characterize global mesospheric circulation anomalies for major SSW events during 2010 and 2013. During these events radar observations and the reanalysis winds exhibited strong southward winds over the two northern midlatitude and high‐latitude stations. By removing seasonal variability from the high‐altitude meteorological analyses, we show that these southward wind anomalies are indeed part of a larger global‐scale circulation, which gets set up during SSW and extend from the Northern pole to low‐latitude regions of Southern Hemisphere in the mesosphere and lower thermosphere altitudes. These results also offer a possible explanation of how low‐latitude ionospheric electrodynamics are influenced by the changes in the circulation set in during SSW at high latitudes. Key Points: SMR and high‐altitude assimilation show southward winds at Northern high latitudes and midlatitudes during SSW The southward feature is seen to extend over the whole Northern hemisphere in assimilated zonal mean meridional wind Direct and indirect roles of this meridional circulation on low‐latitude ionosphere‐thermosphere are discussed