ORCID Profile
0000-0001-6528-0072
Current Organisation
University of Adelaide
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: American Geophysical Union (AGU)
Date: 07-11-2019
DOI: 10.1029/2019JD030735
Publisher: Elsevier BV
Date: 2004
Publisher: Wiley
Date: 07-02-2022
Publisher: American Geophysical Union (AGU)
Date: 04-1998
DOI: 10.1029/98JD00482
Publisher: American Geophysical Union (AGU)
Date: 25-06-1970
DOI: 10.1029/2002JD002500
Publisher: American Geophysical Union (AGU)
Date: 07-08-2022
DOI: 10.1029/2022JD036558
Abstract: Twenty six years of medium frequency (MF) radar wind measurements made from 1994 to 2019 at Davis Station (68.6°S, 77.9°E) are used to study the mean response of the mesosphere‐lower thermosphere to stratospheric warmings in the Southern Hemisphere. Warming events were detected using Modern‐Era Retrospective Analysis for Research and Applications (MERRA2) data with a systematic search for reductions in the zonal‐mean circulation at 60°S and corresponding increases in polar temperatures. Some 37 events were identified, including the 2002 major warming and the large event of 2019, with an average of 1–2 warmings per year. At the 10 hPa level, the polar cap temperature increases ranged from 3 to 28 K, with a mean value of 12 K, while the zonal wind speed reductions varied between −6 and −43 ms −1 , with a mean value of −15 ms −1 . Peak values occurred near 40 km. Warmings occurred mainly between August and October, with a small peak in occurrence in April/May. The MF radar data showed an average reduction in the mesospheric eastward winds of about 5–7 ms −1 at heights near 75 km that occurred 3–4 days prior to the changes in the stratosphere. Warming events were driven by episodic intensifications in planetary wave litudes, with quasi‐stationary planetary scale waves (PW) 1 being especially important. PW Eliassen‐Palm flux ergences show a systematic behavior with time and height that is consistent with a poleward residual circulation and downwelling over the pole prior to the warming events and an equatorward flow and upwelling after the peak of the events.
Publisher: American Geophysical Union (AGU)
Date: 07-2010
DOI: 10.1029/2010GL044086
Publisher: American Geophysical Union (AGU)
Date: 27-10-2004
DOI: 10.1029/2004JD004697
Publisher: American Geophysical Union (AGU)
Date: 25-06-2013
DOI: 10.1002/JGRD.50372
Publisher: American Geophysical Union (AGU)
Date: 02-08-2011
DOI: 10.1029/2011JD015625
Publisher: Elsevier BV
Date: 02-2006
Publisher: American Geophysical Union (AGU)
Date: 10-2005
DOI: 10.1029/2004RS003055
No related grants have been discovered for Sujata Kovalam.