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Stratospheric warmings during February and March 1993
Author(s) -
Manney G. L.,
Zurek R. W.,
O'Neill A.,
Swinbank R.,
Kumer J. B.,
Mergenthaler J. L.,
Roche A. E.
Publication year - 1994
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/94gl00093
Subject(s) - diabatic , polar vortex , anticyclone , vortex , baroclinity , polar , atmospheric sciences , descent (aeronautics) , zonal and meridional , climatology , latitude , geology , troposphere , physics , meteorology , geodesy , astronomy , adiabatic process , thermodynamics
Two stratospheric warmings during February and March 1993 are described using UKMO analyses, calculated PV and diabatic heating, and N 2 O observed by the CLAES instrument on the UARS. The first warming affected temperatures over a larger region, while the second produced a larger region of reversed zonal winds. Tilted baroclinic zones formed in the temperature field, and the polar vortex tilted westward with height. Narrow tongues of high PV and low N 2 O were drawn off the polar vortex, and irreversibly mixed. Tongues of material were drawn from low latitudes into the region between the polar vortex and the anticyclone; diabatic descent was also strongest in this region. Increased N 2 O over a broad region near the edge of the polar vortex indicates the importance of horizontal transport. N 2 O decreased in the vortex, consistent with enhanced diabatic descent during the warmings.