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Observations of Middle Atmosphere CO from the UARS ISAMS during the Early Northern Winter 1991/92Structure and kinematics of carbon monoxide in the upper stratosphere and lower mesosphere (10-0.03 hPa) are studied for the early northern winter 1991/92 using the Upper Atmosphere Research Satellite Improved Stratospheric and Mesospheric Sounder (ISAMS) measurements. The study is aided by data from a 6-week parameterized-chemistry run of the Goddard Space Flight Center 3D Chemistry and Transport Model (CTM), initialized on 8 December 1991. Generally, CO mixing ratios increase with height due to the increasing source contribution from CO, photolysis. In the tropical upper stratosphere. however, a local maximum in CO mixing ratio occurs. A simple photochemical model is used to show that this feature results largely from methane oxidation. In the extratropics the photochemical lifetime of CO is long, and therefore its evolution is dictated by large-scale motion of air. evidenced by strong correlation with Ertel potential vorticity. This makes CO one of the few useful observable tracers at the stratopause level and above. Thus CO maps are used to study the synoptic evolution of the polar vortex in early January 1992. Modified Lagrangian mean mixing diagnostics are applied to ISAMS and CTM data to examine the strength of the mixing barrier at the polar vortex edge. It is demonstrated that planetary wave activity weakens the barrier. promoting vortex erosion. The vortex erosion first appears in the lower mesosphere and subsequently descends through the upper stratosphere. and is attributed to effects of planetary wave dissipation. Agreement between ISAMS and CTM is good in the horizontal distribution of CO throughout the examined period, but vertical CO gradients in the CTM weaken with time relative to the ISAMS observations.
Document ID
19990063632
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Allen, D. R.
(Iowa State Univ. of Science and Technology Ames, IA United States)
Stanford, J. L.
(Iowa State Univ. of Science and Technology Ames, IA United States)
Lopez-Valverde, M. A.
(Instituto de Astrofisica de Andalucia Granada, Spain)
Nakamura, N.
(Chicago Univ. Chicago, IL United States)
Lary, D. J.
(Cambridge Univ. Cambridge, United Kingdom)
Douglass, A. R.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Cerniglia, M. C.
(Applied Research Corp. Landover, MD United States)
Remedios, J. J.
(Oxford Univ. Oxford, United Kingdom)
Taylor, F. W.
(Oxford Univ. Oxford, United Kingdom)
Date Acquired
August 19, 2013
Publication Date
February 15, 1999
Publication Information
Publication: Journal of the Atmospheric Sciences
Publisher: American Meteorological Society
Volume: 56
Subject Category
Environment Pollution
Funding Number(s)
CONTRACT_GRANT: NAG5-2787
Distribution Limits
Public
Copyright
Other

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