Observations of middle atmosphere CO from the UARS ISAMS during the early northern winter 1991/92

Journal Article · Mon Feb 15 04:00:00 EST 1999 · Journal of the Atmospheric Sciences

DOI:https://doi.org/10.1175/1520-0469(1999)056<0563:OOMACF>2.0.CO;2· OSTI ID:323714

Allen, D R; Stanford, J L ^[1]; Lopez-Valverde, M A ^[2]; Nakamura, N ^[3]; Lary, D J ^[4]; Douglass, A R ^[5]; Cerniglia, M C ^[6]; Remedios, J J; Taylor, F W ^[7]

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1. Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
2. Instituto de Astrofisica de Andalucia, Granada (Spain)
3. Univ. of Chicago, IL (United States). Dept. of Geophysical Sciences
4. Cambridge Univ. (United Kingdom). Dept. of Chemistry
5. NASA, Greenbelt, MD (United States). Goddard Space Flight Center
6. Applied Research Corp., Landover, MD (United States)
7. Oxford Univ. (United Kingdom). Dept. of Physics

Structure and kinematics of carbon monoxide in the upper stratosphere and lower mesosphere 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{sub 2} 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 through the examined period, but vertical CO gradients in the CTM weaken with time relative to the ISAMS observations.

• OSTI ID: 323714
• Journal Information: Journal of the Atmospheric Sciences, Journal Name: Journal of the Atmospheric Sciences Journal Issue: 4 Vol. 56; ISSN 0022-4928; ISSN JAHSAK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
AIR POLLUTION MONITORING
ATMOSPHERIC CHEMISTRY
C CODES
CARBON MONOXIDE
MATHEMATICAL MODELS
PHOTOCHEMICAL REACTIONS
REMOTE SENSING