The photochemistry of carbon monoxide in the stratosphere and mesosphere evaluated from observations by the Microwave Limb Sounder on the Aura satellite

K. Minschwaner, G. L. Manney, N. J. Livesey, Hugh Pumphrey, H. M. Pickett, L. Froidevaux, A. Lambert, M. J. Schwartz, P. F. Bernath, K. A. Walker, C. D. Boone

Research output: Contribution to journalArticlepeer-review

Abstract

The photochemical production and loss rates for carbon monoxide (CO) in the stratosphere and mesosphere are evaluated using measurements from the Aura Microwave Limb Sounder (MLS) and the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS). The distributions of reactive trace gases involved in the photochemistry of CO, including OH, CH4, O(D-1), Cl, as well as temperatures for calculating reaction rates, are either directly observed or constrained from observations. We map the CO net production and loss as a function of pressure (10-0.02 hPa, about 30-75 km altitude), latitude (approximately +/- 70 degrees), and season. The results indicate that photochemical loss dominates over production for nearly all conditions considered here. A minimum photochemical loss lifetime of about 10 days occurs near the 2 hPa pressure level, and it follows the region of maximum sunlight exposure. At high latitudes during winter, the CO lifetime is generally longer than 30 days. Time scales become much shorter in spring, however, when CO lifetimes can be 15-20 days poleward of 60 degrees latitude in the upper stratosphere. On the basis of these results, CO is a suitable tracer during autumn to spring above the 0.1 hPa pressure level but not in the upper stratosphere near 1 hPa.

Original languageEnglish
Article numberD13303
Pages (from-to)-
Number of pages9
JournalJournal of Geophysical Research
Volume115
DOIs
Publication statusPublished - 14 Jul 2010

Keywords

  • HALOGEN OCCULTATION EXPERIMENT
  • CROSS-SECTION MEASUREMENTS
  • LOWER THERMOSPHERE
  • MIDDLE ATMOSPHERE
  • TEMPERATURE-DEPENDENCE
  • TERRESTRIAL MESOSPHERE
  • CO
  • VARIABILITY
  • ABSORPTION
  • CH4

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