First multi-year occultation observations of CO2 in the MLT by ACE satellite: observations and analysis using the extended CMAM

• DOI: 10.5194/acp-10-1133-2010
• Publication Date: 2010-04-29T14:20:59Z
• Authors: S. R. Beagley; C. D. Boone; V. I. Fomichev; J. J. Jin; K. Semeniuk; J. C. McConnell; P. F. Bernath
• Keywords: Occultation; Mixing ratio

Abstract. This paper presents the first global set of observations CO2 in mesosphere and lower thermosphere (MLT) obtained by ACE-FTS instrument on SCISAT-I, a small Canadian satellite launched 2003. The use solar occultation technique document fall-off mixing ratio MLT region. beginning CO2, or "knee" occurs at about 78 km lies higher than CRISTA-1 measurements (~70 km) but SABER 1.06 (~80 much rocket measurements. We also present CO concurrently which provide important constraints for analysis. have compared ACE with simulations distributions vertically extended version Middle Atmosphere Model (CMAM). Applying standard chemistry we find that cannot get agreement between model although are adequately reproduced. There appears to be 10 offset observed occurring too high. In analyzing disagreement, investigated variation several parameters interest (photolysis rates, formation rate impact uncertainty turbulent eddy diffusion) order explore parameter space this problem. Our conclusions there must loss process 2–4~times faster photolysis will sequester carbon some form other speculated role meteoritic dust as possible candidate. addition, from study highlighted unresolved vertical diffusion 3-D models determining distribution candidate species requires further study.