Composition and Chemistry
Validation of Aura Microwave Limb Sounder BrO observations in the stratosphere
Article first published online: 20 DEC 2007
Copyright 2007 by the American Geophysical Union.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 112, Issue D24, 27 December 2007
How to Cite
2007), Validation of Aura Microwave Limb Sounder BrO observations in the stratosphere, J. Geophys. Res., 112, D24S41, doi:10.1029/2007JD008817., et al. (
- Issue published online: 20 DEC 2007
- Article first published online: 20 DEC 2007
- Manuscript Accepted: 22 OCT 2007
- Manuscript Revised: 6 SEP 2007
- Manuscript Received: 13 APR 2007
- bromine monoxide;
 Validation of stratospheric BrO vertical profiles obtained by the Microwave Limb Sounder (MLS) on the Aura satellite is discussed. MLS BrO measurements are compared with expectations of its latitudinal and seasonal dependence, as well as with more localized balloon-borne measurements of BrO. We describe the expected precision and systematic errors of the version 2.2 retrieval and show that scientific studies using MLS BrO vertical profiles require extensive averaging to increase the signal-to-noise ratio to useful values. A monthly zonal mean over a 10° latitude bin (about 3,000 individual profiles) results in a precision of approximately ±4 ppt (∼25% of a typical daytime signal). Moreover, it is necessary to take day/night differences to remove large biases. The pressure range over which the data are considered useful is 10 to 3.2 hPa. Over this range, the estimated accuracy in the day/night difference is about ±20%. The vertical resolution is 5.5 km for 10 to 3.2 hPa. Day/night differences are a good measure of daytime BrO from 10 to 4.6 hPa; for 3.2 hPa the nonnegligible nighttime BrO needs to be accounted for. We infer total inorganic bromine (Bry) to be 22.1 ± 5.5 ppt on the basis of analysis of MLS measurements of BrO, which implies a contribution of 6.5 ± 5.5 ppt to stratospheric bromine from sources other than long-lived CH3Br and halons.