Towards a climatology of stratospheric bromine monoxide from SCIAMACHY limb observations

N. Sheode (1) , B.-M. Sinnhuber (1) , A. Rozanov (1) , J. P. Burrows (1)

1 IUP - Institute of Environmental Physics [Bremen]

Retrievals of stratospheric bromine monoxide (BrO) profiles from two years of limb measurements from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instrument onboard ENVISAT are analysed and a global climatology of stratospheric BrO is prepared. A comparison of the SCIAMACHY BrO retrievals with a set of four balloon-borne BrO profiles shows mean relative differences in the altitude range from 18 to 30 km between ?42%. The SCIAMACHY BrO observations provide for the first time a picture of the seasonal variation of stratospheric BrO on a global scale. At mid-latitudes of both hemispheres BrO shows a strong seasonal cycle with a maximum in winter and a minimum in summer. The seasonal variation of BrO is closely correlated with changes in nitrogen dioxide (NO₂), confirming our present understanding of gas phase bromine chemistry. Using the SCIAMACHY BrO observations together with the calculated bromine partitioning from a photochemical model constrained by the SCIAMACHY NO₂ observations, the total stratospheric bromine loading is estimated to be 18.5±4 pptv. This indicates a contribution of about 3.5±4 pptv from short lived bromine species in addition to methyl bromide and the halons.

Domaines: Océan, Atmosphère

N. Sheode, B.-M. Sinnhuber, A. Rozanov, J. P. Burrows. Towards a climatology of stratospheric bromine monoxide from SCIAMACHY limb observations. Atmospheric Chemistry and Physics Discussions, 2006, 6 (4), pp.6431-6466. ⟨hal-00301951⟩