TOTAL AND TROPOSPHERIC BrO DERIVED FROM GOME AND SCIAMACHY AS PART OF THE TEMIS PROJECT

Bromine monoxide plays an important role in the chemistry of the polar atmosphere because of its high efficiency as a catalyst of the ozone destruction in both the stratosphere and the troposphere. In the polar boundary layer, large cyclic emissions are observed every year at spring (the so-called "bromine explosion" phenomenon), which are responsible for the occurrence of fast and efficient tropospheric ozone destruction events. Total columns of BrO have been monitored by the GOME instrument onboard the ESA ERS-2 satellite since 1995. Since July 2002, similar observations can be obtained with SCIAMACHY on the ENVISAT platform. In the present contribution, analyses for total and tropospheric BrO columns derived from both instruments are described, with a focus on the assessment of their mutual consistency. Attempts to extract quantitative estimates of the tropospheric BrO contents over polar and mid-latitude regions are presented, using an algorithm that combines GOME measurements with SLIMCAT 3D chemical transport calculations. Key aspects of the tropospheric BrO retrieval and current sources of uncertainties are discussed.