Albrecht von Bargen

Detection of minor trace species in the atmosphere

The Global Ozone Monitoring Experiment (GOME) is an atmospheric chemistry instrument on-board the ERS-2 satellite which is able to measure a range of important atmospheric trace constituents on a global scale. Atmospheric UV/visible backscatter spectra obtained by the GOME spectrometer were used to retrieve column amounts of key trace species associated with biomass burning events and ozone hole chemistry. In particular, the column distributions of ozone (O3), nitrogen dioxide (NO2), formaldehyde (CH2O), and bromine-monoxide (BrO) were retrieved on an operational basis. The differential optical absorption spectroscopy technique (DOAS) is applied to backscatter spectra and yields slant column distributions of the aforementioned species. Additionally, the vertical columns of O3 and NO2 are provided. A strong enhancement of both the NO2 and CH2O contents were detected during the severe biomass burning event in September 1997 in SE Asia. A higher NO2 content is apparent over a large area within the smoke clouds, where formaldehyde is detected only in areas closest to combustion sources. BrO has been detected on a global scale and under Antarctic winter (ozone hole) conditions. The knowledge about the spatial distribution and the amount of BrO is of high relevance because BrO is a key species for the depletion of stratospheric ozone.

Detection of biomass burning combustion products in the atmosphere from UV/VIS backscatter measurements taken by the GOME spectrometer

The Global Ozone Monitoring Experiment (GOME) is a new atmospheric chemistry instrument on-board the ERS-2 satellite which was launched in April 1995. The GOME is designed to measure a range of atmospheric trace constituents, with particular emphasis on global ozone distributions. We show that atmospheric UV/visible backscatter spectra obtained by the GOME spectrometer may be used to retrieve column amounts of key trace species associated with smoke cloud combustion from biomass burning events. We focus on the severe rain forest burning in SE Asia from August to October 1997. The current operational GOME Data Processor (GDP) was used to retrieve column distributions of NO2 and CH2O in and around the smoke-polluted region. For ground scenes with low cloudiness, the differential optical absorption spectroscopy technique (DOAS) applied to backscatter spectra yields column distributions of NO2 and CH2O in and around the smoke- polluted region. An increase by almost a factor of two of the vertical NO2 content in the tropical atmosphere is apparent over a large area within the smoke cloud; this clearly indicates the ability of GOME to measure tropospheric NO2 content. CH2O is detected only in areas closest to combustion sources and the detected slant column amounts correspond with previous estimations of vertical column amounts of CH2O for biomass savannah burning.