Ozone and NO2 are key species determining the chemistry of both the lower and middle atmosphere. Data sets of these compounds are crucial to validate the performance of chemistry-transport models (CTM's), and the analysis and prediction of anthropogenic changes in the chemical composition of the atmosphere of gases of particular importance for stratospheric ozone depletion and the oxidation capacity of the atmosphere, affecting chemically active greenhouse gases.
The large spectral range in combination with the nadir viewing geometry of the Global Ozone Monitoring Experiment (GOME) spectrometer on the ERS-2 satellite allow for the retrieval of two unique products, namely (a) vertical profiles of ozone, with explicit tropospheric information, and (b) NO2 total columns, including the tropospheric column. Deriving reliable quantitative tropospheric information from GOME, and future instruments like Sciamachy on Envisat and OMI on EOS-Chem, is a major challenge for the future and will be investigated in detail in the GOA project.