Tropospheric NO₂ columns: a comparison between model and retrieved data from GOME measurements

A. Lauer (1) , M. Dameris (1) , A. Richter (2) , J. P. Burrows (2)

1 IPA - DLR Institut für Physik der Atmosphäre = DLR Institute of Atmospheric Physics
2 IUP - Institut für Umweltphysik [Bremen]

Tropospheric NO₂ plays a variety of significant roles in atmospheric chemistry. In the troposphere it is one of the most significant precursors of photochemical ozone (O₃) production and nitric acid (HNO₃). In this study tropospheric NO₂ columns were calculated by the fully coupled chemistry-climate model ECHAM4.L39(DLR)/CHEM. These have been compared with tropospheric NO₂ columns, retrieved using the tropospheric excess method from measurements by the Global Ozone Monitoring Experiment (GOME) of up-welling earthshine irradiance and the extraterrestrial radiance. GOME is part of the core payload of the second European Research Satellite (ERS-2). For this study the first five years of GOME measurements have been used. The period of five years of observational data is sufficient to enable a comparison based on climatological averages and with global coverage, focussing on the geographical distribution of the tropospheric NO₂, for the first time. A new approach of analysing regional differences (i.e. on continental scales) by calculating individual averages for different environments provides more detailed information about specific NO_x sources and of their seasonal variations. The results obtained enable the validity of the model NO₂ source distribution and the assumptions used to separate tropospheric and stratospheric parts of the NO₂ column amount from the satellite measurements to be investigated.

Domaines: Océan, Atmosphère

A. Lauer, M. Dameris, A. Richter, J. P. Burrows. Tropospheric NO₂ columns: a comparison between model and retrieved data from GOME measurements. Atmospheric Chemistry and Physics Discussions, 2001, 1 (2), pp.411-438. ⟨hal-00300882⟩