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

[摘要] TroposphericNO₂ plays a variety of significant roles in atmospheric chemistry. In the troposphere it is one of the mostsignificant precursors of photochemical ozone (O₃) production andnitric acid (HNO₃). In this study tropospheric NO₂ columns were calculated by the fully coupled chemistry-climate modelECHAM4.L39(DLR)/CHEM. These have been compared with tropospheric NO₂ columns, retrieved using the tropospheric excess methodfrom measurements by the Global Ozone Monitoring Experiment (GOME) of up-welling earthshine radiance and the extraterrestrialirradiance. GOME is part of the core payload of the second European Research Satellite (ERS-2). For this study the first five years of GOMEmeasurements have been used. The period of five years of observational data is sufficiently long to facilitatefor the first time a comparison based on climatological averages with global coverage, focussing on thegeographical distribution of the troposphericNO_2.

A new approach of analysing regional differences (i.e. on continental scales) by calculating individual averages for different environmentsprovides more detailed information about specific NO_xsources and of their seasonal variations. The results obtained enable the validity of the modelNO₂ source distribution and theassumptions used to separate tropospheric and stratospheric parts of the NO₂ column amount from the satellite measurements to beinvestigated.

[学科分类] 大气科学