Nighttime nox from sciamachy lunar occultation measurements
Proc. of the First ‘Atmospheric Science Conference’, ESRIN
Vertical profiles of stratospheric NO2 and NO3 have been retrieved from moderately resolution atmospheric lunar transmission spectra measured by SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography) on board the ENVISAT (Environmental Satellite). The measurements were taken over the high Southern latitude (50o S–90o S). The global spectra fitting method by differential optical depth approach were used to fit NO2 and NO3 using the spectral window of 430–460 nm and 615–680 nm respectively. To assess the accuracy of the retrieved NO2 profiles the SCIAMACHY nighttime NO2 profiles were compared with daytime NO2 profiles measured by Halogen Occultation Experiment (HALOE), using photochemical correction model. The validation results show that the quality of SCIAMACHY nighttime NO2 is high within 5–20% in the altitude range of 24–39 km. Our current understanding of NO3 chemistry and the internal consistency of the retrieved NO3 profiles were verified with a complex and a relatively simple model scheme. The complex model uses a comprehensive photochemistry of the stratosphere and the simple model uses only SCIAMACHY ozone and ECMWF temperature and pressure analyses as input. We found that the retrieved NO3 profiles are in very good agreement with the model calculations within the expected accuracy of 20–35 %.
A paper presented at Proc. of the First ‘Atmospheric Science Conference’, ESRIN, Frascati, Italy 8 – 12 May 2006 (ESA SP-628, July 2006)
Proc. of the First ‘Atmospheric Science Conference’, ESRIN, Frascati, Italy 8 – 12 May 2006 (ESA SP-628, July 2006)