Odin/OSIRIS observations of stratospheric NO₃ through sunrise and sunset

C. A. Mclinden (1) , C. S. Haley (2)

1 ECCC - Environment and Climate Change Canada
2 CRESS - Centre for Research in Earth and Space Science [Toronto]

The nitrate radical (NO₃) has been detected in visible limb-scattered spectra measured by the Optical Spectrograph and InfraRed Imager System (OSIRIS) on-board the Odin satellite when observing at large solar zenith angles (91?97°). Apparent slant column densities of NO₃ at tangent heights between 10 and 45 km are derived via spectral fitting in the 590?680 nm window. Using observations from multiple scans spanning solar zenith angles of 91?97°, the rapid evolution of NO₃ through sunrise and sunset can be traced. Slant column densities are found to be consistent with those simulated using a radiative transfer model with coupled photochemistry. In addition, a strong dependence of NO₃ with temperature is observed. These results indicate that OSIRIS possesses signal-to-noise sufficient to make useful measurements of scattered sunlight out to solar zenith angles of 96?97° and suggests the possibility of retrieving profile information for NO₃ and other species at large solar zenith angles.

Domaines: Océan, Atmosphère

C. A. Mclinden, C. S. Haley. Odin/OSIRIS observations of stratospheric NO₃ through sunrise and sunset. Atmospheric Chemistry and Physics Discussions, 2008, 8 (2), pp.5901-5917. ⟨hal-00304049⟩