Intercomparison of ILAS-II Version 1.4 and Version 2 target parameters with MIPAS-Envisat measurements

A. Griesfeller (1) , T. von Clarmann (2) , J. Griesfeller (1) , M. Höpfner (2) , M. Milz (2) , H. Nakajima (1) , T. Steck (2) , T. Sugita (1) , T. Tanaka (1) , T. Yokota (1)

1 NIES - National Institute for Environmental Studies
2 IMK-ASF - Institut für Meteorologie und Klimaforschung - Atmosphärische Spurengase und Fernerkundung

We compared measurements taken by two satellite-borne instruments, ILAS-II and MIPAS-Envisat, between May and October 2003. Using the coincidence criteria of ±300 km in space and ±12 h in time for H₂O, N₂O, and CH₄ and the coincidence criteria of ±300 km in space and ±6 h in time for ClONO₂, O₃, and HNO₃, a different number of coincidences have been found for the gases. The data were separated into sunrise and sunset measurements, which correspond to Northern and Southern Hemisphere data, respectively. For the sunrise data of ILAS-II, a clear improvement from Version 1.4 to Version 2.1 was observed for H₂O, CH₄, ClONO₂, and O₃. For ILAS-II N₂O and HNO₃ data there were no large differences between the two data sets. In particular, the ILAS-II Version 1.4 data were unrealistically small for H₂O, CH₄, and O₃ and unrealistically large for ClONO₂ above 20 km to 30 km. The differences between the two algorithm versions for the sunset data were not as large as for the sunrise data for all gases, and for H₂O and CH₄. ILAS-II Version 1.4 data fitted even better to the MIPAS-Envisat measurements than Version 2.0.

Domaines: Océan, Atmosphère

A. Griesfeller, T. von Clarmann, J. Griesfeller, M. Höpfner, M. Milz, et al.. Intercomparison of ILAS-II Version 1.4 and Version 2 target parameters with MIPAS-Envisat measurements. Atmospheric Chemistry and Physics Discussions, 2007, 7 (4), pp.9319-9365. ⟨hal-00302924⟩