Validation of stratospheric water vapour measurements from the airborne microwave radiometer AMSOS

S. C. Müller (1) , N. Kämpfer (1) , D. G. Feist (2) , A. Haefele (1) , M. Milz (3) , N. Sitnikov (4) , C. Schiller (5) , C. Kiemle (6) , Jakub Urban (7)

1 UNIBE - Universität Bern / University of Bern
2 MPI-BGC - Max Planck Institute for Biogeochemistry
3 IMK - Institute for Meteorology and Climate Research
4 CAO - Central Aerological Observatory
5 FZJ - Forschungszentrum Jülich GmbH | Centre de recherche de Jülich | Jülich Research Centre
6 DLR - German Aerospace Center
7 Chalmers University of Technology [Göteborg]

We present the validation of a water vapour dataset obtained by the Airborne Microwave Stratospheric Observing System AMSOS, a passive microwave radiometer operating at 183 GHz. Vertical profiles are retrieved from spectra by an optimal estimation method. The useful vertical range lies in the upper troposphere up to the mesosphere with an altitude resolution of 8 to 16 km and a horizontal resolution of about 57 km. Flight campaigns were performed once a year from 1998 to 2006 measuring the latitudinal distribution of water vapour from the tropics to the polar regions. The obtained profiles show clearly the main features of stratospheric water vapour in all latitudinal regions. Data are validated against a set of instruments comprising satellite, ground-based, airborne remote sensing and in-situ instruments. It appears that AMSOS profiles have a dry bias of 3?20%, when compared to satellite experiments. A good agreement with a difference of 3.3% was found between AMSOS and in-situ hygrosondes FISH and FLASH and an excellent matching of the lidar measurements from the DIAL instrument in the short overlap region in the upper troposphere.

Domaines: Océan, Atmosphère

S. C. Müller, N. Kämpfer, D. G. Feist, A. Haefele, M. Milz, et al.. Validation of stratospheric water vapour measurements from the airborne microwave radiometer AMSOS. Atmospheric Chemistry and Physics Discussions, 2008, 8 (1), pp.1635-1671. ⟨hal-00303275⟩