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UP: Umweltphysik
UP 11: Datenauswertung und Modellierung (Atmosphäre) - Poster
UP 11.12: Poster
Montag, 18. März 2002, 16:30–18:00, Galerie 1
Validation Of Retrieved Integrated Water Vapour With An Airborne Millimeter–Wave Airborne Radiometer Over Arctic Sea Ice — •Nathalie Selbach1, Tim J. Hewison2, Georg Heygster1, Jungang Miao2, Andrew J. McGrath2, and Jonathan P. Taylor2 — 1Institut für Umweltphysik, Universität Bremen, Postfach 330440, 28334 Bremen — 2Met Office, UK
Recently, an algorithm was developed to retrieve Integrated Water Vapour (IWV) using measurements from the SSM/T2 sensor on the DMSP satellite over the Antarctic. This expects the surface emissivity to be the same for the 3 channels centred on the 183.31 GHz water vapour absorption line. The application of this algorithm was limited to very dry atmospheres, with IWV<1.5 kg/m2, as above this value the 183±1 GHz channel becomes saturated. To extend its range, the 150 GHz channel of the SSM/T2 was used, assuming the emissivity to be the same as at 183 GHz.
Data from a recent airborne campaign over Arctic ice types has been used to validate these algorithms. A microwave radiometer (MARSS) with channels close to those of SSM/T2 was operated on the Met Office C–130 aircraft. Dropsondes were released from the aircraft to provide ground truth for the retrievals.
The algorithm using only the 183 GHz channels accurately retrieved IWV values up to 2 kg/m2. The coefficients of the second algorithm have been modified. The results of this algorithm will be presented and compared with values retrieved from only the 183 GHz channels to test the assumption that the surface emissivity is the same at these frequencies.