Darmstadt 2008 – scientific programme
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UP: Fachverband Umweltphysik
UP 4: Poster: Atmosphäre und Klima
UP 4.5: Poster
Tuesday, March 11, 2008, 16:30–19:00, Poster B1
Airborne Imaging DOAS — •David Walter1, Klaus-Peter Heue1, Stephen Broccardo2, Stuart Piketh2, Kristy Ross3, and Ulrich Platt1 — 1Institute of Environmental Physics (IUP), University of Heidelberg, Heidelberg, Germany — 2Climatology Research Group, University of the Witwatersrand, Johannesburg, South Africa — 3Research and Innovation Department, Eskom, South Africa
In order to map the 2D distribution of a series of relevant trace gases, we built an instrument for airborne measurements, based on Imaging Differential Optical Absorption Spectroscopy (I-DOAS).
An imaging spectrometer combined with a CCD camera analyses sun-light backscattered from the earth’s surface. The CCD camera records the spectral information in one dimension and spatial information (perpendicular to the aircraft’s flight direction) in the other dimension. Due to the forward motion of the aircraft we get 2D-maps of the trace gas slant column densities (SCDs) along the light path. The spatial resolution is given by the instrument characteristics, the flight altitude and the speed. Typical values are in the order of 150 m longitudinal and 50 m perpendicular to the flight direction.
The results have applications for enforcement of air-quality legislation and investigation of plume chemistry and dispersion. A measurement campaign in August 2007 in the Highveld (South Africa) showed strong variations of NO2 column densities in immediate vicinity of various sources e.g. power plants, steel works and highways. Flights in the surveillance area of satellites (e.g. SCIAMACHY) were realized to validate the satellite retrievals on a regional scale.