Berlin 2005 – wissenschaftliches Programm

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UP: Umweltphysik

UP 3: Atmosph
ärische Spurengase und Aerosole: Intrumentelles I

UP 3.3: Fachvortrag

Montag, 7. März 2005, 15:00–15:15, TU TA201

Global Maps of the CH4 and CO vertical column derived from SCIAMACHY onboard ENVISAT — •Christian Frankenberg, Ulrich Platt, and Thomas Wagner — Institut für Umwelphysik, INF 229, 69120 Heidelberg

In the past, differential optical absorption spectroscopy (DOAS) has mostly been employed for trace gas retrieval in the UV/Vis spectral region. New spectrometers such as SCIAMACHY onboard ENVISAT also provide near infrared channels and thus allow the detection of greenhouse gases like CH4, CO2, H2O as well as CO. However, modifications of the classical DOAS algorithm are necessary to account for the idiosyncrasies of this spectral region, i.e. the temperature and pressure dependence of the high resolution absorption lines. This paper presents results of a modified iterative maximum a posteriori-DOAS algorithm (IMAP-DOAS) based on the optimal estimation theory introduced to the remote sensing community by Rodgers (1976). This method directly iterates the vertical column densities of the absorbers of interest until the expected total optical density fits the measurement. Here we present the global maps of the vertical atmospheric column density of CH4 and CO. In contrast to sensors in the thermal infrared SCIAMACHY observations are in particular sensitive to surface near layers.