Heidelberg 2015 – scientific programme

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UP: Fachverband Umweltphysik

UP 13: Postersession Bodenkunde, Kryosphäre, Meßtechnik, Ozeanographie

UP 13.7: Poster

Thursday, March 26, 2015, 10:45–19:45, G/Foyer

Simulation of radiative field modification in the UV/visible/nearIR spectral range due to tropical clouds (Cirrus and convective Clouds) — •Matthias Knecht, Katja Grossmann, Tim Deutschmann, Tilman Hüneke, and Klaus Pfeilsticker — Institut für Umweltphysik, Universität Heidelberg, Heidelberg, Germany

The interpretation of atmospheric trace gas measurements (O₃, NO₂, CH₂O, HONO, C₂H₂O₂, H₂O, O₄) and the detection of water phases (vapor, liquid, ice) by UV/vis/nearIR spectroscopy of scattered sunlight in Limb and Nadir geometry is largely hindered when clouds are present in the troposphere. This paper addresses sensitivity studies on the various microscopic and macroscopic parameters, i.e. the microphysical properties of the clouds and their geometric arrangement. For this purpose, the relevant parameters were varied in 3D Monte Carlo simulations using the radiative transfer model McArtim. Further, the simulations were evaluated in a statistical sense for the photon path lengths as a function of cloud and observation parameters, such as solar position, elevation angle and altitude of the observation. Results for test and proxy gases (O₂ and O₄) are compared with the data retrieved from measurements with our instrumentation. The paper reports on the set-up of the model and discusses major findings of the sensitivity studies.