Heidelberg 2015 – scientific programme

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UP: Fachverband Umweltphysik

UP 13: Postersession Bodenkunde, Kryosphäre, Meßtechnik, Ozeanographie

UP 13.5: Poster

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

Performance of the HALO mini-DOAS instrument and detection of trace gases and cloud properties — •Tilman Hüneke¹, Matthias Knecht¹, Marcel Reichert¹, Jannis Weimar^1,2, and Klaus Pfeilsticker¹ — ¹Institut für Umweltphysik, University of Heidelberg, Heidelberg, Germany — ²Helmholtz-Zentrum für Umweltforschung (UFZ), Leipzig, Germany

The HALO mini-DOAS instrument records scattered sunlight in the UV, visible and near-IR spectral ranges in nadir and limb viewing geometries. It was deployed on the German research aircraft DLR HALO during the recent campaigns Narval (December 2013 / January 2014), ML-Cirrus (March / April 2014) and ACRIDICON-CHUVA (August / September 2014).

Here, we report on the performance of the instrument during the deployments and show validation studies. For the detection of UV/visible absorbing radicals, such as O3, NO2, HONO, CH2O, C2H2O2, BrO and IO the DOAS (Differential Optical Absorption Spectroscopy) technique is used, which together with radiative transfer modelling (McArtim) and mathematical inversion will result in concentration profiles of the targeted gases. Due to the nonlinearity of the absorption features of gaseous, liquid and solid water, the DOAS technique can however not be employed in the traditional way for the interpretation of spectra in the near-IR wavelength range. Therefore a new retrieval scheme has been developed and tested against liquid water path (LWP) and ice water path (IWP) of other instrumentation, for example from the HAMP (HALO Microwave Package).