Jp2.4 Retrieval of Cloud Optical Properties from Infrared Hyper-spectral Measurements: a New Methodology Based on Line-by-line Multiple Scattering Code and Measured Particles Size Distributions

1. ABSTRACT A new methodology to retrieve cloud optical properties using hyper-spectral infrared measurements is presented. The new method makes use of line by line multiple scattering (LbLMS) simulations to retrieve spectrally resolved cloud optical depths from spectral radiance data. The retrieval requires knowledge of the clear sky profile and cloud boundaries. The cloud microphysical properties are retrieved by comparing the infrared spectral optical depths with a precomputed optical depth database. This reference database is generated from an ensemble of measured cloud particle size distributions (PSD) and pre-computed single scattering and single particle optical properties for a variety of ice crystal habits. The full methodology was applied to aircraft (Scanning High-resolution Interferometer Sounder, S-HIS), satellite (Atmospheric Infrared Sounder, AIRS) and ground based (Atmospheric Emitted Radiance Interferometer, AERI) hyper-spectral measurements collected during the Mixed Phase Artic Cloud Experiment (MPACE) 2004 in the North Slope of Alaska. Collocated lidar and radar measurements were used to validate the retrieval results.