Cloud characterization at DYCOMS II from MCR observations

NCAR´s Multichannel Cloud Radiometer (MCR) is a downward-looking scanning radiometer with seven spectral bands. The MCR has flown aboard the NSF/NCAR C-130 during several field campaigns, including the Dynamics and Chemistry of Marine Stratocumulus II (DYCOMS II) experiment, which took place off the coast of southern California during July 2001. In this paper, two near-infrared MCR channels are utilized to determine the cloud liquid water content and cloud drop effective radius during this experiment. To obtain these cloud characteristics from MCR observations, a radiative transfer model is used to compute the expected radiances for a variety of cloud liquid water contents and effective radii. This program incorporates the atmospheric and surface oceanic conditions that were observed by the C-130. The simulated radiances are computed for the two MCR bands, and compared to the observed values. This comparison yields an estimate of cloud liquid water content and cloud drop effective radius. The cloud properties derived using this technique are compared to C-130 in situ observations and to estimates derived from satellite observations of marine stratocumulus in the same area observed during DYCOMS II.