Cloud classification and microphysical properties from multi-sensor retrievals

ASCOS was an interdisciplinary expedition to the central Arctic on the icebreaker Oden from 1 August to 9 September 2008. The expedition focused on processes related to cloud formation in the summer Arctic and included observations of marine biology and chemistry, atmospheric chemistry, physical oceanography, aerosol chemistry and physics, and meteorology. This ASCOS data set includes multi-sensor retrievals of cloud type and microphysical properties. Input data streams for deriving cloud properties include: Millimeter wavelength cloud radar Doppler moments, dual-channel microwave radiometer retrievals of cloud liquid water path, ceilometer measurements of cloud base height, and radiosonde temperature profiles. Phase-specific signatures in each of the measurements are used to classify all clouds observed vertically by this instrument suite as ice, liquid, mixed-phase, or precipitating. Cloud ice microphysical properties are derived primarily from cloud rada r reflectivity. Cloud liquid properties are derived using an adiabatic liquid water profile computed from radar/ceilometer cloud boundaries and temperature profiles. The liquid water is then constrained using the microwave radiometer-derived liquid water path.