Retrieving cloud microphysical properties in a fully 3D environment using scanning radar and zenith radiances

Poster PDF

Description

Very few fully 3D observations of clouds exist. Progress, in the past, has been slow; mostly due to limitations in instrumentation. However, with new ground-based scanning ARM cloud radar (SACR) recently added to ARM’s observational arsenal, expanding retrievals away from just the vertical column is now possible. We will present a pioneering 3D cloud retrieval method that uses an iterative ensemble Kalman Filter to combine SACR data and zenith radiance measurements from new shortwave spectrometers. As well as being one of the first 3D retrievals for the SACRs, the technique uniquely uses 3D radiative transfer as a forward model. This allows us to simultaneously reveal the previously out-of-reach horizontal and vertical structure of liquid water content and effective radius. We will show the method performs well for stratocumulus and even in challenging cumulus cases, using a combination of synthetic measurements from large eddy simulations and AMF measurements from the Azores. It is hoped that these new observations will help unravel the influence of aerosol on clouds in both a macro- and microphysical sense and hence give insight to the 3D radiative properties of clouds.