Retrieval of Vertical Profiles of Cirrus Cloud Microphysical Parameters from Doppler Radar and Infrared Radiometer Measurements

Abstract

This paper describes a new method to retrieve vertical profiles of the parameters of cirrus cloud microphysics that are important for the estimation of climatic feedback. These parameters are the particle characteristic size and ice mass content. The method also allows calculations of vertical profiles of particle concentrations and ice mass flux. The method uses measurements of radar reflectivities and Doppler velocities from the ground-based zenith-viewing radar combined with measurements of downwelling brightness temperatures from an infrared radiometer operating in the ?window? (10?12 µm) region. The proposed method is illustrated on data obtained on 26 November 1991 during FIRE-II [First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment] in Coffeyville, Kansas. This paper also presents estimates of uncertainties of parameter retrieval due to different a priori assumptions about particle shapes, distributions, fall velocity-size relationships and due to errors in measurements. Comparisons with in situ measurements showed reasonable agreement.