On the measurement of stratus cloud properties with a cloud radar and microwave radiometer

Algorithms have been developed to calculate the vertical profiles from cloud radar reflectivity measurements and microwave radiometer measurements of integrated liquid water. In addition, the algorithms calculate the effective radius profiles, and the total number of cloud droplets. When drizzle is present, radar reflectivity, vertical velocity and the spread of the vertical velocity can be used to calculate vertical profiles of liquid water, liquid water flux, effective radius, and droplet number. When there is no drizzle, the authors can use the Doppler capability to profile various vertical velocity turbulence parameters, such as the vertical velocity spectra, variance, and skewness. All parameters are important in the development of cloud models. Data taken during ASTEX (Atlantic Stratocumulus Transition Experiment) have been used to study the behavior of stratus clouds at Porto Santo Island, Madeira, Portugal.