Evaluating lidar-radar microphysics retrieval using in situ measurements

This study reports on a comparison between in situ and combined lidar and radar measurements of extinction and ice water content in ice clouds. The main goal of this exercise is to verify that the lidar-radar method can be confidently used for future satellite radar and lidar measurements. The data used in this study were obtained during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) campaign that was conducted to study the properties of low-latitude, continentally influenced ice cloud layers. Two different methods are used to retrieve the extinction from the lidar signal. The comparison between lidar-derived and in situ-derived extinction values shows that they are strongly correlated for the two different lidar-based methods. Linear fits between the ice water contents derived from the two extinctions and radar reflectivity and the in situ values result in slope parameters of 0.93 ± 0.28 and 1.09 ± 0.35. The precise values depend on the assumed ice particle properties and particle size distribution used in the lidar-radar retrievals.