Radar, Lidar, and In-situ Observations of Tropical Cirrus Clouds

This study investigates radar observations of tropical convection (primarily Florida sea-breeze-driven) and the associated formation of cirrus anvils from the NASA CRYSTAL-FACE field program. High-resolution radar from the NASA Cloud Radar System (CRS) and lidar observations from the NASA Cloud Physics Lidar (CPL) reveal the complex, multi-layered cloud structure in many of the storms observed during July 2002 over south Florida. By combining observations from the CRS and CPL, we investigate differences between radar- and lidar-observed cloud top and cirrus structure as they relate to the regional environmental conditions (e.g., temperature, humidity, and winds). This study also investigates the properties of thin tropopause cirrus (TTC) layers observed during several of the CRYSTAL-FACE flight missions. In several cases, properties of the TTC layers were sampled in-situ, providing information on ice particle size distributions and concentrations. While the TTC layers appeared ubiquitous during many of the missions, they were seldom observed (e.g., absent from CPL imagery) during the latter two flights of the field campaign (28 and 29 July). During this period, a strong ridge of high pressure formed over central Florida and an approaching easterly wave modified the synoptic conditions in the region, which may have contributed to the scarcity of the TTC layers. This study seeks to better understand and relate radar, lidar, and in-situ microphysical observations of the differing cloud structures (e.g., presence and absence of TTC layers) from several mission days to the synoptic conditions by incorporating sounding and model re-analysis data. The main goal of this work is to gain an enhanced understanding of the connections between the synoptic environment and the formation of cirrus and TTC layers associated with tropical convection by utilizing observations from the radar, lidar, and in-situ data available from the CRYSTAL-FACE experiment.