Wednesday, 5 June 2002: 10:30 AM
The morphology of two mixed phase clouds
To gain a better physical understanding of mixed phase non-precipitating clouds in the middle troposphere, the DoD Center for Geosciences and Atmospheric Research at CIRA-CSU recently (8 Oct - 4 Nov 2001) completed the most successful of its Complex Layered Cloud Experiments (CLEX) over the Western Nebraska Panhandle region. The primary observational platform was the University of Wyoming King Air (UWKA) research aircraft. In addition to a comprehensive suite of microphysics and radiation probes, the UWKA carried the upward- or side-looking Wyoming Cloud Radar (WCR). The WCR (95-GHz Doppler) provided high-resolution observations of cloud structure, microphysics and kinematics. These airborne measurements were complemented by a suite of ground-based instruments (CSU surface radiation station, IR interferometer, micro-pulse LIDAR, and supplementary radiosondes and the NOAA ETL and University of Massachusetts/Wyoming dual frequency microwave radiometers) located at the North Platte Regional Airport in North Platte, Nebraska. Utilizing 38 UWKA flight hours, CLEX sampled 9 different mid-level, mixed phase clouds on 8 different mission days. On one of those days, CLEX accomplished a successful dual-aircraft mission (SPEC Inc. Learjet and UWKA) in a multi-layered cloud system.
Of particular interest in this phase of CLEX was the potential influence of shortwave forcing on the post-sunrise dissipation of mid-level clouds. For this study, selected in-situ and remote sensing measurements will be utilized to compare and contrast the microphysical and kinematic structure of clouds that dissipated after sunrise with those that did not dissipate after sunrise. As observed in previous CLEX field campaigns, cloud vertical structures were predominately mixed phase with liquid water peaks generally occurring near cloud top and ice water contents peaking near cloud base. Combining cloud radar and in-situ measurements provided a three-dimensional view of the previously observed vertical profiles of water and ice, revealing molar-shaped mixed phase generating cells and mostly ice fall streaks cascading from the base of the cells.
Supplementary URL: http://www.cira.colostate.edu/GeoSci/clex_home.htm