Airborne Observations of Mixed Phase Clouds in the Southern Rockies

Conducted over mountainous regions of Northern Colorado and Southern Wyoming during the 2010-2011 winter, the Colorado Airborne Multi-Phase Cloud Study (CAMPS) was designed to investigate the complex processes within mid-latitude, orographic, mixed-phase clouds. Over the course of 29 flights, instruments aboard the Wyoming King Air research aircraft made observations of cloud properties within diverse wintertime clouds, including many orographic mixed phase clouds. The aircraft carried a suite of in-situ cloud probes, including PMS-FSSP optical particle counter, PMS-2DC and -2DP cloud particle and precipitation imagers, Gerber PVM-100 optical and DMT LWC-100 hotwire liquid content probes, and a Rosemont icing detector. In addition, the research aircraft carried the University of Colorado closed-path laser hygrometer (CLH), which measures total water concentration by sampling the outside airstream, vaporizing condensed water particles in the sample, and observing infrared absorption in water vapor spectrum. The combination of the total water measurement from the CLH and the condensed particle measurements from the optical and hotwire cloud probes provides an opportunity to estimate the relative concentrations of cloud particles by phase. Using this host of cloud probes and the total water measurement, we develop a method for retrieving in-situ cloud water phase and concentration. We present results of this retrieval for several regions of mixed phase cloud, and describe the observed structure and evolution of these clouds.