An overview of the ASCII 2012 (AgI Cloud Seeding Impact Investigation) campaign

The ASCII campaign was conducted from January to March of 2012 over the Sierra Madre Mountain range in southern Wyoming, in order to study orographic snow growth mechanisms, and the impact of controlled ground-based ice nucleus injection. The instrument suite included the Wyoming King Air (WKA) research aircraft with mm-wave Wyoming Cloud Radar (WCR) and Wyoming Cloud Lidar (WCL), and several in situ aerosol, cloud and precipitation particle probes. A dual-polarization X-band Doppler radar performed volume and RHI scans from the mountain crestline. Radio-soundings monitored the upwind environment. Two Ka band profiling micro-rain radars (MRR) and two passive microwave profiling radiometers were deployed, one of each upwind of the mountain, and near the mountain crest. A SPEC Cloud Particle Imager and a disdrometer, as well as a variety of snow gauges, characterized falling and blowing snow on the ground, from a sheltered site just downwind of the crest. All these data are being used to evaluate very-high resolution numerical simulations. ASCII data are being used to study fundamental orographic snowfall mechanisms, ranging from purely dynamic to microphysical, and to examine the impact of glaciogenic cloud seeding on these processes. An overview and some preliminary findings are presented.