The AgI Seeding Cloud Impact Investigation (ASCII) field campaign is designed within the context of the Wyoming Weather Modification Pilot Project (WWMPP). ASCII will target the Sierra Madre, a NW-SE oriented continental divide mountain range in southern Wyoming. The WWMPP has been operating up to 8 AgI generators in each of two mountain ranges (the Sierra Madre and, to its NE, the Medicine Bow Range) since late 2007, with operations contracted to Weather Modification, Inc (WMI) (Breed et al. 2008). ASCII focuses on studying the cloud microphysical effect of glaciogenic seeding using 3 generators in the Sierra Madre. ASCII will target the Sierra Madre under low-level flow from 225-270°, which provides a longer, rather unobstructed upwind fetch and a higher climatological probability of being able to sample enough “good” cases.
ASCII will deploy a cloud radar and a cloud lidar aboard the University of Wyoming King Air (UWKA) aircraft, the Center for Severe Weather Research Doppler on Wheels radar, and several surface instruments (disdrometer, hotplate, microwave radiometer, microwave rain radar). The Wyoming Cloud Radar (WCR) is a 95 GHz (3 mm) Doppler radar with multiple fixed antennas. The Wyoming Cloud Lidar (WCL) is an incoherent backscatter polarization lidar operating at λ=0.355 um. In a mixed-phase cloud with ice crystals much larger but much fewer than cloud droplets, the WCR reflectivity is dominated by snow, whereas the WCL beam is attenuated mostly by liquid cloud edges.
ASCII is funded by the National Science Foundation (AGS-1058426) in cooperation with the Wyoming Weather Modification Pilot Project, which is funded by the State of Wyoming.