Current WRP Projects: Project 40

Multi-frequency Radar and Precipitation Probe Analysis of the Impact of Glaciogenic Cloud Seeding on Snow

  • Project Number:  40
  • PI:  Bart Geerts, Professor, Dept. of Atmospheric Science, University of Wyoming
  • Period:  03/01/2012 – 02/28/2015



This proposal aims to study the effect of ground-based glaciogenic cloud seeding on snowfall and snow particle characteristics using three different radar systems and snow rate and snow imaging probes deployed at a remote mountain research station. The AgI (silver iodide) seeding is conducted as part of the Wyoming Weather Modification Pilot Project (WWMPP), funded by the state of Wyoming. The data will be collected as part of the ASCII field campaign in the Sierra Madre in Wyoming in January-March 2012.

ASCII (AgI Seeding Cloud Impact Investigation) is funded by the National Science Foundation (NSF). The NSF grant supports flights by the University of Wyoming King Air (UWKA) research aircraft, with an airborne radar (the Wyoming Cloud Radar) on board, as well as numerical modeling work. NSF also awarded a “supplemental” grant, enabling the establishment of the manned mountain research station (“Battle Town site”) and the deployment of several instruments, including two radar systems, a dual-polarization Doppler on Wheels (DOW) scanning radar, and a profiling Micro-Rain Radar (MRR). This supplemental grant, referred to as ASCII Plus, does not cover any personnel expenses for the analysis of the data to be collected at Battle Town site.

The combination of the WWMPP network, which in the 2011-12 season will include several precipitation research instruments, and ASCII Plus is expected to yield a very rich, unique, and high-quality dataset. This proposal aims to conduct analysis of this rich resource, with a very specific objective: to examine how glaciogenic cloud seeding alters snow size distributions and snow particle characteristics in order to understand its impact on snowfall efficacy.

This proposal is focused on data analysis and the training of a PhD-level graduate student. It does not involve any field work, but as part of his/her training, the graduate student is likely to actively participate in the ASCII field campaign.

Water is essential to the economy and the natural resources of the arid western USA. There are few options to improve water supply control, and none are simple. One option, the seeding of clouds to enhance precipitation, is rather simple and has an immediate effect. Yet cloud seeding efficacy has remained clouded in uncertainty. This proposal adds to a growing body of evidence that glaciogenic seeding of orographic clouds does work, and it will provide new insights into the conditions more favorable to cloud seeding.

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