Collaborative Research: Further Investigations from the Seeded and Natural Orographic Wintertime clouds: the Idaho Experiment (SNOWIE)

University Of Wyoming, Laramie WY

Investigators

Abstract

Precipitation enhancement through cloud seeding has taken place in the Western United States and other regions around the globe for several decades. One of the main weather regimes where cloud seeding is attempted is in mountainous terrain in areas where there is a significant amount of liquid water in the clouds. Direct observational evidence of the chain of events from the release of cloud seeding material to the formation of precipitation was shown in data from a recent NSF-supported field campaign. This award will provide researchers with the opportunity to further analyze data from that campaign to answer additional questions about the science behind cloud seeding. The research represents a public-private partnership between NSF-sponsored scientists and a utility that provides hydroelectric power. The next generation of scientists will also be trained during this project. The research team will expand upon the analysis of field campaign data from the Seeded and Natural Orographic Wintertime clouds: the Idaho Experiment (SNOWIE) that was conducted in 2017. Initial results have shown that cloud seeding in orographic regions can initiate snowfall in certain situations. The research team will move beyond the obvious cases of cloud seeding impacts to analyze every case during the campaign, including those where cloud seeding was conducted while natural snowfall was also occurring. The overarching goal of the project is to provide estimates, with uncertainty limits, of precipitation enhancement from glaciogenic cloud seeding for all SNOWIE seeding events. This will involve coupling data analysis using the SNOWIE data set and state of the art modeling. The researchers have identified a set of questions to address the following research hypotheses: 1) Mesoscale and microscale updrafts observed in mostly stratiform orographic clouds are focal areas for the production of supercooled liquid water and sometimes natural ice particles, 2) Airborne seeding of orographic clouds, under the right conditions, will produce changes in microphysical properties of clouds and precipitation detectable with in-situ and remote sensors, even in conditions where natural precipitation is occurring, and 3) For all SNOWIE cases, seeding impacts on precipitation over a mountain basin can be estimated quantitatively, and uncertainties established, through numerical simulations employing seeding parameterizations improved utilizing analyses from the observations. NSF-supported researchers will collaborate with researchers at the National Center for Atmospheric Research and the Idaho Power Company. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.