UW to Lead Cloud

The University of Wyoming, with the use of its King Air research aircraft, is heading a cloud-seeding project -- funded through the National Science Foundation (NSF) -- in southwestern Idaho that began last week.

The research, dubbed SNOWIE (Seeded and Natural Orographic Wintertime Clouds -- the Idaho Experiment), began Jan. 7  in concert with Boise-based Idaho Power Co., which provides a good share of its electrical power through hydroelectric dams.

“They (Idaho Power) are interested in putting more snow on the ground in the mountains, which leads to more water in their rivers,” says Jeff French, a UW assistant professor in the Department of Atmospheric Science and principal investigator for the SNOWIE Project. “This leads to more power generation capability throughout the year.”

Due to water shortages and droughts in some states and in countries around the world, cloud seeding is seen as a potential way to increase water supplies for communities and to irrigate crops. Cloud seeding is typically paid for by water resource managers, power companies (hydropower) and agricultural interests.

“The power company is a partner in this project,” French says. “They are paying for cloud seeding and some instrumentation.”

Cloud seeding is a process by which silver iodide is released into the clouds, either from the air or via ground-based generators. In the case of the SNOWIE Project, the silver iodide will be released by a second aircraft funded through Idaho Power, while the UW King Air will take measurements to understand the impact of the silver iodide, French says.

“SNOWIE is the most comprehensive study, to date, on cloud seeding in winter,” says Nick Anderson, program director in the NSF’s Division of Atmospheric and Geospace Sciences, which funded the research. “Scientists are still uncertain about cloud seeding for increasing precipitation, despite ongoing operations around the globe. SNOWIE researchers have an array of advanced instrumentation and modeling to focus on the fine-scale aspects of clouds to determine whether seeding operations are resulting in precipitation enhancement. Improved information about cloud seeding and winter precipitation, in general, is especially important for water resources questions such as those related to hydropower generation and agriculture.”        

Precipitation in winter orographic storms generally develops when ice crystals form on natural ice nuclei, such as dust particles, and grow. In many storms, the lack of natural ice nuclei active at warmer temperatures results in an inefficient precipitation process. In addition, weak updrafts in these clouds and narrow cloud droplet distributions limit the impacts of any ice processes to multiply.

The project also will receive assistance from researchers at the University of Colorado, the University of Illinois-Urbana/Champaign and the National Center for Atmospheric Research (NCAR’s) Research Applications Laboratory. Those institutions will supply additional instrumentation supported through the NSF proposal. The SNOWIE cloud-seeding campaign is scheduled Jan. 7-March 17 within and near the Payette Basin, located about 50 miles north of Boise.

“We have enough funds to cover about 20 IOPs or intensive observation periods that last 4-8 hours each,” French says. “We will be looking for different conditions, so we can cover a range or spectrum of conditions when we will be seeding and not be seeding to obtain these measurements.

“Part of understanding seeding is understanding the natural process of the storm. It’s important to go out in the (storm’s) evolution to take measurements when seeding is not occurring.”

While a good deal of research will take place aboard the King Air, much of it also will take place on the ground. Numerical modeling of precipitation measurements will be conducted using the supercomputer, nicknamed Cheyenne, at the NCAR-Wyoming Supercomputing Center. The numerical models will simulate clouds and snow precipitation -- created in natural storms and with cloud seeding -- over the Payette Basin.

The numerical models also will allow researchers to study future storm events where measurements have not been obtained in the field.

“This allows us to see how well the numerical model is doing and also to see if the numerical model is capturing important characteristics of a cloud,” French says. “My role is to ensure the models and simulations do an adequate job of capturing key aspects of clouds based on our measurements.”

French says UW was chosen to head the project, in part, because of its King Air research facility and the university’s experience and expertise with cloud-seeding projects.

In 2005, the Wyoming State Legislature approved a five-year weather modification study administered by the Wyoming Water Development Office. The state-funded program, called the Wyoming Weather Modification Pilot Project (WWMPP), began in 2006-07 and concluded in spring 2014. It was designed to evaluate the effectiveness of cloud seeding to enhance snowfall from winter orographic storms in the Medicine Bow and Sierra Madre mountains. Such storms occur when an air mass is forced from a low elevation to a higher one as it moves over rising terrain.

UW piggybacked on this state project. Bart Geerts, a UW professor of atmospheric science, headed a project, titled "Detecting the Signature of Glaciogenic Cloud Seeding in Orographic Snowstorms in Wyoming Using the Wyoming Cloud Radar.” The project was funded by the Wyoming Water Resources Research Institute at UW through the university's Office of Water Programs (OWP). Using radar and lidar instrumentation from the King Air, Geerts gathered data for his own cloud-seeding research.

During 2010, Geerts’ study estimated up to a 25 percent increase in precipitation for seven lightly precipitating storms, a small sample set. Geerts garnered additional funding from the NSF for two more years of aircraft study measurements.

“Results from SNOWIE are expected to provide a new and important understanding of cold-season precipitation -- both naturally and that augmented through cloud seeding -- and will have an impact throughout the American West, a region that increasingly suffers from drought and water shortage,” French says.

About King Air

The UW King Air research aircraft is a specially instrumented twin turbo-prop plane designed and used for atmospheric research. N2UW is the third aircraft utilized for atmospheric research by UW since the 1960s. The King Air, Wyoming Cloud Radar (WCR) and Wyoming Cloud Lidar (WCL) are available to the scientific community. The research aircraft, radar and lidar are funded, in part, by the NSF under cooperative agreements with UW since 1988. The King Air is one of the multiuser national facilities available through NSF’s Lower Atmospheric Observing Facilities (LAOF) Program, which supports the geosciences community. While the program management resides within the NSF, the King Air, WCR and WCL are owned and managed by UW. For more information, go to http://flights.uwyo.edu/uwka/index.shtml.

About the NSF

The NSF is an independent federal agency created by Congress in 1950 to promote the progress of science; advance the national health, prosperity and welfare; and to secure national defense. NSF is a vital agency that supports basic research and people to create knowledge that transforms the future.