Colorado State University graduate student Sarah Tessendorf wins DRI's Peter B. Wagner Memorial Award

Contact: Heather Emmons, DRI PIO heather.emmons@dri.edu
Reno (775) 673-7313 (w), (702) 743-3435

February 9, 2005

Colorado State University graduate student Sarah Tessendorf wins DRI's Peter B. Wagner Memorial Award
Winning research paper asks: During severe storms, how does precipitation form and influence cloud-to-ground lightning, producing large hail?


Tessendorf running a radar field experiment in Mazatlan, Mexico	Tessendorf performs some field experiments at DRI's Storm Peak Laboratory in Steamboat Springs, Colo.

Reno, Nev. -- A Colorado State University graduate student has won the Desert Research Institute's Peter B. Wagner Memorial Award for Women in Atmospheric Sciences for her study of the relationships between air motions, precipitation and lightning in severe storms and why certain combinations of these produce large hail and positive cloud-to-ground lightning. Part of the Severe Thunderstorm Electrification and Precipitation, or STEPS field campaign, a collaborative research initiative between several universities and the University Corporation for Atmospheric Research supported by federal funds, this is the first part of a two-part study that involved observing a severe Kansas storm. The storm exhibited several noteworthy features including frequent positive cloud-to-ground lightning strikes, large hail and a tornado. Using radar data as well as a hail growth model, Tessendorf could see the storm evolve and diagnose the paths along which hail grew.

Tessendorf will receive the Wagner Award's $1,250 prize at DRI in Reno tomorrow, Feb. 10, following a presentation of her winning paper, "The 29 June 2000 Supercell Observed During STEPS. Part 1: Kinematics and Microphysics."

The annual award was established in 1998 by Nevada Gaming Commission member and former Nevada Lt. Gov. Sue Wagner in memory of her late husband, Peter, a DRI scientist who died in the 1980 crash of a DRI research aircraft. The national award is intended to encourage women graduate students in the atmospheric sciences.

Tessendorf's paper notes that four basic conditions had to be met in order for the 29 June 2000 storm to produce large hail: 1) small near-millimeter to millimeter-sized embryonic particles must be present, 2) there must be a mechanism for transporting these particles into the updraft, 3) the updraft must be of sufficient size and intensity to grow these embryonic particles into hail, and 4) the horizontal winds must keep the growing particles within favored hail growth conditions.

"These results not only confirm some previous hypotheses about hail growth, but they also help us identify characteristics of the storm that might influence its electrical behavior," Tessendorf said. "Forecasters can use this information to recognize a storm's potential for producing damaging hail, and we hope to use these results to learn more about how the conditions that allow a storm to produce large hail might influence its cloud-to-ground lightning polarity."

Tessendorf is a Ph.D. student who plans to graduate in the spring of 2006. She also participated in the University Corporation for Atmospheric Research's Significant Opportunities in Atmospheric Research and Science, or UCAR SOARS program, as a student protege for four summers. She credits much of her success as a graduate student in atmospheric science to the experience and mentoring she received in SOARS. She currently serves as a member of the SOARS steering committee and hopes to remain active in the program in the future.

Applicants for the Wagner Award must be pursuing an advanced degree in a program of atmospheric sciences or a related field and must submit a paper based on original research directly related to the identification, clarification and/or resolution of an atmospheric or climatic problem.

A nonprofit, statewide division of the University and Community College System of Nevada, DRI pursues a full-time program of basic and applied environmental research on a local, national, and international scale. Nearly 500 full- and part-time scientists, technicians, and support staff conduct some 150 research projects at DRI annually. DRI generates $45 million in total revenue consisting predominately of competitively won research contracts and grants. The State of Nevada provides critical funding in support of DRI's administration, operations and maintenance, through the University and Community College System of Nevada budget. While DRI’s portion of the UCCSN budget is less than 1 percent, the institute leverages these funds to enhance its competitiveness.

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