New Insights on Snowfall From Observations of Winter Storms

Sandra Yuter's seminar flyer

Prof. Sandra Yuter

North Carolina State University

Monday December 4, 2023, 2 PM ET



Analysis of data from NASA’s Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) airborne field program, operational and research radar, and surface observations have yielded new insights into real snowfall that have ramifications for satellite and radar retrievals, microphysics parameterizations, and forecasting. High resolution images from airborne particle probes such as PHIPS can depict the outcomes of sequences of ice growth as the snow particle moves through different temperature and humidity environments and distinguish between polycrystalline growth forms and aggregates. Over the more than 1 hour that it usually takes a snow particle to fall from radar echo top to the surface, a particle’s trajectory often bends and twists as it falls through layers with different wind speeds and directions. As a result, locally enhanced pockets of ice, originating within instabilities near cloud top, are often tilted and smeared horizontally along 10s of km as they fall through layers with differential shear before reaching the surface. The distributions of spatial and temporal associations among observed snow bands, gravity waves, and surface snowfall are the result of joint interactions between kinematics and microphysics. These findings point the way to more nuanced representations of snow to help address thorny problems in snow fall retrievals and quantitative precipitation forecasting.




Dr. Sandra Yuter is a Distinguished Professor of Atmospheric Sciences at North Carolina State University and a Fellow of the American Meteorological Society. She has over 30 years experience distilling large data sets and combining information from multiple sources including multispectral satellite, radar, lidar, in situ meteorological measurements, and numerical weather model output. She has extensive field project experience including leadership roles in 7 field campaigns.  Her research focus areas include winter weather, marine clouds, orographic precipitation, and tropical convection. A key tenet of her work is “adequacy for purpose” which harmonizes among science questions, sensor capabilities, and observing strategies.




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Dec 04 2023


John Xun Yang