Lake- and Sea-Effect Precipitation Systems in Complex Terrain

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Intense lake-effect snowstorms frequently occur during cold-air outbreaks over large bodies of water such as the Great Lakes of North America. Salty bodies of water, such as the Sea of Japan, can generate similar storms. For example, "sea-effect" snowstorms produce prolific snowfalls in Japan near the Sea of Japan coast. Such storms, however, pose a major challenge for forecasting because they are often highly localized, leading to dramatic contrasts in snowfall from one community to the next. The research seeks to advance the knowledge and prediction of lake- and sea-effect snowstorms by determining how the presence of hills and mountains affects the intensity and distribution of snowfall downstream of large bodies of water such as the Great lakes and Sea of Japan. The project involves the mentoring of two graduate students, a research experience for an undergraduate student from an underrepresented group each summer, and international collaboration with meteorologists in Japan.The research focuses on two critical questions concerning the interaction of lake- and sea-effect snowstorms with complex terrain: (1) how does the interplay between lake- or sea-effect processes and orographic forcing influence storm dynamics and the inland and orographic enhancement of precipitation, and (2) how does the presence (or absence) of orography modulate inland penetration? In addition, the research examines the capabilities and limitations of forecasts produced by convection-permitting models and ensembles, which is a critical step for improving lake- and sea-effect forecasts. To explore a diversity of lake- and sea-effect processes and topographic interactions, the research team will examine and compare lake- and sea-effect systems generated by Lake Ontario and the Sea of Japan. In addition to using observations collected during the 2013/14 Ontario Winter Lake-effect Systems (OWLeS) field program in North America and well-sited radar and dense precipitation networks in Japan, the research will involve the use of real-data simulations by the Weather Research and Forecasting model and idealized simulations by the Bryan Cloud Model version 1 (CM1).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.