With Social Science Woven into Meteorology.
Kenneth A. Blumenfeld
Research Associate, University of Minnesota
Lecturer, University of Wisconsin-Platteville
02 October 2009, 2:00 PM
National Weather Center, Rm. 1350
120 David L. Boren Blvd.
University of Oklahoma
Norman, OK
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Engineers have attempted to make our transportation networks and surface infrastructure resilient to extreme rainfall events by employing “precipitation design values,” which are based on rainfall return period estimates, such as the 100-yr, 24-hr threshold, or, “100-year storm.” In recent decades, the standard, published sources for precipitation design values have been criticized for having insufficient record lengths and for using inappropriate or outdated statistical techniques. Most proposed design value corrections, however, continue to use fixed-point data as the bases for new values. This investigation examines the utility of using Minnesota’s spatially-dense rain gauge network to create small grid cells of observation points that “compete” for each cell’s annual maximum daily precipitation value—the primary input for design value estimation. The resulting rainfall frequency estimates are areal in nature, making them a good fit for the areal nature of extreme rainfall. The inclusion of gauge density in rainfall frequency estimation procedures has many benefits over fixed-point approaches, but brings with it new concerns and limitations that also need to be addressed, ultimately leading us back to the question, “what is a 100-year storm?”
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