Monday, 10 January 2005
The pavement precipitation accumulation estimation system (PPAES)
Road maintenance personnel are responsible for keeping roads safe for travel and thus plow and chemically treat roads upon which snow has fallen. In order to manage this activity, road maintenance personnel require information regarding where and how much snow has fallen. Our ability to determine these, however, is limited. Surface observation data are limited owing to lacking spatial and temporal densities and because few surface observation sites provide information regarding snow accumulation. Radar data, on the other hand, provide much improved spatial and temporal coverage. These data, though, are limited because low-elevation radar beams commonly overshoot winter precipitation systems at moderate to distant ranges and because radar-based snowfall estimates typically have greater errors than do surface-observation-based estimates. Satellite data are limited by their temporal resolution and by the fact that they have not commonly been applied to relatively weak wintertime systems. In response to the road maintenance personnel need for improved information regarding where and how much snow has fallen, the Pavement Precipitation Accumulation Estimation System (PPAES) is being developed. PPAES utilizes surface observations, radar data, and satellite data. It is designed to take advantage of the strengths of available data sets and to limit weaknesses by mitigating artifacts (e.g., anomalous propagation radar data) and by combining information from these three sets of data. Novel aspects of this system include the use of GOES-derived cloud top pressure data in conjunction with radar and surface observation data to enhance areal coverage. Initial results and challenges will be discussed, as will be the role of PPAES in the larger scale surface transportation weather research efforts ongoing at the University of North Dakota.
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