Verification of the Road Weather Forecast System Run During the 2003 Demonstration at the Towa Department of Transportation

摘要

The Road Weather Forecast System (RWFS) was developed by the National Center for Atmospheric Research (NCAR) for the FHWA's winter road maintenance decision support system (MDSS) project The RWFS, which is based on a data fusion technology that NCAR previously developed for general weather forecast applications, was reconfigured to generate specific forecasts for winter road maintenance routes by supplying this information to the U.S. Army Cold Regions Research and Engineering Laboratory's road temperature prediction system and a road condition treatment module developed by Massachusetts Institute of Technology's Lincoln Laboratory. For such a system to provide useful information to road maintenance personnel, it must provide accurate forecasts of the weather and translate that to a reasonable representation of its impact on the road surface. The RWFS attempts to objectively maximize forecast accuracy (minimize error) by blending output from standard and research numerical models with surface observations and statistical regressions. Tuning of the system is done through comparison of model output with surface observations from National Weather Service meteorological aeronautical report (METAR) sites and Iowa Department of Transportation (DOT) road weather information system (RWIS) sites to provide optimized forecasts of bom standard weather and extended highway parameters (e.g., road temperature) for departments of transportation. Overall verification results from the first Iowa DOT RWFS demonstration are presented. Accuracy of RWFS forecasts of air temperature and precipitation type are examined through comparison with METAR and RWIS observations. Road temperature forecasts resulting from the application of MDSS recommended road treatments (plowing, salting) are compared with RWIS measurements of road temperature. A case study from a light snow event is presented to demonstrate some error sources and to compare MDSS recommended and actual Iowa DOT treatments.