The Use of Weather Radar Data in Road Weather Services: Present and Future Needs

Abstract

Road weather services vary in nature across the length and breadth of Europe, but operationally they are mainly concerned with three hazards: the effects of snow and ice in winter, the effects of heavy rain in the warmer months of the year, and the occurrence of fog and bad visibility around the year, with the emphasis, however, on the colder season. For the minimization of the effects of these hazards, weather radar can supply direct information for the first two cases, and can also sometimes provide indirect information of forecasting value in the case of fogs. In many countries, precipitation information has been extracted from weather radar data for more than a decade, and the limitations of radar data in terms of quantitative accuracy have been widely reported. The usefulness of radar information rests to a great extent on its timeliness, based on near-real-time acquisition, and on its three-dimensional coverage of a large volume of the atmosphere. These advantages can be put to good use in an operational road weather service. This paper reviews the problems of providing accurate and timely information on snowfall to road-clearance authorities in winter, and projects some services that could be offered to road users in the warmer season, based upon weather radar data, either alone or in conjunction with other meteorological data sources. The part to be played by an operational European radar network is discussed.