Validation of a present weather observation method for driving rain mapping

Over the past decade, the method of choice for calculating driving rain loads from weather data has been to use long series of hourly wind and rainfall data, preferably of 20 or 30 years. In an earlier article, we presented an alternative method for driving rain mapping in areas where long records of hourly weather data are not available, e.g. in Norway. In this method, annual directional driving rain loads are calculated based on present weather observations and knowledge of average annual rainfall. In this paper, we compare the two methods using data from three weather stations in Great Britain for the 20-year period 1976–1995. The results suggest that the present weather observation method yields comparable results to the hourly wind and rainfall method, and therefore can be used as a substitute in areas where sufficiently long series of hourly values of wind and rainfall amounts are not currently available.