An enquiry into rainfall data measurement and processing for model use in urban hydrology.

Rain data are collected all over the world because water is of paramount importance to all human life. WMO has provided standards for collection and standardized data processing of daily rainfall measurements. Currently no such standards are available for gauges with a resolution suitable for urban hydrology, where the resolution in time must not exceed a few minutes. The Group on Urban Rainfall under the International Water Association has made a comparison of national standards by means of a survey of 77 questions sent to 44 countries. The paper discusses the first results of the answers of the survey. Currently tipping bucket gauges are the dominating method of obtaining high resolution rain data, but the numbers of weighing gauges and radar measurements are rapidly growing. It is necessary to try to increase the awareness of documentation of current standards and to agree on standards for measurements and data processing on an international level in the future.