The Bolton Experiment: An Experimental Test of the Use of Microwave Attenuation to improve Rainfall Estimates in Urban Areas, and hence to Enhance Flood Warning

The Bolton Experiment was a NERC project with matching funds from industry which took place between 1999 and 2002.It was a collaboration between the University of Essex (Propagation and Remote Sensing group, the University of Salford (Telford Research Institute), and the Rutherford Appleton Laboratory (Radiocommunications Research Unit) and the industrial partners North West Water Plc and Norweb Communications (both companies of United Utilities), the UK Meteorological Office, The Environment Agency and Crown Castle International.

The purpose of the study is to test the proposal developed at Essex, in conjunction with RAL, that the difference in attenuation at two microwave frequencies along a given path provides an accurate estimate of path-integrated rainfall rate, and to investigate its application to hydrological studies of urban catchments.

The catchment selected for study is the Bolton catchment, in which the town is largely surrounded by hills, and the River Croal is carried in culverts in the town centre. Four microwave links will be set up, three of them dual frequency and one single frequency. In addition to data from microwave links and radar, there will also be data available from a number of telemetered tipping bucket raingauges.

The dataset contains microwave, raingauge and radar data. It also contains data analysis to extract information from the link attenuation data on path-averaged rainfall rate, and comparison with the results with those obtained from the raingauges and the radar. The dataset is now public.