A GIS toolset for automated processing and analysis of radar precipitation data

A geographical information system (GIS) toolset was developed in this study for automatically processing and evaluating precipitation data from the Norwegian weather radar network. The toolset is implemented within the ArcGIS 9.2 system by using a series of Python scripts. All processing and evaluation procedures are automated for batch-processing in order to handle large number of files. The processing steps include format conversion, geo-referencing, scaling, clipping, filling of missing data and temporal aggregation. The processed radar data is evaluated by comparing it with measurements from precipitation gauges and with distributed areal precipitation derived from gauge measurements. The application of this toolset is demonstrated through a case study where two years of hourly radar precipitation data from the Rissa radar is processed and evaluated by using daily observations from a network of 27 gauges located in and around the Gaula catchment. The toolset greatly facilitates the analysis of radar precipitation data by avoiding tedious manual work. It serves as a tool for preparing and evaluating precipitation input data for distributed hydrological models.