Using geostatistical methods to produce a spatial and temporal gridded dataset of historic river flow across Great Britain

The aim of this research is to obtain a gridded hydrological runoff dataset for Great Britain (GB) that can be compared with other gridded climate data such as temperature, precipitation and satellite-derived vegetation parameters. The source data are an extended version of a network of relatively undisturbed river catchments identified by Bradford and Marsh[1], . Gridded datasets with a 10km2 resolution were created using both ordinary and universal kriging methods; the latter with topography as a predictor variable. Cross-validation was used to evaluate the quality of the two prediction methods. The universal kriging method resulted in a better gridded GB wide runoff dataset, which also accounted for variation in catchment elevation, over the period of 1959-2008. Several comparisons of outputs by the two kriging methods are provided. This paper builds on a previous study by Hannaford and Marsh[2], who assessed trends in GB runoff using the same original network of undisturbed river catchment, by allowing additional spatial and temporal comparisons with climatic data to be examined that was not possible with their original work.