A European daily high-resolution gridded data set of surface temperature and precipitation for 1950-2006

We present a European land-only daily high-resolution gridded data set for precipitation and minimum, maximum, and mean surface temperature for the period 1950-2006. This data set improves on previous products in its spatial resolution and extent, time period, number of contributing stations, and attention to finding the most appropriate method for spatial interpolation of daily climate observations. The gridded data are delivered on four spatial resolutions to match the grids used in previous products as well as many of the rotated pole Regional Climate Models (RCMs) currently in use. Each data set has been designed to provide the best estimate of grid box averages rather than point values to enable direct comparison with RCMs. We employ a three-step process of interpolation, by first interpolating the monthly precipitation totals and monthly mean temperature using three-dimensional thin-plate splines, then interpolating the daily anomalies using indicator and universal kriging for precipitation and kriging with an external drift uncertainty averaged across the entire region is shown to be largely dependent on the season and number of contributing observations. We examine the effect that ineterpolation has on the magnitude of the extremes in the observations by calculating areal reduction factors daily maximum temperature and precipitation events with return periods up to 10 years.