Hybrid 2.0 interpolation of daily precipitation data over Alberta

Agricultural use of climate data has increased considerably during the last two decades due to the rapid development of information technology and the rate of the increase will accelerate in the future. It is thus necessary to interpolate the station-based observational data onto regular grid points. Climate physics shows that topographic precipitation is related to atmospheric circulation patterns and climate dynamics. These patterns may be reflected statistically by empirical orthogonal functions (EOFs). In order to interpolate high quality grid precipitation data, especially over the mountain and lake regions, we take the elevations into account and use EOF-interpolation method to develop Hybrid 2.0 interpolation method, the next generation of hybrid interpolation method based on the initial data derived from Hybrid 1.0 interpolation method. The method to be developed will first calculate a climatology surface as the mean of 1961-1990 data. Climate anomalies will be interpolated by EOF-interpolation to retain the spatial variance. Finally, the nearest-station regression will be applied to retain the temporal variance. With this developed method, we interpolate daily precipitation data onto grids for Alberta, Canada. The accuracy of the final result of Hybrid 2.0 interpolation method is assessed with cross-validation and compared to that of Hybrid 1.0 interpolation method.