Spatial interpolation techniques for climate data in the GAP region in Turkey

Six spatial interpolation techniques (inverse distance weighted, global polynomial interpolation, local polynomial interpolation, completely regularized spline, kriging and cokriging with 4 sub-types) were evaluated to deter-mine the best spatial distribution of 6 different climate parameters (solar radiation, sunshine duration, temperature, relative humidity, wind speed and rainfall) in the region of the Southeastern Anatolia Project (GAP) of Turkey. Based on the root mean square error values of predictions made using measured values from 1971 to 1999, simple cokriging yielded the best results for temperature, solar radiation, relative humidity, wind speed and completely regularized spline for sunshine duration and rainfall.