Investigation of Monthly Pan Evaporation in Turkey with Geostatistical Technique

The aim of this study is to evaluate the spatial variations of monthly average pan evaporation amounts throughout Turkey by applying Geostatistical methods. Monthly averages of Class A pan evaporation data are reported by the General Directorate of State Meteorological Works using series of record lengths between 20 and 45 years at about 200 stations scattered over an 814.578 km2 surface area of Turkey. The data belonging to the summer months of June, July, and August are used in this study because the evaporation in this three-month period is greater than the sum of those of the other nine months. Monthly averages of the observed pan evaporation data are considered and the spatial variation of evaporation is analyzed. Kriging estimate maps are drawn and interpreted for the summer months. The study indicates that the spatial variation of monthly average pan evaporation values can be reasonably estimated by the geostatistical method based on observed pan evaporation data. It is suggested that this map may be used by decision-makers for accurate estimation of monthly pan evaporation in any reservoir management or irrigation projects where data availability is limited