DETERMINATION OF SPATIAL VARIATION OF REFERENCE EVAPOTRANSPIRATION CASE STUDY OF SEYHAN BASIN

Geographic Information Systems (GIS) are computer-based tools for mapping and analyzing features and events onearth. GIS technology integrates common database operations such as query and statistical analysis with the uniquevisualization and geographic analysis benefits offered by maps Evapotranspiration mapping with classical methodsmay take months and even years based on the size of the area to be mapped. However, recently developed methodsdecreased the time consumed for such mapping practices to minutes. Geostatistical methods are the most commonlyused methods for mapping over large areas in a short time. In present study, Reference Evapotranspiration (ETo) valueswere calculated by ASCE Standardize Penman Monteith method using long-term climate data in the Seyhan basin. Thecalculated ETo values were mapped for April, May, June, July, August, September and yearly total by usinggeostatistical methods. It was used 7 stations in basin and 9 stations out of basins for calculation. In the production ofgeostatistical maps, cokriging was used as interpolation method and spherical model was used for model of semivariogram. At the end of the study, it was determined that ETo maps could be produced with reliable this method andmodel.