Modeling and estimation of evapotranspiration using remote sensing and GIS technologies in some areas of southern Iraq

A study was conducted in southern Iraq. The study area was 16485.4418 km2 with the administrative boundaries of Basrah (North region) and Dhi-Qar (south region) Governorates. The aim of this study to design a digital model for estimating evapotranspiration values (mm) using remote sensing data and geographic information systems and comparing the results with the actual values calculated from four climatic stations distributed within the study area. As well as to study January and July from each year for a four-years chronology. The results showed that there is a highly significant correlation (r = 0.923**) between the calculated and actual values, and this proves the accuracy of the proposed model in estimating the values of evapotranspiration. The results also showed that there is a rise in the values of evapotranspiration in the month of July compared to the month of January of each year due to the high temperatures and the angle of incidence of the sun’s rays, which is almost vertical in the month of July. The results also showed that the study area varies in the values of evapotranspiration according to the different vegetation cover, as the values decrease with the increase of vegetation cover and Vice versa. As well as the effect of the values of evapotranspiration by rising for limited areas in the areas of electric power plants and oil fields, and this gives evidence of large quantities of thermal and radioactive emissions in the areas. The results also showed that there is a inconsistency between the values of evapotranspiration and the areas covered, which were divided into four categories for each scene, and that the values of these categories differ according to the types of land cover.