Estimation of the evaporative losses from Lake Nasser, Egypt using optical satellite imagery

Water shortage in the arid region is an existing and future severe problem that threatens this part of the world. Egypt has a limited budget of 55 BM3 per year from the river Nile basin that has always been stored in the Lake Nasser reservoir, southern Egypt. It has been estimated that the water losses from the lake ranges from 10 to 20 BM3 a year(-1). This paper discusses the possibility of estimating the surface evaporation from Lake Nasser using optical remotely sensed data. The surface energy balance algorithm for land (SEBAL) algorithm was used to estimate the monthly evaporation rate using National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer (NOAA-AVHRR) satellite images based on the energy balance components. The main variable within these components is the surface temperature, which was calculated by a calibrated split window equation from the remotely sensed data. Twenty-four satellite images during the year 2008 were used to estimate the maximum and minimum evaporative losses from the lake at 16.3 and 12.5 BM3 year(-1), respectively. When compared with the Penman-Monteith mathematical formula, a high correlation was obtained with r(2) = 0.78. The study demonstrated that remotely sensed data can provide a robust estimate of evaporative losses from Lake Nasser that can aid decision makers in better management and Digital Earth studies.