Evaporation, Evapotranspiration, Climate change, Spatial variation, Water Management, Arid Lands, Trends Climate change and variability is receiving much attention recently. Changes in the world temperature and other natural phenomenon such as rainfall variability are being considered as indicators to climate change. These changes can have significant effect on water resources and therefore on the livelihood of society especially in water scarce countries such Saudi Arabia. The Kingdom of Saudi Arabia suffers a chronic water scarcity, despite the fact that the agricultural sector consumes around 90% of the water budget in the kingdom. The objective of this article is to study the variability in evaporation rates to achieve water balance in arid regions, by using remote sensing data from different sensors to estimate the evaporation rates by implementing different algorithms of Surface Energy Balance models. Work plan 1- Evaporation rate, using different ways to calculate the rate of evaporation. Then evaluate the best one will be appropriate within the designated study area (SEBS, NDVI derivatives, Metrics) 2- Evaporation sensitivity analysis of the inputs, such as: (humidity, wind speed, radiation, temperature) After selecting the appropriate method to calculate the evaporation rate. 3- Time series analysis of the most adequate model Looking for the best essay writer? Click below to have a customized paper written as per your requirements.