Evapotranspiration mapping over Egypt using MODIS / Terra satellite data

The evapotranspiration (ETo) is one of the most important regulating factors of climate, at both local and global scales. It is the sum of evaporation and plant transpiration from the Earth's land and ocean surface to the atmosphere. Remote sensing technique is an important tool supporting the management of natural resources and agricultural practices for wider spatial coverage. The aim of this study is to calculate the potential evapotranspiration over Egypt using remote sensing technique and estimate the water loss from agricultural lands. MODIS/TERRA – LST (Land surface Temperature) and NDVI (Normalize difference Vegetation Index) were used as a variable to calculating the ETo by Hargreaves potential evapotranspiration equation during the period from 2001 to 2013 and estimate the water loss by evapotranspiration. The results indicated that, remotely sensed information, along with ancillary meteorological data, provides the capability to estimate evapotranspiration on pixel basis and well suited for ETo mapping over all Egypt. From the ETo mapping over Egypt one can found that, the highest area of low and high ETo range are found in the years of 2001 and 2008 respectively, while the lowest and highest values were observed in the years of 2004 and 2009 .The maximum value of monthly averages ETo of the 2nd period (from 2008 up to 2013) greater than the 1st period (from 2001 up to 2007), while the minimum value of monthly averages ETo of the 2nd period is lower than the 1st period at most of months. The amount of annual water that are loss from agricultural lands by evapotranspiration have been ranged from about 34.4 to 42.4 billion m3 of water by the year of 2012. Finally the remote sensing information was able to reproduce the evapotranspiration mapping over all land cover in Egypt.