Estimation of Urmia Lake Evaporation Using Remote Sensing Data

Evaporation which is the most important water output from terminal lakes, plays a significant role in the lakes water balance. It can also vary chemical compositions of lakes. This study aims at providing an accurate estimate of the evaporation rate from Urmia Lake. To accomplish this task, the SDDE (Salinity Dependent Daily Evaporation) model was developed based on the energy balance model and conjunctive use of the MODIS satellite data including water surface temperature, albedo, emissivity, cloud mask and precipitable water vapour and GIS techniques. The model was validated using insitu data. Then, evaporation maps of Urmia Lake were calculated using the SDDE model during 2010. Results showed that the rate and volume of evaporation during the non_cloudy months (April-Novemebr) were 1136 mm and 3.8 km3, respectively. Consequently, even if the environmental water requirement of the lake is supplied, the declining trend of its water level will continue.