Evaluation of drought effect on Urmia Lake salinity changes using remote sensing techniques

Urmia Lake located in the northwestern corner of Iran is one of the largest permanent hypersaline lakes in the world and the largest lake in the Middle East. This lake with the area of 4500-6000 km2، as the largest lake in Iran and Twentieth Lake in the world has a particular importance. The lake is full in danger of drying and in the recent years، height of the water level has decreased about of 7 meters. This study، estimated the changes of lake water salinity and modeled the lake salinity patterns by remote sensing techniques. For this purpose، the amount of water reflection values of landsats TM data was considered. Radiometric and geometric corrections were performed in the preprocessing stage. Furthermore، the range of variation of reflectance between bands correlation images were examined to investigate the effects of fluctuations in the defined time period. According to the results، the effects of salinity and the range of factors such as drought، excessive use of resources and procedures، and mismanagement is very clear. Based on the results a positive relationships between band 1 (450-520 nm)، band 2 (520-600 nm)، band 4 (775-900 nm) and salinity were found. In addition negative relationships between band 3 (630- 690 nm)، band 5 (1550-1750 nm) were observed.