Efficiency of Spectral Indices Derived from Landsat-8 Images of Maharloo Lake and Its Surrounding Rangelands

Abstract. Maharloo Lake is one of the salty lakes located in the southeast of Fars province, Iran. Presence of salt domes has a significant role in its salinity. Magnesium-sodium chloride and sodium sulfate are dominant salts of the lake. Due to the drying up of lake, widespread lands surrounding the area are exposed to secondary salinity. It seems necessary to investigate the changes to find salinity level in order to predict the changes of vegetation and its margin uses. The purpose of the study was to evaluate the spectral indices derived from the images of Landsat8 sensors in detection of salty levels of the Maharloo Lake. In this study, Landsat8 imagery was used to obtain salinity indicators in the salt lake. Fourteen salinity indices have been calculated using the ENVI. The results showed that the indices of BI, SI, SI1, SI2, SI3, VSSI, YSI and SR could detect the area covered by salt crust on the lake and then, isolate and separate it from the rest of reflection spectrum. However, MSI and NDBI indicators were unsuccessful in detection of salt crust. NDVI and COSRI indicators used in plant detection could not detect the salt crust and just identified the typical vegetation. Finally, I2 and NDSI indicators also partially with low accuracy succeeded to detect some salinity areas and had no satisfactory performance.