Land Surface Temperature in the Yardang Region of Lut Desert (Iran) Based on Field Measurements and Landsat Thermal Data

Due to the hard climatic conditions of the yardang region in the Lut Desert, not much information about land surface temperatures of this region, one of the extremely arid climatic zones of Iran, has been extracted. Therefore, in this study in order to obtain some information about important surface features of the Lut Desert (marl, grey sand, bright sand and salt affected land), field temperature measurements were taken and remotely sensed data processing were made. Temperature was measured eight times from 6 a.m. to 8 p.m. during a 15-day period in October 2000. In addition to field measurements, Land sat satellite TM thermal data dated on the 25th of June, 1989 and other sources of data and maps were used. Thermal remote sensing analysis was applied for mapping surface temperatures in the south-eastern part of the Lut Desert in Iran. In this research, the methodology comprised : 1) field temperature measurements, 2) the relationship between the temperature of different soil surfaces and land cover types, 3) diurnal variations in the surface temperature of land cover types, 4) primary image processing and fieldwork, 5) image processing and calibration,6) image classification and accuracy assessment, and 7) land surface temperature mapping. The results obtained have shown the differences between the surface temperatures of the studied features. The significant differences between surface temperatures were discussed. The results obtained have also shown the importance of thermal sensor selection from the viewpoint of satellite overpass time. The results obtained from thermal data and field temperature measurements have shown the time of Landsat satellite overpass has to be considered for image interpretation. As a result, the temperature lowers, respectively, in regions such as yardangs, desert pavement, salty lands, and wetlands; however, it increases in sandy regions