A study of the effect of changes in the area of Maharlu Lake on climatic parameters of Shiraz and its surrounding areas

Remote sensing is increasingly used in studies of periodic changes of land use and land surface temperature (LST) calculations. In this paper, the effect of change in the area of Maharlu Lake on climatic elements, land surface temperature and vegetation cover in the areas surrounding the lake were studied. To this end, the ETM + & TM sensor data of LANDSAT satellite on May 22, 1987, May 17, 2000, March 20, 1999 and March 18, 2009 were used. The findings suggested that the average percentage of vegetation index in the 10-km buffer of the lake in 1987 (wet year) compared to 2000 (dry year) had dropped by 15% in the same month. In March 1999 and 2009, however, only a 3 percent decline was recorded. The minimum, average and maximum LST in the periphery of the lake registered an increase on the same dates during the wet period, but the temperature pattern was identical in both periods. Most climatic elements increased in dry years compared to that of the wet years. Also, comparing the statistical features of climatic elements in synoptic stations of Shiraz at the time of capturing images and for the long-term average (1956- 2012) suggested a relatively lower increase in temperature during wet years compared to the average long-term period. In most of the years when the precipitation was below average (300 mm), the lake dried in May. In contrast, in years when the precipitation was more than 400 mm, the lake received abundant rainfall in all months. The heavy dependence of the lake on rainfall, the small size of the catchment and the seasonality of rivers flowing into the lake make conditions extremely sensitive, critical and rainfalldependent.