Evaluating the changes in Gavkhuni Wetland using MODIS satellite images in 2000-2016

The changes in desert areas depend on climate conditions and the water balance of upstream watersheds. Satellite images can help us in distinguishing the trend of areas of Playa Wetland and with achieving these trends, both the status of the non-conventional water resources will be identified and this information can be used in wind erosion management.

In the present study, the changes in Gavkhuni Wetland was evaluated using MODIS satellite images from 2000 to 2016. For this purpose, after performing the required modifications on the satellite images, they were classified and their changes in studies time intervals were detected. Since the changes of desert areas depend on the humidity variations, the TVDI، MTVDI، VTCI indices were calculated to enhance the satellite images. The indices along with the bands of MODIS images were used in classification. The classification was done in August and March (maximum changes in desert areas and wet age) during 16 years. Due to the large number of used images, coding in MATLAB software was used to facilitate calculation of these parameters.

Results and conclusion:

The results indicated that in August and March, the desert areas faced descending precipitation, which led to reducing water rights. In the studied intervals, in 78.98% of the study areas, no changes were observed and the maximum changes (15%) were for a wet edge. Evaluating the validity of the maps revealed that the Kappa coefficient and total validation were respectively 95% and 96%.