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

Background and objectives: The changes in desert areas depend on climate condition and water balance of upstream watershed. satellite image can help us in distinguishing the trend of areas of Playa wetland.And with achieving these trend, both the status of the non-conventional water resources will be identified and this information can be used in wind erosion management. Materials and methods: 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 on August and March, the desert areas faced the descending precipitation, which led to reducing water right. In the studied intervals, in 78.98% of the study areas, no changes were observed and the maximum changes (15%) was for a wet edge. Evaluating the validity of the maps revealed that the Kappa coefficient and total validation were respectively 95% and 96%.

Keywords:

satellite imagery , MODIS , Gavkhuni Wetland , Desert surface