Monitoring Snow Cover Changes and the Volume of Snow Water Equivalent Using MODIS and AMSR-2/AMSR-E Sensor Data (Case Study: Karun, Karkheh and Dez Basins)

The aim of this study was to investigate the spatio-temporal changes of snow cover and snow water equivalent in Karun, Karkheh and Dez basins and the effect of changes in the discharge of these basins.

In order to extract snow cover and measure snow water equivalent and their correlation with the discharge of Karun, Karkheh and Daz basins, from the thresholding method on reflective and thermal bands, Man Kendal method, Spearman correlation and MODIS measurement data (2000-2020), available images of AMSR-2/AMSR-E sensor (2003-2020) and monthly discharge at the same time with the mentioned satellite images have been used.

The results of time series analysis in all three studied basins show a decreasing trend of snow cover area and volume of the snow water equivalent in most months And The most decreasing changes in snow cover area were observed in Dez basins and March with a value of -3.26 and the most decreasing changes of snow water equivalent were observed in Karun basin and February with a value of -3.86. The highest correlation in all three basins was related to Dez basin in June with a value of 0.775 (p<0.01) and the lowest was related to Karkheh basin in February with a value of 0.183. Examination of the relationship between discharge and snow water equivalent AMSR-E/AMSR-2 images also showed that the highest correlation was related to Karun Basin in January with a value of 0.721 (p<0.01).

Generally, in the observed years, the area of snow cover and snow water equivalent in all months has decreased and is more severe in Karun and Dez basins. In addition, in most months, there is no significant relationship between snow cover area and basin discharge.