Monitoring of Ashtrankoh glaciers in the catchment area of Gohar Lake in Lorestan and investigating its relationship with vegetation reduction using MODIS images and NDSI index between 1380 and 1395

Subject Areas : SANJESH AZ DOOR

mohammad ebrahim afifi ¹ , vahid sohrabi ²

1 - Member of the Faculty of Geography Department of Islamic Azad University, Larestan Branc
2 - Geography and Urban Planning, Faculty of Humanities, Larestan Branch Azad University, Iran

Received: 2022-08-23 Accepted : 2022-11-30 Published : 2022-12-22

Keywords: Lorestan province, MODIS sensor, NDSI Index, Snow cover,

Abstract :

In this study، MODIS satellite images related to the years 2001 to 2015 have been used to prepare a map of the surface under snow cover in Lorestan Province، Ashrankuh Region. The main purpose of the research was to investigate the relationship between natural glaciers and vegetation. In this study، it was the NDSI index، which is actually the normalized difference of two spectral bands (visible band and near-infrared band or short-wavelength infrared band)، which is used to extract snow-covered surfaces. k-means algorithm was used for clustering. The results obtained from the changes in the glacial zones have shown a decreasing trend. So that the area covered by glaciers in 2001 was estimated to be around 7500 square meters and in 2015 this amount was estimated to be approximately 5000 square meters. Fluctuation in the changes of each year compared to the next year is very low due to the wideness of the Modis image cell، but in the long term، the decreasing trend of glacier levels is quite clear.