Examining Snow Cover Changes in Relation to Drought Using Remote Sensing Techniques and GIS (Case Study of the West and East Azerbaijan Provinces)

In this research, to determine the changes in the level of snow cover in relation to drought, satellite data has been used in order to determine the snow cover and meteorological station data has been applied to estimate the drought. In this regard, at the first stage, satellite data was collected from NASA's Web site from 1385 to 1395, and after geometric and atmospheric corrections based on the NDSI index and using of bands 4 and 6, was applied to determine the level of snow cover and  drought rate has been estimated based on SPI index. Studies of snow cover reveal that the level of snow cover has been reduced and this is proportional to the drought rate, and the prevailing trend in the level of snow cover and SPI is a downward trend. However, in spite of the prolonged and increased SPI index, the level of snow cover has been reduced or vice versa. The reason for this can be investigated through the type of precipitation during these years and it is possible that most type of the precipitation, during the years in which snow cover has been less, has been rainy type and in the drought years with increased snow cover, type of downfall has been more snowy.