Drought Monitoring using MODIS Sensor Data and Comparison with SPI Meteorological Index in Short-term Periods (Case study: Golestan province)

Drought is one of the most complex natural disasters that causes economic, social and environmental damage and is often described as a creeping phenomenon. Drought monitoring using satellite images can represent the severity of drought in areas with a lack of meteorological precipitation data and compensate for its spatial and temporal deficiency. In this research, the drought of Golestan province has been investigated using SPI, TCI, VCI and VHI indices and with the help of MODIS sensor satellite images. Therefore, first, VHI, VCI and TCI drought index maps were extracted. The findings in the TCI index study showed that in 2000, more than 80% of the studied area experienced severe drought. Similarly, in 2010, 2017 and 2018, a significant part of the studied area was in a severe drought situation. By examining the VCI index, 2008, and 2011. The maps also show that a very severe meteorological drought occurred in 2008. In the study of the VHI index during a period of 21 years in the studied area, it showed that the years 2000, 2001, 2002, 2008, 2010, 2011, 2014, 2015, 2017, 2018 and 2021 have experienced a critical drought situation. Also, in the years 2000, 2008 and 2018, more than 60% of the area of the region was in a very severe drought situation. In general, most of the studied area is in the range of severe and severe drought classes, which requires attention to the optimal management of water resources in these areas.