Spatial Monitoring of Drought in the Khatun Abad Basin Using Spi and Remote Sensing Technique

Drought is a natural and recurrent phenomenon. it is considered ‘a natural disaster’ whenever it occurs intensively in highly populated regions, resulting in significant damage (material and human) and loss (socioeconomic). in this regard, this research aims to evaluate the drought of the khatun abad basin using the combination of ndvi (normalized difference vegetation index) and lst (land surface temperature) modis sensors and an spi indicator. for this purpose, the vhi index was calculated from the combination of vci and tci indices based on the 18year time series (20002017) in june. finally, drought zoning maps based on the vhi index were produced in five classes: very intense, intense, median, and mild and without drought. the evaluation of the time series derived from the vci and tci indices shows that there is a significant relationship between ndvi and lst variations. the results show that an extreme drought class is observed in 2017, covering an area of 46 km² from the plain involved with the extreme drought. this is despite the fact that the highest levels of severe drought class occurred in 2008 with an area of approximately 900 km². the total severe and extreme drought classes are observed in 2007, 2008 and 2017. in 2017, a total area of approxiamtely 844 km² from the khatun abad basin was involved with the drought, reaching 902 km² in 2008 and 809 km² in 2007. according to the results, the lowest level of drought in khatun abad in 2009 was 34 km² classified as a severe and extreme drought. additionally, the results of the data analysis using the index spi show that, the most severe drought in the region occurred in 2008. as a result, 33% of the area was severely subjected to drought, and 65% was placed in the middle class drought. in general, the research results indicate that drought changes in the khatun abad plain are not logical, and in different years, different drought intensities have been observed.

Spatial monitoring of drought in the Khatun Abad basin using SPI and remote sensing technique

Drought is a natural and recurrent phenomenon. It is considered ‘a natural disaster’ whenever it occurs intensively in highly populated regions, resulting in significant damage (material and human) and loss (socioeconomic). In this regard, this research aims to evaluate the drought of the Khatun Abad basin using the combination of NDVI (Normalized Difference Vegetation Index) and LST (Land surface temperature) MODIS sensors and an SPI indicator. For this purpose, the VHI index was calculated from the combination of VCI and TCI indices based on the 18year time series (20002017) in June. Finally, drought zoning maps based on the VHI index were produced in five classes: very intense, intense, median, and mild and without drought. The evaluation of the time series derived from the VCI and TCI indices shows that there is a significant relationship between NDVI and LST variations. The results show that an extreme drought class is observed in 2017, covering an area of 46 km² from the plain involved with the extreme drought. This is despite the fact that the highest levels of severe drought class occurred in 2008 with an area of approximately 900 km². The total severe and extreme drought classes are observed in 2007, 2008 and 2017. In 2017, a total area of approxiamtely 844 km² from the Khatun Abad basin was involved with the drought, reaching 902 km² in 2008 and 809 km² in 2007. According to the results, the lowest level of drought in Khatun Abad in 2009 was 34 km² classified as a severe and extreme drought. Additionally, the results of the data analysis using the index SPI show that, the most severe drought in the region occurred in 2008. As a result, 33% of the area was severely subjected to drought, and 65% was placed in the middle class drought. In general, the research results indicate that drought changes in the Khatun Abad plain are not logical, and in different years, different drought intensities have been observed.