Monitoring the temporal-spatial changes of desertification in Gavakhoni Basin based on climatic criteria

In the present study, the spatio-temporal changes of the desertification status of Gavkhoni Basin during 6 decades from 1961 to 2020 were determined by using the IMDPA desertification intensity model.According to the results of this research, it was determined that the first decade with an average score of 3.17, the fourth decade with a score of 2.22 and the last decade with a score of 2.36 are the highest, lowest and average intensity of desertification, respectively.Although the findings of this study showed that the trend of desertification variability based on the decade average is decreasing, but in the last two decades, the maximum area of the basin has been in the severe desertification class, which is a warning about the vulnerability of the basin to the phenomenon of desertification.From the results of this research, it was found that among the 3 indicators of climate criteria, the highest score (average 3.6) is related to Transo index and other indicators are in the next ranks.Desertification intensity zonation map of Gaukhoni basin showed that the central and eastern regions have higher risk and the northwestern and southeastern regions have lower risk. In this research, NDVI index was used to validate the climate model.The variability of this index over time indicates the increase of barren lands and the decrease of the area of water areas and vegetation.Therefore, it can be seen that the outputs of the NDVI index and the climate criterion confirm each other's findings. Although the results of other previous studies show that the consequences of global warming lead to an increase in temperature -evaporation and a decrease in precipitation in dry areas, however, with the location of the Gavkhoni basin in a dry area, the possibility of the impact of climate change on the aggravation of natural hazards will be significant.