Agricultural Drought Monitoring in the Aras River Catchment using Satellite and Meteorological Indicators

Drought is the most damaging natural phenomenon that occurs in all climates of the world, even in humid regions. Agricultural drought not only damages crops and causes changes in vegetation cover, but also causes social and economic damage. The aim of this study is to monitor agricultural drought and analyze the spatial-temporal distribution of drought severity in the Aras River Basin for the vegetation growth months (April to July) in the statistical period 2012 to 2021. To assess drought conditions, the Standard Precipitation Index (SPI) obtained from precipitation data from 7 synoptic stations was used as the dependent variable, and the Normalized Difference Vegetation Index (NDVI), Vegetation Condition Index (VCI), Temperature Conditions Index (TCI), and Vegetation Health Index (VHI) were used as independent variables. The results of the correlation between meteorological indices and satellite indices showed that the SPI index has the highest correlation with the VCI index. This index also had high accuracy compared to other indices based on validation criteria, indicating its ability to monitor agricultural drought. Examination of classified drought severity maps based on SPI, VCI, VHI, and NDVI indices showed that April and May were the wettest months and July was the driest month. According to the TCI index, April was the driest month and July was the wettest month during the statistical period, and in all indices, 2021 was accompanied by severe drought. In terms of location, stations located in the western half of the Aras River Basin had more severe drought and rainfall deficiency than stations in its eastern half.