Analysis of Vegetation Response to Climate Dynamics and Drought in the Al-Gharraf River Basin Using Remote Sensing Data (1989–2025)

Abstract

This study analysed the spatial and temporal relationship between climatic drought indices and vegetation indices in the Al-Gharraf River basin for the period 1989–2025, to assess the response of vegetation cover to changes in rainfall. The study relied on a comparison of four selected years to demonstrate variations in drought and moisture conditions, using three main indices: the Six-Month Standardised Precipitation Index (SPI-6), the Normalised Difference Vegetation Index (NDVI), and the Vegetation Condition Index (VCI). The results showed a positive linear correlation between the SPI-3 index and the vegetation indices (NDVI and VCI), confirming the high sensitivity of the ecosystem in the study area to medium-term rainfall fluctuations. The study recorded a strong correlation between the NDVI and VCI indices, reaching 0.81, demonstrating their high efficiency in accurately monitoring environmental stress and assessing plant health.  Years with peak rainfall (among the four selected years) showed an immediate vegetative response, manifested as higher values of the vegetation indices, resulting from improved soil moisture and enhanced plant physiological processes, The study thus demonstrates the effectiveness of integrating remote sensing with climatic indices in developing early warning systems for drought, and supports decision-making for agricultural planners and water resource managers in the Al-Gharraf region to address the risks of future climate change...