COMPREHENSIVE ASSESSMENT OF DEGRADATION RISK IN THE ARID TERRITORIES OF THE ILI DISTRICT BASED ON SATELLITE INDICES AND CLIMATIC FACTORS

Abstract

This article presents a comprehensive assessment of degradation risk in the arid territories of the Ili district, Almaty region, based on Sentinel-2 satellite indices, MODIS NPP and ERA5-Land hydroclimatic variables. The aim of the study was to identify the spatial distribution of degradation risk and to determine how the condition of the soil-vegetation cover is related to moisture and temperature factors during 2020–2025. The integrated risk map was produced using four normalized components: NDVI, BSI, surface albedo and VCI. MODIS NPP for 2020–2024, precipitation, air temperature, wind speed, snow water equivalent and 0–28 cm soil moisture were used as additional explanatory variables. High and very high integrated risk classes occupy 7318.9 km², or 88.91% of the analysed area, whereas strict hotspot zones cover 24.7 km² (0.30%). The strongest significant relationships were found between NPP and May–September precipitation (r = 0.954; p = 0.0118) and between NPP and 0–28 cm soil moisture (r = 0.962; p = 0.0087). NDVI and VCI were positively associated with snow water equivalent, while NDVI showed a negative relationship with May–September temperature. The Mann–Whitney test confirmed that hotspot areas have lower NPP and soil moisture than non-hotspot areas. The results indicate that degradation risk is formed by the combined effects of reduced vegetation condition, increased soil exposure, higher surface reflectance and moisture deficit.