Uporaba daljinskega zaznavanja pri oceni tveganja za sušo s spektralnimi indeksi in modeliranjem: študija primera v severnem delu osrednjega Vietnama

Application of remote sensing in drought risk assessment using spectral indices and modelling: a case study in North Central Vietnam

Author(s):

Le Hung Trinh, Thi Thu Trang Tran, Van Phu Le, Thi Hanh Tong

Abstract:

Drought is one of the most pressing environmental hazards, severely impacting agriculture, ecosystems, and water availability, especially in vulnerable regions such as Central Vietnam. This study assessed drought risk in Quang Tri province during the period from 2016 to 2025 using Sentinel-2 surface reflectance imagery and a multi-index remote sensing approach. Five drought-related indices including NDVI, NDWI, EVI, MSI, and SAVI were calculated and integrated using a Weighted Overlay Analysis on the Google Earth Engine platform. Each index was assigned a weight based on its contribution to drought characterization: NDVI (30%), NDWI (25%), EVI (20%), MSI (15%), and SAVI (10%). The resulting drought risk maps were classified into five levels. The analysis showed that mild drought dominated, covering between 60.14% and 70.16% of the total area annually. Moderate drought ranged from 15.41% to 20.76%, while severe drought reached a peak of 476.96 km² (9.84%) in 2020. Extreme drought which though less frequent was most severe in 2020, affecting 187.35 km² (3.87%). In contrast, non-drought areas dropped significantly over time, reaching a minimum of 111.46 km² (2.30%) in 2023. The findings highlight increasing drought severity and spatial disparity, particularly in upland and coastal zones. This approach proves effective for large-scale drought monitoring and supports local authorities in implementing targeted mitigation and climate adaptation strategies.

Keywords:

Drought, Sentinel-2, multi-index, Weighted Overlay Analysis, Quang Tri province

DOI: 10.15292/geodetski-vestnik.2026.02.213-229

Citation:

Le Hung Trinh, Thi Thu Trang Tran, Van Phu Le, Thi Hanh Tong (2026). Uporaba daljinskega zaznavanja pri oceni tveganja za sušo s spektralnimi indeksi in modeliranjem: študija primera v severnem delu osrednjega Vietnama. | Application of remote sensing in drought risk assessment using spectral indices and modelling: a case study in North Central Vietnam. Geodetski vestnik, 70 (2), 213-229. DOI: 10.15292/geodetski-vestnik.2026.02.213-229