1,2,1,5,1,2- 1Centre for the Research and Technology of Agro-Environmental and Biological Sciences, Institute for Innovation, Capacity Building, and Sustainability of Agri-Food Production, University of Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal (nazare
- 2Agronomy Department, School of Agrarian and Veterinary Sciences, University of Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal
- 3Departamento de Expresión Gráfica, Escuela de Ingenierías Industriales, Universidad de Extremadura, Avda. de Elvas, s/n., 06006 Badajoz, Spain (fjmoral@unex.es)
- 4Departamento de Expresión Gráfica, Escuela de Ingenierías Agrarias, Universidad de Extremadura, Avda. Adolfo Suárez, s/n., 06007 Badajoz, Spain (frebollo@unex.es)
- 5Engineering Department, School of Sciences and Technology, University of Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal
- 6LEAF—Linking Landscape, Environment, Agriculture and Food—Research Center, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal (pparedes@isa.ulisboa.pt)
Rainfed olive orchards are highly vulnerable to drought in Mediterranean regions, where climate change is intensifying water scarcity and climatic variability. This study presents a spatio-temporal assessment of drought impacts on rainfed olive groves in two traditional olive-growing areas of the Iberian Peninsula: the Trás-os-Montes (TM) agrarian region in northeastern Portugal and the province of Badajoz (BA) in southwestern Spain. These regions share Mediterranean climatic conditions but differ in drought severity, land characteristics, and agro-environmental contexts.
Vegetation dynamics were analyzed over an eight-year period (2015–2023) using satellite data from the Harmonized Landsat–Sentinel-2 (HLSL30) product. Two vegetation indices were selected to characterize olive orchard conditions: the Soil-Adjusted Vegetation Index (SAVI), which reduces soil background effects in sparsely vegetated systems, and the Normalized Difference Moisture Index (NDMI), which is sensitive to canopy water content and vegetation moisture status. These indices enabled the evaluation of seasonal and interannual variability in vegetation response to water stress.
Drought conditions were quantified using the Mediterranean Palmer Drought Severity Index (MedPDSI), a drought indicator specifically adapted to Mediterranean climates and olive tree ecophysiology. The relationship between drought severity and vegetation response was examined through correlation and lagged-response analyses, allowing the identification of delayed vegetation reactions to drought events.
The results indicate clear regional contrasts in both drought characteristics and vegetation response. BA experienced more intense, prolonged, and frequent drought episodes than TM, particularly during the warm season. Seasonal variations in SAVI and NDMI were strongly correlated with MedPDSI values in both regions, with the strongest vegetation response observed at a lag of approximately two months. This delay reflects the cumulative physiological effects of water stress on olive trees rather than immediate responses.
Extreme drought years, especially 2017 and 2022, were associated with pronounced declines in both vegetation indices, indicating increased stress and reduced canopy vigor during the dry season. Rainfed olive orchards in BA showed greater susceptibility to long-term drought impacts, whereas TM exhibited slightly higher resilience, potentially related to milder climatic conditions or local environmental and management factors.
This study demonstrates the value of integrating satellite-derived vegetation indices with drought indicators to monitor drought impacts on rainfed olive systems. The proposed approach provides useful information for drought monitoring, risk assessment, and the development of adaptive management strategies aimed at improving the resilience and sustainability of Mediterranean olive orchards under ongoing climate change.
How to cite: Moral García, F. J., Crespo-Cotrina, N., Rebollo Castillo, F. J., Padua, L., Paredes, P., Santos, J. A., and Fraga, H.: Integrating satellite vegetation indices and drought metrics for agro-hydrological monitoring of rainfed olive orchards, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3046, https://doi.org/10.5194/egusphere-egu26-3046, 2026.
