Recommended citation: Sori, R; Stojanovic, M., Pérez-Alarcón, A., Vazquez, M., Ernst, J., Heidarizad, M., Valero-Jorge, A., Nieto, R., Gimeno, L. (2024). Assessment of drought conditions in vegetated areas of northwestern Africa during the 1980-2022 period. MedGU Annual Meeting. Barcelona, Spain, 25-28 November 2024.

Abstract

Northwestern Africa is characterized by different types of climates and land use, with agricultural development, semiarid environments, and Mediterranean forests and woodlands. It is a region of special socioeconomic and environmental interest, and has attracted the attention of the scientific community. Despite the advances in the knowledge of the drought phenomenon in this region, in this work, we focus on its study for vegetative development areas due to their importance in ecosystems and socio-economic activities. The spatiotemporal drought evolution during 73 years (1950 - 2022), and its relationship with global climate variations were primarily investigated. To do it, we used high-resolution precipitation datasets from the ERA5 Land reanalysis, drought indices like the Standardized Precipitation Index (SPI), the Leaf area index for low and high vegetation, and other oceanic and climatic variables such as the sea surface temperature and the vertically integrated moisture flux. The results revealed that precipitation variability over the northwestern African vegetated regions is positively correlated with the sea surface temperature and evaporation over the tropical North Atlantic, the Persian Gulf, the equatorial Pacific Ocean, the great part of the Mediterranean Sea, and other northern regions. The analysis of drought conditions involved the identification of drought episodes at various time scales, that affected the region, and characterize them in terms of duration and severity. The results highlight the 9/1998 to 12/2002 episode, with a duration of 52 months. A trend analysis confirmed a tendency toward dryness, in agreement with previous studies. It was mostly observed in the northwest of Morocco, also affected with the major frequency of years under extreme drought conditions, as well as the northern coast of Algeria and the north-northeastern Tunisia. The relationship between vegetation and temporal variations in drought was assessed. This analysis revealed a trend towards drying for the planting window because of the autumn rainfall reduction, and for the growing season, which has affected both the rainfed and the irrigated agriculture areas. These results contribute to the management of water and forest resources in the region, which is of vital importance for the socio-economic development of the countries in the region.