Seasonal Drought Persistence Over Southern Africa and Four of Its Major River Basins

ABSTRACT Knowing the likelihood of a drought event persisting from one season to the next is vital for informing anticipatory actions that minimise its impacts. Using logistic regression, this study examines the odds of a drought episode persisting from one season to the next over Southern Africa during the 1950–2021 period. The study further investigates the influence of nine climate modes of variability on drought persistence over Southern Africa and four of its major river basins, namely, Limpopo, Zambezi, Okavango and Orange. Results show seasonal and spatial variability of drought frequency and persistence over Southern Africa, with the Limpopo River basin experiencing the highest drought frequency. The likelihood of drought conditions persisting from one season to the next over a larger portion of Southern Africa is increased when El Niño conditions linger from one season to the next. Additional climate modes also play a role in modulating drought persistence over Southern Africa. The outcome of this study may assist water resource managers, humanitarian actors and other stakeholders in elaborating robust drought preparedness plans.