Abstract:
The spatial-temporal variability of drought characteristics and propagation mechanisms in
the hydrological cycle is a pertinent topic to policymakers and to the diverse scientific community.
This study reports on the analysis of drought characteristics and propagation patterns in the
hydrological cycle over South Africa. In particular, the analysis considered daily precipitation
and streamflow data spanning from 1985 to 2016, recorded from 74 weather stations, distributed
across South Africa and covering the country’s 19Water Management Areas (WMAs). The results
show that all the WMAs experience drought features characterized by an inherent spatial-temporal
dependence structure with transition periods categorized into short (1–3 months), intermediate
(4–6 months), long (7–12 months) and extended (>12 months) time-scales. Coupled with climate
and catchment characteristics, the drought propagation characteristics delineate the WMAs into
homogenous zones subtly akin to the broader climatic zones of South Africa, i.e., Savanna, Grassland,
Karoo, Fynbos, Forest, and Desert climates. We posit that drought evolution results emanating from
the current study provide a new perspective of drought characterization with practical use for the
design of drought monitoring, as well as early warning systems for drought hazard preparedness
and effective water resources planning and management. Overall, the analysis of drought evolution
in South Africa is expected to stimulate advanced drought research topics, including the elusive
drought termination typology.
