Abstract:
There is large consensus among the scientific community that the global climate is changing and that climate change will accelerate the hydrological cycle with increased frequency of occurrence of flood and drought events. Botswana is characterized by an arid to semi-arid climate with low annual rainfall amounts in most parts of the country. Climate change is expected to exacerbate the impacts already being felt from a highly variable natural climate and most of the impacts will be imposed on communities whose livelihoods largely depend on rainfed agriculture. Droughts are a common and recurrent feature especially in most arid regions of the world. In order to safeguard livelihoods and food security against the adverse impacts of droughts, drought preparedness and early warning must be prioritized in policy making. Provision of timely information that informs the decision making process under the context of droughts requires monitoring tools that are able to capture both historical and real time events and at the
same time being flexible and adaptive to different conditions. Most
parts of southern Africa are characterized by paucity of observed
station data which makes them limited in spatial and temporal
coverage in such instances, satellite imagery can therefore be used as
surrogate monitoring data. For a long time satellite-based remote
sensing has been used to reliably monitor environmental activities.
One advantage of remote sensing is that it provides continuous data
with a large spatial coverage. This study explores the use of remotesensed data in near real time monitoring of droughts in Botswana. Satellite-based drought indices are assessed and a comparison is made relative to the standardized precipitation index (SPI) which is derived from observed station data. Positive correlations (>05) exist between SPI and the remote sensed indices indicating that satellite based indices can be used to reliably inform drought risk
management.