Drought monitoring ARC - Forum for Agricultural Risk

Recent drought conditions over the North West Province have revitalized interest in drought
monitoring over South Africa. The Agricultural Research Council - Institute for Soil, Climate
and Water (ARC-ISCW) monitors climate and vegetation responses operationally and provides
near-real time products for the delineation of adversely affected areas. The Institute produces a
monthly newsletter (named Umlindi) which provides updates of climate and vegetation
conditions throughout the year, contributing to the near-real time understanding of how a specific
rainy season unfolds. The maps published in the newsletter are based on products derived at the
ARC-ISCW. These include: total rainfall, derivatives of rainfall totals at various time scales
relevant to agriculture, vegetation conditions and cumulative vegetation conditions and
derivatives thereof. The maps are also available in JPEG format for separate use. Figure 1 is an
example of one of the drought monitoring products: a 12-month Standardized Precipitation Index
(SPI) map by June 2013, showing severe drought conditions over parts of the North West
Province at this time scale.
Figure 1: 12-Month Standardized Precipitation Index (SPI) per quaternary catchment by June
While operational drought monitoring is an on-going process at the ARC-ISCW, contributions
are also made towards other projects involving the phenomenon of drought. The Institute has
been involved in the European Union-funded African Monitoring of Environment for
Sustainable Development (AMESD) project. As part of the project deliverables, the ARC-ISCW
developed a Drought Monitoring System (DMS) to be used in SADC with available remotelysensed data for the area. The DMS is a decision support tool to be used at national or provincial
level for drought monitoring and has been employed for the creation of maps used in the SADC
Drought Report. The tool is an open source, stand-alone application specifically geared towards
allowing the user to choose from a range of drought monitoring indices based on data available
over EUMETCast. The data are received via a satellite dish so reception is not necessarily
dependent on a good Internet connection. The system was developed for use in a Windows
environment. The monitoring system combines the current rainfall estimates and vegetation
responses (Normalized Difference Vegetation Index (NDVI), cumulative NDVI) as input. These
are used to obtain products such as comparisons with long-term averages and other indices
relevant for drought monitoring and possible with available near-real time data with resultant
“Drought Maps” as an output product. The Long-Range Forecast of the South African Weather
Service (SAWS) has been integrated into the system, and “drought outlooks” are also produced
by combining the 3-month rainfall forecast with rainfall and vegetation conditions during the
previous few months. The user is guided to apply existing algorithms to input data with freedom
to choose areas and periods of interest.
The Disaster Management Act stresses the shift from a reactive to a proactive disaster
management approach. Towards enabling a proactive approach, the ARC-ISCW is contributing
to drought risk profiles regionally covering the country. The Institute’s contribution entails firstly
a historical assessment of drought occurrence over the country as a whole in terms of various
definitions of drought related to intensity, extent, duration and potential impacts. Secondly, it
involves the characterization regionally of drought frequency and intensity according to various
definitions of drought related to impacts. Operational assessment of climate and vegetation
conditions through monitoring products focussing on a range of time scales further assists in
early detection of developing drought conditions.
For more information contact:
Johan Malherbe
Tel: +27 12 310 2577
E-mail: [email protected]