The Drought Information System for Southern South America

The Drought Information System for southern South America (formerly known as SADIS, hereafter, SISSA for the Spanish acronym) is being developed by the six member countries of the Regional Climate Center for Southern South America (RCC-SSA): Argentina, Bolivia, Brazil, Chile, Paraguay, Uruguay. Since the early stage of the RCC-SSA’s activities, its members identified drought as a common focus around which initial collaboration activities could be organized. In the spirit of regional and global collaboration embodied in the WMO’s Global Framework for Climate Services, the countries and organizations involved in SISSA seek to join efforts to improve the capacity of South American nations to manage drought-related risks pro-actively.

The SISSA’s mission is to provide data, information and knowledge to support decisions and policy-making in sectors sensitive to drought: agricultural production, hydropower generation and waterway transportation. To date, SISSA has compiled a regional database of daily climate data for the six member countries including over 300 conventional weather stations. Protocols for quality control for the data have been implemented. The plan is to start incorporating data from automated weather stations in the next few months. With the in situ climate data, several drought indices are currently being calculated (SPI, SPEI, deciles, percentage of normal precipitation). Initially, these indices were being calculated for each calendar months. At the request of stakeholders who desired a more frequent update of conditions, the indices are now produced every 5 days approximately (for the multiple temporal scales considered for all indices). The typically low spatial density of in situ observation networks throughout southern South America needs to be complemented with the extensive spatial coverage and frequent return periods offered by sensors aboard satellites. SISSA is relying on satellite-derived precipitation fields (CHIRPS), vegetation indices (NDVI and EVI) and soil moisture is in the process of being incorporated. An area where considerable work remains to be done is in the generation of forecasts of drought onset, intensity and duration over scales of 1-3 months.

The assessment of drought impacts is essential to identify the social, economic, and environmental sectors/activities that are sensitive to drought in southern South America. SISSA is developing a probabilistic characterization of historical drought events in the region, including univariate and multivariate descriptions of various event metrics (intensity, magnitude, duration). The occurrence of dry events will subsequently be collated with observed or simulated impacts in the various drought-sensitive sectors. Plans are ongoing to understand the reasons underlying drought impacts on each sector.

SISSA is a multi-national, multi-institutional organization with participation of policy-makers, resource managers and individual and corporate decision makers from the targeted sectors. A major challenge for SISSA is to be able to address the diverse needs and contexts of the many drought-sensitive sectors and groups in this region. Real progress in the production and dissemination of useful and usable drought information only can occur through the involvement of those who stand to benefit from use of that information to mitigate negative impacts. For this reason, the institutional design chosen for SISSA not only seeks to encourage the participation of a wide variety of stakeholders from different sectors and jurisdictional levels, but also to provide a structure that promotes collective and shared efforts, allowing multiple groups to participate and cooperate in a decentralized manner.