Drought -- National Drought Mitigation Center


Date of this Version



World Meteorological Organization, 2012: Standardized Precipitation Index User Guide (M. Svoboda, M. Hayes and D. Wood). (WMO-No. 1090), Geneva.



Published by World Meteworological Organization, 2012


Over the years, there has been much discussion on what drought indices should be used in a particular climate and for what application. Many drought definitions and indices have been developed and attempts have been made to provide some guidance on this issue. With this in mind, the Interregional Workshop on Indices and Early Warning Systems for Drought was organized and held at the University of Nebraska-Lincoln, United States of America, from 8 to 11 December 2009. It was jointly sponsored by the School of Natural Resources (SNR) of the University of Nebraska, the United States National Drought Mitigation Center (NDMC), the World Meteorological Organization (WMO), the United States National Oceanic and Atmospheric Administration (NOAA), the United States Department of Agriculture (USDA) and the United Nations Convention to Combat Desertification (UNCCD). The workshop brought together 54 participants representing 22 countries from all over the world. They reviewed the drought indices currently in use in different regions of the world to explain meteorological, agricultural and hydrological droughts; assessed the capacity for collecting information on the impacts of drought; reviewed the current and emerging technologies for drought monitoring, and discussed the need for consensus standard indices to describe different types of droughts. The experts at the meeting elaborated and approved the Lincoln Declaration on Drought Indices, which recommended that the Standardized Precipitation Index (SPI) be used by all National Meteorological and Hydrological Services (NMHSs) around the world to characterize meteorological droughts, in addition to other drought indices that were in use in their service. The Lincoln Declaration also recommended the development of a comprehensive SPI user manual. In June 2011, the Sixteenth World Meteorological Congress adopted a resolution that endorsed both of these recommendations. The Congress also requested that the SPI manual be published and distributed in all official languages of the United Nations. The full Lincoln Declaration on Drought Indices can be found on the WMO website at http:// www.wmo.int/pages/prog/wcp/agm/meetings/wies09/documents/Lincoln_Declaration_Drought_ Indices.pdf.