Global Drought Hazard Frequency and Distribution is a 2.5 minute grid based upon the International Research Institute for
Climate Prediction's (IRI)
Weighted Anomaly of Standardized Precipitation (WASP). Utilizing average monthly precipitation data from 1980 through 2000
at a resolution of 2.5 degrees, WASP assesses the precipitation
deficit or surplus over a three month temporal window that is weighted by the magnitude of the seasonal cyclic variation in
precipitation. The three months' averages are derived from the
precipitation data and the median rainfall for the 21 year period is calculated for each grid cell. Grid cells where the three
month running average of precipitation is less than 1 mm per
day ae excluded. Drought events are identified when the magnitude of a monthly precipitation deficit is less than or equal
to 50 percent of its longterm median value for three or more
consecutive months. Grid cells are then divided into 10 classes having an approximately equal number of grid cells. Higher
grid cell values denote higher frequencies of drought occurrences.
This dataset is the result of collaboration among the Columbia University Center for Hazards and Risk Research (CHRR), Columbia
University International Research Institute for Climate
Prediction (IRI), and Columbia University Center for International Earth Science Information Network (CIESIN).
To provide a means of assessing the relative distribution and frequency of global drought hazard.
Maintenance_and_Update_Frequency: As needed
Theme_Keyword_Thesaurus: GCMD SCIENCE PARAMETERS
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Theme_Keyword: EARTH SCIENCE > HUMAN DIMENSIONS > ENVIRONMENTAL GOVERNANCE/MANAGEMENT > WATER MANAGEMENT