Global Drought Hazard Frequency and Distribution

The 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 data set 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).

全球干旱灾害频率与分布数据集基于国际气候预测研究所（IRI）的标准化降水加权异常（WASP），采用2.5分钟网格尺度。该数据集通过利用1980年至2000年间的月平均降水量数据，以2.5度分辨率进行评估，WASP对三个月时间窗口内的降水亏缺或盈余进行评估，该时间窗口的权重由降水季节性循环变化的幅度决定。三个月的平均降水量由降水数据得出，并计算每个网格单元21年周期的降雨量中位数。降水量日平均值小于1毫米的网格单元被排除在外。当月降水量亏缺幅度小于或等于其长期中位值的50%，并且连续三个月或更长时间出现时，即认定为干旱事件。网格单元随后被划分为具有大致相等网格单元数量的10个类别。较高的网格单元值表示干旱发生的频率更高。本数据集是哥伦比亚大学灾害与风险评估研究中心（CHRR）、哥伦比亚大学国际气候预测研究所（IRI）和哥伦比亚大学国际地球科学信息网络中心（CIESIN）合作成果。