Standardised Precipitation Index - ERA5_QM SPI-2

The Standardized Precipitation Index (SPI) represents a standardized measure of what a certain amount of precipitation over the selected time period means in relation to expected amount of precipitation for this period. SPI is used on different time scales (1, 2, 3, 6, 12 months). The value of the SPI index around 0 represents the normal expected conditions regarding the amount of precipitation in the selected time scale compared to the long-term average (1981-2020). Value 1 represents approximately one standard deviation of precipitation amount during wet conditions and -1 denotes about one standard deviation of precipitation amount during dry conditions. Drought is usually defined as period when SPI values fall below -1. Input precipitation data is downscaled from ERA5 reanalysis using quantile mapping.
Contains modified Copernicus Climate Change Service information [1978-current year]; Contains modified Copernicus Atmosphere Monitoring Service information [1978-current year].
Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.

标准化降水指数（Standardized Precipitation Index，SPI）是一类标准化度量指标，用于量化选定时段内实际降水量与该时段长期预期降水量的偏离程度。SPI可适配1、2、3、6、12个月等多种时间尺度。当SPI数值接近0时，表示对应时间尺度下的降水量与长期平均（1981-2020年）水平一致，处于正常降水状态；数值为1时大致对应偏湿条件下的一个标准差降水距平，数值为-1则代表偏干条件下的一个标准差降水距平。干旱通常被定义为SPI数值低于-1的时段。本数据集的输入降水数据通过分位数映射法，对ERA5再分析数据进行降尺度处理得到。

本数据集包含经修改的哥白尼气候变化服务（Copernicus Climate Change Service）信息[1978-当前年份]；包含经修改的哥白尼大气监测服务（Copernicus Atmosphere Monitoring Service）信息[1978-当前年份]。

欧洲委员会及欧洲中期天气预报中心（ECMWF）不对基于其所含哥白尼相关信息或数据的任何使用行为承担责任。