等级 | 类型 | SPI | MCI (月) | 降水距平百分率% (月) | 降水距平百分率% (年) |
1 | 无旱 | −0.5 < SPI | −0.5< MCI | −40 < P | −15 < P |
2 | 轻旱 | −1.0 < SPI ≤ −0.5 | −1.0 < MCI ≤ −0.5 | −60 < P ≤ −40 | −30 < P ≤ −15 |
3 | 中旱 | −1.5 < SPI ≤ −1.0 | −1.5 < MCI ≤ −1.0 | −80 < P ≤ −60 | −40 < P ≤ −30 |
4 | 重旱 | −2.0 < SPI ≤ −1.5 | −2.0 < MCI ≤ −1.5 | −95 < P ≤ −80 | −45 < P ≤ −40 |
5 | 特旱 | SPI ≤ −2.0 | MCI ≤ −2.0 | P ≤ −95 | P ≤ −45 |