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