Standardized Water Budget Index and Validation in Drought Estimation of Haihe River Basin, North China

Table 1

SWBI classification.

SWBI value	SWBI category
SWBI > 2.0	Extreme wet conditions
1.5 < SWBI ⩽ 2.0	Severe wet conditions
1.0 < SWBI ⩽ 1.5	Moderate wet conditions
0.5 < SWBI ⩽ 1.0	Mild wet conditions
−0.49 < SWBI ⩽ 0.5	Near normal
−1.0 < SWBI ⩽ −0.5	Mild drought
−1.5 < SWBI ⩽ −1.0	Moderate drought
−2.0 ⩽ SWBI ⩽ −1.5	Severe drought
SWBI < −2.0	Extreme drought