Analysis of Drought Characteristics in Xilingol Grassland of Northern China Based on SPEI and Its Impact on Vegetation

Table 1

The standardized precipitation index (SPEI) categories based on the initial classification of SPEI values.

Categories	SPEI values
Extreme drought	Less than −2.00
Severe drought	−1.99 to −1.50
Moderate drought	−1.49 to −1.00
Light drought	−0.99 to −0.50
Near normal	−0.49 to 0.50
Humid	More than 0.50