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

Figure 9

Pearson correlation coefficient of NDVI and SPEI in four grasslands at different timescales (the horizontal axis was the months, and the vertical axis was the correlation coefficient between SPEI and NDVI). is 0.1 significance level and is 0.05 significance level.

(a) Meadow steppe

(b) Typical steppe

(c) Steppe desert

(d) Desert steppe