Spatiotemporal Variations of Drought in the Arid Region of Northwestern China during 1950–2012

Figure 4

Seasonal changes in the drought indexes in (a–c) spring, (d–f) summer, (g–i) autumn, and (j–l) winter. 0.05 significance level.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)

(j)

(k)

(l)