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

Table 4

Sen + M-K test for the changes in the SPI, SPEI, and SC-PDSI in each subregion.

Subregion	Drought index	β	|Zc|	Trend
I	SPI	0.013 > 0	>1.96	↑
	SPEI	0.012 > 0	>1.96	↑
	SC-PDSI	0.031 > 0	>1.96	↑
II	SPI	0.012 > 0	>1.96	↑
	SPEI	0.012 > 0	>1.96	↑
	SC-PDSI	0.026 > 0	>1.96	↑
III	SPI	0.009 > 0	>1.96	↑
	SPEI	0.009 > 0	>1.96	↑
	SC-PDSI	0.022 > 0	>1.96	↑
	SPI	0.011 > 0	>1.96	↑
IV	SPEI	0.013 > 0	>1.96	↑
	SC-PDSI	0.033 > 0	>1.96	↑
	SPI	−0.001 < 0	≤1.96	↓
V	SPEI	−0.001 < 0	≤1.96	↓
	SC-PDSI	0.009 > 0	≤1.96	↑
	SPI	−0.007 < 0	≤1.96	↓
VI	SPEI	−0.003 < 0	≤1.96	↓
	SC-PDSI	−0.005 < 0	≤1.96	↓

0.05 significance level.