Meteorological Drought, Hydrological Drought, and NDVI in the Heihe River Basin, Northwest China: Evolution and Propagation

Table 4

The distribution peak, intensity, duration, and severity for MD characteristics based on SPI-1 using thresholds of −1, −1.5, and −2 in the UHRB and MHRB.

	Threshold	Peak			Intensity			Duration			Severity
		Mean	Max	Min	Mean	Max	Min	Mean	Max	Min	Mean	Max	Min
Ql	−1.0	1.7	3.6	1.1	1.7	4.0	1.0	4.6	15.0	1.0	3.1	10.2	1.1
	−1.5	2.0	3.6	1.2	1.3	3.0	1.0	4.6	15.0	1.0	3.6	10.2	1.5
	−2.0	2.5	3.6	2.0	1.0	1.0	1.0	4.3	15.0	1.0	4.1	10.2	2.0
Yg	−1.0	1.6	3.1	1.7	1.7	5.0	1.0	4.4	23.0	1.0	3.8	12.9	1.0
	−1.5	2.2	3.1	2.5	1.6	3.0	1.0	5.5	23.0	1.0	5.4	12.9	1.8
	−2.0	2.5	3.1	2.0	1.2	2.0	1.0	6.9	23.0	1.0	5.1	12.5	2.0
Gt	−1.0	1.4	2.9	1.0	1.5	4.0	1.0	4.1	14.0	1.0	3.1	8.1	1.0
	−1.5	1.8	2.9	1.5	1.1	2.0	1.0	4.5	14.0	1.0	3.6	8.1	1.6
	−2.0	2.7	2.9	2.5	1.0	1.0	1.0	2.0	3.0	1.0	3.5	4.0	2.9
Zy	−1.0	1.6	2.7	1.0	1.6	6.0	1.0	4.7	30.0	1.0	3.5	18.8	1.0
	−1.5	2.0	2.7	1.5	1.5	4.0	1.0	5.5	30.0	1.0	4.4	18.8	1.9
	−2.0	2.3	2.7	2.0	1.1	2.0	1.0	4.0	15.0	1.0	3.9	10.0	2.0
Sd	−1.0	1.6	3.0	1.0	1.6	5.0	1.0	4.2	17.0	1.0	3.2	9.4	1.0
	−1.5	1.9	3.0	1.5	1.2	3.0	1.0	3.5	14.0	1.0	3.4	9.4	1.5
	−2.0	2.3	3.0	2.0	1.1	2.0	1.0	3.1	11.0	1.0	3.7	9.4	2.0