Droughts in Pakistan: a spatiotemporal variability analysis using the Standardized Precipitation Index

Figures & data

Table 1. The classification of drought severity based on the Standardized Precipitation Index (McKee et al., 1993)

SPI	Drought classification
0 to −1.0	Mild
−1.0 to −1.5	Moderate
−1.5 to −2.0	Severe
<−2.0	Extreme

Figure 1. Rain-gauge network in Pakistan.

Table 2. Rejection rates of the Kolmogorov–Smirnov goodness-of-fit test for gridded APHRODITE data

	3 month (%)	6 month (%)	12 month (%)
0.01	1.6	1.4	1.2
0.05	7.0	5.5	4.8

Figure 2. PCA loadings maps of SPI on (a) 3-month, (b) 6-month, and (c) 12-month scales.

Figure 3. Elevation in Pakistan.

Figure 4. Scores of first principal component (PC1) for SPI on (a) 3-month, (b) 6-month, and (c) 12-month scales.

Table 3. Results of trend detection for PC1 scores

	3 month	6 month	12 month
Sen’s slope^1	0.00071	0.00082	0.00097
Kendall’s p-value^2	0.42	0.45	0.29

¹Computed for the original PC1 score series.

²Computed for the final blended series.

Figure 5. Periodograms of PC1 scores on (a) 3-month, (b) 6-month, and (c) 12-month scales.

Figure 6. Temporal evolution of drought-affected area in Pakistan.

Oki, T. , & Kanae, S. (2006). Global hydrological cycles and world water resources. Science, 313(5790), 1068–1072.

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