# Exploring the Evolution of Drought Characteristics in Balochistan, Pakistan
## 3 Results
### Drought Evolution  
Tables 1 and 2 display the results of the Mann-Kendall trend analysis applied to 3-month and 12-month SPEI time series, along with the drought characteristics. The p-value for the SPEI of all the zones is less than 0.05 with negative tau and Sen's slope values. This suggests that the whole province of Balochistan is experiencing increasing dryness. Nevertheless, Zone 5 has experienced the most change in its 3-month SPEI time series, while Zone 1 encountered the same for its 12-month SPEI time series. This is evident when comparing the magnitude of Sen's slope for each zone. Comparing Tables 1 and 2, we note that there are nearly twice the characteristics having non-statistically significant trends in 12-month analysis when compared with the results of 3-month analysis. This is understandable in view of the 12-month SPEI reflecting accumulated conditions over a longer period than the 3-month SPEI, so the effective number of independent data in the time series is less.  
Figure 14: (**a**) 3-month and (**b**) 12-month peak of droughts.  
Figure 12: (**a**) 3-month and (**b**) 12-month severity of droughts.  
Figure 13: (**a**) 3-month and (**b**) 12-month intensity of droughts.  
Moreover, the duration is seen to be increasing with time in all the zones. However, the increase in duration is not statistically significant in Zones 2, 3, and 4 for 3-month SPEI and in Zones 1, 2, 4, and 5 for 12-month SPEI. Similarly, severity, intensity, and peak are also decreasing in all the zones, as indicated by the negative values of the respective Sen slopes. However, trends in none of these characteristics are statistically significant in Zone 3 for the 3-month SPEI and in Zones 1 and 2 for the 12-month SPEI. Additionally, duration and severity show no statistically significant trend in Zone 5, whereas intensity and peak show no statistically significant trend in Zone 6 for the 12-month SPEI. From 1902 to 2015, for the 12-month SPEI, Zone 4 saw the most change in duration, severity, and intensity, whereas, for the 12-month SPEI, Zone 1 witnessed the most change in severity and intensity, as opposed to Zone 5, which noted the most change in duration and peak.  
Following the trend analysis for the entire period, the time series were divided in the year 1960. Figure 15 displays the total drought count, pre-1960 and post-1960 drought count for 3-month and 12-month SPEI. According to the 3-month SPEI, a larger number of droughts occurred after 1960 in all the zones (Figure 15a). The 12-month SPEI showed that the majority of the droughts occurred after 1960 in Zones 1, 3 and 5. Additionally, all the long duration droughts that occurred in Balochistan were experienced after the 1960s (Figure 16). The most severe droughts also occurred after the 1960s in all the zones (Figure 17). The 3-month SPEI indicated that apart from Zone 4, the most intense droughts occurred after 1960 (Figure 18a). According to the 12-month SPEI, the most intense droughts occurred after 1960 in all the zones, except for Zone 6. As for the droughts with the lowest peak SPEI, all the  
\begin{table}
\begin{tabular}{|c c c c|} \hline \multicolumn{4}{c}{**Mann-Kendall Test Results for 3-month SPEI**} \\ \hline  & \(\mathbf{p}\)**-Value** & **Tau** & **Sen’s Slope** \\ \hline SPEI & \(1.41\times 10^{-19}\) & \(-1.63\times 10^{-1}\) & \(-6.15\times 10^{-4}\) \\ Duration & \(7.83\times 10^{-3}\)