## 4 Discussion  
The zones produced after running the SKATER algorithm to a large extent reflect the climatological regions that exist in Pakistan. The trend analysis indicated no statistically significant trend--at a confidence interval of 95%--for SPEI in zone 1, whereas, in zones 2 and 3, the trend was positive. Zones 4 and 5 showed a statistically significant decreasing trend. Similar results were obtained by [PERSON] [17] where he found that rainfall in Punjab and Khyber Pakhtunkhwa (KPK) had increased by 2.45 mm year\({}^{-1}\) and 1.55 mm year\({}^{-1}\), corresponding to the wetting trend we found in zones 2 and 3. A statistically significant decrease in annual evapotranspiration was also reported by [PERSON] [17] in KPK and Punjab at the rate of \(-\)0.36 mm year\({}^{-1}\) and \(-\)0.43 mm year\({}^{-1}\), further validating our results obtained over zones 2 and 3. This decrease in annual evapotranspiration could be due to the expansion and intensification of irrigation in this area, which would increase air humidity and lower the PET. Additionally, the mean annual trends in minimum and maximum temperatures over different provinces also confirm our findings. Over Sindh and Baluchistan, an increasing trend was reported for both maximum and minimum temperatures, whereas a decreasing trend was reported for KPK. The trend for maximum temperature showed a decrease in Punjab, but an increase was noted for minimum temperature. Furthermore, it can be concluded based on the historic trends that zone 1 is likely to face longer duration and severer droughs as opposed to zone 2, which will face short duration--and less severe--droughs. No trend in any drought characteristic was found to be statistically significant for zone 3. Zone 4 is likely to experience increasingly severe and intense droughs in the future. Droughs \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Zone** & **Start** & **End** & **Duration (Months)** & **Severity** & **Intensity** & **Peak** \\ \hline \multirow{3}{*}{Zone 1} & 16 November 1999 & 16 May 2001 & 19 & \(-\)20.92 & \(-\)1.10 & \(-\)1.88 \\  & 16 August 1920 & 16 May 1921 & 11 & \(-\)14.98 & \(-\)1.36 & \(-\)1.89 \\ \hline \multirow{6}{*}{Zone 2} & 16 July 1940 & 16 October 1941 & 16 & \(-\)15.91 & \(-\)0.99 & \(-\)1.38 \\  & 16 July 1920 & 16 June 1921 & 12 & \(-\)17.55 & \(-\)1.46 & \(-\)1.94 \\  & 16 January 1952 & 16 December 1952 & 12 & \(-\)12.67 & \(-\)1.06 & \(-\)1.47 \\  & 16 December 1945 & 16 September 1946 & 10 & \(-\)10.37 & \(-\)1.04 & \(-\)1.73 \\ \hline \multirow{3}{*}{Zone 3} & 16 January 1918 & 16 October 1918 & 10 & \(-\)10.71 & \(-\)1.07 & \(-\)1.62 \\  & 16 April 1968 & 16 May 1969 & 14 & \(-\)15.07 & \(-\)1.08 & \(-\)1.42 \\  & 16 December 1970 & 16 November 1971 & 12 & \(-\)15.47 & \(-\)1.29 & \(-\)1.65 \\ \multirow{3}{*}{Zone 4} & 16 August 1987 & 16 June 1988 & 11 & \(-\)11.27 & \(-\)1.02 & \(-\)1.36 \\  & 16 December 1999 & 16 September 2000 & 10 & \(-\)9.75 & \(-\)0.97 & \(-\)1.53 \\  & 15 February 2004 & 16 November 2004 & 10 & \(-\)12.27 & \(-\)1.23 & \(-\)1.94 \\  & 16 April 1968 & 16 January 1970 & 22 & \(-\)23.12 & \(-\)1.05 & \(-\)1.39 \\  & 16 September 2001 & 16 November 2002 & 15 & \(-\)15.80 & \(-\)1.05 & \(-\)1.44 \\ \multirow{3}{*}{Zone 5} & 15 February 2000 & 16 March 2001 & 14 & \(-\)14.38 & \(-\)1.03 & \(-\)1.38 \\  & 16 July 1920 & 16 June 1921 & 12 & \(-\)13.62 & \(-\)1.13 & \(-\)1.39 \\ \multirow{3}{*}{Zone 6} & 16 July 1987 & 16 June 1988 & 12 & \(-\)14.84 & \(-\)1.24 & \(-\)1.53 \\ \hline \end{tabular}
\end{table} 
Table 2: Drought characteristics of droughs with duration \(\geq\)10 months. having significantly worse peaks are expected to occur in zone 5. Drought mitigation plans, therefore, must be prepared keeping in mind the trends observed for the characteristics of droughts in each zone. Moreover, the results also revealed prolonged periods of drier than normal conditions which occurred in each zone. Two of these periods, the 1920s and 1999-2000, are particularly interesting as they occurred in three zones for at least ten months.