## 4 Results  
### Climatology  
Figure 2 shows the seasonal mean precipitation climatology of different seasons for the GPPs employed over the 1998-2016 study period. We see that across all GPPS, the northwestern part of the country exhibited more precipitation than the southeast, with mean values being observed at \(>\)50 mm in the winter. From this maximum, all GPPs displayed a pattern of precipitation gradually decreasing towards the east and south. Likewise, during the pre-monsoon season, precipitation was also relatively consistent in all GPPs with relatively higher precipitation in the northern parts of the country (80 mm), while the central and southern regions received approximately 40 mm and \(<\)20 mm, respectively. A similar decrease in precipitation from north (maxima) to south (minima) was observed. In all GPPs, a similar monsoonal precipitation pattern was obvious with relatively large amounts of precipitation in the northeast and southeast of the study region. A precipitation maximum of \(>\)120 mm was recorded in the north, while a minimum of \(\geq\) 80 mm occurred in southern coastal regions. During autumn, the precipitation distribution across the whole country ranged from \(<\)10 mm in the south, to \(>\)40 mm in the north. The GPPs showed a consistent precipitation pattern, with minor deviations in the mean observed in the northwest. Two precipitation patterns are observed in Pakistan, the first is due to disturbances of westerlies in the winter and pre--monsoon season and the South Asian monsoon, which is the primary driver of the hydrological cycle in the region [(37; 48)]. The GPPs clearly showed these two precipitation patterns, with a slight deviation from the mean; however, during the winter and autumn seasons, MSWEP and CHIRPS captured higher precipitation values in the northwest which could be associated with relatively higher grid size resolution of these two GPPs. Figure 3a-d shows the mean annual precipitation cycle for the four selected regions as shown in Table 1. From Figure 3a it can be seen that precipitation maxima occurred in April (\(\geq\)50 mm) and the minima occurred in October (\(<\)20 mm). With in-situ as reference, all GPPs were able to show the seasonality but overestimated the [monthly average] precipitation (Figure 3a). MSWEP, PERSIANN-CDR and CHIRPS captured larger values than in-situ throughout the seasonal cycle; however, TMPA performed relatively well. Figure 2: Climatological mean precipitation amounts for winter, pre—monsoon, monsoon and autumn seasons calculated from GPPs. In Figure 3b, we see that the hydrological cycle of region 2 is dependent on westerlies during the winter (>30 mm) and the monsoon (>180 mm) during the warm summer. GPPs closely followed in-situ precipitation pattern, with similar maxima and minima captured for the monsoon and winter seasons. For the winter, the precipitation observed was around 60 mm, GPPs exhibited similar variation in precipitation to that of in-situ data. However, for monsoonal precipitation, there were obvious deviations in magnitude, which are more obvious for PERSIANN-CDR. In Figure 3c, peak precipitation occurred during winter (February >45 mm) followed by the monsoon season. MSWEP, CHIRPS and TMPA displayed similar seasonal precipitation dynamics to in-situ data, with the peak precipitation occurring in February, with estimated precipitation values of 38, 40 and 50 mm, respectively. PERSIANN-CDR performed well during the winter but during the summer, it overestimated the observed precipitation. In region 4 (Figure 3d), most of the precipitation occurred during the monsoon season (with August values reaching >70 mm), GPPs captured precipitation dynamics quite well but there were slight deviations in magnitude. MSWEP, CHIRPS and TMPA displayed peak precipitation during the monsoon season, with an abrupt decrease in autumn. PERSIANN-CDR also captured this seasonal cycle but overestimated precipitation.