## 4 Results
### Comparison on a Daily Scale  
For a daily scale comparison, frequency versus intensity histograms were plotted in Figure 4 for the precipitation in each region. In-situ stations (traditional rain gauges) might not capture precipitation events with magnitudes of less than 0.25 mm/day very well, which is generally treated as traces, thus precipitating days considered were \(\geq\)0.25 mm per day [(49)]. Figure 4a-d shows the frequency and relative intensity of in-situ and GPPs at each region, while the arrows indicate 95 th percentiles. Figure 3: Climatological mean annual precipitation cycle at four selected locations. (**a–d**) are equivalent to regions 1, 2, 3 and 4 in Table 1.  
Figure 4a indicates that in-situ data had a lower frequency of days with relatively low precipitation amounts than the GPPs. Both in-situ and GPPs had a similar frequency of precipitation events of <25 mm and excluding MSWEP, rest of the GPPs showed good agreement at the 95 th percentile moreover PERSIANN-CDR does not identify days with precipitation amount > 25 mm/day. Figure 4b shows that both in-situ and the GPPs had an alike frequency and intensity for events with precipitation of <45 mm, although relatively lower magnitude events had a higher frequency in CHIRPS and PERSIANN-CDR than in TMPA and MSWEP. In Figure 4c, we see that in region 3, GPPs reported a relatively similar pattern to in-situ data in terms of the frequencies of precipitation events of \(\leq\)15 mm, while above 15 mm, GPPs appeared to show deviations in magnitude. For precipitation events with an intensity of \(\geq\)20 mm, CHIRPS and TMPA captured relatively similar frequencies. In Figure 4d, both in-situ and GPPs captured the highest frequency of the days with low precipitation amount, while PERSIANN-CDR captured more precipitation events with smaller intensities as compared to in-situ and the GPPs. The 95 th percentile shows closer agreements with that of in-situ data, while the frequency of high precipitation events was also well captured by TMPA and MSWEP. Figure 4: Normalized frequency of daily precipitation in different climatic zones for in-situ and GPPs. The arrows mark the 95 th percentile, the bin size used is 1.85 mm/day. (**a–d**) are equivalent to regions 1, 2, 3 and 4 in Table 1.  
From Figure 4 it can be deduced that GPPs generally captured the frequency and intensities of precipitation events quite well. GPPs produced closer distribution of higher percentile with those of in-situ as a reference, however deviations and differences were obvious for MSWEP and PERSIANN-CDR. The capability of GPPs to locate higher percentile precipitation estimates closely resemble in-situ data, especially TMPA and CHIRPS [28; 47]. The performance of GPPs and in-situ precipitation products was further assessed based on the ECDFs of daily scale precipitation at three thresholds (2.5, 5 and 10 mm/day). Based on results of a K-S test, the GPPs that significantly (K-S test) matched the in-situ data distribution were identified inside their respective threshold boxes in Figure 5. In region 1, Figure 5a-c, for precipitation events characterized by \(\geq\)2.5 mm/day, only TMPA had a significant similarity with in-situ, although observed precipitation was nonetheless overestimated. For precipitation events of \(\geq\)5 mm/day, PERSIANN-CDR underestimated the observed precipitation, while CHIRPS significantly represented a similar pattern to that of in-situ. For precipitation events of \(\geq\)10 mm/day, all precipitation products except PERSIANN-CDR overestimated in-situ but MSWEP and TMPA were significantly closer to in-situ precipitation. In Figure 5d-f, we see that in region 2 GPPs underestimated precipitation events of \(\geq\)2.5 mm/day. For precipitation events of \(\geq\)5 mm/day, all GPPs consistently underestimated in-situ precipitation, while CHIRPS and TMPA had a significant resemblance to in-situ precipitation. For precipitation events of \(\geq\)10 mm/day, MSWEP, CHIRPS and TMPA had a significant similarity to the in-situ.