## 2 Materials and Methods
### Detailed Information on Gridded Precipitation Products (GPPs)  
During the last three decades, the construction of the analyzed fields of precipitation across the globe has been extensively improved. As documented in the introduction, several global/regional scale GPPs are now accessible for hydro-meteorological studies. Giving importance to a primary group of datasets, thus, at least one product from each dataset category has been selected in this study to evaluate their accuracy and highlight intrinsic errors associated with these products. The attributes of selected GPPs are summarized in Table 2. The selection criteria were: (I) a good cross-section of their sources and methods of generation; (II) ease of accessibility and availability as final products in published datasets; (III) possible appropriateness for regional-scale applications; and (IV) potential usefulness for hydrological modeling research. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Product** & **Time Period** & \begin{tabular}{c} **Spatial** \\ **Resolution** \\ \end{tabular} & \begin{tabular}{c} **Highest Temporal** \\ **Resolution** \\ \end{tabular} & **Category** & **Category** \\ \hline APHRO & 1951-present & 0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) & Daily & Gauge & RHHN and JMA/MRI (Japan) \\ CHIRPS & 1981–present & 0.05\({}^{\circ}\)\(\times\) 0.05\({}^{\circ}\) & Daily & Satellite-gauge & University of California \\ ERA-5 & 1979–present & 0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) & Hourly/Daily & Reanalysis & \begin{tabular}{c} **Groupee Centre for** \\ Medium-Range \\ Weather Forecasts \\ (ECMWF) \\ \end{tabular} \\ MSWEP & 1979-to \(\sim\)3 h from real-time & 0.1\({}^{\circ}\)\(\times\) 0.1\({}^{\circ}\) & 3-hourly & \
\begin{tabular}{c} Multi-Source \\ Weighted \\ Reanalysis, gauge \\ \end{tabular} &
\begin{tabular}{c} GloH2O, Almere, \\ the Netherlands \\ Princeton University \\ \end{tabular} \\ PGMFD & 1948–2010 & 0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) & Daily & Reanalysis, gauge & Princeton University \\ \hline \hline \end{tabular}
\end{table} 
Table 2: General information of five GPPs assessed in this study. The Multi-Source Weighted-Ensemble Precipitation (MSWEP) data version 2.2 is derived from the gauge, reanalysis, and satellite datasets, providing global data from 1979 to the present with a high spatial resolution of 0.1\({}^{\circ}\)\(\times\) 0.1\({}^{\circ}\), at the temporal resolution of 3-h near to real-time, particularly developed for hydrological modeling. The MSWEP dataset is unique owing to it combines gauged, for instance, Global Precipitation Climatology Centre (GPCC), Global Summary of the Day (GSOD), Global Historical Climatology Network-Daily (GHCN-D), and WorldClim, atmospheric model-based reanalyzes, i.e., interim reanalysis (ERA-Interim), Japanese 55-year Reanalysis (JRA-55) and European Centre for Medium-Range Weather Forecasts (ECMWF), satellites, for instance, Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) 3B42 RT), Gridded Satellite (GridSat), Global Satellite Mapping of Precipitation (GSMaP), and Climate Prediction Center morphing technique (CMORPH) precipitation measures to exhibit better performance in both homogeneous gauged and scarcely gauged region. A more exhaustive overview of algorithm development of MSWEP is given in [35]. It provides good opportunities to investigate the spatio-temporal variations in precipitation to understand hydrological processes and their parameterization better and enhance hydrological model performance. We accessed the latest and improved version of MSWEP data (version 2.2) which was released in March 2018 for the period spanning from 1979 to 2009. The MSWEP data is available at [[http://www.glob2o.org/mswep](http://www.glob2o.org/mswep)]([http://www.glob2o.org/mswep](http://www.glob2o.org/mswep)) (accessed on 21 November 2020).