## 2 Materials and Methods
### Precipitation Observations  
Precipitation measurements were available for the period between 2000 and 2018 at eleven conventional weather stations (Table 1) as obtained from the Instituto National de Meteorologia (INMET) through the Meteorological Database for Education and Research (BDMEP) [17]. These stations are installed in the municipalities of Caceres (CCR), Canarana (CNR), Cuiaba (CBA), Diamantino (DMT), Gleba Celeste (GBC), Matupa (MTP), Nova Xavantina (NVX), Padre Ricardo Remetter (PRR), Poxoreu (PXR), Rondonopolis (RDP), and Sao Jose do Rio Claro (SJRC). The spatial distribution of these weather station is shown in Figure 1. These 11 stations were selected because they provided more consistent long-term measurements with minimal number of missing observations (less than 5-10%). Increased number of missing data makes the comparison at the monthly and annual time scale unrealistic. The highest temporal resolution of these measurements was a daily time scale; thus, the data did not allow to compare precipitation at the sub-daily time scale.  
The distribution of weather stations does not homogenously represent the entire extent of the state for several reasons. One of the main reasons is the difficulty of geographic access. The southern part of the state is formed by the Pantanal which is the world's largest floodplain, the northern region is formed by the Amazon rainforest and the northeast region is formed by a complex mosaic of indigenous lands (i.e., managed by native people). The locations of the weather stations have followed the state's territorial occupation pattern since the 1970s.  
The CBA and PRR stations are near each other with only 30 km apart. Thus, the pixels (the station location nearest to the center of the pixel) of the GLDAS, TRMM, and GPM products in these two stations are not the same, but the corresponding pixels of the MERRA and GPCP products related to these two stations can be the same. The precipitation measurements by these two stations were not averaged as they provided statistically different averages at the daily and monthly time scale.  
\begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Station**} & **Elevation** & **Data Availability (Year)** & **Precipitation Estimates** \\ \hline GBC & 415 & \\ CCR & 118 & \\ SJRC & 350 & \\ RDP & 284 & \\ MTP & 285 & \\ DMT & 286 & \\ CBA & 145 & \\ PRR & 140 & \\ PXR & 450 & \\ NVX & 316 & \\ CNR & 430 & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Available data from conventional weather stations, including Cáceres (CCR), Canarana (CNR), Cuiaba (CBA), Diamantino (DMT), Gleba Celeste (GBC), Matupa (MTP), Nova Xavantina (NVX), Padre Ricardo Remetter (PRR), Poxoreu (PXR), Rondonopolis (RDP), and São José do Rio Claro (SJRC), used to validate precipitation estimates for Global Land Data Assimilation (GLDAS), Modern-Era Retrospective Analysis for Research and Applications (MERRA), Tropical Rainfall Measurement Mission (TRMM), Global Precipitation Measurement (GPM), and the Global Precipitation Climatology Project (GPCP) products in the state of Mato Grosso, Brazil.  
Figure 1: Distribution of conventional weather stations in the state of Mato Grosso, Brazil along with the ground surface elevation and the distribution of the biomes (Amazon Forest, Brazilian Savanna, and Pantanal).