## 3 Ground Dataset
### Analysis of the Spatial Representativeness of Tower Measurements
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \# & **Site ID** & **Name** & **Country** & **Network** & **Land Cover** & **Lat** & **Lon** \\  & & & & & & & **(deg)** & **(deg)** \\ \hline
**1** & USA\_BND & Bondville & USA & SURFRAD & Croplands & 40.052 & \(-\)88.373 \\
**2** & USA\_BAO & Boulder & USA & BSRN & Croplands & 40.050 & \(-\)105.004 \\
**3** & BEL\_BRA & Brasschaat & Belgium & FLUXNET & Mixed Forest & 51.309 & 4.521 \\
**4** & NET\_CAB & Cabauw & Netherlands & BSRN & Grasslands & 51.971 & 4.927 \\
**5** & AUS\_CLP & Calperum & Australia & FLUXNET & Shrublands & \(-\)34.003 & 140.588 \\
**6** & USA\_DRA & Desert Rock & USA & SURFRAD & Bare Soil & 36.624 & \(-\)116.019 \\
**7** & USA\_FPR & Fort Peck & USA & SURFRAD & Grasslands & 48.308 & \(-\)105.102 \\
**8** & GER\_GEB & Gebesee & Germany & FLUXNET & Croplands & 51.100 & 10.914 \\
**9** & NAM\_GOB & Gobabeb & Namibia & BRSN & Bare Soil & \(-\)23.561 & 15.042 \\
**10** & USA\_GCM & Goodwin & USA & SURFRAD & Decidous Broadleaf & 34.255 & \(-\)89.873 \\
**11** & FRA\_GRI & Grignon & France & FLUXNET & Croplands & 48.844 & 1.952 \\
**12** & FRA\_GUY & Guyaflux & French & FLUXNET & Evergreen Broadleaf & 5.279 & \(-\)52.925 \\
**13** & GER\_HAI & Hainich & Germany & FLUXNET & Mixed Forest & 51.070 & 10.450 \\
**14** & USA\_NRF & Niwot Ridge & USA & FLUXNET & Evergreen Needleaf & 40.033 & \(-\)105.546 \\
**15** & ITA\_REN & Renon & Italy & FLUXNET & Evergreen Needleaf & 46.587 & 11.434 \\
**16** & USA\_PSU & Rock Springs & USA & SURFRAD & Decidous Broadleaf & 40.720 & \(-\)77.931 \\
**17** & USA\_SFS & Sioux Falls & USA & SURFRAD & Croplands & 43.730 & \(-\)96.620 \\
**18** & USA\_SGP & Southern & USA & FLUXNET & Croplands & 36.606 & \(-\)97.489 \\  & & Great Plains & & & & & \\
**19** & USA\_TBL & Table Mountain & USA & SURFRAD & Bare soil and Rocks & 40.125 & \(-\)105.237 \\
**20** & AUS\_TMB & Tumbarumba & Australia & FLUXNET & Evergreen Broadleaf & \(-\)35.657 & 148.152 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Characteristics of the 20 GBOV sites providing data during the 2014–2018 period. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \# & **Site ID** & \begin{tabular}{c} **Footprint** \\ **(m)** \\ \end{tabular}  & \begin{tabular}{c} **Seasonal** \\ **Period** \\ \end{tabular}  & \begin{tabular}{c} **R\({}_{\text{CV}}\)** \\ **(\%)** \\ \end{tabular}  & \begin{tabular}{c} **R\({}_{\text{SE}}\) (\%)** \\ \end{tabular}  & \begin{tabular}{c} **R\({}_{\text{ST}}\) (\%)** \\ \end{tabular}  & \begin{tabular}{c} **R\({}_{\text{SV}}\)** \\ **(\%)** \\ \end{tabular}  & \ \begin{tabular}{c} **ST\({}_{\text{score}}\)** \\ \end{tabular}  & \begin{tabular}{c} **RAW\({}_{\text{score}}\)** \\ \end{tabular}  \\ \hline
**1** & USA\_BND & 126 & \begin{tabular}{c} Leaf-off \\ Leaf-on \\ \end{tabular}  & \begin{tabular}{c} 5.24 \\ \(-\)4.56 \\ \end{tabular}  & \begin{tabular}{c} 42.63 \\ \(48.50\) \\ \end{tabular}  & \begin{tabular}{c} \(-\)5.17 \\ \(2.84\) \\ \end{tabular}  & \begin{tabular}{c} 59.16 \\ \(37.10\) \\ \end{tabular}  & \ \begin{tabular}{c} 1.52 \\ \(1.58\) \\ \end{tabular}  & \begin{tabular}{c} 9.54 \\ \(10.9\) \\ \end{tabular}  \\ \hline
**2** & USA\_BAO & 3788 & \begin{tabular}{c} Leaf-off \\ Leaf-on \\ \end{tabular}  & \begin{tabular}{c} 175.37 \\ \(19.43\) \\ \end{tabular}  & \begin{tabular}{c} 0.00 \\ \(0.00\) \\ \end{tabular}  & \begin{tabular}{c} \(-\)3.30 \\ \(2.77\) \\ \end{tabular}  & \begin{tabular}{c} \(-\)15.64 \\ \(-\)44.65 \\ \end{tabular}  & \ \begin{tabular}{c} 1.54 \\ \(4.49\) \\ \end{tabular}  & \begin{tabular}{c} 0.29 \\ \(2.57\) \\ \end{tabular}  \\ \hline
**3** & BEL\_BRA & 505 & \begin{tabular}{c} Leaf-off \\ Leaf-on \\ \end{tabular}  & \begin{tabular}{c} 11.24 \\ \(12.74\) \\ \end{tabular}  & \begin{tabular}{c} 0.01 \\ \(0.06\) \\ \end{tabular}  & \begin{tabular}{c} 0.15 \\ \(-\)0.39 \\ \end{tabular}  & \begin{tabular}{c} \(-\)4.37 \\ \(-\)14.61 \\ \end{tabular}  & \ \begin{tabular}{c} 19.02 \\ \(10.74\) \\ \end{tabular}  & \begin{tabular}{c} 4.45 \\ \(3.93\) \\ \end{tabular}