## Study Areas and Data
### Ground Verification Data  
FluxNet is a global network of micrometeorological flux measurement sites that measure the exchanges of carbon dioxide, water vapor, and energy between the biosphere and atmosphere. It was established based on other observation networks including AmeriFlux, CarboEurope, AsiaFlux, OzFlux, and a few independent sites. At present, over 140 Flux tower stations are operating on a long-term and continuous basis. Data and site information are available online at the FluxNet website, [[http://fluxnet.fluxdata.org/](http://fluxnet.fluxdata.org/)]([http://fluxnet.fluxdata.org/](http://fluxnet.fluxdata.org/)). Land surface types include temperate conifer and broadleaf (deciduous and evergreen) forests, tropical and boreal forests, crops, grasslands, chaparral, wetlands, and tundra. Sites exist on five continents and their latitudinal distribution ranges from 70 \({}^{\circ}\)N to 30 \({}^{\circ}\)S. The FluxNet site records upwelling and downwelling shortwave radiative flux data with a half-hour observation period. For our purposes, we selected observation data from 0.5 hours before  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Site Name** & **Network** & **Latitude (\({}^{\circ}\))** & **Longitude (\({}^{\circ}\))** & **Land Cover Type** & **Data Year** \\ \hline CA-Oas \({}^{\star}\) & FluxNet & 53.6289N & 106.1978W & DBF & 2009 \\ IT-Col \({}^{\star}\) & FluxNet & 41.8494N & 13.5881E & DBF & 2009 \\ IT-Ro2 \({}^{\star}\) & FluxNet & 42.3903N & 11.9209E & DBF & 2010 \\ US-Bar + & AmeriFlux & 44.0646N & 71.2881W & DBF & 2009 \\ FR-Pue \({}^{\star}\) & FluxNet & 43.7414N & 3.5958E & EBF & 2009 \\ MY-Pso \({}^{\star}\) & FluxNet & 2.9730N & 102.3062E & EBF & 2009 \\ AU-Wac \({}^{\star+}\) & FluxNet & 37.4259S & 145.1878E & EBF & 2007 \\ CH-Day \({}^{\star}\) & FluxNet & 46.8153N & 9.8559E & ENF & 2009 \\ FI-Hyy \({}^{\star}\) & FluxNet & 61.8474N & 24.2948E & ENF & 2009 \\ NL-Loo \({}^{\star}\) & FluxNet & 52.1666N & 5.7436E & ENF & 2010 \\ IT-Sro + & FluxNet & 43.7279N & 10.2844E & ENF & 2009 \\ DE-Kli \({}^{\star}\) & FluxNet & 50.8931N & 13.5224E & CRO & 2009 \\ IT-Bci \({}^{\star}\) & FluxNet & 40.5238N & 14.9574E & CRO & 2010 \\ FR-Gri \({}^{\star}\) & FluxNet & 48.8442N & 1.9519E & CRO & 2010 \\ US-Arm + & AmeriFlux & 36.6058N & 97.4888W & CRO & 2010 \\ AU-DaP \({}^{\star}\) & FluxNet & 14.06335 & 131.3181E & GRA & 2008 \\ US-Ib2 \({}^{\star}\) & AmeriFlux & 41.8406N & 88.2410W & GRA & 2010 \\ AU-Stp \({}^{\star}\)+ & FluxNet & 17.1507S & 133.3502E & GRA & 2009 \\ \hline \hline \end{tabular}  
* Cropland (CRO); deciduous broadleaf forest (DBF); evergreen needleleaf forest (ENF); grassland (GRA); evergreen broadleaf forest (EBF). Sites with \({}^{\star}\) are used for estimating and verifying single-point time series albedo, sites with \({}^{\star}\) are selected as the central pixel for estimating and verifying regional time series albedo.  
\end{table}
Table 1: Ground stations used for validation.  
and after noon. The shortwave albedo of the site was calculated as the ratio of upwelling radiation and downwelling radiation. After eliminating invalid observations (filled data) and data with albedos less than 0 or greater than 1, each selected site was associated with sufficient time series ground albedo data for validation.