## 2 Materials and Methods
### Model Simulation  
#### 2.3.1 Forcing Data  
Off-line single point simulations with a 30 min time step were performed using observed meteorological data and land-surface data. Half-hourly meteorological data, including downwelling solar radiation (in W\(\cdot\)m\({}^{-2}\)), precipitation (in mm), wind speed (in m\(\cdot\)s\({}^{-1}\)), air temperature (in K), and relative humidity (in %), were measured at the EC towers. For these key model inputs, missing half-hourly values, which were due to periods of instrument failure, were gap-filled by linear interpolation for gaps of less than 2 hours. Larger gaps were filled by applying a simple interpolation technique of mean diurnal variation [74,75]. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Number** & **Site ID*** & **Latitude** & **Longitude** & **Elevation** & **Biome Type*** & **Climate Zone** & **Site-Years** & **Precipitation** & **LAImax** & **References** \\  & & **(”N)** & **(”E)** & **(m)** & & & & **(mm-yr”)** & **(m”-m”)** & & \\ \hline  & & & & & & & & & & [PERSON] _et al._ \\
1 & CA-Ca1 & 49.867 & \(-\)125.334 & 313 & NEF & Temperate & 2001–08(06) \({}^{\circ}\) & 1456 & 7.3 & & (2011), \\  & & & & & & & & & & [PERSON] _et al._ \\
2 & CA-Ca2 & 49.871 & \(-\)125.291 & 170 & NEF & Temperate & 2007–10(08) & 619 & 2.7 & ([PERSON] _et al._ \\  & & & & & & & & & (2010) [40] \\
3 & CA-Ca3 & 49.535 & \(-\)124.900 & 153 & NEF & Temperate & 2003–07(05) & 1683 & 7.0 & ([PERSON] _et al._ \\  & & & & & & & & & (2010) [40] \\
4 & DE-Tha & 50.964 & 13.567 & 380 & NEF & Temperate & 2001–05(01) & 804 & 7.6 & Bernhofer \\
5 & ES-ES1 & 39.346 & \(-\)0.319 & 1 & NEF & Mediterranean & 2004–07(05) & 414 & 2.6 & ([PERSON] _et al._ \\  & & & & & & & & & (2010) [42] \\
6 & US-Ho1 & 45.204 & \(-\)68.740 & 72 & NEF & Temperate & 1996–98, & & [PERSON] _et al._ \\  & & & & & & & 2003–04(03) & & 951 & 5.7 & (2004) [43] \\
7 & CN-Qia & 26.741 & 115.058 & 86 & NEF & Temperate & 2003–04, & & & [PERSON] _et al._ (2007) \\  & & & & & & & & & (2006) [44] \\  & & & & & & & & & [PERSON] _et al._ \\
8 & CA-Ojp & 53.916 & \(-\)104.692 & 518 & NEF & Boreal & 2007–10(08) & 418 & 2.0 & (2007), [PERSON] _et al._ (2006) \\  & & & & & & & & & & (2004) [45,46] \\
9 & CA-Obs & 53.987 & \(-\)105.118 & 598 & NEF & Boreal & 2001–05(01) & 408 & 3.4 & _et al._ (2014) \\  & & & & & & & & & (2007), [PERSON] _et al._ (2006) \\  & & & & & & & & & (2011) [48] \\
10 & CA-NS1 & 55.879 & \(-\)98.484 & 253 & NDF & Boreal & 2002–06(03) & 213 & 3.0\({}^{\circ}\) & [PERSON] _et al._ (2011) [48] \\  & & & & & & & & & (2011) [48] \\
11 & FI-Hyy & 61.847 & 24.295 & 185 & NDF & Boreal & 2005–08(06) & 500 & 6.7 & [PERSON] _et al._ (2003) [49] \\
12 & FR-Pue & 43.741 & 3.596 & 270 & BEF & Mediterranean & 2004–09(08) & 1116 & 2.9 & ([PERSON] _et al._ (2003) [50] \\  & & & & & & & & & (2003) [50] \\  & & & & & & & & & (2011) [48] \\
13 & IT-Cpz & 41.705 & 12.376 & 9 & BEF & Mediterranean & 2006–09(07) & 593 & 3.5 & [PERSON] _et al._ (2007) [51,52] \\
14 & IT-Col & 41.849 & 13.588 & 1645 & BDF & Mediterranean & 2004–07(05) & 954 & 6.4 & [PERSON] _et al._ (1996) [53] \\
15 & US-MOz & 38.744 & \(-\)92.200 & 212 & BDF & Mediterranean & 2004–08(05) & 1023 & 4.0 & [PERSON] _et al._ (2006) [54] \\  & & & & & & & & & [2007], \\  & & & & & & & & & (2006) [55,56] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Descriptions of the study sites. Monthly LAI values for each site were extracted from a global LAI map based on 10-day synthesis VEGETATION images with 1 km spatial resolution taken in 2003. The values had been corrected based on a global clumping index map produced from the multi-angle observation of the POLDER 1, 2 and 3 sensors [4, 76, 77]. We further corrected monthly LAI for each site using the ratio of the LAI\({}_{\text{max}}\) value (Table 1) against the extracted LAI value within the same month, in which LAI\({}_{\text{max}}\) was supplied by the biological information for each site.