## 2 Method and Data
### Main Data for GLOPEM-CEVSA Model Input and Validations
#### 2.2.3 Validation and Comparison of the Derived GPPs  
The observations for eight forest sites across Southeast Asia (Table 1 [65; 66; 67; 68; 69; 70; 71; 72; 73; 74], Figure 2) were used to assess the performance of the modeled GPP and the remote sensing based FPAR in this study. Figure 2: The vegetation classification map according to the MODIS land cover product (MOD12Q1). The locations of the flux tower sites used to assess the remote sensing based FPAR and GPP in this study are also shown as symbols. More detailed descriptions of the eight sites are given in Table 1.  
GPP validation was conducted for two levels: (1) seasonal variability using the daily GPP data from the Qianyanzhou (QYZ) site of ChinaFlux and the Palangkaraya (PDF) site of AsiaFlux; (2) annual GPP magnitude with data derived from the literature for eight flux towers (Table 1). The eddy covariance observations began in 2002 at the QYZ Forest Station, Jiangxi province, China (26 \(\lx@math@degree\)45'16.0\"N, 115 \(\lx@math@degree\)4'15.0\"E) [65, 75]. It has a typical subtropical monsoon climate and the dominant species are masson pine (_Pinus massoniana_), slash pine (_Pinuselliotti_) and Chinese fir (_Cunningham lanecolata_) planted in 1984 and 1985 [65, 75, 76, 77]. The quality of the measured turbulence flux over this hilly region was evaluated and the fluctuation in CO\({}_{2}\) density caused by temperature and water vapor variations was corrected [66]. Mean diurnal variations and nonlinear regression were used in the gap-filling of the missing observations [65]. RE was estimated from the relationship between the nighttime NEE and temperature, then GPP was estimated from NEE and RE [65, 78, 79]. The eddy covariance tower PDF is located near Palangkaraya, Indonesia (2 \(\lx@math@degree\)20'42\"S, 114 \(\lx@math@degree\)2'11\"E, 30 m above sea level). The site is tropical and has clear wet and dry seasons, with the dry season lasting from May or June to October or November. The vegetation type is tropical peat swamp evergreen forest with _Combretocarpus rotundatus_, _Cratoxylum arborescens_, _Buchanania sessifolia_ and _Tetramerista glabra_ as the dominant species. The area of the forest is \(>50\) km\({}^{2}\). CO\({}_{2}\) and energy \begin{table}
\begin{tabular}{l c c c c c c} \hline
**Site name** & **Latitude and** & **Elevation** & \multirow{2}{*}{**Forest Type**} & **Annual** & \multirow{2}{*}{**Annual**} & \multirow{2}{*}{**Period**} & \multirow{2}{*}{**References**} \\ (**Site Code), Country** & **Longitude ( \(\lx@math@degree\)**)** & **(m)** & & & **Mean T ( \(\lx@math@degree\)**)** & & \\ \hline Qianyanzhou (**QYZ**), & 26.73, 115.07 & 102 & Subtropical & 18 & 1485 & 2003–2005 & [65, 66] \\ China & & & evergreen confer & & & \\  & & plantation & & & & \\ Dinghushan (**DHS**), & 23.17, 112.53 & 100–700 & Subtropical & 21 & 1700 & 2003–2009 & [67, 68] \\ China & & & evergreen broadleaf & & & & \\  & & forest & & & & \\ Xishuangbanna & 21.93, 101.27 & 750 & Tropical rain forest & 22 & 1487 & 2003–2008 & [69] \\
**(XSF)**, China & & & & & & \\ Mae Klong & 14.57, 98.83 & 160 & Tropical seasonal & 25 & 1200 & 2003–2004 & [70, 71] \\
**(MKL)**, Thailand & & & deciduous forest & & & \\ Sakarent (**SKR**), & 14.48, 101.90 & 535 & Tropical dry & 24 & 1500 & 2002–2003 & [70, 71] \\ Thailand & & & evergreen forest & & & \\ Pasoh Forest Reserve & 2.97, 102.30 & 75–150 & Tropical rain forest & 26 & 1700 & 2003–2005 & [70, 71] \\
**(PSO)**, Malaysia & & & & & & \\ Bukit Soeharto & –0.86, 117.04 & 20 & Tropical secondary & 27 & 3300 & 2002 & [70, 72] \\
**(BKS)**, Indonesia & & & forest & & & \\ Palangkaraya drained & –2.35, 114.03 & 30 & Tropical peat swamp & 26 & 2540 & 2004–2008 & [70, 73, 74] \\ forest (**PDF**), Indonesia & & & forest & & & \\ \hline \end{tabular}
\end{table} 
Table 1: Description of the eddy covariance towers used for the GPP validation. The daily GPP was available from the Qianyanzhou (QYZ) site in the ChinaFlux Network and the Palangkaraya (PDF) site in the AsiaFlux Network.