## 2 Data and Methodology
### Methodology  
#### 2.3.1 Remote Sensing-Based Ecohydrorological Model  
(1) Penman-Monteith-Leuning model  
In this study, the \(ET\) model includes soil evaporation (\(E_{s}\): mm), plant transpiration (\(E_{c}\): mm), and intercepting canopy evaporation (\(E_{i}\): mm) (Equation (1)). \[ET=E_{c}+E_{s}+E_{i} \tag{1}\]  
Here, the PML model [16; 24] was applied to simulate \(E_{s}\) and \(E_{c}\). Soil evaporation (Equations (2)-(7)) and plant transpiration (Equations (8)-(12)) were calculated as follows:  
\[E_{c}=\frac{1000}{A_{\mathrm{ps}}}\left(\frac{\frac{5}{2}R_{nc}+86.400\left( \frac{\mathrm{c}E_{s}}{2}\right)D_{4}G_{u}}{\frac{5}{7}+1+\frac{500}{\mathrm{ c}}}\right) \tag{2}\]  
\[R_{nc}=R_{n}(1-\exp(-K_{A}LAI)) \tag{3}\]  
\[R_{ns}=R_{n}-R_{nc} \tag{4}\]  
\[R_{n}=(1-\alpha)R_{s}-\sigma\mathrm{T}^{4}(0.34-0.14\sqrt{e_{s}})(1.35\frac{R_ {s}}{R_{so}}-0.35) \tag{5}\]  
\[G_{u}=\frac{k^{2}u_{m}}{\frac{\ln([Z_{m}-d)/Z_{m}]}{\ln([Z_{m}-d)/Z_{m}]}} \tag{6}\]  
Figure 1: Spatial land cover, regional division, and flux sites over Mainland China. Base map shows land cover in 2005. Note: The full names of EBF, MF, GRA, and CRO are shown in Table 1. In addition, WAT represents water; DNF(DBF) represents deciduous needleleaf (deciduous) forest; CS(OS) represents closed (open) shrubland; WS and SAV, respectively, represent wood savannas and savannas; CNV represents crop/natural vegetation mosaics; PSI represents permanent snow and ice; BAR represents barren land. Sub-regions are divided based on climatic regions in the China Natural Geography Atlas [2]. TMon represents temperate monsoonal region, TCon represents temperate continental region, SubT represents subtropical–tropical monsoonal region, and TP represents high–cold Tibetan Plateau region. \[G_{c}=\frac{g_{xx}}{k_{Q}}\ln\left[\frac{Q_{h}+Q_{50}}{Q_{h}\exp(-k_{Q}LAI)+Q_{50}} \right]\left[\frac{1}{1+D_{a}/D_{50}}\right] \tag{7}\]  
where \(\lambda\) represents the latent heat of vaporization (MJ kg\({}^{-1}\)); \(\rho_{w}\) and \(\rho\), respectively, represent the water and air density (kg m\({}^{-3}\)); \(s\) and \(\gamma\) denote the slope of the saturated vapor pressure curve and psychometric constant (kPa \({}^{\circ}\)C\({}^{-1}\)); \(c_{p}\) represents the specific heat of air at constant pressure (MJ kg\({}^{-1}\)\({}^{\circ}\)C\({}^{-1}\)); \(R_{n}\) and \(R_{nc}\), respectively, represent the net radiation and net radiation absorbed by the canopy (MJ m\({}^{-2}\)); \(R_{s}\) is the incoming solar radiation (MJ m\({}^{-2}\) day\({}^{-1}\)); \(a\) is the albedo; \(T\) is the average temperature (K day\({}^{-1}\)); \(e_{a}\) is the actual pressure (Pa); \(R_{so}\) is the clear-sky radiation (MJ m\({}^{-2}\) day\({}^{-1}\)); \(\sigma\) is the Stefan-Boltzmann constant; \(D_{a}\) is the vapor pressure deficit; \(G_{a}\) and \(G_{c}\), respectively, represent the aerodynamic and canopy conductance (m s\({}^{-1}\)); \(g_{xx}\) is the maximum stomatal conductance. In addition, \(K_{A}\) is the extinction coefficient for net radiation (\(-\)), \(k\) is a constant set to 0.41, \(u_{m}\) is the wind speed at height m (m s\({}^{-1}\)), \(z_{m}\) represents the height of wind measurement (m), \(d\) is the zero plane displacement height (m), \(z_{om}\) is the roughness length governing momentum transfer, \(z_{ov}\) is the transfer of heat and vapor (m), \(Q_{h}\) is the photosynthetically active radiation at the top of the canopy (MJ m\({}^{-2}\) d\({}^{-1}\)), and \(Q_{50}\) and \(D_{50}\) are the absorbed photosynthetic active radiation and the humidity deficit (MJ m\({}^{-2}\) d\({}^{-1}\)), respectively, when the stomatal conductance is reduced to half of \(g_{xx}\).