Table 1.

Formulation Comparisons Across the Five Dry Deposition Models

	ZHANG	Noah-GEM	C5DRY	WESELY	MLM
Modeling framework	Vd(z) = (Ra(z) + Rb + Rc)−1 and $\frac{1}{R_c}=\frac{1-W_{\mathrm{st}}}{R_s+R_m}+\frac{1}{R_{\mathrm{ns}}}$ $\frac{1}{R_{\mathrm{ns}}}=\frac{1}{R_{\mathrm{cut}}}+\frac{1}{R_{\mathrm{ac}}+R_g}$				$V_{\text{d}}={\left(R_a+\frac{1}{{\int }_0^{h_c}S(z)dz+\frac{1}{R_{\mathrm{ac}}+R_g}}\right)}^{-1}$ and $S\left(z\right)=\mathrm{LAI}\left(z\right)\left(\frac{\begin{array}{l}1\end{array}}{r_s\left(z\right)+r_b\left(z\right)+r_m}+\frac{2}{r_b\left(z\right)+r_{\mathrm{cut}}}\right)$
Aerodynamic resistance (Ra)	For stable conditions, $R_a=\frac{0.74\ln \left(\frac{z}{z_0}\right)+4.7\frac{z}{L}}{\kappa u_{*}}$ For unstable conditions, $R_a=\frac{0.74}{\kappa u_{*}}$ $\left[\ln \left(\frac{z}{z_0}\right)-2\ln \left(\frac{\sqrt{1-9\frac{z}{L}}+1}{2}\right)\right]$	$R_a=\frac{\ln \left(\frac{z}{z_0}\right)+{\psi }_h\left(\frac{z}{L}\right)-{\psi }_h\left(\frac{z_0}{L}\right)}{k{u}_{*}}$ For stable conditions, ${\psi }_h=5\frac{z}{L}$ For unstable conditions, ${\psi }_h=-2\ln \left(\frac{\sqrt{1-16\frac{z}{L}}+1}{2}\right)$	$R_a=\frac{0.95\left[\ln \left(\frac{z}{z_0}\right)+{\psi }_h\left(\frac{z}{L}\right)-{\psi }_h\left(\frac{z_0}{L}\right)\right]}{k{u}_{*}}$ For stable conditions, ${\psi }_h=5\frac{z}{L}$ For unstable conditions, ${\psi }_h=-2\ln \left(\frac{\sqrt{1-16\frac{z}{L}}+1}{2}\right)$	For stable conditions, $R_a=\frac{0.74\ln \left(\frac{z}{z_0}\right)+4.7\frac{z-z_0}{L}}{k{u}_{*}}$ For unstable conditions, $R_a=\frac{0.74}{\kappa u_{*}}$ $\left\{\ln \left[\frac{\sqrt{1-9\frac{z}{L}}-1}{\sqrt{1-9\frac{z}{L}}+1}\right]-\ln \left[\frac{\sqrt{1-9\frac{z_0}{L}}-1}{\sqrt{1-9\frac{z_0}{L}}+1}\right]\right\}$	For stable conditions, $R_a=\frac{4}{u{\sigma }_{\theta }^2}$ For unstable conditions, $R_a=\frac{9}{u{\sigma }_{\theta }^2}$
Quasi-laminar sublayer resistance (Rb)	Rb = 2(κu*)−1(Dθ/Dc)2/3		Rb = 2(κu*)−1(SC/Pr)2/3		$r_b(z)=\alpha {\left(\frac{\delta }{u}\right)}^{0.5}$
Stomatal resistance (Rs)a	$R_s=\frac{R_s(\mathrm{PAR})}{f_T{f}_{\mathrm{vpd}}{f}_w}$ $\frac{1}{R_s(\mathrm{PAR})}=\frac{{\mathrm{LAI}}_{\mathrm{sun}}}{r_s({\mathrm{PAR}}_{\mathrm{sun}})}+\frac{{\mathrm{LAI}}_{\mathrm{shade}}}{r_s({\mathrm{PAR}}_{\mathrm{shade}})}$ $r_s(\mathrm{PAR})=\frac{r_{s,\min }}{f_{\mathrm{PAR}}}$	$R_s={\left[\mathrm{LAI}(m\frac{A_n{h}_s}{C_s}P+b)\right]}^{-1}$	$R_s=\frac{r_{s,\min }}{{\mathrm{LAI}f}_{\mathrm{PAR}}{f}_T{f}_{\mathrm{vpd}}{f}_w}$	$R_s=R_{s,\min }\left\{1+\frac{1}{{[200(R_G+0.1)]}^2}\right\}\frac{400}{T_s(40-T_s)}$	$r_s(z)=\frac{r_{s,\min }}{f_{\mathrm{PAR}}{f}_T{f}_{\mathrm{vpd}}{f}_w}$
Cuticular resistance (Rcut)	For dry surface, $R_{\mathrm{cut}}=\frac{R_{\mathrm{cut}d0}}{e^{0.03RH}{\mathrm{LAI}}^{0.25}{u}_{*}}$ For wet surface, $R_{\mathrm{cut}}=\frac{R_{\mathrm{cut}w0}}{{\mathrm{LAI}}^{0.5}{u}_{*}}$		Prescribed values for dry and wet surfaces; Rcut,dry for O3 is adjusted if RH >70%: Rcut = Rcut, dry(1 − FRH) + Rcut, wet × FRH FRH = (RH − 70)/30	Prescribed values for dry and wet surfaces	Prescribed values for dry and wet surfaces
In-canopy aerodynamic resistance (Rac)	$R_{\mathrm{ac}}=\frac{R_{\mathrm{ac}0}{\mathrm{LAI}}^{0.25}}{{u_{*}}^2}$		$R_{\mathrm{ac}}=14\mathrm{LAI}\frac{h_c}{u_{*}}$	Prescribed values	$R_{\mathrm{ac}}={\left[h_{\mathrm{free}}+6.86\times {10}^{-6}\frac{1+2i_u}{L_c\ln (z/z_0)}{\mathrm{Re}}^{0.8}\right]}^{-1}$
Ground resistance (Rg)	Prescribed values for dry and wet surfaces; adjusted if frozen		Prescribed values for dry and wet surfaces; adjusted if frozen	Prescribed values for dry and wet surfaces; adjusted if frozen	Prescribed values for dry and wet surfaces; adjusted if frozen

Note. W_st = the fraction of stomatal blocking under wet conditions; R_m/r_m = the mesophyll resistance; z = reference height; z₀ = the roughness length for momentum; L = the Obukhov length; κ = the von Karman’s constant; u_* = the friction velocity; u = the mean wind speed; σ_θ = the standard deviation of the wind direction; D_θ = the thermal diffusivity; D_c = the molecular diffusivity of a specific gas; S_c = the Schmidt number; P_r = the Prandtl number for air; α = the constant depending on gas species; δ = the characteristic leaf dimension; f_PAR = the environmental stress function of radiation; f_T = the environmental stress function of temperature; f_vpd = the environmental stress function of humidity; f_w = the environmental stress function of leaf water potential; LAI_sun = the total sunlit leaf area indexes; LAI_shade = the total shaded leaf area indexes; PAR_sun = the photosynthetically active radiation (PAR) received by sunlit leaves; PAR_shade = PAR received by shaded leaves; r_s,min = the minimum leaf stomatal resistance for water vapor; R_s,min = the minimum canopy stomatal resistance for water vapor; A_n = net CO₂ assimilation/photosynthesis rate; h_s = the relative humidity (RH) fraction at the leaf surface, C_s = CO₂ partial pressure at the leaf surface; P = the atmospheric pressure; m = the slope obtained by linear regression analysis of data from gas exchange experiments; b = the intercept obtained by linear regression analysis of data from gas exchange experiments; R_G = the solar irradiation; T_s = surface air temperature; R_cutd0 = the reference value for dry cuticle resistance; R_cutw0 = the reference value for wet cuticle resistance; R_cut,dry = dry cuticle resistance; R_cut,wet = wet cuticle resistance; R_ac0 = the reference value for in-canopy aerodynamic resistance; h_free = the free convection offset; i_u = the turbulence intensity; L_c = a within canopy length scale; R_e = the local Reynolds number.

^aStomatal resistance for a specific gas x (R_s,x) is scaled by the ratio of molecular diffusivities (D) between the gas of interest and water vapor as follows: R_s,x = R_sD_H2O/D_x.