Resistance-Model

ModelingToolkit implementation of the complete gas dry-deposition velocity model from Seinfeld & Pandis (2006), Atmospheric Chemistry and Physics, 2nd ed., Chapter 19 (Dry Deposition), Eq. 19.2 (deposition velocity) and Eq. 19.1 (deposition flux). The gas dry-deposition velocity follows the resistance-in-series model: a depositing gas crosses three resistances stacked in series between the reference height and the surface -- the aerodynamic resistance r_a (turbulent transport through the surface layer, Eq. 19.14), the quasi-laminar resistance r_b (molecular diffusion across the thin stagnant sublayer in contact with the surface, Eq. 19.17), and the surface resistance r_c (uptake by the canopy along four parallel pathways, Wesely 1989, Eq. 19.50). The deposition velocity is the reciprocal of their sum, v_d = 1/(r_a + r_b + r_c), and the downward deposition flux is F = -v_d*C for a gas concentration C at the reference height. Migrated from AtmosphericDeposition.jl@e4468c79 src/seinfeld_pandis_ch19.jl:416 (`DryDepositionGas` @component), which composes three MTK subsystems via `System(eqs, t; systems=[aero, qlam, surf])` plus its own coupling equations. Represented here as a subsystem-composed ESS model (spec section 4.7): the `aero` subsystem inlines the already-migrated AerodynamicResistance component (aerodynamic_resistance.esm, esm-x8pg), `qlam` inlines QuasiLaminarResistanceGas (quasi_laminar_gas.esm, esm-t3wp), and `surf` inlines SurfaceResistance (surface_resistance.esm, esm-ug1i), wired together by seven top-level coupling equations. Algebraic (no time derivative): u_star, C, G and T_s are input parameters; r_t, v_d and F are algebraic state outputs.

ModelingToolkit implementation of the quasi-laminar (boundary-layer) resistance to gaseous dry deposition from Seinfeld & Pandis (2006), Atmospheric Chemistry and Physics, 2nd ed., Chapter 19 (Dry Deposition), Eq. 19.17. The quasi-laminar resistance r_b [s/m] is the second of the three series resistances of the gas dry-deposition resistance model (r_a aerodynamic + r_b quasi-laminar + r_c surface) and represents molecular diffusion of the depositing gas across the thin, quasi-laminar sublayer of stagnant air in direct contact with the surface. It is computed as r_b = 5*Sc^(2/3)/u_star, where the Schmidt number Sc = nu/D_g is the ratio of the kinematic viscosity of air nu to the molecular diffusivity D_g of the gas, and u_star is the friction velocity. Slower-diffusing (higher-Sc) gases face a larger boundary-layer resistance, and stronger surface turbulence (higher u_star) thins the sublayer and lowers r_b. Migrated from AtmosphericDeposition.jl@e4468c79 src/seinfeld_pandis_ch19.jl:143 (`QuasiLaminarResistanceGas` @component). Algebraic (no time derivative) two-equation system: Sc and r_b are the algebraic outputs (the upstream component's computed @variables, migrated as type:state); nu and D_g are the input @parameters and u_star is the upstream input @variable (migrated as type:parameter -- it carries no defining equation and the upstream test suite compiles the component with u_star declared as an input).

Wesely (1989) bulk surface (canopy) resistance to gaseous dry deposition. Computes the total surface resistance r_c [s/m] along Wesely's three parallel mass-transfer pathways — the upper-canopy leaf cuticles, the lower-canopy structures, and the ground — from the gas species' Henry's-law solubility and reactivity, solar irradiation, surface air temperature, terrain slope, season, land-use category, and surface wetness (rain/dew). Migrated from AtmosphericDeposition.jl@e4468c79 src/wesley1989.jl:360 (the `WesleySurfaceResistance` builder function); implements Wesely (1989) Eq. 2 with the stomatal, mesophyll, cuticle, lower-canopy and ground sub-resistances of Eqs. 3-14 and the Walmsley & Wesely (1996) corrections.