Values for the characteristic radii of collectors [m] where the columns are land use categories and the rows are seasonal categories. Land-use categories (LUCs)

1. Evergreen–needleleaf trees
2. Deciduous broadleaf trees
3. Grass
4. Desert
5. Shrubs and interrupted woodlands

Seasonal categories (SC)

1. Midsummer with lush vegetation
2. Autumn with cropland not harvested
3. Late autumn after frost, no snow
4. Winter, snow on ground
5. Transitional

given in Seinfeld and Pandis Table 19.2

Description: This is a box model used to calculate the gas species concentration rate changed by dry deposition. Build Drydeposition model (gas)

Example

	@parameters t 
	d = DrydepositionG(t)

Description: This is a box model used to calculate wet deposition based on formulas at EMEP model. Build Wetdeposition model

Example

	@parameters t 
	wd = Wetdeposition(t)

Function DryDepGas calculates dry deposition velocity [m/s] for a gas species, where z is the height of the surface layer [m], zo is roughness length [m], u_star is friction velocity [m/s], L is Monin-Obukhov length [m], T is surface air temperature [K], ρA is air density [kg/m3] gasData is data about the gas species for surface resistance calculations, G is solar irradiation [W m-2], Θ is the slope of the local terrain [radians], iSeason and iLandUse are indexes for the season and land use, dew and rain indicate whether there is dew or rain on the ground, and isSO2 and isO3 indicate whether the gas species of interest is either SO2 or O3, respectively. Based on Seinfeld and Pandis (2006) equation 19.2.

Function DryDepParticle calculates particle dry deposition velocity [m/s] where z is the height of the surface layer [m], zo is roughness length [m], u_star is friction velocity [m/s], L is Monin-Obukhov length [m], Dp is particle diameter [m], Ts is surface air temperature [K], P is pressure [Pa], ρParticle is particle density [kg/m3], ρAir is air density [kg/m3], and iSeason and iLandUse are indexes for the season and land use. Based on Seinfeld and Pandis (2006) equation 19.7.

Function RbGas calculates the quasi-laminar sublayer resistance to dry deposition for a gas species [s/m], where Sc is the dimensionless Schmidt number and u_star is the friction velocity [m/s]. From Seinfeld and Pandis (2006) equation 19.17.

Function RbParticle calculates the quasi-laminar sublayer resistance to dry deposition for a particles [s/m], where Sc is the dimensionless Schmidt number, u_star is the friction velocity [m/s], St is the dimensionless Stokes number, Dp is particle diameter [m], and iSeason and iLandUse are season and land use indexes, respectively. From Seinfeld and Pandis (2006) equation 19.27.

Calculate wet deposition based on formulas at https://www.emep.int/publ/reports/2003/emepreport1part12003.pdf. Inputs are fraction of grid cell covered by clouds (cloudFrac), rain mixing ratio (qrain), air density (ρ_air [kg/m3]), and fall distance (Δz [m]). Outputs are wet deposition rates for PM2.5, SO2, and other gases (wdParticle, wdSO2, and wdOtherGas [1/s]).

Function cc calculates the Cunnningham slip correction factor where Dp is particle diameter [m], T is temperature [K], and P is pressure [Pa]. From Seinfeld and Pandis (2006) equation 9.34.

Function dH2O calculates molecular diffusivity of water vapor in air [m2/s] where T is temperature [K] using a regression fit to data in Bolz and Tuve (1976) found here: http://www.cambridge.org/us/engineering/author/nellisandklein/downloads/examples/EXAMPLE_9.2-1.pdf

Function dParticle calculates the brownian diffusivity of a particle [m2/s] using the Stokes-Einstein-Sutherland relation (Seinfeld and Pandis eq. 9.73) where T is air temperature [K], P is pressure [Pa], Dp is particle diameter [m], and μ is air dynamic viscosity [kg/(s m)]

Function mfp calculates the mean free path of air [m] where T is temperature [K] P is pressure [Pa], and Mu is dynamic viscosity [kg/(m s)]. From Seinfeld and Pandis (2006) equation 9.6

Function mu calculates the dynamic viscosity of air [kg m-1 s-1] where T is temperature [K].

Function Ra calculates aerodynamic resistance to dry deposition where z is the top of the surface layer [m], z₀ is the roughness length [m], u_star is friction velocity [m/s], and L is Monin-Obukhov length [m] Based on Seinfeld and Pandis (2006) [Seinfeld, J.H. and Pandis, S.N. (2006) Atmospheric Chemistry and Physics: From Air Pollution to Climate Change. 2nd Edition, John Wiley & Sons, New York.] equation 19.13 & 19.14.

Function sc computes the dimensionless Schmidt number, where μ is dynamic viscosity of air [kg/(s m)], ρ is air density [kg/m3], and D is the molecular diffusivity of the gas speciesof interest [m2/s]

Function stSmooth computes the dimensionless Stokes number for dry deposition of particles on smooth surfaces or surfaces with bluff roughness elements, where vs is settling velocity [m/s], u_star is friction velocity [m/s], μ is dynamic viscosity of air [kg/(s m)], and ρ is air density [kg/m3], based on Seinfeld and Pandis (2006) equation 19.23.

Function stVeg computes the dimensionless Stokes number for dry deposition of particles on vegetated surfaces, where vs is settling velocity [m/s], u_star is friction velocity [m/s], and A is the characteristic collector radius [m], based on Seinfeld and Pandis (2006) equation 19.24.

Function vs calculates the terminal setting velocity of a particle where Dp is particle diameter [m], ρₚ is particle density [kg/m3], Cc is the Cunningham slip correction factor, and μ is air dynamic viscosity [kg/(s m)]. From equation 9.42 in Seinfeld and Pandis (2006).