Steady state Vertical diffusion equation

AI Thread Summary
The discussion focuses on solving the steady-state vertical diffusion equation for a species X in the atmosphere, represented by the equation dJ/dz - P + S = 0. The flux J incorporates gravitational sedimentation and turbulent diffusion, while P denotes the loss of species X and S represents its source term. Key boundary conditions include an equilibrium condition at a specific altitude and zero flux at ground level. The species X is generated at an altitude of 31 km and diffuses through the atmosphere. Participants are encouraged to reference relevant literature for further insights into the modeling approach.
Juliousceasor
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Hallo everyone,

I am trying to find the way to solve the vertical diffusion equation for a spicies X in the atmosphere for steady state conditions (dc/dt=0).

The equation has the form,

dJ/dz -P+S=0

where J =(vs*C(z)) + rho*kz*d/dz(C(z)/rho(z)) is the flux of spicies X at height z above ground level and C is the concentration of the spicies X at height z.

P = (lambda+sigma)*C(z) is the loss of X per unit time and per volume with the unit base
area and height dz at the altitude z.

S = source term of X
vs = gravitational sedimentory velocity
rho = air density
kz = turbulant diffusion coefficient

The boundary conditions that apply are

1) at altitude z= zn
lambda*C(zn)=q*S(zn) (equilibrium between formation and decay of X)

2) J (z=0) = 0


(Basically spices X is formed at z=31 Km and distributed or diffused in the atmosphere given by the equation above)


Help is greatly appricieted!

Thanks
 
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Juliousceasor said:
Hallo everyone,

I am trying to find the way to solve the vertical diffusion equation for a spicies X in the atmosphere for steady state conditions (dc/dt=0).

The equation has the form,

dJ/dz -P+S=0

where J =(vs*C(z)) + rho*kz*d/dz(C(z)/rho(z)) is the flux of spicies X at height z above ground level and C is the concentration of the spicies X at height z.

P = (lambda+sigma)*C(z) is the loss of X per unit time and per volume with the unit base
area and height dz at the altitude z.

S = source term of X
vs = gravitational sedimentory velocity
rho = air density
kz = turbulant diffusion coefficient

The boundary conditions that apply are

1) at altitude z= zn
lambda*C(zn)=q*S(zn) (equilibrium between formation and decay of X)

2) J (z=0) = 0(Basically spices X is formed at z=31 Km and distributed or diffused in the atmosphere given by the equation above)Help is greatly appricieted!

Thanks
See Miller, C., Meakin, P., Franks, R.G.E., and Jesson, J.P., The Fluorocarbon-Ozone Theory – V. One Dimensional Modeling of the Atmosphere: The Base Case, Atmospheric Environment, 12, 2481-2500 (1978)
 
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