Atmospheric Dispersion Models - Solving the Mass Balance Flashcards
Which initial models assumed the dispersion process?
Diffusion
Which diffusivity is predominant?
Eddy diffusivity
What does the value of diffusivity depend on?
Local turbulent conditions
What do local turbulent conditions depend on?
- wind speed
- proximity to the ground or other solid surfaces
- temperature gradients
What assumptions is made in the diffusivity model?
- Steady wind speed
- Discharge in infinite air
What is the material balance for diffusivity model?
input - output = accumulation
What happens to the size as the cloud drifts downwind?
Increase in size with time
What happens to the shape as the cloud drifts downwind?
It starts as spherical but distorts into an oblate ellipsoid.
Why is there need to consider the proximity to the ground?
The ground reflects material that flows it.
How does the concentration increase in the region above the ground?
The concentration doubles in the region above the group.
