Atmosphere-sea fluxes of nutrients and gases
Nutrient atmosphere-sea flux
Atlantis has always allowed for atmospheric deposition of NH and NO. We’ve now made that explicit (i.e. parameters in physics.prm) and added the capacity to have P, CO2, Si and micronutrients flux too.
This new functionality is optional. You can turn it on by adding the following to your physics prm file:
include_atmosphere 1
If you have an existing model you should probably turn this off, ie:
include_atmosphere 0
To ensure that you get results consistent with your past results.
If this functionality is turned on the following parameters should be added to physics.prm
Atmospheric concentrations of gases or dust based inputs (mg m-3)
atmospheric_NH 0.017
atmospheric_NO 0.025
atmospheric_F 0.0
atmospheric_CO2 0.0
atmospheric_P 0.0
atmospheric_Si 0.0
In the code all of these fluxes are implemented as follows:
If it is a surface layer then
localWCFlux_nutrient += (atmospheric_XX / layer_depth) / 86400 (with the last bit to make sure its per second so in correct units for the integrator)
Oxygen atmosphere-sea flux
We’ve added explicit temperature-dependent atmosphere-sea flux for oxygen too. This uses a relationship
calculated off Figure 1 in Gruber et al Global Biogeochemical Cycles paper “Air-sea flux of oxygen estimated from bulk data:
Implications for the marine and atmospheric oxygen cycles”
You need to add the following param to the physics.prm
atmospheric_O2 198.9
In the code the flux is implemented as follows: if it is a surface layer then
localWCFlux_o2 += ((atmospheric_O2 - 0.0008 * H2Otemp^4 + 0.0594 * H2Otemp^3 - 1.1908 * H2Otemp^2 + 0.613 * H2Otemp) / layer_depth) / 86400