Modifying Sea Salt CCN Properties

[sfaber1@uwyo_edu]

First off, I’m very green to all things CESM so forgive me if this comes across as rambling… I’m trying to set up a run to investigate the effects of cloud seeding marine stratus decks off thecoast of North America, South America, and Africa. I’m using the AIE_2000 case (CESM 1.2, CAM 5) as a starting point.I’d like to somehow increase the amount of sea salt CCN for specific grids in theafore-mentioned coastal areas. Which files should I be looking for in order to make such changes? I see references to sea salt variables in models/atm/cam/src/chemistry/bulk_aero/progseasalts_intr.F90 but I don't want to go breaking things deep in the code. I've heard that sea salt fluxes aren't a prescribed value, but rather depend on ocean activity. If that is the case then I expect modifying fluxes for specific grids is going to be a problem. This work is for a fairly minor class project so I'm absolutely fine with simplifying the experimental setup; for example...-Just increasing sea salt fluxes globally.-Using another CCN as a proxy for sea salts I'm in over my head here so any pointers would be much appreciated.  

 

[andrew]

Hi Spencer,The model is not easily set up to do this. Sea-salt is emitted as a function of wind speed, so it is interactive and not geographically specific. If you were just looking for a cloud brightening effect, you could alter the surface emissions of either DMS or SO2/SO4 (in the external forcing specifier files in the namelist) to add sulfur in a region which will increase CCN as well.Hope that helps,Andrew