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Add Emission Source, Specifying Location, Time, and Amount

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AshaJain

Asha Jain
New Member
Hello,

I am interested in adding emission sources to WACCM that represent space debris reentries. Ideally, I would like to specify the lat/lon, time, altitude, and concentration of the emission that vary from year to year. However, I have only seen options to add emissions sources that are fixed with no time variability (meaning a constant source), cyclical (meaning a repeating source every year), or serial with interpolation between events.

I am not seeing a way to specify numerous single emission events. Also, I am confused as to what is contained in the netCDF file that specifies an emission source, and how WACCM interprets that information to include the emission in the model. The particular source of my confusion is documentation suggesting that I can use any naming convention in my emission netCDF file. If that is the case, then how does WACCM interpret this emission netCDF file?

Thank you for all the help!

Best,

Asha
 
mmills

mmills

CSEG and Liaisons
Staff member
An example of single emission events that we include in WACCM6 is volcanic eruptions. This is done with serial interpolation, so each event must have 4 times in the external forcing file:

(1) zero emissions the timestep prior to the start of the event
(2) the event emission rate at the timestep when the event starts
(3) the event emission rate at the timestep when the event ends
(4) zero emissions the timestep after the end of the event

Therefore, the interpolated emission between events is zero, and during events is whatever constant emission rate you specify for the start and end timesteps.

As for the variable name, it can have any name. WACCM will sum up all of the variables in the file that have the appropriate dimensionality to get the emission rate. Each species that is emitted must therefore have its own file.

Here is an example external forcing file for volcanic eruptions:


This was created with this NCL script:


The latest version of the script is here:

 
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