Evaluating Emission Effects on Glacier Melt: ATM and CISM Interactions

[Hemraj]

Hi CESM community,

In the current component settings (compset), can I see how changes in emissions (such as CB1, CB2; black carbon listed in "srf_emis_specifier" under atm_in) affect snow and glacier melt? I believe glaciers fall under the CISM earth component, so does the ATM interact with CISM?

Do emissions in "srf_emis_specifier" or GHGs in "chem_surfvals_nl" interact with CISM? Which compset would best suit examining how changes in emissions (e.g., BC) affect glaciers?

Many thanks.

 

[slevis]

@sacks do you have a quick response to this question?

 

[sacks]

I only have a partial answer: The impact of emissions on snow and glacier melt happens in CTSM, via the SNICAR model (I think): there is no direct ATM -> CISM interaction. It's somewhat complicated: Emissions like black carbon impact snow melt in CTSM. This snow melt doesn't have any direct connection to CISM, but the snow melt is needed to expose the bare ice underneath (see 2.13. Glaciers — ctsm CTSM master documentation). I believe that, once the snow melts, the bare ice albedo is *not* affected by black carbon, etc., but is instead a constant value.

 

[Hemraj]

Thank you @slevis and @sacks
Sorry for my late response.

It seems it is not as straightforward as I thought. Let me simplify my question, maybe that would help to find some solution.

We have BC emissions for different SSP scenarios. I want to see how the change in BC under different SSP scenarios affects glaciers over three poles (Arctic, Antarctic, and Tibetan Plateau (TP)).

If there is no direct coupling of atmospheric emissions with CISM, is there any indirect way I can still do this analysis?

Thanks lot.

 

[slevis]

My first thought is that you could make the necessary code modifications. I think that this would likely require significant coding experience and time commitment to accomplish.