mvparke@sandia_gov
New Member
Hello,I am running CESM 1.2(rel06) and trying to look at the climatological effects of various methane emissions scenarios. I am new to CESM and don't fully understand what parameters I need to change to specify my own methane emissions. I am using the FMOZMAM (F_2000_MOZMAM_CN) compset, but am open to other compsets as long as methane is advected. I prepared my own methane emissions file based on /ccsm/inputdata/atm/cam/chem/methane/CH4_2000-2009_clim_c090605.nc and indicated 0 methane emissions as a test. I was then specifying in user_nl_cam that this altered file be used as the methane surface emissions file (srf_emis_specifier = 'BIGALK -> /projects/ccsm/inputdata/atm/cam/chem/emis/1992-2010/emissions.BIGALK.surface.1.9x2.5_c110426.nc', ... , 'CH4 -> /gscratch/mvparke/EmissionsBoundaryFiles/methane_emissions/Worldwide/CH4_2000-2009_clim_c090605_NONE.nc', with all of the other necessary species indicated as well). However, even when the altered file indicated 0 methane emissions worldwide, the result is exactly the same as it is when the srf_emis_specifier line is not included. So clearly the code is not reading methane from the file indicated by srf_emis_specifier. I next tried to change methane through the lower boundary condition file, and indeed when I changed the lower boundary conditions file to specify 0 methane emissions, the atmospheric methane was reduced (although not eliminated). Unfortunately the lower boundary condition file specifies methane only by latitude and time, not longitude. For the research we are hoping to do, we'd like to specify increased/decreased methane emissions from a well-defined area, which would be specified by lat/lon. The lower boundary condition file doesn't seem to have the geographic specificity we are looking for. At this point, I don't know what to try next and would appreciate any suggestions here. Specifically, I have the following questions:1. Is F_2000_MOZMAM_CN an appropriate compset to use for this problem?2. Is there a way to specify that methane emissions should come from the srf_emis_specifier file?3. If I can't specify methane emissions from the srf_emis_specifier file, I believe I can add a longitude dimension to the lower boundary condition file. Is this the best way to proceed?4. What are the other sources of methane in the model, other than the lower boundary conditions file? Thank you in advance for any guidance on this issue! Marie