Hi everyone, I am trying to model the radiative effects of HFCs using CESM2.1.5 I am finding that the lower boundary condition files in most compsets do not include any HFCs. Some have a CFC11eq (such as the FW1850 compset) which is a weighted aggregate that includes HFCs and other gases. However, I am interested specifically in the contribution of HFCs to the radiative forcing, so I am looking for lower boundary condition files that contain mole fractions of HFCs.
I read the Historical greenhouse gas concentrations for climate modelling (CMIP6) by Meinshausen et al (2017) which contain input options for prescribing greenhouse gas concentrations in models. According to the paper, modelers can use
Option 1: "climate models implement a subset of 43 GHGs."
Option 2: "climate models implement the four most important GHGs with their actual mole fractions explicitly, namely CO2, CH4, N2O and CFC-12, and summarize the effect of all other 39 gases in an equivalence concentration of CFC-11. For this purpose, we provide CFC-11 eq. concentrations (“full equivalence”)."
Option 3: "like option 2, but with a different split up of gases other than CO2, CH4 and N2O. Climate models implement the three most important GHGs with their actual mole fractions explicitly, namely CO2, CH4 and N2O, and summarize the radiative effect of the ODSs in a CFC-12 eq. concentration and the radiative effect of all other fluorinated gases as a HFC-134a eq. concentration. For this purpose, we provide CFC-12 eq. and HFC134a eq. concentrations (“full equivalence”)."
Based on my research, it seems like most compsets in CESM2 are using the Option 2 configuration. So here is my question: Are there any compsets that have the Option 3 configuration in their lower boundary condition files which include HFC-134a-equivalent? If not, where can I get lower boundary condition files which include the HFC-134a-equivalent?
I would really appreciate any help on this. I also had some follow up questions about the radiation code so it would be great if someone could point me to a contact who would know more about this. Thank you so much!
I read the Historical greenhouse gas concentrations for climate modelling (CMIP6) by Meinshausen et al (2017) which contain input options for prescribing greenhouse gas concentrations in models. According to the paper, modelers can use
Option 1: "climate models implement a subset of 43 GHGs."
Option 2: "climate models implement the four most important GHGs with their actual mole fractions explicitly, namely CO2, CH4, N2O and CFC-12, and summarize the effect of all other 39 gases in an equivalence concentration of CFC-11. For this purpose, we provide CFC-11 eq. concentrations (“full equivalence”)."
Option 3: "like option 2, but with a different split up of gases other than CO2, CH4 and N2O. Climate models implement the three most important GHGs with their actual mole fractions explicitly, namely CO2, CH4 and N2O, and summarize the radiative effect of the ODSs in a CFC-12 eq. concentration and the radiative effect of all other fluorinated gases as a HFC-134a eq. concentration. For this purpose, we provide CFC-12 eq. and HFC134a eq. concentrations (“full equivalence”)."
Based on my research, it seems like most compsets in CESM2 are using the Option 2 configuration. So here is my question: Are there any compsets that have the Option 3 configuration in their lower boundary condition files which include HFC-134a-equivalent? If not, where can I get lower boundary condition files which include the HFC-134a-equivalent?
I would really appreciate any help on this. I also had some follow up questions about the radiation code so it would be great if someone could point me to a contact who would know more about this. Thank you so much!