Help Needed with CESM and CAM: Replicating Study and Configuring CAM-CHEM4

[tgm]

Hi,
I'm a new user of CESM and CAM. I'm attempting to replicate a study described in this paper: Global environmental implications of atmospheric methane removal through chlorine-mediated chemistry-climate interactions - Nature Communications. However, I'm currently facing some confusion regarding the model.
(1) I've noticed that most publications related to halogens, as discussed in Publications | Community Earth System Model, have used CESM1 and CAM-CHEM4 recently. Is this a recommended configuration for studying halogens? Are there any issues with the newer versions of CESM and CAM in relation to halogen studies?

(2) I've successfully ported CESM1.1, but I'm struggling to find sufficient user guides for CAM-CHEM4. Can I use the CAM-CHEM wiki and CAM6 guide for CAM-CHEM4?

(3) The papers mention " a version of CAM-Chem with improved representations of very short-lived halogens (Cl, Br, and I)." Which chemical mechanism does this version of CAM use? From the information available on the UCAR site, it seems it might be Morzart-Ts1. However, I couldn't find it in the case compset in cesm1.1. Am I mistaken, or does it have another name in the compset?

(4) In the study I referenced, the experiments were conducted under RCP8.5 and RCP6.0. Are there compsets in CESM1 and CAM-CHEM4 that cater to different RCP scenarios? If not, how should I configure it?

I appreciate any information or guidance you can provide. THANKS A LOT ! ! !

 

[behroozr]

Hi,
I'm a new user of CESM and CAM. I'm attempting to replicate a study described in this paper: Global environmental implications of atmospheric methane removal through chlorine-mediated chemistry-climate interactions - Nature Communications. However, I'm currently facing some confusion regarding the model.
(1) I've noticed that most publications related to halogens, as discussed in Publications | Community Earth System Model, have used CESM1 and CAM-CHEM4 recently. Is this a recommended configuration for studying halogens? Are there any issues with the newer versions of CESM and CAM in relation to halogen studies?

(2) I've successfully ported CESM1.1, but I'm struggling to find sufficient user guides for CAM-CHEM4. Can I use the CAM-CHEM wiki and CAM6 guide for CAM-CHEM4?

(3) The papers mention " a version of CAM-Chem with improved representations of very short-lived halogens (Cl, Br, and I)." Which chemical mechanism does this version of CAM use? From the information available on the UCAR site, it seems it might be Morzart-Ts1. However, I couldn't find it in the case compset in cesm1.1. Am I mistaken, or does it have another name in the compset?

(4) In the study I referenced, the experiments were conducted under RCP8.5 and RCP6.0. Are there compsets in CESM1 and CAM-CHEM4 that cater to different RCP scenarios? If not, how should I configure it?

I appreciate any information or guidance you can provide. THANKS A LOT ! ! !

Hi,

Sorry for the confusion. The mechanism that was discussed in that paper is not available in current CESM models. However, the updated version of that mechanism will be included in the next CESM version (that will be released next summer). In the meantime, please contact the authors (Qinyi Li, Rafael Fernandez, or Alfonso Saiz-Lopez) for further information on the mechanism specifications and RCP scenarios.

Most of the reactions are also included in MOZART_TS1 as you mentioned. But, MOZART_TS1 was added to the model starting from CESM2 (i.e., not included in CESM1). More information on MOZART-TS1 could be found here.

Also, the overall running procedure is similar between CESM1 and CESM2. You can use this document on how to run CESM1.

Best,
Behrooz

 

[tgm]

Hi,

Sorry for the confusion. The mechanism that was discussed in that paper is not available in current CESM models. However, the updated version of that mechanism will be included in the next CESM version (that will be released next summer). In the meantime, please contact the authors (Qinyi Li, Rafael Fernandez, or Alfonso Saiz-Lopez) for further information on the mechanism specifications and RCP scenarios.

Most of the reactions are also included in MOZART_TS1 as you mentioned. But, MOZART_TS1 was added to the model starting from CESM2 (i.e., not included in CESM1). More information on MOZART-TS1 could be found here.

Also, the overall running procedure is similar between CESM1 and CESM2. You can use this document on how to run CESM1.

Best,
Behrooz

Hi Behroozr,

Thank you for your prompt reply! I'm thrilled about the upcoming update. I'll be reaching out to the author later for more details on the mechanism and RCP scenarios.

Once again, I appreciate your time and assistance.