CESM2.1-SCAM-RCE

Background

The Single Column Atmosphere Model (SCAM) is a single column model version of the Community Atmosphere Model (CAM). The overview and application of SCAM can be found in Gettelman et al. (2019).

Running SCAM RCE in CESM2.1

1. Get the code of CESM2.1 and put it wherever you like (hereafter [CESMDIR]), and check how to run SCAM in CESM2.
2. Download InputFiles and put it wherever you like (hereafter [INPUTDIR])
3. Copy both scam5_rcemip (in SCAM5 directory) and scam6_rcemip (in SCAM6 directory), which are the RCE modified source code for SCAM5 and SCAM6, respectively, to [CESMDIR]/components/cam/cime_config/usermods_dirs/.
4. In SCAM5 or SCAM6 directory, edit the shell script scam*_rcemip_single (for a single run) or scam*_rcemip_loop (for simultaneously multiple runs or parameter sweep experiments). Particular focuses include:
   • the job setting information such as project account, timewall, and queue;
   • the machine and compiler;
   • the paths of [CESMDIR], [INPUTDIR], [CASEDIR] (where the run case and output should be), and [MODSDIR] (where the modified source code sits - basically the path mentioned in 3);
   • the names of run case [CASENAME] and baseline run [BASECASENAME] when using scam*_rcemip_loop;
   • the run case setting, including number of vertical levels [NL], time step [DT], sea surface temperature [SST], and period of simulation [LT];
   • the customized setting such as output fields.
5. Execute the modified shell script scam*_rcemip_single or scam*_rcemip_loop.

The InputFiles folder includes all the required input data files and can be categorized into several different groups:

• SST*.nc: uniformly global SST data, currently with three SST values – 295, 300, and 305 K – as required in RCEMIP.
• *init*.nc: initial condition files which have uniformly global data of state; can choose either RCEMIP analytical profiles or RCEALT (ALTernative) profiles.
• *iop*.nc: IOP data files which carry the same data of state as in the corresponding *init*.nc files; the current available running period is 1200 days (can easily be extended).
• *solar*.nc: these files are basically used to fix the solar constant to 551.58 W/m2; the one with "CAM6" is for SCAM6.
• RCEMIPozone*.nc: the analytical ozone profile following RCEMIP protocols; the "L26" and "L32" are for SCAM5 and SCAM6, repsectively.
• aero_zero.nc: this one is used to zero all the aerosol fields in SCAM5.

Additionally, there is this NCLscripts directory, which includes all the NCL scripts for generating *init*.nc, *iop*.nc, and RCEMIPozone*.nc.

Details of the SCAM-RCE configuration

The current SCAM-RCE configuration in CESM2.1.0 is based on the RCEMIP protocols in Wing et al. (2018), along with additional modifications as options. The RCEMIP protocols and their corresponding parts of modified code in CESM2.1.0 are descibed in RCEMIP_SCAM5&6_CESM2.pdf.