CESM2 Ocean Model


The ocean component of the CESM2 is the Parallel Ocean Program version 2 (POP2). This model is based on the POP version 2.1 of the Los Alamos National Laboratory; however, it includes many physical and software developments incorporated by the members of the Ocean Model Working Group detailed in the CESM2 What's New page.

New Ocean Component

A new ocean component model based on the Modular Ocean Model version 6 (MOM6) has been incorporated into CESM and is anticipated to replace POP2 as the default ocean component in CESM3. An early functional release of the MOM6 ocean component is being made available to users beginning with CESM2.2. Instructions for using MOM6 in CESM are available on the MOM_interface Github Wiki page.


Namelist and Input Parameters

POP2 Port Validation and Model Verification

Before running any experiements with CESM2 on a local machine, the user should make sure the POP2 code has ported to their machine properly and subsequently verify the POP2 model output.

In a successful port, CESM2 POP2 ocean-model solutions are expected to be the same "to roundoff level" as solutions generated on a trusted machine. Follow the procedure outlined in the CESM2 POP2 Port-Validation Information to assess the validity of your ported POP2 code.

For model verification, solutions generated on a user's local machine should produce the same climate as an identical simulation on a trusted machine. A 10-year, ocean-only control simulation forced with the Coordinated Ocean-ice Reference Experiments (CORE) Version 2 Normal Year Forcing using global, 1° resolution integrated on NCAR's bluefire machine is provided for comparison. We recommend the user conduct an identical simulation on their local machine and compare the output to that from the NCAR control simulation. Follow the procedure outlined in the CESM1.1 POP2 Model Verification Procedure below.

POP2 Post-Processing Utilities

The scripts provided below are used to create the plots found on the CESM1.0 Diagnostics page for the ocean model and on the POP2 "Stand Alone" Diagnostics page (CESM1.1 simulations will be made available after CESM1.1 is scientifically validated). These scripts are configured to run on NCAR's Data Analysis Services Group (DASG) machines (mirage0, mirage1, etc.); however, you can export them to your local machine. If you are running them locally, you will need NCL and will also need to download the observational data from the repository. Running these scripts on a machine other than the DASG machines is untested and unsupported. These modules are a work in progress as they were initially intended for internal use; therefore, some of the modules will fail to create a plot (or data). Updates will be made periodically.