CESM2 Mechanically Decoupled

The CESM2 Mechanically Decoupled (MDM) model is designed to simulate buoyancy coupled climate variability. The MDM consists of the same model components, including the dynamic ocean model POP2, as the CESM2 fully coupled model (FCM), but lacks anomalous wind stress (momentum) driven ocean dynamics. Ocean variability in the MDM is therefore primarily buoyancy driven. Different from a slab ocean model (SOM) with a time invariant mixed layer depth, the MDM includes a freely evolving seasonally varying mixed layer depth, seasonally varying mean ocean circulation, and time varying buoyancy driven ocean circulation variability like the Atlantic meridional overturning circulation (AMOC). Key sources of ocean damping are present in the MDM, including vertical mixing, entrainment, and advection by the mean ocean circulation, whereas many dynamical sources of ocean variability, as facilitated through anomalous wind stress driven ocean dynamics, are absent. Comparing a SOM and the MDM can uncover the collective role of mixed layer depth variability, buoyancy coupled ocean circulation variability, and ocean damping on climate variations, whereas comparing the MDM and FCM can uncover the role of anomalous wind driven ocean dynamics on climate variability.

When run under historical or future climate scenario forcings, the CESM2 MDM version does not allow anomalous wind stress driven changes to ocean circulation deriving from either internal variability or external forcing. The ocean in the MDM historical and future ensembles can warm via changes in buoyancy forcing only. See the Documentation tab for important details about each set of simulations.

Data included in this entry are: * CESM2-MDM-PI: A pre-industrial control version of the MDM. * CESM2-MDM-historical: a 20-member MDM historical ensemble with CMIP6 forcings and smoothed biomass burning run from 1850-2014. * CESM2-MDM-historical-to-SSP370: a 5-member MDM historical ensemble with CMIP6 forcings and smoothed biomass burning run from 1850-2014. These 5 members are used to branch a 10-member future ensemble run under SSP370 out to 2100.

Further information about these simulations is available under the documentation tab.

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Temporal Range

  • Begin:  1051
    End:  2101

Keywords

Resource Type dataset
Temporal Range Begin 1051
Temporal Range End 2101
Temporal Resolution N/A
Bounding Box North Lat N/A
Bounding Box South Lat N/A
Bounding Box West Long N/A
Bounding Box East Long N/A
Spatial Representation N/A
Spatial Resolution N/A
Related Links N/A
Additional Information N/A
Resource Format NetCDF
Standardized Resource Format NetCDF
Asset Size 35251904.593 MB
Legal Constraints

Creative Commons Attribution 4.0 International License
Access Constraints None
Software Implementation Language N/A

Resource Support Name N/A
Resource Support Email datahelp@ucar.edu
Resource Support Organization
Distributor NSF NCAR Geoscience Data Exchange

Metadata Contact Name N/A
Metadata Contact Email datahelp@ucar.edu
Metadata Contact Organization NSF NCAR Geoscience Data Exchange

Author Larson, Sarah ORCID icon
McMonigal, Kay
Bailey, Dave
Publisher NSF National Center for Atmospheric Research

Publication Date 2022-01-01
Digital Object Identifier (DOI) https://doi.org/10.26024/ffeq-wr08
Alternate Identifier d651079
Resource Version N/A
Topic Category climatologyMeteorologyAtmosphere
Progress completed
Metadata Date 2026-03-13T16:50:53Z
Metadata Record Identifier edu.ucar.gdex::d651079
Metadata Language eng; USA
Suggested Citation Larson, Sarah, McMonigal, Kay, Bailey, Dave. (2022). CESM2 Mechanically Decoupled. NSF National Center for Atmospheric Research. https://doi.org/10.26024/ffeq-wr08. Accessed 28 March 2026.

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