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Global Climate Model, CM4

GFDL’s CM4.0 consists of:

  • AM4.0 atmosphere at approximately 1o resolution with 33 levels and sufficient chemistry to simulate aerosols (including aerosol indirect effect) from precursor emissions
  • OM4 MOM6-based ocean at 1/4o resolution with 75 levels using hybrid pressure/isopycnal vertical coordinate
  • SIS2 sea ice with radiative transfer and C-grid dynamics for compatibility with MOM6
  • LM4 land model with dynamic vegetation

As described in Held et al (submitted), CM4.0 produces a very good simulation of the present-day climatology and ENSO variability.  The “portrait plot” below compares the accuracy of GFDL CM4.0’s present day climatology globally with that of the previous (CMIP5) generation of climate models.  The color is a relative measure of quality — blue is good, red is poor — and the four triangles show the four seasons.  For these four important metrics GFDL CM4.0 is very blue!

CMIP Experiments with CM4

CM4 has performed the CMIP6 1850 control, idealized CO2 increase (abrupt quadrupling and 1%/year increase), historical and two future projection (SSP2.6 and SSP8.5) experiments.  The data is available from the CMIP6 archive here.  OM4 has been used for the CMIP6 OMIP experiments.


Adcroft, A., et al, 2019: The GFDL Global Ocean and Sea Ice Model OM4.0:  Model Description and Simulation Features, JAMES, DOI:10.1029/2019MS001726.

Held, I.M., et al, 2019: Structure and Performance of GFDL’s CM4.0 Climate Model, JAMES, DOI:10.1029/2019MS001829.

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