ModelE4 Climate Simulations

Configuration of the ModelE4 Simulations

ModelE4 is the next-generation model configuration for the GISS Earth System Model. It is based on the calibrated physics of the ModelE3 atmosphere combined with a high-resolution eddy-permitting ocean and sea ice module that has 8x the detail of the ocean used in GISS-E3 (submitted to CMIP6), allowing for a greatly expanded evaluation of ocean processes and their impact on climate and climate change. Current runtime on the NCCS Discover platform with 500 cores is around one modeled year per day.

  • Atmosphere: C90 (Cubed-sphere, nominal 1 deg resolution), 110 levels, model top at 0.002 hPa (~85 km).
  • Ocean: nominal 1/8th degree resolution on a stretched latitude-longitude grid (around 12 km resolution near the equator, reducing to 6 km at 60ยบ), with 40 levels in the vertical.

Currently, we have configured a pre-industrial control run (using circa 1850 atmospheric and land surface conditions). Evaluation of this simulation is ongoing, both to examine the mean climate state and long-term behaviour.

Selected Initial Results

Surface ocean currents: Snapshots of surface currents show the complexity of the resolved ocean eddy field, and compare well to average ocean surface current fields taken from the OSCAR dataset.

Ocean surface speed snapshot from the ModelE4 simulation
Figure 1: ModelE4 surface currents (m/s) snapshot.
Decadal average surface ocean current speed in ModelE4 Decadal average surface ocean current speed in the OSCAR dataset
Figure 2: ModelE4 time averaged (10 year) surface currents (m/s) compared to the OSCAR dataset.

Sea Surface Temperature (SST): Snapshots of sea surface temperature show the clear imprints of the ocean eddy field, particularly in the sub-tropics and in Gulf Stream region. As expected the the higher ocean resolution leads to a reduction in bias in the SST field compared to observations in the initial spin-up, though these patterns will evolve in the longer-term averages.

Snapshot of the sea surface temperature in ModelE4
Figure 3: ModelE4 sea surface temperature snapshot (°C).
SST bias compared to observations for ModelE4 SST bias compared to observations for ModelE3
Figure 4: ModelE4 SST bias (°C) compared to ModelE3 SST bias with respect to observations from the initial spin up.

Ongoing work: The initial results from this ModelE4 simulation will continue to be evaluated, and development will continue, including improved calibration of the model. While substantially more computationally more expensive than previous ModelE configurations, ModelE4 will allow us to greatly expand our understanding of how the ocean will respond to, and affect climate changes in the future. Further experimentation using a 1/12th degree ocean (~8 km) is also underway.

Data License

All GISS ModelE4 data is released under was under CC0 (no restrictions).

Contact

Please notify us about any additional issues or anomalies that you come across and we will endeavour to deal with them.

Dr. Gavin Schmidt
NASA Goddard Institute for Space Studies
2880 Broadway, New York, NY 10025 USA
gavin.a.schmidt@nasa.gov

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