Clouds and the Earth’s Radiant Energy System (CERES) Model Intercomparison Project (CERESMIP)

The Clouds and the Earth's Radiant Energy System (CERES) project has now produced over two decades of observed data on the Earth’s Energy Imbalance (EEI) and has revealed substantive trends in both the reflected shortwave and outgoing longwave top-of-atmosphere radiation components. Available climate model simulations suggest that these trends are incompatible with purely internal variability, but that the full magnitude and breakdown of the trends are outside of the model ranges. Unfortunately, the Coupled Model Intercomparison Project (Phase 6) (CMIP6) protocol only uses observed forcings to 2014 (and Shared Socioeconomic Pathways (SSP) projections thereafter), and furthermore, many of the ‘observed’ drivers have been updated substantially since the CMIP6 inputs were defined. Most notably, the sea surface temperature (SST) inputs for AMIP-style atmospheric simulations have been revised and now show up to 50% greater trends since 1979, particularly in the southern hemisphere. Additionally, estimates of short-lived aerosol and gas-phase emissions have been substantially updated. These revisions will likely have material impacts on the model-simulated EEI.

CERESMIP is a new, relatively low-cost, model intercomparison that will target the CERES period (2000-present), with updated forcings to at least the end of 2021. The focus will be on atmosphere-only simulations, using updated SST, forcings and emissions from 1990 onwards. The focus will be on the EEI and atmospheric feedbacks, and so diagnostics will benefit from output from satellite cloud observation simulators. The Tier 1 request would consist of a single AMIP-style simulation, while the Tier 2 request would encompass uncertainties in the applied forcing, atmospheric composition, single and all-but-one forcing responses.

The paper describing the protocol is currently under review.

Updated input datasets

...will be listed here as they are made available.

Experiment requests

The requested experiments are listed in the following table:

Experiment name

Description

Tier

Start year

End year

Notes

1. Combined forcings atmospheric simulations

1.1 amip

All forcings (single run) with observed SST/SIC

1

1990

2021

As CMIP6 AMIP but with updated forcings.

1.2 amip

All forcings (ensemble) with observed SST/SIC

2

1990

2021

1.3 amip-nudge

All forcings (single run, nudged winds) with observed SST/SIC

2

1990

2021

1.4 amip-nat

Natural forcings (solar + volcanic + orbital) with observed SST/SIC

2

1990

2021

AMIP SST/SIC and natural forcings only. All other boundary conditions set to 1850.

2. Single forcing atmospheric simulations

2.1 amip-ghg

Well-mixed greenhouse-gas-only simulations with observed SST/SIC

2

1990

2021

AMIP SST/SIC and WM-GHG forcings only. All other boundary conditions set to 1850.

2.2 amip-aer

Anthropogenic-aerosol-only simulations with observed SST/SIC

2

1990

2021

AMIP SST/SIC and aerosol forcings only. All other boundary conditions set to 1850.

2.3 amip-slcf

Anthropogenic changes in short-lived climate forcings (for use with models including interactive composition) with observed SST/SIC

2

1990

2021

forcings except with WM-GHGs set to 1850 levels.

2.4 amip-sst

Observed SST/SIC change only

2

1990

2021

AMIP SST/SIC only. All other boundary conditions set  to 1850.

3. All-but-one atmospheric simulations

3.1 amip-noghg

As with amip, but no changes in well-mixed GHGs

2

1990

2021

All AMIP forcings except with WM-GHGs set to 1850 levels.

3.2 amip-noaer

As with amip, but no changes in aerosols

2

1990

2021

All AMIP forcings except with aerosols set to 1850 levels.

3.3 piclim-histall

As with amip, but using fixed pre-industrial SST/SIC

2

1990

2021

All historical forcings with SST/SIC fixed at PI (~1850) conditions.

Links to results

...will be listed here when available.

Contact

Please contact Dr. Gavin Schmidt if you have any questions or comments about these data.

Note: PDF documents require the free Adobe Reader or compatible viewing software to be viewed.