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Title: The Radiative Forcing Model Intercomparison Project (RFMIP): Experimental protocol for CMIP6

The phrasing of the first of three questions motivating CMIP6 – “How does the Earth system respond to forcing?” – suggests that forcing is always well-known, yet the radiative forcing to which this question refers has historically been uncertain in coordinated experiments even as understanding of how best to infer radiative forcing has evolved. The Radiative Forcing Model Intercomparison Project (RFMIP) endorsed by CMIP6 seeks to provide a foundation for answering the question through three related activities: (i) accurate characterization of the effective radiative forcing relative to a near-preindustrial baseline and careful diagnosis of the components of this forcing; (ii) assessment of the absolute accuracy of clear-sky radiative transfer parameterizations against reference models on the global scales relevant for climate modeling; and (iii) identification of robust model responses to tightly specified aerosol radiative forcing from 1850 to present. Complete characterization of effective radiative forcing can be accomplished with 180 years (Tier 1) of atmosphere-only simulation using a sea-surface temperature and sea ice concentration climatology derived from the host model's preindustrial control simulation. Assessment of parameterization error requires trivial amounts of computation but the development of small amounts of infrastructure: new, spectrally detailed diagnostic output requested as two snapshots at present-day and preindustrial conditions, and resultsmore » from the model's radiation code applied to specified atmospheric conditions. In conclusion, the search for robust responses to aerosol changes relies on the CMIP6 specification of anthropogenic aerosol properties; models using this specification can contribute to RFMIP with no additional simulation, while those using a full aerosol model are requested to perform at least one and up to four 165-year coupled ocean–atmosphere simulations at Tier 1.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Univ. of Colorado, Boulder, CO (United States); NOAA Earth System Research Lab., Boulder, CO (United States)
  2. Univ. of Leeds, Leeds (United Kingdom)
  3. Max Planck Institute for Meteorology, Hamburg (Germany)
Publication Date:
Grant/Contract Number:
SC0012549
Type:
Accepted Manuscript
Journal Name:
Geoscientific Model Development (Online)
Additional Journal Information:
Journal Name: Geoscientific Model Development (Online); Journal Volume: 9; Journal Issue: 9; Journal ID: ISSN 1991-9603
Publisher:
European Geosciences Union
Research Org:
The Regents of the Univ. of Colorado, Denver, CO (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1361558

Pincus, Robert, Forster, Piers M., and Stevens, Bjorn. The Radiative Forcing Model Intercomparison Project (RFMIP): Experimental protocol for CMIP6. United States: N. p., Web. doi:10.5194/gmd-9-3447-2016.
Pincus, Robert, Forster, Piers M., & Stevens, Bjorn. The Radiative Forcing Model Intercomparison Project (RFMIP): Experimental protocol for CMIP6. United States. doi:10.5194/gmd-9-3447-2016.
Pincus, Robert, Forster, Piers M., and Stevens, Bjorn. 2016. "The Radiative Forcing Model Intercomparison Project (RFMIP): Experimental protocol for CMIP6". United States. doi:10.5194/gmd-9-3447-2016. https://www.osti.gov/servlets/purl/1361558.
@article{osti_1361558,
title = {The Radiative Forcing Model Intercomparison Project (RFMIP): Experimental protocol for CMIP6},
author = {Pincus, Robert and Forster, Piers M. and Stevens, Bjorn},
abstractNote = {The phrasing of the first of three questions motivating CMIP6 – “How does the Earth system respond to forcing?” – suggests that forcing is always well-known, yet the radiative forcing to which this question refers has historically been uncertain in coordinated experiments even as understanding of how best to infer radiative forcing has evolved. The Radiative Forcing Model Intercomparison Project (RFMIP) endorsed by CMIP6 seeks to provide a foundation for answering the question through three related activities: (i) accurate characterization of the effective radiative forcing relative to a near-preindustrial baseline and careful diagnosis of the components of this forcing; (ii) assessment of the absolute accuracy of clear-sky radiative transfer parameterizations against reference models on the global scales relevant for climate modeling; and (iii) identification of robust model responses to tightly specified aerosol radiative forcing from 1850 to present. Complete characterization of effective radiative forcing can be accomplished with 180 years (Tier 1) of atmosphere-only simulation using a sea-surface temperature and sea ice concentration climatology derived from the host model's preindustrial control simulation. Assessment of parameterization error requires trivial amounts of computation but the development of small amounts of infrastructure: new, spectrally detailed diagnostic output requested as two snapshots at present-day and preindustrial conditions, and results from the model's radiation code applied to specified atmospheric conditions. In conclusion, the search for robust responses to aerosol changes relies on the CMIP6 specification of anthropogenic aerosol properties; models using this specification can contribute to RFMIP with no additional simulation, while those using a full aerosol model are requested to perform at least one and up to four 165-year coupled ocean–atmosphere simulations at Tier 1.},
doi = {10.5194/gmd-9-3447-2016},
journal = {Geoscientific Model Development (Online)},
number = 9,
volume = 9,
place = {United States},
year = {2016},
month = {9}
}