Title: Quantifying CanESM5 and EAMv1 sensitivities to Mt. Pinatubo volcanic forcing for the CMIP6 historical experiment

Abstract

Large volcanic eruptions reaching the stratosphere have caused marked perturbations to the global climate including cooling at the Earth's surface, changes in large-scale circulation and precipitation patterns and marked temporary reductions in global ocean heat content. Many studies have investigated these effects using climate models; however, uncertainties remain in the modelled response to these eruptions. This is due in part to the diversity of forcing datasets that are used to prescribe the distribution of stratospheric aerosols resulting from these volcanic eruptions, as well as uncertainties in optical property derivations from these datasets. To improve this situation for the sixth phase of the Coupled Model Intercomparison Project (CMIP6), a two-step process was undertaken. First, a combined stratospheric aerosol dataset, the Global Space-based Stratospheric Aerosol Climatology (GloSSAC; 1979–2016), was constructed. Next, GloSSAC, along with information from ice cores and Sun photometers, was used to generate aerosol distributions, characteristics and optical properties to construct a more consistent stratospheric aerosol forcing dataset for models participating in CMIP6. This “version 3” of the stratospheric aerosol forcing has been endorsed for use in all contributing CMIP6 simulations. Recent updates to the underlying GloSSAC from version 1 to version 1.1 affected the 1991–1994 period and necessitated an update to themore » stratospheric aerosol forcing from version 3 to version 4. As version 3 remains the official CMIP6 input, quantification of the impact on radiative forcing and climate is both relevant and timely for interpreting results from experiments such as the CMIP6 historical simulations. This study uses two models, the Canadian Earth System Model version 5 (CanESM5) and the Energy Exascale Earth System Model (E3SM) Atmosphere Model version 1 (EAMv1), to estimate the difference in instantaneous radiative forcing in simulated post-Pinatubo climate response when using version 4 instead of version 3. Differences in temperature, precipitation and radiative forcings are generally found to be small compared to internal variability. An exception to this is differences in monthly temperature anomalies near 24 km altitude in the tropics, which can be as large as 3 °C following the eruption of Mt. Pinatubo.« less

Authors:

Rieger, Landon A.  ^[1];

• Search DOE PAGES for author "Rieger, Landon A."
• Search DOE PAGES for ORCID "0000-0002-9980-7095"

Cole, Jason N. S.  ^[2];

• Search DOE PAGES for author "Cole, Jason N. S."
• Search DOE PAGES for ORCID "0000-0003-0450-2748"

Fyfe, John C. ^[2]; Po-Chedley, Stephen  ^[3];

• Search DOE PAGES for author "Po-Chedley, Stephen"
• Search DOE PAGES for ORCID "0000-0002-0390-238X"

Cameron-Smith, Philip J. ^[3]; Durack, Paul J.  ^[3];

• Search DOE PAGES for author "Durack, Paul J."
• Search DOE PAGES for ORCID "0000-0003-2835-1438"

Gillett, Nathan P.  ^[2];

• Search DOE PAGES for author "Gillett, Nathan P."
• Search DOE PAGES for ORCID "0000-0002-2957-0002"

Tang, Qi  ^[3]

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• Search DOE PAGES for ORCID "0000-0003-2959-0203"

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+ Show Author Affiliations

1. Univ. of Saskatchewan, Saskatoon, SK (Canada)
2. Environment Canada, Victoria, BC (Canada)
3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:

Fri Oct 09 00:00:00 EDT 2020

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Laboratory Directed Research and Development (LDRD) Program

OSTI Identifier:

1673200

Report Number(s):

LLNL-JRNL-800287
Journal ID: ISSN 1991-9603; 1003696

Grant/Contract Number:  

AC52-07NA27344; 18-ERD-054

Resource Type:

Accepted Manuscript

Journal Name:

Geoscientific Model Development (Online)

Additional Journal Information:

Journal Name: Geoscientific Model Development (Online); Journal Volume: 13; Journal Issue: 10; Journal ID: ISSN 1991-9603

Publisher:

European Geosciences Union

Country of Publication:

United States

Language:

English

Subject:

58 GEOSCIENCES