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Title: Shortwave radiative forcing, rapid adjustment, and feedback to the surface by sulfate geoengineering: analysis of the Geoengineering Model Intercomparison Project G4 scenario

Abstract

This paper evaluates the forcing, rapid adjustment, and feedback of net shortwave radiation at the surface in the G4 experiment of the Geoengineering Model Intercomparison Project by analysing outputs from six participating models. G4 involves injection of 5 Tg yr -1 of SO 2, a sulfate aerosol precursor, into the lower stratosphere from year 2020 to 2069 against a background scenario of RCP4.5. A single-layer atmospheric model for shortwave radiative transfer is used to estimate the direct forcing of solar radiation management (SRM), and rapid adjustment and feedbacks from changes in the water vapour amount, cloud amount, and surface albedo (compared with RCP4.5). The analysis shows that the globally and temporally averaged SRM forcing ranges from -3.6 to -1.6 W m -2, depending on the model. The sum of the rapid adjustments and feedback effects due to changes in the water vapour and cloud amounts increase the downwelling shortwave radiation at the surface by approximately 0.4 to 1.5 W m -2 and hence weaken the effect of SRM by around 50 %. The surface albedo changes decrease the net shortwave radiation at the surface; it is locally strong (~-4 W m -2) in snow and sea ice melting regions, but minor for the global average. The analysesmore » show that the results of the G4 experiment, which simulates sulfate geoengineering, include large inter-model variability both in the direct SRM forcing and the shortwave rapid adjustment from change in the cloud amount, and imply a high uncertainty in modelled processes of sulfate aerosols and clouds.« less

Authors:
 [1];  [2];  [2];  [2];  [3];  [3];  [4]; ORCiD logo [5]
  1. Japan Agency for Marine-Earth Science and Technology, Yokohama (Japan); Kobe Univ., Kobe (Japan)
  2. Japan Agency for Marine-Earth Science and Technology, Yokohama (Japan)
  3. Beijing Normal Univ., Beijing (China). College of Global Change and Earth System Science
  4. Environment and Climate Change Canada, Victoria, BC (Canada). Canadian Centre for Climate Modelling and Analysis
  5. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Sciences and Global Change Division
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1358481
Report Number(s):
PNNL-SA-118834
Journal ID: ISSN 1680-7324
Grant/Contract Number:
AC05-76RL01830
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Atmospheric Chemistry and Physics (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 17; Journal Issue: 5; Journal ID: ISSN 1680-7324
Publisher:
European Geosciences Union
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES

Citation Formats

Kashimura, Hiroki, Abe, Manabu, Watanabe, Shingo, Sekiya, Takashi, Ji, Duoying, Moore, John C., Cole, Jason N. S., and Kravitz, Ben. Shortwave radiative forcing, rapid adjustment, and feedback to the surface by sulfate geoengineering: analysis of the Geoengineering Model Intercomparison Project G4 scenario. United States: N. p., 2017. Web. doi:10.5194/acp-17-3339-2017.
Kashimura, Hiroki, Abe, Manabu, Watanabe, Shingo, Sekiya, Takashi, Ji, Duoying, Moore, John C., Cole, Jason N. S., & Kravitz, Ben. Shortwave radiative forcing, rapid adjustment, and feedback to the surface by sulfate geoengineering: analysis of the Geoengineering Model Intercomparison Project G4 scenario. United States. doi:10.5194/acp-17-3339-2017.
Kashimura, Hiroki, Abe, Manabu, Watanabe, Shingo, Sekiya, Takashi, Ji, Duoying, Moore, John C., Cole, Jason N. S., and Kravitz, Ben. Wed . "Shortwave radiative forcing, rapid adjustment, and feedback to the surface by sulfate geoengineering: analysis of the Geoengineering Model Intercomparison Project G4 scenario". United States. doi:10.5194/acp-17-3339-2017. https://www.osti.gov/servlets/purl/1358481.
@article{osti_1358481,
title = {Shortwave radiative forcing, rapid adjustment, and feedback to the surface by sulfate geoengineering: analysis of the Geoengineering Model Intercomparison Project G4 scenario},
author = {Kashimura, Hiroki and Abe, Manabu and Watanabe, Shingo and Sekiya, Takashi and Ji, Duoying and Moore, John C. and Cole, Jason N. S. and Kravitz, Ben},
abstractNote = {This paper evaluates the forcing, rapid adjustment, and feedback of net shortwave radiation at the surface in the G4 experiment of the Geoengineering Model Intercomparison Project by analysing outputs from six participating models. G4 involves injection of 5 Tg yr-1 of SO2, a sulfate aerosol precursor, into the lower stratosphere from year 2020 to 2069 against a background scenario of RCP4.5. A single-layer atmospheric model for shortwave radiative transfer is used to estimate the direct forcing of solar radiation management (SRM), and rapid adjustment and feedbacks from changes in the water vapour amount, cloud amount, and surface albedo (compared with RCP4.5). The analysis shows that the globally and temporally averaged SRM forcing ranges from -3.6 to -1.6 W m-2, depending on the model. The sum of the rapid adjustments and feedback effects due to changes in the water vapour and cloud amounts increase the downwelling shortwave radiation at the surface by approximately 0.4 to 1.5 W m-2 and hence weaken the effect of SRM by around 50 %. The surface albedo changes decrease the net shortwave radiation at the surface; it is locally strong (~-4 W m-2) in snow and sea ice melting regions, but minor for the global average. The analyses show that the results of the G4 experiment, which simulates sulfate geoengineering, include large inter-model variability both in the direct SRM forcing and the shortwave rapid adjustment from change in the cloud amount, and imply a high uncertainty in modelled processes of sulfate aerosols and clouds.},
doi = {10.5194/acp-17-3339-2017},
journal = {Atmospheric Chemistry and Physics (Online)},
number = 5,
volume = 17,
place = {United States},
year = {Wed Mar 08 00:00:00 EST 2017},
month = {Wed Mar 08 00:00:00 EST 2017}
}

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