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The Climate Response to Stratospheric Aerosol Geoengineering Can Be Tailored Using Multiple Injection Locations

MacMartin, Douglas G. and Kravitz, Ben and Tilmes, Simone and Richter, Jadwiga H. and Mills, Michael J. and Lamarque, Jean-Francois and Tribbia, Joseph J. and Vitt, Francis (2017) The Climate Response to Stratospheric Aerosol Geoengineering Can Be Tailored Using Multiple Injection Locations. Journal of Geophysical Research. Atmospheres, 122 (23). pp. 12574-12590. ISSN 2169-897X. doi:10.1002/2017JD026868.

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By injecting different amounts of SO_2 at multiple different latitudes, the spatial pattern of aerosol optical depth (AOD) can be partially controlled. This leads to the ability to influence the climate response to geoengineering with stratospheric aerosols, providing the potential for design. We use simulations from the fully coupled whole-atmosphere chemistry climate model CESM1(WACCM) to demonstrate that by appropriately combining injection at just four different locations, 30°S, 15°S, 15°N, and 30°N, then three spatial degrees of freedom of AOD can be achieved: an approximately spatially uniform AOD distribution, the relative difference in AOD between Northern and Southern Hemispheres, and the relative AOD in high versus low latitudes. For forcing levels that yield 1–2°C cooling, the AOD and surface temperature response are sufficiently linear in this model so that the response to different combinations of injection at different latitudes can be estimated from single-latitude injection simulations; nonlinearities associated with both aerosol growth and changes to stratospheric circulation will be increasingly important at higher forcing levels. Optimized injection at multiple locations is predicted to improve compensation of CO_2-forced climate change relative to a case using only equatorial aerosol injection (which overcools the tropics relative to high latitudes). The additional degrees of freedom can be used, for example, to balance the interhemispheric temperature gradient and the equator to pole temperature gradient in addition to the global mean temperature. Further research is needed to better quantify the impacts of these strategies on changes to long-term temperature, precipitation, and other climate parameters.

Item Type:Article
Related URLs:
URLURL TypeDescription ItemCompanion Article ItemCompanion Article ItemCompanion Article ItemCompanion Article ItemSimulation output
MacMartin, Douglas G.0000-0003-1987-9417
Kravitz, Ben0000-0001-6318-1150
Tilmes, Simone0000-0002-6557-3569
Richter, Jadwiga H.0000-0001-7048-0781
Mills, Michael J.0000-0002-8054-1346
Lamarque, Jean-Francois0000-0002-4225-5074
Tribbia, Joseph J.0000-0003-1639-9688
Vitt, Francis0000-0002-8684-214X
Additional Information:©2017. American Geophysical Union. Received 30 MAR 2017. Accepted 8 SEP 2017. Accepted article online 6 NOV 2017. Published online 7 DEC 2017. Special Section: Simulations of Stratospheric Sulfate Aerosol Geoengineering with the Whole Atmosphere Community Climate Model (WACCM) This article is a companion to Mills et al. (2017),, Richter et al., (2017),, Kravitz et al. (2017),, and Tilmes et al. (2017), Albert Chu at Cornell assisted in generating the fit in Figure 4d. The CESM project is supported by the National Science Foundation and the Office of Science (BER) of the U.S. Department of Energy. The National Center for Atmospheric Research is sponsored by the National Science Foundation. The Pacific Northwest National Laboratory is operated for the U.S. Department of Energy by Battelle Memorial Institute under contract DE-AC05-76RL01830. Computing resources were provided by the Climate Simulation Laboratory at NCAR's Computational and Information Systems Laboratory (CISL) (Computational and Information Systems Laboratory, 2012), sponsored by the National Science Foundation and other agencies with high-performance computing support from Yellowstone (ark:/85065/d7wd3xhc). This research was developed with funding from the Defense Advanced Research Projects Agency (DARPA). The views, opinions, and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government. Simulation output are available at
Funding AgencyGrant Number
Department of Energy (DOE)DE-AC05-76RL01830
Defense Advanced Research Projects Agency (DARPA)UNSPECIFIED
Subject Keywords:geoengineering; stratospheric aerosols; design
Issue or Number:23
Record Number:CaltechAUTHORS:20180118-133731408
Persistent URL:
Official Citation:MacMartin, D. G., Kravitz, B., Tilmes, S., Richter, J. H., Mills, M. J., Lamarque, J.-F., Tribbia, J. J., & Vitt, F. (2017). The climate response to stratospheric aerosol geoengineering can be tailored using multiple injection locations. Journal of Geophysical Research: Atmospheres, 122, 12,574–12,590.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84391
Deposited By: George Porter
Deposited On:18 Jan 2018 22:57
Last Modified:15 Nov 2021 20:19

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