Sensitivity of historical climate simulations to uncertain aerosol forcing

Dittus, A. J. ORCID: https://orcid.org/0000-0001-9598-6869, Hawkins, E. ORCID: https://orcid.org/0000-0001-9477-3677, Wilcox, L. J. ORCID: https://orcid.org/0000-0001-5691-1493, Sutton, R. ORCID: https://orcid.org/0000-0001-8345-8583, Smith, C. J., Andrews, M. B. and Forster, P. M. (2020) Sensitivity of historical climate simulations to uncertain aerosol forcing. Geophysical Research Letters, 47 (13). e2019GL085806. ISSN 0094-8276 doi: 10.1029/2019GL085806

Abstract/Summary

The relative importance of anthropogenic aerosol in decadal variations of historical climate is uncertain, largely due to uncertainty in aerosol radiative forcing. We analyse a novel large ensemble of simulations with HadGEM3-GC3.1 for 1850-2014, where anthropogenic aerosol and precursor emissions are scaled to sample a wide range of historical aerosol radiative forcing with present-day values ranging from -0.38 to -1.50 Wm-2. Five ensemble members are run for each of five aerosol scaling factors. Decadal variations in surface temperatures are strongly sensitive to aerosol forcing, particularly between 1950 and 1980. Post-1980, trends are dominated by greenhouse-gas forcing, with much lower sensitivity to aerosol emission differences. Most realisations with aerosol forcing more negative than about -1 Wm-2 simulate stronger cooling trends in the mid-twentieth century compared to observations, while the simulated warming post-1980 always exceeds observed warming, likely due to a warm bias in the Transient Climate Response in HadGEM3-GC3.1.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/90549
Identification Number/DOI	10.1029/2019GL085806
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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