Uncertainty in aerosol radiative forcing impacts the simulated global monsoon in the 20th century

Shonk, J. K. P., Turner, A. G. ORCID: https://orcid.org/0000-0002-0642-6876, Chevuturi, A. ORCID: https://orcid.org/0000-0003-2815-7221, Wilcox, L. J. ORCID: https://orcid.org/0000-0001-5691-1493, Dittus, A. J. ORCID: https://orcid.org/0000-0001-9598-6869 and Hawkins, E. ORCID: https://orcid.org/0000-0001-9477-3677 (2020) Uncertainty in aerosol radiative forcing impacts the simulated global monsoon in the 20th century. Atmospheric Chemistry and Physics Discussions, 20 (23). pp. 14903-14915. ISSN 1680-7375 doi: 10.5194/acp-20-14903-2020

Abstract/Summary

Anthropogenic aerosols are dominant drivers of historical monsoon rainfall change. However, large uncertainties in the radiative forcing associated with anthropogenic aerosol emissions, and the dynamical response to this forcing, lead to uncertainty in the simulated monsoon response. We use historical simulations in which aerosol emissions are scaled by factors from 0.2 to 1.5 to explore the monsoon sensitivity to aerosol forcing uncertainty (−0.38 W m−2 to −1.50 W m−2). Hemispheric asymmetry in emissions generates a strong relationship between scaling factor and both hemispheric temperature contrast and meridional location of tropical rainfall. Increasing the scaling from 0.2 to 1.5 reduces the global monsoon area by 3 % and the global monsoon intensity by 2 % over the period 1950–2014, and switches the dominant influence on the 1950–1980 monsoon rainfall trend between greenhouse gas and aerosol. Regionally, aerosol scaling has a pronounced effect on Northern Hemisphere monsoon rainfall.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/91405
Item Type	Article
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Copernicus Publications
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