The impacts of aerosol emissions on historical climate in ukesm1

Seo, Jeongbyn and Shim, Sungbo and Kwon, Sang Hoon and Boo, Kyung On and Kim, Yeon Hee and O’connor, Fiona and Johnson, Ben and Dalvi, Mohit and Folberth, Gerd and Teixeira, Joao and Mulcahy, Jane and Hardacre, Catherine and Turnock, Steven and Woodward, Stephanie and Abraham, Luke and Keeble, James and Griffiths, Paul and Archibald, Alex and Richardson, Mark and Dearden, Chris and Carslaw, Ken and Williams, Jonny and Zeng, Guang and Morgenstern, Olaf (2020) The impacts of aerosol emissions on historical climate in ukesm1. Atmosphere, 11 (10): 1095. ISSN 2073-4433

Abstract

As one of the main drivers for climate change, it is important to understand changes in anthropogenic aerosol emissions and evaluate the climate impact. Anthropogenic aerosols have affected global climate while exerting a much larger influence on regional climate by their short lifetime and heterogeneous spatial distribution. In this study, the effective radiative forcing (ERF), which has been accepted as a useful index for quantifying the effect of climate forcing, was evaluated to understand the effects of aerosol on regional climate over a historical period (1850–2014). Eastern United States (EUS), Western European Union (WEU), and Eastern Central China (ECC), are regions that predominantly emit anthropogenic aerosols and were analyzed using Coupled Model Intercomparison Project 6 (CMIP6) simulations implemented within the framework of the Aerosol Chemistry Model Intercomparison Project (AerChemMIP) in the UK’s Earth System Model (UKESM1). In EUS and WEU, where industrialization occurred relatively earlier, the negative ERF seems to have been recovering in recent decades based on the decreasing trend of aerosol emissions. Conversely, the radiative cooling in ECC seems to be strengthened as aerosol emission continuously increases. These aerosol ERFs have been largely attributed to atmospheric rapid adjustments, driven mainly by aerosol-cloud interactions rather than direct effects of aerosol such as scattering and absorption.