Present and future aerosol impacts on Arctic climate change in the GISS-E2.1 Earth system model

• Published in: Atmospheric Chemistry and Physics
• Main Authors: U. Im, K. Tsigaridis, G. Faluvegi, P. L. Langen, J. P. French, R. Mahmood, M. A. Thomas, K. von Salzen, D. C. Thomas, C. H. Whaley, Z. Klimont, H. Skov, J. Brandt
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2021
• Subjects: Physics; QC1-999; Chemistry; QD1-999; Arctic; black carbon; Climate change
• Online Access: https://doi.org/10.5194/acp-21-10413-2021; https://doaj.org/article/8254d64649dd4284b127fb868ca72947

The Arctic is warming 2 to 3 times faster than the global average, partly due to changes in short-lived climate forcers (SLCFs) including aerosols. In order to study the effects of atmospheric aerosols in this warming, recent past (1990–2014) and future (2015–2050) simulations have been carried out using the GISS-E2.1 Earth system model to study the aerosol burdens and their radiative and climate impacts over the Arctic ( >60 ∘ N), using anthropogenic emissions from the Eclipse V6b and the Coupled Model Intercomparison Project Phase 6 (CMIP6) databases, while global annual mean greenhouse gas concentrations were prescribed and kept fixed in all simulations. Results showed that the simulations have underestimated observed surface aerosol levels, in particular black carbon (BC) and sulfate ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="6060a0eb6022af681aa55d19b3180df9"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-10413-2021-ie00001.svg" width="29pt" height="17pt" src="acp-21-10413-2021-ie00001.png"/></svg:svg> ), by more than 50 %, with the smallest biases calculated for the atmosphere-only simulations, where winds are nudged to reanalysis data. CMIP6 simulations performed slightly better in reproducing the observed surface aerosol concentrations and climate parameters, compared to the Eclipse simulations. In addition, simulations where atmosphere and ocean are fully coupled had slightly smaller biases in aerosol levels compared to atmosphere-only simulations without nudging. Arctic BC, organic aerosol (OA), and <math ...