Arctic temperature responses to East Asian and European anthropogenic organic carbon emissions: impacts of externally vs internally mixed aerosols

Fully coupled equilibrium simulations have been performed using the NASA Goddard Institute of Space Sciences (GISS) Earth system model (GISS-E2.1.2), where the East Asian and European land-based anthropogenic organic carbon (OC) emissions have been perturbed by five and seven times, respectively. GISS-E2.1.2 has been driven by the Coupled Model Intercomparison Project Phase 6 (CMIP6) anthropogenic emissions. GISS-E2.1.2 simulations have been performed using both the one moment aerosol (OMA) and the Multiconfiguration Aerosol TRacker of mIXing state (MATRIX) aerosol models, respectively, to quantify the impact of aerosol optical properties and the mixing state assumptions, i.e., external mixing in OMA vs internal mixing in MATRIX. 70 years of baseline and perturbation simulations have been performed for the year 2000 using a 5-member ensemble, where the last 30 years of simulations have been used for analyses.

In the present study, we will present the impact of the aerosol optical properties and mixing state on the OC and black carbon (BC) burdens and lifetimes, as well as the Arctic surface temperature response to the East Asian and European OC emissions in the form of regional temperature potentials (RTP). The preliminary results showed the OMA model simulated a general decrease in the global surface temperatures in response to the East Asian OC emissions, with no statistically significant response over the Arctic, while the MATRIX model showed increases over the globe, including statistically significant increases over the Arctic. Overall, the Arctic RTP in response to the East Asian OC emissions are -0.02 K Tg^-1 and +0.00003 K Tg^-1 using the OMA and MATRIX aerosol models, respectively.