Evaluating Advanced Aerosol Activation Treatments in a Coupled Climate/Mixing-State Resolving Aerosol Model
Using off-line calculations with a detailed numerical parcel model and output from a coupled climate-aerosol model which resolves mixing between sulfate and both black/organic carbon species, it has been shown that existing activation parameterizations can over-predict the CDNC by 50% in highly anthropogenically-polluted conditions. We re-evaluate these error metrics using a new iteration of advanced activation parameterizations which have been corrected for kinetic/inertial limits on droplet growth and tuned to use a more realistic condensation coefficient. In addition, we present a new activation parameterization and framework built by emulating a detailed numerical parcel with globally-approximating polynomials; against our parcel model as a metric, the emulator performs better than other complex activation parameterizations and reduces biases in CDNC in the global average.
Finally, the impact each parameterization has on the coupled model's total aerosol indirect effect is evaluated.