Coordinating Natural Aerosol Simulations

Abstract

Carslaw et al. have argued eloquently and recently (2013) that a major source of uncertainty in our near term understanding of the Earth System lies hidden in the natural background aerosol. The major points may be distilled as follows: Uncertainty deriving from our lack of comprehension of background effects is so large that even the poorly known anthropogenic contribution is overwhelmed.  The pristine-remote aerosol system is complex, involving detailed marine, terrestrial and atmospheric organic chemistries and also their coupling to inorganics through multiphase processes. But due to a confluence of legacy capabilities and new collaborations, the Department of Energy is now uniquely positioned to disentangle some of the critical effects (Elliottetal_ ACME_FD_Poster_48x48_042615a.pdf). We overview detailed mechanisms under development for ACME in the areas of marine-terrestrial POA-SOA emissions (P= Primary and S=Secondary Organic Aerosol respectively). Interactions with other particle classes are included plus the ensuing atmospheric, aerosol and cloud chemical processing. Taken together, current efforts distributed across the complex promise to elucidate major geochemical influences on cloud structure and radiation transfer. Our presentation ranges from oceanic biopolymers in spray, to biomass burning byproducts to terrestrial vegetation emissions of volatile carbon. We propose an orchestrated effort spanning the laboratories, to apply ACME as a tool for quantification of the implied uncertainties. Although less directly related to the radiation budget, we will further extend development and simulations to the chemistry of mineral dust and its ocean fertilization. Our concepts follow logically from the commitment of ACME to soon release marine ecodynamics and carbon cycling, since together these are major drivers on the ocean side. All current simulation themes of DOE Earth System modeling are impacted. Connections with overall global biogeochemistry are clear, plus aerosol-cloud relations play into hydrological cycling and the stability of land ice.