Recent advances in measurement-based insights of secondary organic aerosols and their impact on global climate sensitivity
Abstract
Anthropogenic emissions and land-use changes have modified organic aerosol (OA) concentrations and size distributions over time. Understanding background (pre-industrial) OA concentrations and changes in OA over time due to anthropogenic activities is important because these variations 1) influence estimates of aerosol radiative forcing and 2) confound our estimates of the historical response to climate increases in greenhouse gases (e.g. the `climate sensitivity'). Secondary organic aerosols (SOA) represent a major fraction of submicron size atmospheric OA in many regions of the world. Current climate models employ very-crude treatments that do not include important SOA-relevant processes. Over the past decade, significant advances in our understanding of SOA properties, and formation mechanisms have occurred through a combination of laboratory/field measurements and process-level modeling. We summarize the discussion from a recent workshop on SOA, highlighting some of the important emerging advances that could impact our understanding of aerosol radiative forcing and climate. The importance of some recently discovered processes such as formation of extremely low volatility organics (ELVOCs), isoprene epoxydiols (IEPOX) chemistry, particle-phase oligomerization, and potential diffusion-limitations in particles are described. Significant gaps remain in our understanding of SOA, which can be addressed through integrated modeling-measurement approaches. We highlight the importance of combining bottom-up information on the molecular speciation of SOA precursors with top-down insights on the size-evolution dynamics of SOA. Additional research is needed to rank the most influential processes affecting SOA to help guide future measurement and modeling efforts. Our goal is to foster discussions on how community efforts may be combined and coordinated to more rapidly address the remaining uncertainties in our understanding of SOA climate effects.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.A43N..07S
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3311 Clouds and aerosols;
- ATMOSPHERIC PROCESSESDE: 3337 Global climate models;
- ATMOSPHERIC PROCESSESDE: 3275 Uncertainty quantification;
- MATHEMATICAL GEOPHYSICS