Model-measurement comparisons over the Southern Ocean indicate a missing source of remote marine aerosols
Abstract
Measurements taken in remote near-pristine environments such as the Southern Ocean offer the rare opportunity to understand what aerosols may have been like in the pre-industrial atmosphere. We compare global climate model output to measurements made on the Antarctic Circumnavigation Expedition (ACE-SPACE). We use a sample of around 1 million variants of the HadGEM aerosol-climate model that account for the uncertainties in 26 aerosol emission, process and deposition parameters and rule out model variants that are deemed observationally implausible when compared to the ACE-SPACE measurements. Model variants that compare well to the measurements have very high natural aerosol emissions and low removal rates. These values are often at the extremes of the parameter ranges defined through expert elicitation. Despite sampling many important causes of aerosol uncertainty, we identify some measurements that are not simulated well by any of the model variants. This model-measurement comparison suggests there are missing sources of remote marine aerosols that need to be included in models. It also implies that the strongest pre-industrial to present-day aerosol radiative forcings (associated with low natural aerosol conditions) are observationally implausible.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A13G2530R
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0320 Cloud physics and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3310 Clouds and cloud feedbacks;
- ATMOSPHERIC PROCESSESDE: 3349 Polar meteorology;
- ATMOSPHERIC PROCESSES