The Critical Role of Ice-nucleation in the Southern Ocean Cloud Radiative Bias.
Abstract
Clouds simulated by climate models in the Southern Ocean region tend to reflect too little solar radiation when compared with satellite observations. This bias in radiative properties has been identified to be mainly produced by the representation of low-level mixed phase clouds in the cold sector of extratropical cyclones. Here, we perform high-resolution simulations with a state-of-the-art double moment microphysics scheme to show that these types of low-level clouds are strongly sensitive to the representation of the concentration of ice-nucleating particles. Specifically, we show that when droplet freezing is suppressed by representing the very low concentration of ice-nucleating particles present in this remote region, our simulated clouds are able to reflect much more sunlight due to the increase in liquid water content, agreeing with satellite observations. These results help to determine and quantify the crucial role that aerosol-cloud interactions through the ice phase have in explaining the Southern Ocean cloud radiative bias.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A13G2528V
- 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