Robust winter warming over Eurasia under stratospheric sulfate geoengineering – the role of stratospheric dynamics
Robust winter warming over Eurasia under stratospheric sulfate geoengineering – the role of stratospheric dynamics
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DOI：
10.5194/acp-2020-965
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发表时间：
2020-11
影响因子：
6.3
通讯作者：
A. Banerjee;A. Butler;L. Polvani;A. Robock;I. Simpson;Lantao Sun
中科院分区：
文献类型：
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作者：
A. Banerjee;A. Butler;L. Polvani;A. Robock;I. Simpson;Lantao Sun
摘要。有研究表明，在低纬度大的火山喷发之后，平流层硫酸盐气溶胶负荷的增加可以通过平流层-对流层动力学耦合导致欧亚大陆冬季变暖。我们在此研究了在地球工程大集合模拟中假设的未来平流层硫酸盐地球工程背景下提出的联系。在这些地球工程模拟中，我们发现类似于冬季北环模正相的平流层环流异常是一种独特的气候响应，而当只规定增加温室气体时则不存在这种气候响应。这种平流层动力响应映射到北大西洋涛动的正相位，导致这种气候干预策略的相关副作用，如欧亚大陆变暖和降水变化。季节性是地表动态响应的一个关键特征。我们发现北大西洋涛动在夏季有相反的响应，而在夏季，平流层没有动力作用。冬季强迫反应的稳健性与先前提出的火山反应形成鲜明对比。
Abstract. It has been suggested that increased stratospheric sulfate aerosol loadings following large, low latitude volcanic eruptions can lead to wintertime warming over Eurasia through dynamical stratosphere–troposphere coupling. We here investigate the proposed connection in the context of hypothetical future stratospheric sulfate geoengineering in the Geoengineering Large Ensemble simulations. In those geoengineering simulations, we find that stratospheric circulation anomalies that resemble the positive phase of the Northern Annular Mode in winter are a distinguishing climate response which is absent when increasing greenhouse gases alone are prescribed. This stratospheric dynamical response projects onto the positive phase of the North Atlantic Oscillation, leading to associated side effects of this climate intervention strategy, such as continental Eurasian warming and precipitation changes. Seasonality is a key signature of the dynamically driven surface response. We find an opposite response of the North Atlantic Oscillation in summer, when no dynamical role of the stratosphere is expected. The robustness of the wintertime forced response stands in contrast to previously proposed volcanic responses.