The Effect of Anthropogenic Aerosols on the Aleutian Low
The Effect of Anthropogenic Aerosols on the Aleutian Low
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DOI：
10.1175/jcli-d-20-0423.1
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发表时间：
2020-11
影响因子：
4.9
通讯作者：
William J. Dow;A. Maycock;M. Löfverström;Christopher J. Smith
中科院分区：
文献类型：
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作者：
William J. Dow;A. Maycock;M. Löfverström;Christopher J. Smith
过去的研究表明，人为气溶胶的区域趋势可以通过调制阿留申低压来影响太平洋年代际振荡（PDO）。然而，这种连接的鲁棒性是有争议的。这项研究分析了阿留申低的变化，强迫与大，理想化的全球和区域黑碳（BC）和硫酸盐气溶胶扰动的气候模式的合奏。为了分离海洋反馈的作用，实验是在相互作用的海洋和规定的海面温度下进行的。结果表明，一个强大的阿留申低压的削弱迫使全球十倍增加BC在两个实验配置。一个线性化的稳态原始方程模式被迫与非绝热加热异常调查的机制，通过加热BC排放影响阿留申低。印度和东亚地区的BC吸收加热产生Rossby波列，传播到北太平洋地区，形成对流层上部的脊。东亚以外的BC来源增强了阿留申低压的减弱。对亚洲硫酸盐气溶胶全球5倍和区域10倍增加的响应在气候模式间表现出较差的一致性，多模式平均响应并不强烈投射到阿留申低压。这些发现的一个大的，理想的步骤增加区域硫酸盐气溶胶不同于以往的研究表明，在亚洲上空的硫酸盐气溶胶的短暂增加，在世纪初削弱了阿留申低压，并诱导过渡到一个负PDO阶段。
Past studies have suggested that regional trends in anthropogenic aerosols can influence the Pacific decadal oscillation (PDO) through modulation of the Aleutian low. However, the robustness of this connection is debated. This study analyzes changes to the Aleutian low in an ensemble of climate models forced with large, idealized global and regional black carbon (BC) and sulfate aerosol perturbations. To isolate the role of ocean feedbacks, the experiments are performed with an interactive ocean and with prescribed sea surface temperatures. The results show a robust weakening of the Aleutian low forced by a global tenfold increase in BC in both experiment configurations. A linearized steady-state primitive equation model is forced with diabatic heating anomalies to investigate the mechanisms through which heating from BC emissions influences the Aleutian low. The heating from BC absorption over India and East Asia generates Rossby wave trains that propagate into the North Pacific sector, forming an upper-tropospheric ridge. Sources of BC outside of East Asia enhance the weakening of the Aleutian low. The responses to a global fivefold and regional tenfold increase in sulfate aerosols over Asia show poor consistency across climate models, with a multimodel mean response that does not project strongly onto the Aleutian low. These findings for a large, idealized step increase in regional sulfate aerosol differ from previous studies that suggest the transient increase in sulfate aerosols over Asia during the early twenty-first century weakened the Aleutian low and induced a transition to a negative PDO phase.