Stratospheric influence on tropospheric climate change in the Northern Hemisphere
Stratospheric influence on tropospheric climate change in the Northern Hemisphere
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DOI：
10.1029/2011jd017036
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发表时间：
2012-03
影响因子：
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通讯作者：
A. Karpechko;E. Manzini
中科院分区：
文献类型：
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作者：
A. Karpechko;E. Manzini
[1] 通过使用大气环流模型 ECHAM5 进行和分析一组模拟，探讨了平流层在北半球冬季对流层气候对温室气体浓度增加的响应中的作用。值得注意的是低顶模型与平流层解析模型版本之间对二氧化碳浓度加倍以及相关海面温度和海冰浓度异常的响应差异。我们发现，与平流层解析模型相比，低顶模型在冬末时北极海平面压力下降幅度更大。响应对平流层表示的这种依赖性与之前的多模型结果一致，表明不同模型之间的差异可能是稳健的。对流层环流的不同反应可能会产生重要的气候后果；例如，我们在这些实验中展示了欧洲不同的降水响应。不同的对流层响应被证明源自极地平流层的不同响应，这归因于平流层解析模型中更强的布鲁尔-多布森环流响应。布鲁尔-多布森环流响应对解析过程和参数化过程贡献的分解表明，两者都有助于平流层解析模型中极地平流层更强的下降流响应。额外的敏感性实验表明，北极海平面压力响应的大小取决于热带太平洋海温异常的大小，而不是平流层分辨和平流层模型响应之间的差异。
[1] The role of the stratosphere in tropospheric climate response to increased concentrations of the greenhouse gases during Northern Hemisphere winter is addressed by performing and analyzing a set of simulations with the atmosphere general circulation model ECHAM5. Attention is paid to the difference in the response to doubled CO2 concentration and associated sea surface temperature and sea ice concentration anomaly between a low-top and a stratosphere-resolving model version. We find a larger decrease of the Arctic sea level pressure in late winter in the low-top model when compared to the stratosphere-resolving one. Such dependence of the response on the representation of the stratosphere is consistent with previous multimodel results, indicating that the difference is likely robust across different models. The different response of the tropospheric circulation may have important climatic consequences; for example, we demonstrate a different precipitation response over Europe in these experiments. The different tropospheric response is shown to originate from different response in the polar stratosphere which is attributable to a stronger Brewer-Dobson circulation response in the stratosphere-resolving model. A decomposition of the Brewer-Dobson circulation response to contributions from resolved and parameterized processes show that both contribute toward the stronger downwelling response in the polar stratosphere in the stratosphere-resolving model. Additional sensitivity experiments reveal that the magnitude of the Arctic sea level pressure response, but not the difference between the stratosphere-resolving and low-top model responses, depends on the magnitude of SST anomaly in the tropical Pacific.