Extratropical Influence on ITCZ Shifts in Slab Ocean Simulations of Global Warming
Extratropical Influence on ITCZ Shifts in Slab Ocean Simulations of Global Warming
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DOI：
10.1175/jcli-d-11-00116.1
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发表时间：
2012-01-15
影响因子：
4.9
通讯作者：
Hwang, Yen-Ting
中科院分区：
文献类型：
--
作者：
Frierson, Dargan M. W.;Hwang, Yen-Ting
最近的气候模式研究表明，热带外强迫的力量导致热带辐合带（ITCZ）向北或向南移动，古气候数据支持ITCZ随时间推移发生大规模移动的观点。结果表明，类似的概念适用于板海洋模拟全球变暖。九个板块海洋模型模拟从不同的模拟中心显示了广泛的ITCZ的变化，在响应加倍的二氧化碳浓度，这是经历了一个相当纬向对称的方式在热带地区。使用基于基本能量约束的归因策略，结果表明热带外云和冰的响应解释了ITCZ响应的大部分范围。由于新ITCZ位置的水汽含量增加和高云，热带内也有一些正反馈，这放大了热带外的变化。这项研究表明，具有保真度的模拟热带外气候响应的明显重要性，因为除了他们的本地重要性，这些气候响应的影响有很大的非本地影响在热带地区的降雨。
Recent studies with climate models have demonstrated the power of extratropical forcing in causing the intertropical convergence zone (ITCZ) to shift northward or southward, and paleoclimate data support the notion that there have been large shifts in the ITCZ over time. It is shown that similar notions apply to slab ocean simulations of global warming. Nine slab ocean model simulations from different modeling centers show a wide range of ITCZ shifts in response to doubling carbon dioxide concentrations, which are experienced in a rather zonally symmetric way in the tropics. Using an attribution strategy based on fundamental energetic constraints, it is shown that responses of clouds and ice in the extratropics explain much of the range of ITCZ responses. There are also some positive feedbacks within the tropics due to increasing water vapor content and high clouds in the new ITCZ location, which amplify the changes driven from the extratropics. This study shows the clear importance of simulating extratropical climate responses with fidelity, because in addition to their local importance, the impacts of these climate responses have a large nonlocal impact on rainfall in the tropics.