Nonlinearity of ocean heat uptake during warming and cooling in the FAMOUS climate model
Nonlinearity of ocean heat uptake during warming and cooling in the FAMOUS climate model
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DOI：
10.1002/2014gl062807
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发表时间：
2015-04-16
影响因子：
5.2
通讯作者：
Lowe, J. A.
中科院分区：
文献类型：
--
作者：
Bouttes, N.;Good, P.;Lowe, J. A.
大气中的二氧化碳浓度预计将在未来几十年继续上升，但自然或人为过程最终可能会降低它。我们表明，在FAMOUS大气-海洋环流模式中，随着辐射强迫的减少，海洋热含量的减少比对施加强迫响应的线性模式模拟所期望的要大。我们将这种效应与大西洋经向翻转环流（AMOC）的行为联系起来：大西洋经向翻转环流强时，海洋冷却效率更高。AMOC随着CO2的上升而减弱，然后随着CO2的下降而增强，但暂时超过了其原始强度。这种非线性主要来自北大西洋积累的盐平流，这使系统具有更长的记忆。这意味着观测到的针对不同二氧化碳情景或不同初始状态的变化，例如来自过去变化的变化，可能不是进行预估的可靠基础。
Atmospheric CO2 concentration is expected to continue rising in the coming decades, but natural or artificial processes may eventually reduce it. We show that, in the FAMOUS atmosphere-ocean general circulation model, the reduction of ocean heat content as radiative forcing decreases is greater than would be expected from a linear model simulation of the response to the applied forcings. We relate this effect to the behavior of the Atlantic meridional overturning circulation (AMOC): the ocean cools more efficiently with a strong AMOC. The AMOC weakens as CO2 rises, then strengthens as CO2 declines, but temporarily overshoots its original strength. This nonlinearity comes mainly from the accumulated advection of salt into the North Atlantic, which gives the system a longer memory. This implies that changes observed in response to different CO2 scenarios or from different initial states, such as from past changes, may not be a reliable basis for making projections.