Global and European climate impacts of a slowdown of the AMOC in a high resolution GCM
Global and European climate impacts of a slowdown of the AMOC in a high resolution GCM
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DOI：
10.1007/s00382-015-2540-2
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发表时间：
2015-12-01
期刊：
影响因子：
4.6
通讯作者：
Wood, R. A.
中科院分区：
文献类型：
--
作者：
Jackson, L. C.;Kahana, R.;Wood, R. A.
在一个最先进的全球气候模式(HadGEM3)中评估了假设的大西洋子午线翻转环流(AMOC)减速的影响，其中特别强调了欧洲。这是迄今为止用于研究AMOC放缓影响的最高分辨率耦合全球气候模式。发现的许多结果与之前的研究一致，可以认为是AMOC大幅减少或崩溃带来的强大影响。这些因素包括：整个北大西洋和北半球普遍降温；北半球中纬度地区降水减少；热带地区降水变化较大；北大西洋风暴路径加强。在分辨率提高的帮助下，对欧洲的关注揭示了以前未讨论过的影响，特别是与大气环流模式变化有关的影响。欧洲北部(南部)夏季降水减少(增加)，并与夏季北大西洋涛动负信号有关。冬季降水也受到大气环流变化的影响，随着冬季风暴的增多和冬季风暴路径的加强，降水量局部增加。冬季较强的西风增强了变暖的海洋效应，而夏季较弱的西风减弱了变冷的海洋效应。如果没有这些环流变化，欧洲大陆上的降温在两个季节都会更大。总体降温和大气环流变化导致河流峰值流量和植被生产力减弱，这可能会带来水资源供应和作物生产的问题。
The impacts of a hypothetical slowdown in the Atlantic Meridional Overturning Circulation (AMOC) are assessed in a state-of-the-art global climate model (HadGEM3), with particular emphasis on Europe. This is the highest resolution coupled global climate model to be used to study the impacts of an AMOC slowdown so far. Many results found are consistent with previous studies and can be considered robust impacts from a large reduction or collapse of the AMOC. These include: widespread cooling throughout the North Atlantic and northern hemisphere in general; less precipitation in the northern hemisphere midlatitudes; large changes in precipitation in the tropics and a strengthening of the North Atlantic storm track. The focus on Europe, aided by the increase in resolution, has revealed previously undiscussed impacts, particularly those associated with changing atmospheric circulation patterns. Summer precipitation decreases (increases) in northern (southern) Europe and is associated with a negative summer North Atlantic Oscillation signal. Winter precipitation is also affected by the changing atmospheric circulation, with localised increases in precipitation associated with more winter storms and a strengthened winter storm track. Stronger westerly winds in winter increase the warming maritime effect while weaker westerlies in summer decrease the cooling maritime effect. In the absence of these circulation changes the cooling over Europe's landmass would be even larger in both seasons. The general cooling and atmospheric circulation changes result in weaker peak river flows and vegetation productivity, which may raise issues of water availability and crop production.