Skilful predictions of the winter North Atlantic Oscillation one year ahead
Skilful predictions of the winter North Atlantic Oscillation one year ahead
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DOI：
10.1038/ngeo2824
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发表时间：
2016-11-01
影响因子：
18.3
通讯作者：
Knight, Jeff
中科院分区：
文献类型：
--
作者：
Dunstone, Nick;Smith, Doug;Knight, Jeff
冬季北大西洋涛动是北大西洋地区大气变化的主要模式，对欧洲和北美的冬季气候有深远的影响。直到最近，北大西洋涛动的季节变化被认为在很大程度上是由混乱和内在不可预测的过程驱动的(1，2)。然而，最新一代季节性预报系统在冬季来临前一个月(3-5个月)启动时，已显示出预测北大西洋涛动的显著技能。在这里，我们将巧妙的动力学模型预测延长到一年多以后。由于模式中的信噪比低得令人难以置信，因此随着集合大小的增加，技能大大增加，因此更大的集合预计将进一步提高预测北大西洋涛动的技能。我们确定了北大西洋涛动第二个冬季预报的两个技能来源：热带太平洋地区的气候变异性和太阳强迫对平流层极涡强度的可预测影响。我们还确定了北冰洋海冰中的模型偏差，如果减少，可能会进一步提高技能。我们的结果为一系列新的气候服务打开了可能性，包括交通(6，7)、能源、水管理(8)和保险部门。
The winter North Atlantic Oscillation is the primary mode of atmospheric variability in the North Atlantic region and has a profound influence on European and North American winter climate. Until recently, seasonal variability of the North Atlantic Oscillation was thought to be largely driven by chaotic and inherently unpredictable processes(1,2). However, latest generation seasonal forecasting systems have demonstrated significant skill in predicting the North Atlantic Oscillation when initialized a month before the onset of winter(3-5). Here we extend skilful dynamical model predictions to more than a year ahead. The skill increases greatly with ensemble size due to a spuriously small signal-to-noise ratio in the model, and consequently larger ensembles are projected to further increase the skill in predicting the North Atlantic Oscillation. We identify two sources of skill for second-winter forecasts of the North Atlantic Oscillation: climate variability in the tropical Pacific region and predictable effects of solar forcing on the stratospheric polar vortex strength. We also identify model biases in Arctic sea ice that, if reduced, may further increase skill. Our results open possibilities for a range of new climate services, including for the transport(6,7), energy, water management(8) and insurance sectors.