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Ocean Dynamics as Driver of Seasonal to Decadal European Atmospheric variability (ODYSEA)

海洋动力学作为欧洲大气季节到十年变化的驱动因素（ODYSEA）

基本信息

批准号：
NE/M006085/1
负责人：
David Brayshaw
金额：
$ 32.04万
依托单位：
University of Reading
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FM006085%2F1
关键词：
Ocean Dynamics Driver Seasonal Decadal

项目摘要

ODYSEA will assess how, when, and where the ocean affects atmospheric variability and weather in Europe and in particular in the UK on timescales up to a decade. Particular emphasis will be on the identification of oceanic precursors that indicate the development of unusually warm, cold, dry or wet conditions several months or years in advance, especially related to extreme weather events. Such precursors can include changes in the ocean surface temperature or in the position of major ocean currents such as the Gulf Stream.On a climatological level, the large heat capacity of the Atlantic ocean acts to moderate the seasonal cycle of temperature over Western Europe. The Atlantic also provides much of the moisture precipitating over Europe, including the recent widespread flooding in the UK in late 2013/early 2014. Together, the circulation of the ocean and the atmosphere act to reduce the temperature difference between low and high latitudes by carrying heat polewards from the tropics. In the Atlantic, the meridional overturning circulation (MOC) transports heat northward at a rate of more than 1000 Terawatts (TW) - equivalent to the energy produced by 1,000,000 average sized nuclear power stations. This heat transport leads to an additional warming of Western Europe that is present throughout the year and temperatures in Western Europe are on average higher than at similar latitudes in the maritime climate of Northwest America. Both theoretical arguments and GCM simulations suggest that ocean poleward heat transports are capable of having very profound impacts on the atmospheric storm tracks which are responsible for much of the day-to-day variability in European weather. Such changes may also influence the pathways of the proposed "teleconnections" that link atmospheric variability in remote regions to the European continent. In ODYSEA we will therefore investigate how variability in the ocean circulation modulates the atmospheric circulation and its impact on Europe. Research suggests that meanders of the Gulf Stream affect the atmosphere in a region that is key to the formation of North Atlantic Storms. The MOC has also been shown to be highly variable with likely impacts on ocean surface temperatures. This affects the amount of heat released to the atmosphere overlying the ocean, but also the atmospheric circulation through which oceanic heat and moisture is carried towards the continents. A recent study performed at NOC suggests that anomalies of surface ocean temperatures were key to the development of the atmospheric conditions that led to the extremely cold December of 2010. These anomalous ocean surface temperatures were preceded by a particularly weak MOC in 2009. In ODYSEA we will establish if similar oceanic impacts can be identified for previous weather extremes that have affected Europe and the UK (e.g. wet summers of 2005, 2007 and 2012, the heat waves in the summer of 2003 and of July 2006). Emphasis will be on acquiring a better understanding of the mechanisms through which the ocean can impact the atmosphere and therefore our weather and climate. Current knowledge strongly suggests that the ocean affects variability of European weather and climate on timescales of months to years, but the underlying mechanisms are far from fully understood. This hampers prediction and attribution of those events. ODYSEA will reduce this gap in our understanding of the variability of UK/European weather and climate by using cutting edge ocean and atmosphere models available in the UK as well as by analysing data from the latest seasonal to decadal forecasting systems run by the UK Met Office.

奥迪西将评估海洋如何、何时和在哪里影响欧洲，特别是英国的大气变异性和天气，时间尺度长达十年。将特别强调查明海洋前兆，这些前兆表明异常温暖、寒冷、干燥或潮湿的状况提前几个月或几年出现，特别是与极端天气事件有关。这些前兆可以包括海洋表面温度的变化或主要洋流位置的变化，如墨西哥湾流。在气候学层面上，大西洋的巨大热容量起到了缓和西欧温度季节性循环的作用。大西洋也提供了欧洲上空的大部分降水，包括最近2013年底/2014年初英国发生的大范围洪水。海洋和大气的环流共同作用，通过携带热带地区的热量来缩小低纬度和高纬度之间的温差。在大西洋，经向翻转环流(MOC)以超过1000太瓦(TW)的速度向北输送热量-相当于100万个平均规模的核电站产生的能量。这种热传输导致西欧全年都在变暖，西欧的平均气温高于美洲西北部海洋性气候中类似纬度的温度。理论论证和GCM模拟都表明，海洋极地热量输送能够对大气风暴路径产生非常深远的影响，而大气风暴路径是欧洲天气日变化的主要原因。这种变化还可能影响拟议的将偏远地区的大气可变性与欧洲大陆联系起来的“远程联系”的路径。因此，在奥迪西，我们将调查海洋环流的变化如何调节大气环流及其对欧洲的影响。研究表明，墨西哥湾流的曲折影响了该地区的大气，而该地区是北大西洋风暴形成的关键。MOC也被证明是高度可变的，可能会对海洋表面温度产生影响。这不仅会影响向海洋上方的大气释放的热量，还会影响将海洋热量和水分输送到大陆的大气环流。NOC最近进行的一项研究表明，表层海洋温度的异常是导致2010年12月极端寒冷的大气条件发展的关键。在这些异常的海洋表面温度之前，2009年出现了一个特别弱的MOC。在奥迪西，我们将确定以前影响欧洲和英国的极端天气(例如2005年、2007年和2012年的潮湿夏季、2003年夏季和2006年7月的热浪)是否可以确定类似的海洋影响。重点将放在更好地了解海洋可以影响大气层从而影响我们的天气和气候的机制上。目前的知识有力地表明，海洋在几个月到几年的时间尺度上影响欧洲天气和气候的可变性，但其潜在机制远未完全了解。这妨碍了对这些事件的预测和归因。奥迪西将通过使用英国现有的尖端海洋和大气模式，以及通过分析英国气象局运行的最新季节到十年预报系统的数据，缩小我们对英国/欧洲天气和气候变异性的理解的差距。