Attribution of 2012 extreme climate events: does air-sea interaction matter?
Attribution of 2012 extreme climate events: does air-sea interaction matter?
复制标题
DOI：
10.1007/s00382-020-05321-3
复制
发表时间：
2020-06
期刊：
影响因子：
4.6
通讯作者：
B. Dong;R. Sutton;L. Shaffrey;L. Wilcox
中科院分区：
文献类型：
--
作者：
B. Dong;R. Sutton;L. Shaffrey;L. Wilcox
2012年，全球出现极端异常气候状况。北美大片地区经历了异常炎热的夏季，降水量严重不足，导致严重干旱。在欧洲，2012 年夏季出现了强烈的降水异常，英国经历了 1912 年以来最潮湿的夏季，而西班牙则遭受严重干旱。是什么原因导致2012年各地出现极端气候状况？本研究基于两组不同模型配置（耦合海洋混合层模型或指定海面温度）的平行实验，比较了2012年气候异常相对于基准期（1964-1981）的归因结论，以评估2012年气候异常的归因结论是否对海气相互作用的表征敏感。模拟结果表明，北半球冬季和夏季大规模地表气温（SAT）变化的归因结论通常是稳健的，并且对海气相互作用不太敏感。在南欧、欧亚大陆、北美、南美和北非尤其如此。其他一些反应似乎也对海气相互作用不敏感：例如，北欧和萨赫勒地区的降水量被迫增加，北半球夏季北美和亚马逊地区的降水量减少。然而，其他一些地区的环流和降水变化的归因表现出对海气相互作用的敏感性。包括与海洋混合层模型耦合在内的实验结果表明，北半球冬季大西洋扇区出现类似 NAO 的正环流响应，而东亚夏季风和东亚降水变化较弱。在规定的海面温度下，这两个区域会出现一些不同的反应。与观测变化的比较表明，耦合模拟总体上与观测吻合较好，说明基于大气环流模型的归因方法存在局限性，可能导致对区域环流、降水和地表气温异常的错误归因结论。
In 2012, extreme anomalous climate conditions occurred around the globe. Large areas of North America experienced an anomalously hot summer, with large precipitation deficits inducing severe drought. Over Europe, the summer of 2012 was marked by strong precipitation anomalies with the UK experiencing its wettest summer since 1912 while Spain suffered severe drought. What caused these extreme climate conditions in various regions in 2012? This study compares attribution conclusions for 2012 climate anomalies relative to a baseline period (1964–1981) based on two sets of parallel experiments with different model configurations (with coupling to an ocean mixed layer model or with prescribed sea surface temperatures) to assess whether attribution conclusions concerning the climate anomalies in 2012 are sensitive to the representation of air-sea interaction. Modelling results indicate that attribution conclusions for large scale surface air temperature (SAT) changes in both boreal winter and summer are generally robust and not very sensitive to air-sea interaction. This is especially true over southern Europe, Eurasia, North America, South America, and North Africa. Some other responses also appear to be insensitive to air-sea interaction: for example, forced increases in precipitation over northern Europe and Sahel, and reduced precipitation over North America and the Amazon in boreal summer. However, the attribution of circulation and precipitation changes for some other regions exhibits a sensitivity to air-sea interaction. Results from the experiments including coupling to an ocean mixed layer model show a positive NAO-like circulation response in the Atlantic sector in boreal winter and weak changes in the East Asian summer monsoon and precipitation over East Asia. With prescribed sea surface temperatures, some different responses arise over these two regions. Comparison with observed changes indicates that the coupled simulations generally agree better with observations, demonstrating that attribution methods based on atmospheric general circulation models have limitations and may lead to erroneous attribution conclusions for regional anomalies in circulation, precipitation and surface air temperature.