Observational analysis of decadal and long-term hydroclimate drivers in the Mediterranean region: role of the ocean–atmosphere system and anthropogenic forcing
Observational analysis of decadal and long-term hydroclimate drivers in the Mediterranean region: role of the ocean–atmosphere system and anthropogenic forcing
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DOI：
10.1007/s00382-021-05765-1
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发表时间：
2021-04
期刊：
影响因子：
4.6
通讯作者：
R. Suárez-Moreno;Y. Kushnir;R. Seager
中科院分区：
文献类型：
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作者：
R. Suárez-Moreno;Y. Kushnir;R. Seager
使用观测和再分析，我们开发了一个强大的统计方法，典型相关分析（CCA）的基础上，探索在历史上，半年雨季的十年和长期地中海水文气候变化的主要驱动因素。因此，进行了一系列的共同国家评估分析与组合，多成分的大规模驱动器的地中海降水和地面气温。结果强调了十年尺度的北大西洋涛动（NAO）作为整个地中海盆地水文气候变化的主要驱动力。值得注意的是，南极-地中海海表温度（SST）的年代际变化，其对地中海气候的影响到目前为止已被提议为仅限于夏季，被发现在冬季半年的季节，以提高NAO引起的水文气候响应。至于长期的，世纪尺度的趋势，人为强迫，表示在全球SST变暖（GW）的信号，强烈与流域范围内的地面气温上升。我们的分析提供了更详细的信息，比迄今为止已经提出的大规模的气候变率在地中海地区的亚季节演变和空间依赖性，分离的自然变率和人为强迫的影响，后者与长期干燥的地区由于全球变暖引起的局部亚热带干旱带向极移动。对这些机制的实际了解对于改进地中海地区十年期和更长时期水文气候演变的模型模拟和预测至关重要，这有助于制定适应战略，减轻气候多变性和变化对脆弱区域人口的影响。
Using observations and reanalysis, we develop a robust statistical approach based on canonical correlation analysis (CCA) to explore the leading drivers of decadal and longer-term Mediterranean hydroclimate variability during the historical, half-year wet season. Accordingly, a series of CCA analyses are conducted with combined, multi-component large-scale drivers of Mediterranean precipitation and surface air temperatures. The results highlight the decadal-scale North Atlantic Oscillation (NAO) as the leading driver of hydroclimate variations across the Mediterranean basin. Markedly, the decadal variability of Atlantic-Mediterranean sea surface temperatures (SST), whose influence on the Mediterranean climate has so far been proposed as limited to the summer months, is found to enhance the NAO-induced hydroclimate response during the winter half-year season. As for the long-term, century scale trends, anthropogenic forcing, expressed in terms of the global SST warming (GW) signal, is robustly associated with basin-wide increase in surface air temperatures. Our analyses provide more detailed information than has heretofore been presented on the sub-seasonal evolution and spatial dependence of the large-scale climate variability in the Mediterranean region, separating the effects of natural variability and anthropogenic forcing, with the latter linked to a long-term drying of the region due to GW-induced local poleward shift of the subtropical dry zone. The physical understanding of these mechanisms is essential in order to improve model simulations and prediction of the decadal and longer hydroclimatic evolution in the Mediterranean area, which can help in developing adaptation strategies to mitigate the effect of climate variability and change on the vulnerable regional population.