Structure and impact of atmospheric blocking over the Euro‐Atlantic region in present‐day and future simulations
Structure and impact of atmospheric blocking over the Euro‐Atlantic region in present‐day and future simulations
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DOI：
10.1002/2013gl058570
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发表时间：
2014-02
影响因子：
5.2
通讯作者：
G. Masato;T. Woollings;Brian J. Hoskins
中科院分区：
文献类型：
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作者：
G. Masato;T. Woollings;Brian J. Hoskins
冬季大气阻塞的空间结构及其对地面温度的影响进行了分析，目前的气候和欧洲-大西洋部门的强CO2排放情景，使用四种不同的全球环流模式。该模型在描述与阻塞相关的气象场的空间格局方面表现得非常好，尽管与欧洲阻塞频率相关的负偏差是众所周知的。虽然观察到未来气候的大西洋阻塞频率略有增加，但欧洲阻塞频率保持不变，欧洲暖阻塞事件的净东移明显。在增强的CO2强迫下，大西洋阻塞与500 hPa位势高度和表面温度的正异常和负异常的幅度减小有关，特别是后者。与两种类型的欧洲阻塞（由暖空气和冷空气质量为主）的发生相关的异常表现出改变的形状和位置的位势高度场和地面温度场，只有寒冷的情况下，导致欧洲和极地地区的大部分地区的严寒天气条件。此外，与未来暖事件相关联的反气旋的东移和放大被发现在整个极盖上产生强烈的正表面温度异常。总的来说，结果显示，北极温度对未来阻塞的敏感性显著增加。
The spatial structure of winter atmospheric blocking and its impact on the surface temperatures are analyzed for the current climate and a strong CO2 emission scenario over the Euro‐Atlantic sector, using four different global circulation models. The models perform very well in describing the spatial pattern of meteorological fields associated with blocking, despite the well‐known negative bias associated with the European blocking frequency. While a slight increase in the frequency of the Atlantic blocking is observed for the future climate, the European blocking frequency remains unchanged, with a net eastward shift apparent for the European warm blocking events. Under enhanced CO2 forcing, Atlantic blocking is associated with reduced amplitudes for positive and negative anomalies both in the geopotential height at 500 hPa and in the surface temperature, in particular for the latter. The anomalies associated with the occurrence of the two types of European blocking (those dominated by warm and cold air masses) exhibit changed shapes and locations in both the geopotential height and surface temperature fields, with only the cold cases leading to severe cold weather conditions over Europe and most of the polar region. Moreover, the eastward shift and amplification of the anticyclone associated with the warm events in the future is found to generate strong positive surface temperature anomalies over the entire polar cap. As a whole, the results show a marked increase in the sensitivity of Arctic temperatures to blocking in the future.