Atmospheric blocking and its relation to jet changes in a future climate
Atmospheric blocking and its relation to jet changes in a future climate
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DOI：
10.1007/s00382-013-1699-7
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发表时间：
2013-11-01
期刊：
影响因子：
4.6
通讯作者：
Hazeleger, Wilco
中科院分区：
文献类型：
--
作者：
de Vries, Hylke;Woollings, Tim;Hazeleger, Wilco
用ECHAM 5/MPI-OM模式对17个全球气候模式进行的数值模拟结果分析表明，未来欧洲-大西洋地区大气阻塞的变化可以从500 hPa平均纬向环流及其方差的变化中得到很好的解释。平均纬向环流的变化很好地解释了大西洋阻塞频率的减少和60 A ° N偏东上层气流向极的频率的增加。在冬季和秋季的额外的下游移动的频率最大值进行了模拟。这也见于具有RCP 8.5的CMIP 5模型的子集中。为了解释这种下游转移，需要包括变化的方差。这表明，下游方差的增加是由更强的，更东移的未来急流，这促使罗斯贝波破碎和阻塞发生在更远的下游。急流强度和中心阻塞经度之间的关系在当前气候的变率中也存在。
The future changes of atmospheric blocking over the Euro-Atlantic sector, diagnosed from an ensemble of 17 global-climate simulations obtained with the ECHAM5/MPI-OM model, are shown to be largely explainable from the change of the 500 hPa mean zonal circulation and its variance. The reduction of the blocking frequency over the Atlantic and the increased frequency of easterly upper-level flow poleward of 60A degrees N are well explained by the changes of mean zonal circulation. In winter and autumn an additional downstream shift of the frequency maximum is simulated. This is also seen in a subset of the CMIP5 models with RCP8.5. To explain this downstream shift requires the inclusion of the changing variance. It is suggested that the increased downstream variance is caused by the stronger, more eastward extending future jet, which promotes Rossby wave breaking and blocking to occur further downstream. The same relation between jet-strength and central-blocking longitude is found in the variability of the current climate.