Multi-model analysis of Northern Hemisphere winter blocking: Model biases and the role of resolution
Multi-model analysis of Northern Hemisphere winter blocking: Model biases and the role of resolution
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DOI：
10.1002/jgrd.50231
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发表时间：
2013-05-27
影响因子：
4.4
通讯作者：
Yang, Shuting
中科院分区：
文献类型：
--
作者：
Anstey, James A.;Davini, Paolo;Yang, Shuting
本文研究了北半球冬季(12-1-2月)对流层急流的阻塞。该研究是在由耦合模式对比计划第五阶段(CMIP5)获得的多模式大气-海洋环流模式(GCM)集合中进行的。CMIP5模式在对流层急流纬度的阻塞频率和相关偏差方面表现出很大的偏差，类似于早期的GCM。在高纬度地区，特别是在欧洲上空，被低估的阻塞是很常见的。一般而言，模型偏差随着模型分辨率的增加而减小。大西洋和太平洋盆地高纬度阻塞频率的增加，以及大西洋急流纬度的更现实的变化，与对流层中部到最低平流层的垂直分辨率增加有关。水平分辨率越高，大西洋盆地所有纬度的阻塞频率越高，但对格陵兰附近或太平洋盆地的阻塞似乎没有系统性的影响。CMIP5分析的结果得到了用选定的GCM进行的额外对照实验的证实。
Blocking of the tropospheric jet stream during Northern Hemisphere winter (December-January-February) is examined in a multi-model ensemble of coupled atmosphere-ocean general circulation models (GCMs) obtained from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The CMIP5 models exhibit large biases in blocking frequency and related biases in tropospheric jet latitude, similar to earlier generations of GCMs. Underestimated blocking at high latitudes, especially over Europe, is common. In general, model biases decrease as model resolution increases. Increased blocking frequency at high latitudes in both the Atlantic and Pacific basins, as well as more realistic variability of Atlantic jet latitude, are associated with increased vertical resolution in the mid-troposphere to lowermost stratosphere. Finer horizontal resolution is associated with higher blocking frequency at all latitudes in the Atlantic basin but appears to have no systematic impact on blocking near Greenland or in the Pacific basin. Results from the CMIP5 analysis are corroborated by additional controlled experiments using selected GCMs.