On the Discrepancies in Tropical Belt Expansion between Reanalyses and Climate Models and among Tropical Belt Width Metrics
On the Discrepancies in Tropical Belt Expansion between Reanalyses and Climate Models and among Tropical Belt Width Metrics
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DOI：
10.1175/jcli-d-16-0371.1
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发表时间：
2017-02
影响因子：
4.9
通讯作者：
N. Davis;T. Birner
中科院分区：
文献类型：
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作者：
N. Davis;T. Birner
干旱的亚热带位于热带边缘，Hadley环流的沉降抑制了降水。这些边缘纬度的任何纬向变化都可能对地表气候产生重大影响。最近的研究调查了过去和未来热带带宽度的变化，发现不同尺度估计的扩张速度存在差异，气候模型和再分析之间也存在差异。在这里，CMIP 5模拟和四个现代再分析使用一个集合的客观热带带宽度指标重新检查，如果存在这种不一致。作者没有找到足够的证据来证明模型和再分析之间的这种差异，因为热带带宽度的再分析趋势在任何给定度量的模型趋势范围内。此外，只有基于Hadley细胞的指标被发现表现出强大的历史和未来的扩展。基于副热带急流和对流层顶的反演结果表明，
AbstractThe arid subtropics are situated at the edges of the tropical belt, where subsidence in the Hadley cells suppresses precipitation. Any meridional shift in these edge latitudes could have significant impacts on surface climate. Recent studies have investigated past and future changes in the tropical belt width and have found discrepancies in the rates of expansion estimated with different metrics and between climate models and reanalyses. Here, CMIP5 simulations and four modern reanalyses are analyzed using an ensemble of objective tropical belt width metrics to reexamine if such inconsistencies exist. The authors do not find sufficient evidence to demonstrate this discrepancy between models and reanalyses, as reanalysis trends in the tropical belt width fall within the range of model trends for any given metric. Furthermore, only metrics based on the Hadley cells are found to exhibit robust historical and future expansion. Metrics based on the subtropical jet and the tropopause show no robust resp...