A Comparison of the Response of the Hadley Circulation to Different Tropical SST Meridional Structures During the Equinox Seasons
A Comparison of the Response of the Hadley Circulation to Different Tropical SST Meridional Structures During the Equinox Seasons
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DOI：
10.1002/2017jd028219
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发表时间：
2018-03
期刊：
影响因子：
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通讯作者：
Juan Feng;Jianping Li;F. Jin;F. Zheng
中科院分区：
文献类型：
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作者：
Juan Feng;Jianping Li;F. Jin;F. Zheng
分析了春分季节（即寒带春季和秋季）不同热带海温型对哈德利环流的响应。虽然春分季节和秋分季节都表现出准赤道对称结构，但其气候学和年际变化都表现出相当大的差异，即秋（春）季更为赤道不对称（对称）。将海温和纬向海温的变化分解为赤道不对称分量（即HC的赤道不对称变化（HEA）和海温的赤道不对称变化（SEA））和对称分量（即HC的赤道对称变化（HES）和海温的赤道对称变化（SES）），发现春季和秋季海温的差异主要来源于HEA分量。同时，HEA对SEA的响应与HES对SES的响应在春季的对比大于秋季，说明HC对春季海温条件更为敏感。HEA的变化与春季和秋季的不同信号有关，春季与中太平洋El Niño有关，秋季与大西洋多年代际涛动有关。不同的贡献者与HEA的空间范围和时间变化的差异有关。相比之下，春季和秋季HES都与规范El Niño密切相关，有利于春季和秋季HES的相似变化。这一结果可能解释了春季和秋季海温的不同变化，并突出了海温对海温响应的季节依赖性。
The response of the Hadley circulation (HC) to different tropical sea surface temperature (SST) patterns during the equinox seasons (i.e., boreal spring and autumn) is analyzed. Although the HC shows quasi‐equatorially symmetric structure in both equinox seasons, both the climatology and the interannual variations of the HC display considerable differences, that is, being more equatorially asymmetric (symmetric) during autumn (spring). After decomposing the variations of the HC and zonal SST into the equatorially asymmetric (i.e., HC's equatorially asymmetric variation (HEA) for HC and SST's equatorially asymmetric variation (SEA) for SST) and symmetric (i.e., HC's equatorially symmetric variation (HES) for HC and SST's equatorially symmetric variation (SES) for SST) components, the differences in the HC between spring and autumn are shown to derive mainly from the HEA. Meanwhile, the contrast in the response of the HEA to SEA against HES to SES is greater in spring than in autumn, suggesting the HC is more sensitive to the SST conditions in spring. The variation of the HEA is related to different signals in spring and autumn that is linked to the central Pacific El Niño during spring but to the Atlantic Multidecadal Oscillation during autumn. The different contributors are associated with the differences in both the spatial extent and temporal variations in the HEA. In contrast, both spring and autumn HES are closely linked to the canonical El Niño, favoring similar variations in spring and autumn HES. The results here provide a possible explanation of the different variations in the HC during spring and autumn and highlight the seasonal dependence of the response of the HC to SST.