The relative influence of ENSO and SAM on Antarctic Peninsula climate
The relative influence of ENSO and SAM on Antarctic Peninsula climate
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DOI：
10.1002/2016jd025305
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发表时间：
2016-08-27
影响因子：
4.4
通讯作者：
Fogt, Ryan L.
中科院分区：
文献类型：
--
作者：
Clem, Kyle R.;Renwick, James A.;Fogt, Ryan L.
南极半岛在秋季、冬季和春季的近期变暖与热带太平洋和热带大西洋的海表温度（SST）趋势有关，而半岛东北部在夏季的变暖则与穿越半岛的西风加强有关，这与南部环形模态（SAM）的正趋势有关。在这里，我们表明，环流变化与SAM主导整个南极半岛的年际温度变率在夏季和秋季，而与热带太平洋SST变率与厄尔尼诺南方涛动（ENSO）的关系是最强的，主要是在冬季和春季统计显着。我们发现ENSO-半岛温度关系在秋季是弱的年际时间尺度和区域环流异常与SAM更重要的年际温度变率在整个半岛在秋季。与以前的研究一致，半岛西部的温度在秋季，冬季和春季的阿蒙森海低（ASL）和相关的纬向风异常的变化密切相关。秋季ASL深度的年际变化与SAM指数的相关性最强，而冬春季与ENSO的相关性最强。西部和东北半岛温度的调查分别揭示，东北半岛温度的年际变化主要是敏感的纬向风异常穿越半岛和由此产生的背风绝热变暖，而不是纬向风异常，这是密切相关的SAM模式的纬向部分的变化。
Recent warming of the Antarctic Peninsula during austral autumn, winter, and spring has been linked to sea surface temperature (SST) trends in the tropical Pacific and tropical Atlantic, while warming of the northeast Peninsula during summer has been linked to a strengthening of westerly winds traversing the Peninsula associated with a positive trend in the Southern Annular Mode (SAM). Here we demonstrate that circulation changes associated with the SAM dominate interannual temperature variability across the entire Antarctic Peninsula during both summer and autumn, while relationships with tropical Pacific SST variability associated with the El Nino-Southern Oscillation (ENSO) are strongest and statistically significant primarily during winter and spring only. We find the ENSO-Peninsula temperature relationship during autumn to be weak on interannual time scales and regional circulation anomalies associated with the SAM more important for interannual temperature variability across the Peninsula during autumn. Consistent with previous studies, western Peninsula temperatures during autumn, winter, and spring are closely tied to changes in the Amundsen Sea Low (ASL) and associated meridional wind anomalies. The interannual variability of ASL depth is most strongly correlated with the SAM index during autumn, while the ENSO relationship is strongest during winter and spring. Investigation of western and northeast Peninsula temperatures separately reveals that interannual variability of northeast Peninsula temperatures is primarily sensitive to zonal wind anomalies crossing the Peninsula and resultant leeside adiabatic warming rather than to meridional wind anomalies, which is closely tied to variability in the zonal portion of the SAM pattern.