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1850年以来东亚冬季风多年代际变化特征及其与大西洋多年代际振荡的关系研究

[发布日期: 2021-08-23 浏览量 414]

      本文基于多套观测和再分析资料,研究了1850年以来东亚冬季风多年代际变化特征及物理机制。结果表明,在多年代际时间尺度上,东亚冬季风在1869‒1919年和1986‒2004年期间偏弱,在1920‒1985年期间偏强,东亚冬季平均气温的变化特征也与之相似。进一步分析发现,东亚冬季风多年代际变化与一支准定常罗斯贝波波列密切相关,该波列从北大西洋副热带区域经欧亚大陆传播至东北亚。在此波列正位相时,对流层低层欧亚大陆北部反气旋异常使得西伯利亚高压增强,对流层中、高层东北亚气旋异常有利于东亚大槽加深、东亚急流加强,进而导致东亚冬季风增强;反之亦然。通过对罗斯贝波波源的诊断发现,北大西洋上空辐散风异常有利于激发该波列,高频涡旋的反馈作用则对其维持起重要作用。进一步分析可知,大西洋多年代际振荡(AMO)的位相转换可以激发相似的波列,进而影响东亚冬季风多年代际尺度变化。AMO暖位相时,东亚冬季风增强,欧亚大陆中纬度区域偏冷;反之亦然。本文已在《Journal of Climate》正式发表。

Figure (Upper) The East Asian winter monsoon index (bars) and its multidecadal component (black line) during the period of 1850–2018 based on the HadSLP2r dataset, with results from other three reanalysis datasets (i.e., JRA-55, NCEP-DOE, ERA-Interim) overlaid. The linear trend is plotted as a dashed line. (Middle) Similar with upper plot except that the East Asian winter monsoon index is detrended, and the datasets includes HadSLP2r, 20CRv2c and ERA-20C. (Bottom) Detrended time series of East Asian (20°–50°N, 100°–145°E) averaged winter suraface air temperature anomalies (bars; units: °C) and its multidecadal component (black line) based on the HadCRUT5 dataset, with result from GISTEMP overlaid (red line). All three plots share the same baseline period of 1981–2010.


引用格式

Miao, J. P., Jiang D. B., 2021: Multidecadal variations in the East Asian winter monsoon and their relationship with the Atlantic Multidecadal Oscillation since 1850. Journal of Climate, 34, 7525–7539.