Reconstructing an Interdecadal Pacific Oscillation Index from a Pacific Basin–Wide Collection of Ice Core Records
Reconstructing an Interdecadal Pacific Oscillation Index from a Pacific Basin–Wide Collection of Ice Core Records
复制标题
DOI：
10.1175/jcli-d-20-0455.1
复制
发表时间：
2021-02
影响因子：
4.9
通讯作者：
S. Porter;E. Mosley‐Thompson;L. Thompson;A. Wilson
中科院分区：
文献类型：
--
作者：
S. Porter;E. Mosley‐Thompson;L. Thompson;A. Wilson
利用在太平洋盆地周围收集的四个冰芯的组合，创造了太平洋气候变化的第一个全盆地历史。该冰芯衍生的年代际太平洋涛动（IPO）指数结合了南美、喜马拉雅山、南极半岛和北美西北部的冰芯记录。重建的首次公开募股每年进行一次决议，日期为公元1450年。IPO指数与仪器期间的观测结果以及整个记录中与古代理同化的数据集比较良好，这表明最近一个时期的IPO信号强劲且时间平稳；550年。热带太平洋地区的古气候在小冰期（LIA）期间变化很大，尽管本研究中重建的IPO指数表明，小冰期主要由一个弱的、负的IPO阶段定义，因此更多的La Niña-like条件。虽然热带太平洋在小年期间的平均状态仍然不确定，但重建的IPO揭示了与热带辐合带（ITCZ）的一些有趣的动力学关系。在当前暖期，正（负）IPO与ITCZ季节性纬度范围的扩张（收缩）相一致。然而，这种关系不是固定的，而且在整个LIA中几乎不存在，这表明外部强迫，例如来自火山和/或太阳辐照度减少的强迫，可能驱动ITCZ的移动或主导IPO重建中使用的冰芯地点的气候。
Using an assemblage of four ice cores collected around the Pacific basin, one of the first basinwide histories of Pacific climate variability has been created. This ice core–derived index of the interdecadal Pacific oscillation (IPO) incorporates ice core records from South America, the Himalayas, the Antarctic Peninsula, and northwestern North America. The reconstructed IPO is annually resolved and dates to 1450CE. The IPO index compares well with observations during the instrumental period and with paleo-proxy assimilated datasets throughout the entire record, which indicates a robust and temporally stationary IPO signal for the last;550 years. Paleoclimate reconstructions from the tropical Pacific region vary greatly during the Little IceAge (LIA), although the reconstructed IPO index in this study suggests that the LIA was primarily defined by a weak, negative IPO phase and hence more La Niña–like conditions. Although the mean state of the tropical Pacific Ocean during the LIA remains uncertain, the reconstructed IPO reveals some interesting dynamical relationships with the intertropical convergence zone (ITCZ). In the current warm period, a positive (negative) IPO coincides with an expansion (contraction) of the seasonal latitudinal range of the ITCZ. This relationship is not stationary, however, and is virtually absent throughout the LIA, suggesting that external forcing, such as that from volcanoes and/or reduced solar irradiance, could be driving either the ITCZ shifts or the climate dominating the ice core sites used in the IPO reconstruction.