Aleutian Low variability for the last 7500 years and its relation to the Westerly Jet
Aleutian Low variability for the last 7500 years and its relation to the Westerly Jet
复制标题
DOI：
10.1017/qua.2020.116
复制
发表时间：
2021-02
影响因子：
2.3
通讯作者：
K. Nagashima;J. Addison;T. Irino;T. Omori;K. Yoshimura;N. Harada
中科院分区：
文献类型：
--
作者：
K. Nagashima;J. Addison;T. Irino;T. Omori;K. Yoshimura;N. Harada
摘要阿留申低压是决定北太平洋冬季环境条件的主要大气系统之一，其影响从中纬度到高纬度影响亚洲和北美的气候。然而，在全新世期间AL的多世纪和更长尺度的行为还没有完全理解。在这项研究中，AL的变化，因为7.5 ka的应用主成分分析技术，以发表的δ 18 O数据来自沉积方解石，泥炭，冰，和洞穴从北美西部。提取的主成分1（PC 1）代表了一个戏剧性的变化，从中到晚全新世，似乎反映了长期加强的AL之间的相互作用的轨道驱动的西风急流（WJ）在东亚和西北太平洋的南移，和厄尔尼诺南方涛动的加强。相比之下，PC 2的特点是多百年到千年尺度的振荡，与空间加载模式，表明PC 2反映AL强度和位置的变化。这些振荡是同期的WJ纬度和/或曲折的路径转移在东亚和太阳活动的变化，这表明太阳辐照度的减少/增加是通过与WJ的相互作用与AL的变化。
Abstract The Aleutian Low (AL) is one of the major atmospheric systems that determines environmental conditions during winter in the North Pacific Ocean, with impacts that affect the climates of both Asia and North America from mid- to high latitudes. However, the multi-centennial and longer scale behavior of the AL during the Holocene is not fully understood. In this study, AL variability since 7.5 ka was examined by applying the principal component analysis technique to published δ18O data derived from sedimentary calcite, peat, ice, and speleothem from western North America. The extracted Principal Component 1 (PC1) represents a dramatic change from the mid- to late Holocene, and appears to reflect long-term intensified AL related to interactions between orbitally-driven southward shift of the Westerly Jet (WJ) over East Asia and the northwestern Pacific, and intensification of the El Niño–Southern Oscillation. In contrast, PC2 is characterized by multi-centennial to millennial-scale oscillations, with a spatial loading pattern that suggests PC2 reflects AL intensity and position shifts. These oscillations are contemporaneous with both WJ latitude and/or the meandering path shifts over East Asia and solar activity change, suggesting that a decrease/increase in solar irradiance is related to AL variability via interactions with the WJ.