The preferred structure of variability of the northern hemisphere atmospheric circulation
The preferred structure of variability of the northern hemisphere atmospheric circulation
复制标题
北半球大气环流变率的首选结构
DOI：
--
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
J. Fyfe
中科院分区：
文献类型：
--
作者：
A. Monahan;L. Pandolfo;J. Fyfe
将主成分分析（PCA）的非线性推广应用于北半球温带大气的500mb位势高度场。研究发现，对流层中层的低频变化具有三种不同的准静止状态的特征。对这些状态进行了描述，并将其与通过对高度场应用聚类分析和线性 PCA 获得的状态进行比较。有证据表明，通过 PCA 获得的模式（特别是北极涛动 (AO)）并不是北半球温带气候变化的独立动力模式。相反，它们是作为循环的首选准稳态之间的最佳线性折衷而出现的。
A nonlinear generalisation of Principal Component Analysis (PCA) is applied to the 500mb geopotential height field of the Northern Hemisphere extratropical atmosphere. It is found that the low‐frequency variability of the mid‐troposphere is characterised by three distinct quasi‐stationary states. The states are described and compared to those obtained from applications of cluster analyses and linear PCA to the height field. Evidence is provided that modes obtained through PCA (notably the Arctic Oscillation (AO)) are not independent dynamical modes of variability of the Northern Hemisphere extratropics. Rather they arise as the optimal linear compromise between the preferred quasi‐stationary states of the circulation.