John M. Wallace

TL;DR: In this article, the authors identify a robust, recurring pattern of ocean-atmosphere climate variability centered over the midlatitude North Pacific basin over the past century, the amplitude of this climate pattern has varied irregularly at interannual-to-interdecadal timescales.

TL;DR: The Arctic Oscillation (AO) as mentioned in this paper is the signature of modulations in the strength of the polar vortex aloft, and it resembles the NAO in many respects; but its primary center of action covers more of the Arctic, giving it a more zonally symmetric appearance.

TL;DR: In this paper, a review of existing literature on the subject reveals the existence of at least four such patterns: the North Atlantic and North Pacific Oscillations identified by Walker and Bliss (1932), a zonally symmetric seesaw between sea level pressures in polar and temperature latitudes, first noted by Lorenz (1951), and what we will refer to as the Pacific/North American pattern, which has been known to operational long-range forecasters in this country since the 1950's.

TL;DR: In this article, the authors compared the structure and seasonality of the Southern Hemisphere (SH) annular mode and the Northern Hemisphere (NH) mode, referred to as the Arctic Oscillation (AO), based on data from the National Centers for Environmental Prediction and National Center for Atmospheric Research reanalysis and supplementary datasets.

TL;DR: In this paper, the authors compare the structure of the interannual variability associated with the ENSO cycle and documents its time history back to 1900, using the leading EOFs of the SST anomaly and anomaly deviation fields in various domains and the associated expansion coefficient (or principal component) time series, which are used to construct global regression maps of SST, sea level pressure (SLP), and a number of related variables.