The Arctic oscillation signature in the wintertime geopotential height and temperature fields
TLDR
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.Abstract:
The leading empirical orthogonal function of the wintertime sea-level pressure field is more strongly coupled to surface air temperature fluctuations over the Eurasian continent than the North Atlantic Oscillation (NAO). 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. Coupled to strong fluctuations at the 50-hPa level on the intraseasonal, interannual, and interdecadal time scales, this "Arctic Oscillation" (AO)can be interpreted as the surface signature of modulations in the strength of the polar vortex aloft. It is proposed that the zonally asymmetric surface air temperature and mid-tropospheric circulation anomalies observed in association with the AO may be secondary baroclinic features induced by the land-sea contrasts. The same modal structure is mirrored in the pronounced trends in winter and springtime surface air temperature, sea-level pressure, and 50-hPa height over the past 30 years: parts of Eurasia have warmed by as much as several K, sea-level pressure over parts of the Arctic has fallen by 4 hPa, and the core of the lower stratospheric polar vortex has cooled by several K. These trends can be interpreted as the development of a systematic bias in one of the atmosphere's dominant, naturally occurring modes of variability.read more
Citations
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Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change
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Annular Modes in the Extratropical Circulation. Part I: Month-to-Month Variability*
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.
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Volcanic eruptions and climate
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Observational evidence of recent change in the northern high-latitude environment
Mark C. Serreze,John Walsh,F. S. Chapin,T. E. Osterkamp,Mark B. Dyurgerov,Vladimir E. Romanovsky,Walter C. Oechel,James H. Morison,Tingjun Zhang,Roger G. Barry +9 more
TL;DR: In this paper, the authors present asynthesis of these observations, and conclude that roughly half of the pronounced recent rise in Northern Hemispherewinter temperatures reflects shifts in atmosphericcirculation. But, such changes are not consistent with anthropogenic forcing and include generally positive phases of the North Atlantic and ArcticOscillations and extratropical responses to the El-NinoSouthern Oscillation.
References
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Journal ArticleDOI
Decadal Trends in the North Atlantic Oscillation: Regional Temperatures and Precipitation
TL;DR: An evaluation of the atmospheric moisture budget reveals coherent large-scale changes since 1980 that are linked to recent dry conditions over southern Europe and the Mediterranean, whereas northern Europe and parts of Scandinavia have generally experienced wetter than normal conditions.
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Teleconnections in the Geopotential Height Field during the Northern Hemisphere Winter
John M. Wallace,David S. Gutzler +1 more
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.
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Sampling Errors in the Estimation of Empirical Orthogonal Functions
TL;DR: In this paper, the authors reviewed the necessary weighting factors for gridded data and the sampling errors incurred when too small a sample is available, and a rule of thumb indicating when an EOF is likely to be subject to large sampling fluctuations is presented.
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ENSO-like Interdecadal Variability: 1900–93
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.
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