Arctic Oscillation


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Arctic Oscillation

[¦ärd·ik ‚äs·ə′lā·shən]
(meteorology)
Atmospheric pressure fluctuations (positive and negative phases) between the polar and middle latitudes (above 45° North) that strengthen and weaken the winds circulating counterclockwise from the surface to the lower stratosphere around the Arctic and, as a result, modulate the severity of the winter weather over most Northern Hemisphere middle and high latitudes. Also known as the Northern Hemisphere annular mode.
References in periodicals archive ?
Xu, "Effect of arctic oscillation on sandstorm in the eastern part of Northwest China," Journal of Desert Research, vol.
Arctic Oscillation (also named Northern Annular Mode) is a dominant pattern of non-seasonal SLP variations north of 20[degrees]N latitude and is characterized by pressure anomalies of one sign in the Arctic with the opposite anomalies centred on sub-tropical latitudes about 37-45[degrees]N.
The interactions between these systems are controlled in part by regional atmospheric circulation patterns, namely the Pacific Decadal Oscillation (PDO), the North Pacific (NP) index, and the Arctic Oscillation (AO) index.
Building on this success in unraveling ENSO, meteorologists and oceanographers have begun to identify a host of other ocean-atmosphere oscillations operating in the earth's climate system: the North Atlantic Oscillation, the Arctic Oscillation, the Antarctic Oscillation, the Pacific Decadal Oscillation, the Indian Ocean Dipole, and the Antarctic Circumpolar Wave.
That creates stronger westerlies and increases the warm periods of the Arctic oscillation - the El Nino-like weather system that affects the northern hemisphere.
Thompson of the University of Washington called this pattern the Arctic oscillation in the May 1, 1998 GEOPHYSICAL RESEARCH LETTERS.
Our results also imply that even under human-induced warming, extreme cold events can still occur as a result of natural variability, such as Arctic Oscillation, which was believed to be responsible for the reporting event (Cheung et al.
Diminishing Arctic sea ice can cause changes in atmospheric circulation that lead to a circulation pattern that is different than the "negative phase" of the Arctic Oscillation.
The lag between bowhead whale incursion into the northern CAA and driftwood delivery from the Arctic Ocean is significant, because it may have occurred during an interval when the Arctic Oscillation was in a positive phase (Kaufman et al.
Weeks to months later, the weakened polar vortex transfers the wave anomaly back to the troposphere, evident as a negative Arctic Oscillation, which effectively perpetuates the influence of autumn AA on late-winter circulation patterns.
They believe the increased snow cover has an intricate effect on the Arctic Oscillation - an atmospheric pressure pattern in the mid- to high-latitudes - causing it to remain in the "negative phase".

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