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Throughout much of the latter half of the 20th century, the dominant mode of Northern Hemisphere (NH) extratropical wintertime circulation variability−the Arctic Oscillation (AO)−exhibited a positive trend, with decreasing high-latitude sea-level pressure (SLP) and increasing mid-latitude SLP. Gener...
Main Authors: | , |
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Format: | Text |
Language: | English |
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Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.174.1171 http://dust.ess.uci.edu/ppr/ppr_AlZ102.pdf |
Summary: | Throughout much of the latter half of the 20th century, the dominant mode of Northern Hemisphere (NH) extratropical wintertime circulation variability−the Arctic Oscillation (AO)−exhibited a positive trend, with decreasing high-latitude sea-level pressure (SLP) and increasing mid-latitude SLP. General circulation models (GCMs) show this trend is related to several factors, including North Atlantic SSTs1,2, greenhouse gas/ozone induced strato-7 spheric cooling 3−6, and warming of the Indo-Pacific warm pool 7−8. Over the last ∼2 decades, 8 however, the AO has been decreasing, with 2009-2010 featuring the most negative AO since 9 1900. Observational 9−11 and idealized modeling 12−14 studies suggest that snow cover, partic- |
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