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North Atlantic Oscillation impact on tropical North Atlantic winter atmospheric variability
Author(s) -
George Steve E.,
Saunders Mark A.
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl012449
Subject(s) - north atlantic oscillation , climatology , tropical atlantic , atlantic multidecadal oscillation , precipitation , teleconnection , zonal and meridional , environmental science , sea surface temperature , oceanography , geology , atmospheric sciences , geography , el niño southern oscillation , meteorology
The dominant mode of windspeed variability in the wintertime tropical north Atlantic (TNA) is represented by the North Atlantic Oscillation (NAO). For the December–January–February (DJF) season the leading principal component of TNA windspeed (representing 46% of the total variance) exhibits a 0.68 correlation with the NAO time‐series. We show that the NAO impact on TNA trade winds peaks in January and is statistically significant at the 99% level for each month from November through to April. This association arises through the meridional pressure gradient equatorward of the Azores high pressure covarying with the NAO. We also show that the winter NAO index determines monthly precipitation levels across the northern Caribbean throughout the following year. We suggest this rainfall impact is due to long lasting, DJF forced perturbations to the north Atlantic sea surface temperature tripole characteristic of the NAO signal.