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Tropical Pacific control of intraseasonal oscillations off Chile by way of oceanic and atmospheric pathways
Author(s) -
Hormazabal Samuel,
Shaffer Gary,
Pizarro Oscar
Publication year - 2002
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 - 10.1029/2001gl013481
Subject(s) - equator , climatology , teleconnection , madden–julian oscillation , kelvin wave , satellite , environmental science , equatorial waves , atmosphere (unit) , atmospheric sciences , geology , el niño southern oscillation , meteorology , latitude , geography , convection , physics , geodesy , astronomy
Sea level, current, satellite wind data and a simple model of wind‐forced, low frequency waves are used to study the origins of strong, observed intraseasonal variability in the ocean and atmosphere off Chile. There intraseasonal wind fluctuations are correlated to wind fluctuations in the equatorial Pacific, associated with the Madden‐Julian Oscillation. Results suggest intraseasonal teleconnections via two distinct atmospheric pathways. Very simple model simulations forced by satellite winds from the equator and the South American coast compare well with observed fluctuations of currents and sea level off central Chile. There most of this intraseasonal variability, particularly during summer and during El Niño events, arrives as free, oceanic, coastal trapped waves via oceanic, equatorial Kelvin waves, forced by tropical Pacific winds. South of 20°S, some oceanic intraseasonal variability is forced by local winds associated with the atmospheric teleconnections.