Ivchenko, V.O., Zalesny, V.B. and Drinkwater, M.R.
Can the equatorial ocean quickly respond to Antarctic sea ice/salinity anomalies?
Geophysical Research Letters, 31, . (doi:10.1029/2004GL020472).
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El Niño Southern Oscillation (ENSO) plays a critical role in many of the extremes or anomalies of climate, causing floods, droughts and the collapse of fisheries. Recent studies have revealed a statistically–significant link between equatorial processes and sea-ice anomalies in the Southern Ocean. The generally accepted view is that the primary interaction of the equatorial and polar oceans takes place via the atmosphere. Indeed, the lag in these processes is usually of the order of a few months, and is much too quick to be connected with ocean currents. The question is: can climate anomaly signals effectively and rapidly propagate by another oceanic mechanism? It is demonstrated that signals generated by anomalies in the Antarctic sea-ice cover/salinity distribution can propagate in a wave-like manner in the form of fast-moving barotropic Rossby waves. Such waves propagates from the Drake Passage to the western Pacific in only few days. This signal is reflected at the western boundary of the Pacific and generates an coastally trapped Kelvin wave moving equatorwards. The resulting temperature anomaly propagates northwards along the western coastline to the vicinity of the equator and increases in amplitude in time. The anomaly in the western edge of the equatorial Pacific then begins to move eastward along the equator as a trapped equatorial wave. After about 2–3 months this wave reaches the eastern coast. This process is suggested as one possible direct mechanism by which the extra–tropical ocean can induce anomalies in the equatorial ocean.
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