Enhanced Atlantic freshwater export during El Niño

• Main Authors: Andreas Schmittner, Christof Appenzeller, Thomas F. Stocker
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2000
• Subjects: North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.36.7295; http://www.climate.unibe.ch/pdf/schmittner00grl.pdf

. Using two reanalysis data sets, the influence of El Nino/Southern Oscillation (ENSO) on the surface freshwater balance of the Atlantic ocean is examined. We present evidence that the transport of water vapour out of the tropical Atlantic is enhanced during warm ENSO phases, while it is reduced during cold phases. These tropical changes alter the freshwater budget of the entire Atlantic drainage basin. The di#erence in freshwater export between La Nina and El Nino years is on the order of 0.1 Sv (1 Sv=10 6 m 3 s -1 ) for the entire Atlantic. Results from an idealized coupled ocean-atmosphere model suggest that this amplitude is of significance for the strength of the North Atlantic thermohaline ocean circulation, if the persistence of the anomaly is on the order of decades. Introduction The Atlantic thermohaline circulation (THC) and its associated heat transport has a profound impact on the North Atlantic and European climate. Paleoclimatic indications for THC variability [e.