Advances in Geosciences www.adv-geosci.net 1680-7340 1680-7359 6 1st Alexander von Humboldt International Conference 2006 10.5194/adgeo-6-83-2006 http://www.adv-geosci.net/6/83/2006/ http://www.adv-geosci.net/6/83/2006/adgeo-6-83-2006.html http://www.adv-geosci.net/6/83/2006/adgeo-6-83-2006.pdf 83 86 2006-01-09 Opposing oceanic and atmospheric ENSO influences on the Ross Sea Region, Antarctica N. A. N. Bertler T. R. Naish P. A. Mayewski P. J. Barrett Antarctic Research Centre, Victoria University, PO Box 600, Wellington, New Zealand Institute of Geological and Nuclear Sciences Ltd., P.O. Box 30368, Lower Hutt, New Zealand Climate Change Institute, University of Maine, Bryand Global Sciences Center, Orono, Maine 04469, USA Here we discuss the cause and effect of opposing atmospheric and oceanic ENSO forcings in the Ross Sea, that lead to a net warming in the eastern Ross Sea and a net cooling in the western Ross Sea during El Niño years. During La Niña years the opposite is observed. The oceanic ENSO effect causes a ~1 K warming with a 3 month lag during El Niño years in comparison to La Niña time periods. During El Niño events, the atmospheric ENSO effect leads to a shift and weakening of the Amundsen Sea Low, causing enhanced import of colder West Antarctic air masses into the western Ross Sea. We find that this indirect ENSO effect is about one order of magnitude stronger (up to 15 K) in the western Ross Sea than the direct effect (~1 K), leading to a net cooling during El Niño and net warming during La Niña events.