Extra-tropical response to ENSO as expressed in an ice core from the Saint Elias mountain range

Abstract

The El-Nino Southern Oscillation (ENSO) is the dominant mode of inter-annual variability of the atmosphere-ocean system in the tropical Pacific and exerts its influence in the extra-tropics through persistent large-scale wave-like patterns in the atmosphere known as teleconnections. Although the physics of ENSO in the tropics is relatively well understood, our knowledge of its extra-tropical response is based on teleconnection patterns that are statistical in origin and derived from relatively short time series. In this paper we analyze the ENSO signal in an annually resolved record of snow accumulation covering the period 1736-1985 from an ice core obtained in the Saint Elias Mountains of the Yukon. This region is located in the center of an area with one of the most significant teleconnection signatures associated with ENSO. The high elevation of the site where the ice core was obtained allows it to sample the mid and upper-tropspheric flow where the extra-tropical response to ENSO has its largest amplitude. As we show these characteristics of the site result in a significant ENSO signal in the snow accumulation time series.