Testing of the Tropically Excited Arctic Warming Mechanism (TEAM) with Traditional El Niñ o and La Niñ a

• Main Author: Sukyoung Lee
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1089.2575; http://www.meteo.psu.edu/%7Esxl31/papers/Lee_ENSO.pdf

ABSTRACT By analyzing El Niñ o and La Niñ a composites with 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) data, evidence is presented here that the surface air temperature of the Arctic winter (December-February) is anomalously warm during La Niñ a and cold during El Niñ o. Surface and top-of-the-atmosphere energy fluxes were used to calculate the composite zonal-mean poleward moist static energy transport. The result shows that the La Niñ a warming in the Arctic is associated with an increased poleward energy transport in the extratropics. The opposite characteristics are found for El Niñ o. Because the total tropical convective heating is more localized during La Niñ a than El Niñ o, these findings suggest that the Arctic surface air temperature anomalies associated with ENSO may be attributed to the tropically excited Arctic warming mechanism (TEAM). In the tropics, consistent with previous studies, the anomalous poleward energy transport is positive during El Niñ o and negative during La Niñ a. Given the debate over whether a warmer world would take on more El Niñ o-like or La Niñ a-like characteristics, the findings of this study underscore the need for further investigation of tropical influence on polar climate.