Understanding sea temperature-atmospheric pressure links in the North Atlantic

ScienceDaily (Mar. 29, 2009) — Feedback effects between the ocean and atmosphere are important to understanding the mechanisms affecting climate variations.

Previous studies have found that atmospheric anomalies associated with a variation in atmospheric pressure above the North Atlantic Ocean called the North Atlantic Oscillation produce a three-part pattern (tripole) of sea surface temperature anomalies at midlatitudes. Scientists refer to such anomalies as the North Atlantic sea surface temperature tripole, and scientists have debated to what extent the atmosphere responds to these midlatitude sea surface temperature variations.

Reporting in the journal Geophysical Research Letters, Mochizuki et al. identify oceanic feedback signals poleward of the tropics, taking a new approach based on a model used in four-dimensional variational data assimilation to determine the sensitivity of the model to fluctuations in physical variables.

Their results reveal that oceanic thermal feedback beyond the tropics is an important process influencing the North Atlantic Oscillation, providing a better understanding of the factors affecting climate variations in the North Atlantic.

The authors include: Takashi Mochizuki, Toshiyuki Awaji, and Nozomi Sugiura: Frontier Research Center for Global Change, JAMSTEC, Yokohama, Japan; Awaji is also at Department of Geophysics, Kyoto University, Kyoto, Japan.

Mochizuki et al. Possible oceanic feedback in the extratropics in relation to the North Atlantic SST tripole. Geophysical Research Letters, 2009, 36 (5), L05710; DOI: 10.1029/2008GL036781

Link to article: http://www.sciencedaily.com/releases/2009/03/090325155634.htm