Influence of Atlantic SST anomalies on the atmospheric circulation in the Atlantic-European sector

• Main Authors: E. Kestenare, P. Friederichs, C. Frankignoul
• Format: Article
• Language: English
• Published: Istituto Nazionale di Geofisica e Vulcanologia (INGV) 2003-06-01
• Series: Annals of Geophysics
• Subjects: air-sea interaction; climate variability; Atlantic SST anomalies
• Online Access: http://www.annalsofgeophysics.eu/index.php/annals/article/view/3390
• ISSN: 1593-5213; 2037-416X

Recent studies of observational data suggest that Sea Surface Temperature (SST) anomalies in the Atlantic Ocean
 have a significant influence on the atmospheric circulation in the Atlantic-European sector in early winter and in
 spring. After reviewing this work and showing that the spring signal is part of a global air-sea interaction, we
 analyze for comparison an ensemble of simulations with the ECHAM4 atmospheric general circulation model in
 T42 resolution forced by the observed distribution of SST and sea ice, and a simulation with the ECHAM4/OPA8
 coupled model in T30 resolution. In the two cases, a significant influence of the Atlantic on the atmosphere is
 detected in the Atlantic-European sector. In the forced mode, ECHAM4 responds to SST anomalies from early
 spring to late summer, and also in early winter. The forcing involves SST anomalies not only in the tropical
 Atlantic, but also in the whole tropical band, suggesting a strong ENSO influence. The modeled signal resembles
 that seen in the observations in spring, but not in early winter. In the coupled mode, the Atlantic SST only has a
 significant influence on the atmosphere in summer. Although the SST anomaly is confined to the Atlantic, the
 summer signal shows some similarity with that seen in the forced simulations. However, there is no counterpart in
 the observations.