The Summer North Atlantic Oscillation: Past, Present, and Future

Abstract Summer climate in the North Atlantic–European sector possesses a principal pattern of year-to-year variability that is the parallel to the well-known North Atlantic Oscillation in winter. This summer North Atlantic Oscillation (SNAO) is defined here as the first empirical orthogonal function (EOF) of observed summertime extratropical North Atlantic pressure at mean sea level. It is shown to be characterized by a more northerly location and smaller spatial scale than its winter counterpart. The SNAO is also detected by cluster analysis and has a near-equivalent barotropic structure on daily and monthly time scales. Although of lesser amplitude than its wintertime counterpart, the SNAO exerts a strong…

• DF
  Department for Environment, Food and Rural Affairs, UK Government

  Awards: CBC/2B/0417_Annex C5, GA01101
• EC
  European Commission
• MO
  Met Office

  Award: GA01101
• V
  Vetenskapsrådet