1. Antonov J, Locarnini R, Boyer T, Mishonov A, Garcia H (2006) World Ocean Atlas 2005, vol 2: salinity. NOAA Atlas NESDIS 62
2. Ayrault F, Lalaurette F, Joly A, Loo C (1995) North-Atlantic ultra-high frequency variability: an introductory survey. Tellus Ser A Dyn Meteorol Oceanogr 47(5, Part1):671–696
3. Barnston A, Livezey R (1987) Classification, seasonality and persistence of low-frequency atmospheric circulation patterns. Mon Weather Rev 115(6):1083–1126
4. Bindoff N, Willebrand J, Artale V, Cazenave A, Gregory J, Gulev S, Hanawa K, Qur CL, Levitus S, Nojiri Y, Shum C, Talley L, Unnikrishnan A (2007) Observations: oceanic climate change and sea level. Climate change 2007: the physical science basis contribution of working Group I to the fourth assessment report of the intergovernmental panel on climate change
5. Bretherton C, Widmann M, Dymnikov V, Wallace J, Blade I (1999) The effective number of spatial degrees of freedom of a time-varying field. J Clim 12(7):1990–2009