On North Atlantic Intedecadal Variability: A Stochastic View
a)
b)
120W : ..
60W
1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990
.'
-~ ' . .
,, '
"
............
...
'.'
.:. ~.
30W
.. '
o
'. '.
30E
151
120E
60E
Fig. 9.1 a) Time series of the North Atlantic Oscillation (NAO) index as defined by the
normalized SLP difference between Lisbon (Portugal) and Stykkisholmur (Iceland). b)
Spatial pattern ofthe NAO as defined by the difference in SLP between 'high' and 'Iow NAO
index' winters. From Hurrell (1995).