11 6
a) ·5
·4
·3
·2
., 0
2
3
4
5
5
5
4
4
3
3
2
2
....
u.
0
w
c
0
0
0
t .,
.,
·2
·2
·3
·3
·4
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·5
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5
Pro). on EOF 4
b)
Figure 13: a) 2-D cut of the PDF from 100 consecutive winters of a multi-decadal integration in the T21L3 quasi-geostrophic model of Marshall and Molteni (1993). b), c) The
model empirical orthogonal functions , used to define the axes in a). From Palmer et at
(1994) .