282
1960
1970
1980
1990
2~~~~~~~~~~~~~~~~~~~~~~2
-1
- . - OVIIS. "C"
--0-. 1ST EOF
North Atlantic Ocean
Depth of 125 meters
Gl
I
I
I
I
\
I
\ I
\I
/!;
, 0
~
\
\
-1
-2
-2
1960
1970
Year
1980
1990.
Figure 9: Time series of subsurface temperature anomalies at 125 m measured at weather
ship "e" (35.5°W, 52.5° N) and time series of the first EOF (multiplied by -1) of North
Atlantic temperature anomalies at the same depth. Redrawn after Levitus et al. (1994).
LX only in our simple coupled model. Thus, the wind stress curl is given
by the meridional derivative of LX :
(2)
The (mean) forcing curl I. for our ocean model is assumed to be of
the form A· sin(21T-fi), with B the meridional extent of the basin. This is
a reasonable approximation of the real westwind regime in mid-latitudes,
leading to a double-gyre circulation which can be identified with the subtropical and subpolar gyres.
The coupling with the atmosphere is respresented in a rather crude way
and by wind stress only. Consistent with the scenario developed above, we