18 
Sy, A. et al. (2002): Upper Ocean Climate Ship-of-Opportunlty Programme of BSH - A Status Report 
Paleo-climate records and model results show that climate changes have occurred in the 
geological past and have been associated with sometimes sudden changes of the MOC, i.e. 
within a few decades (Duplessy at al., 1988; Fichefet et al., 1994; Manabe and Stouffer, 1995). 
In extreme cases a more or less complete collapse of the MOC occurred which led to dramatic 
changes of the European climate. 
3.2 Some preliminary results 
As has been stated above, the northward transport of heat in the Atlantic Ocean is a key 
process governing the climate in Europe. Systematic measurements of temperature and current 
velocity are necessary to determine oceanic heat transport. Because basin wide direct current 
measurements are not available, the geostrophic method of calculating the relative velocities is 
appropriate to estimate currents and its transport rates from hydrographic data. To obtain the 
required information on the density field, derived from the measured distribution of temperature 
and salinity versus depth, BSH has carried out 10 transatlantic full depth CTD sections between 
the English Channel and the Grand Banks since 1992, supplemented by 6 XCTD sections 
(Table 3). For our upper ocean climate SOOP the XCTD depth range of only 600 m is just 
sufficient. Finally, XBT data are used to obtain a better statistical data base in time and space 
providing good access to the seasonal and long-term variability of the upper ocean thermal 
structure within the GOOS A-2 corridor. 
Table 3: Flydrographic sections carried out in the GOOS A2 corridor 1992 - 2002 
Cruise Date 
(vessel, cruise no.) (first/last profile) 
Year 
Instrument 
(type) 
depth 
(range (m)) 
Position 
(in corridor) 
Köln Express 172 
22.-26.2. 
1992 
XCTD 
600 
south 
Köln Express 177 
23.-26.7. 
1992 
XCTD 
600 
south 
Gauss 226/1 
16.-26.6. 
1993 
XCTD 
1000 
south 
Gauss 226/2 
6.-26.7. 
1993 
CTD 
bottom 
south 
Meteor 30/3 
15.10.-10.11. 
1994 
CTD 
bottom 
south 
Köln Express 195 
29.9.-2.10. 
1995 
XCTD 
600 
(north) 
Gauss 276/2 
13.5.-2.6. 
1996 
CTD 
bottom 
south 
Gauss 276/3 
16.-27.6. 
1996 
XCTD 
1000 
north 
Meteor 39/3 
13.-30.6. 
1997 
CTD 
bottom 
south 
Gauss 316/1 
1 .-20.5. 
1998 
CTD 
bottom 
south box 
Gauss 316/2 
30.5.-14.6. 
1998 
CTD 
bottom 
north 
Köln Express 212 
11.-14.-1. 
2000 
XCTD 
600 
north 
Gauss 350/1 
10.5.-4.6. 
2000 
CTD 
bottom 
south box 
Gauss 350/2 
10.-29.6. 
2000 
CTD 
bottom 
north 
Gauss 384/1 
21.5.-9.6. 
2002 
CTD 
bottom 
south box 
Gauss 384/2 
20.6.-7.7. 
2002 
CTD 
bottom 
north 
A first impression of the mean and fluctuating fields of the GOOS A-2 corridor can be 
obtained from Fig. 11 which shows the main features of the dynamical system of the North 
Atlantic Current regime in the transition zone between subtropical and subpolar gyres of the 
upper 750 m. The frontal system of the so-called ’’Cold Wall”, which separates the southward 
flow of cold Labrador Current water and the northward flow of warm NAC water, is clearly