12 
speed cm/s speed cm/s speed cm/s 
column with an estimated volume transport of 6xl0 5 m 3 /s between 3° 30’ E and 4° 30’ E (see Figs. 2 and 3). 
At M9, the deepest station in the trench, there is an outflow of about 2xl0 5 mVs below a depth of 300 m and 
an inflow of about 4xl0 5 m 3 /s above 150 m depth. At M7 there is a northwestward outflow below 200 m 
and a westward outflow in the upper 150 m. Regarding the general circulation pattern as outlined in figure 1 
and the inflow at M8 and at M9 in the upper 150 metres, we would have expected an inflow of AW at M7 
at least in the upper 100 metres. However, there is an outflow from September 7 to September 29. Thereafter 
the current rotates slowly anticyclonically, reaching its initial (outflow!) direction on October 12. With the 
exception of the first few days the distinct directional tidal signal is suppressed and the (scalar) velocity is 
enhanced (see Fig. 4b). This pattern can be observed in all sampling depths at M7. For comparison. Figure 
4 shows the unfiltered time series of M8, M7, and M9 in 286 m, 288 m, and 300 m depths, respectively. Evi 
dent are the directional stability at M8 at the western slope of the trench (Fig.4c) and the great directional 
variability at M9, close to the center of the broad opening of the Norwegian Trench (Fig.4a). Here the time 
series shows a steady succession of eddy structures, rotating both cyclonically and anticyclonically. These 
current structures represent a signal which is evident in all depth levels. Especially in 240 m depth the low- 
passed current is extremly variable with a stability factor of only 9% and negligible volume transport (see 
Table 3). 
1986 1986 1986 
Fig. 4 Time series of current speed and direction (unfiltered data): 
a) M9, 300 m sampling depth, 
b) M7, 288 m sampling depth, 
c) M8, 286 m sampling depth. 
The M6 mooring was positioned about 60.5° N at the western edge of the Norwegian Trench. There is 
an inflow of AW down to a depth of about 250 m, but close to the bottom we observe an outflow like that 
at M9. In general, the stability factor is less than 32%. 
3 Tidal Streams and Tides 
3.1 Relating Tidal Streams to Aberdeen as the Port of Reference 
The previous part mainly dealt with low-passed current meter data. Residual currents are shown to vi 
sualize the general in- and outflow pattern and the respective volume transports are estimated. This part fo 
cusses on tidal streams and elevations. Firstly, we give a more qualitative description of the tidal streams 
and the variation of tidal stream figures along our sections. In a more quantitative approach we determine 
up to 17 tidal constituents by means of harmonic analysis. Our analysis of observed tidal elevations will be 
compared to model results. 
direction deg direction deg direction deg