Tab. 5 cont. 
21 
Sampling depth = 55 m 
Sampling depth = 75 m 
Sampling depth = 205 m 
MIO 
EC 
NC 
EC 
NC 
EC 
NC 
210m 
H 
G 
H 
G 
H 
G 
H 
G 
H 
G 
H 
G 
Q, 
- 
- 
- 
- 
- 
- 
- 
- 
.54 
105 
1.02 
198 
O, 
1.74 
275 
2.93 
249 
1.79 
288 
2.47 
252 
.98 
256 
3.52 
249 
M, 
.66 
313 
1.43 
343 
1.19 
6 
2,40 
314 
.57 
67 
1,40 
314 
K, 
1.39 
72 
2.26 
41 
1.51 
98 
1.78 
53 
.54 
73 
1.94 
42 
MNSj 
1.20 
34 
.80 
270 
- 
- 
- 
- 
- 
- 
- 
— 
O2 
1.96 
255 
1.46 
160 
.37 
271 
1.00 
171 
- 
- 
- 
- 
N2 
- 
- 
- 
- 
1.00 
248 
.95 
180 
.92 
212 
1.23 
156 
M 2 
3.12 
319 
6.66 
238 
1.17 
251 
3.03 
235 
2.83 
153 
2.14 
186 
s 2 
1.24 
218 
,79 
250 
- 
- 
- 
- 
.93 
220 
1.09 
211 
MSN : 
1,51 
336 
1.44 
251 
- 
- 
- 
- 
- 
- 
- 
- 
2SM 2 
1.02 
302 
.72 
199 
- 
- 
- 
- 
- 
- 
- 
F = 
0.72 
F =0.10 
F = 
0.40 
F = 
1.69 
Results are listed only, if the amplitude of one of the two components is greater than 1 cm/s 
EC = east component 
NC = north component 
H = amplitude (cm/s) 
G = phase (degree) 
F = form ratio (K, + 0|) / (M ; + S 2 ) 
The reliability of tidal constituents determined from a single month of data is problematic. The har 
monic constituents derived from each time series were therefore synthesized to allow a comparison with the 
results of the reference to HW Aberdeen. If the time series contain a recognizable tidal signal, both methods 
yield reliable results. If non-tidal variability dominates, neither method is successful. However, it is simpler 
to describe local tidal streams by using the relation between the tidal stream and HW at a reference station 
than by using harmonic analysis and synthesis. 
Generally, phase errors increase with decreasing amplitudes of the constituents. The amplitude errors 
which are less than 1 cm/s are often of the same order of magnitude as the amplitude itself. The amplitude 
and phase of the M 2 stream constituent presented in this paper can be compared with data published by 
Davies and Fumes [1980]. Despite large vertical and horizontal variations of amplitudes and phases, 
there is good agreement: not only with respect to the amplitudes of the components, but also with regard to 
the phases of the dominant north component. Figure 7 shows the phases of the M 2 and S 2 north components. 
In our view the number and distribution of data points are insufficient for a more detailed presentation of 
isolines. As regards the NORA section, the M 2 and S 2 constituents of the north component suggest a phase 
lag from west to east of about one hour, confirming the delay of the overall tidal stream which is evident in 
the stream ellipses. 
The M 2 and S 2 amplitudes of both stream components in the NORA and MO YENS section are shown 
in Figure 8. The amplitudes of the north components are at least twice as large as those of the east compo 
nents in the NORA section except near the surface at position N8. In the MOVENS area, however, the am 
plitudes of both components are relatively small and are approximately of the same order. 
The ratio between the amplitudes of the diurnal constituents K, and O] and those of the semi-diurnal 
constituents M 2 and S 2 gives the form ratio F which determines the type of the tide: 
F=(K, + 0,)/(M 2 +S 2 ). 
If F is smaller than 0.25, as is the case for the components of the major stream axis along the NORA 
section, the tide is semi-diurnal. Values between 0.25 and 1.50 indicate a mixed but mainly semi-diurnal tide 
with large inequalities in range and time between the high and low waters each day. In the MOVENS sec 
tion, F is larger than 0.3, indicating mixed tidal stream conditions (see Table 5).