Volume 51 (1999) Number 4 
473 
tide period [h] 
M 2 
12.4 
energy density [(cm/s) 2 /cph] 
M 4 , MS 4 
6.2 
M 6 , 2MS 6 
4.2 
model 
u-comp. 
4 m: 
303941 
1682 
373 
v-comp. 
4 m: 
25749 
255 
42 
ADCP 
u-comp. 
6 m: 
311958 
2947 
312 
v-comp. 
6 m: 
12216 
1341 
223 
model 
u-comp. 
18 m: 
237147 
1822 
199 
v-comp. 
18 m: 
44562 
197 
32 
ADCP 
u-comp. 
18 m: 
234280 
3061 
327 
v-comp. 
18 m: 
40134 
179 
77 
model 
u-comp. 
34 m: 
150306 
1098 
280 
v-comp. 
34 m: 
37854 
165 
182 
ADCP 
u-comp. 
34 m: 
131285 
1384 
789 
v-comp. 
34 m: 
37009 
200 
269 
Table 5: Spectral energy density distribution 
6 Water level 
The modelled water level data are given in me 
tres relativ to NN. The WLR data give the absolute 
pressure at the sensor in dbar. After recovery, the 
data were corrected for atmospheric pressure vari 
ations and related to the mean pressure value to 
be comparable to the model data. The correlation 
between both curves is 0.99, the mean difference 
amounts to 0.11 ± 0.08 m. Figure 7 shows the time 
series of both curves for the first 30 days and the 
difference (WLR - model) between both curves. 
For this figure, the time series have been averaged 
to 30-minute values. During neap tide the ampli 
tude of the model data is smaller than the ampli 
tude of the measured values while during the 
spring periods a small offset of the model values is 
observed. 
June July 
1999 
Fig. 7 Model sea level data (red), WLR measurements (black), and difference WLR-model (blue). The data are aver 
aged to a 30 minutes time interval.