49 
-90 -45 -4.0 -55 AO -25 -20 -1.5 -1.0 -0l5 OiO 0i5 1.0 1.5 20 25 50 55 4.0 4.5 50 -50 -45 -4.0 -55 -50 -25 -20 -1.5 -1.0 -05 00 05 1.0 1.5 20 25 50 55 4.0 4.5 50 
Fig. 7.2.3: Water level distribution after 1.5 hours (top left), 2.5 hours (top right), 3.5 hours 
(bottom left), and 4.5 hours (bottom right) (input signal: 3 positive single signals from 
W, T 1800 s, H 3 m, North-East Atlantic model 10 km) 
7.2.2 Travel times and water levels 
Travel times are read more accurately from local water level time series. At Plymouth (Fig. 
7.2.4), the first maximum of the signal coming from the south arrives after about 3 hours. The 
signal coming from the western boundary takes about twice as long and is evidently 
weakened, as compared to the initial signal. 
A signal from the northern boundary reaches Wick (Fig. 7.2.5) after a considerably longer 
time than it takes to reach the open North Sea near Shetland (Fig. 7.2.6). It arrives at Wick 
almost after the same time as the signal from the western boundary. However, the two 
signals differ significantly in shape. The signal from the south arrives 2 hours later than the 
northern and western signals. In all three cases, the maximum water level is lower than the 
initial wave height. 
In contrast, in Fig. 7.2.6, the signal from the northern boundary has clearly increased to 5 m 
wave height due to shoaling. The signal from the west has the same height as that arriving in 
Wick. The latter two signals have different shapes. Near Shetland, the western signal has 
preserved its initial shape (3 single waves, 7=1800 s), while in Wick the water level for the 
western signal reaches values of up to 2 m which last for more than 4 hours.