Numerical modeling of waves for a tsunami early warning system

Numerical modeling of waves for a tsunami early warning system
case. Thus the far field sea level gauges reproduce the more regular waves,
radiating offshore, and the near field gauges measure a more complex wave
field, composed by irregular and nonlinear waves.
ηS12(m)
ηS7(m)
ηS10(m)
0.02
0.01
0
−0.01
−0.02
12 14 16 18 20 22
0.02
0.01
0
−0.01
−0.02
12 14 16 18 20 22
0.02
0.01
0
−0.01
−0.02
12 14 16 18 20 22
t(s)
ηS20(m)
ηS11(m)
0.02
0.01
0
−0.01
−0.02
12 14 16 18 20 22
0.02
0.01
0
−0.01
−0.02
12 14 16 18 20 22
t(s)
Figure 4.31: Comparison of the free surface elevations at the near field gauges
position, measured (red dashed line) and obtained from the numerical model
(black solid line). The numerical results are achieved by using the registration
of the free surface elevation at the gauge 12S to estimate the wave source
term.
Figure 4.30 shows the wave energy spectra for the same simulation at
gauge 12S and 15S. The dashed red lines again represent the energy
spectra measured experimentally and the solid black one the energy spectra
calculated by the numerical model. It is shown only the wave energy spectra
at two gauges, choosen as representative of the wave field near and far
from the generation/shallower area. From the figure it can be noted that
the wave gauge 12S register a wave energy spectrum which presents two
maxima, the higher frequency one is not simulated by the numerical model
implemented as described before. As already said, only the frequencies up to
2 Hz are solved numerically, thus, as can be view by the figure 4.30, even the
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