It is clear in Figure 3(a) that the biggest rates of change are derived from the tidal component of the current.
To obtain the pure tsunami-induced currents, a filtering technique was applied to eliminate the natural surface current field, which included tidal components. The velocity measurements were achieving accuracy of a few cm/s, which means that the sensitivity of radar measurements was good enough to catch the small changes caused by the tsunami in deep water.
The largest tidal component
is the lunar principal wave M2 with a period of 12.42 hours.
TABLE I PRINCIPAL TIDAL COMPONENT FOR INGENIERO WHITE HARBOR TIDAL GAUGE [PHI] Tidal Component Speed (deg/hr) H (cm) ([degrees]) [Z.sub.0] 0.000 263.544 0.000 [M.sub.2] 28.984 169.123 186.072 L2 29.528 25.475 255.364 N2 28.440 23.983 103.593 M4 57.968 22.764 178.277 S2 30.000 21.589 307.350 K1 15.041 21.151 61.178 O1 13.943 15.528 0.701 MU2 27.968 14.523 291.531 NU2 28.513 10.954 137.915 H: amplitude, [PHI]: phase.
In contrast to traditional harmonic analysis, which is used only in the prediction of periodic tidal components, the neural network model can be trained to recognize and predict both nonlinear and nonperiodic signals.
where [A.sub.o]: mean water level, [A.sub.i] and [B.sub.i]: coefficients of tide components, [w.sub.i]: angular frequency of the tidal components, and N: number of component tides.
Thus, like the three aforementioned crabs, some horseshoe crabs display a complex pattern of activity that is a mixture of daily and tidal components
A daily average tide volume was computed from annual data, so the volume reflects a combination of tidal components
. Flood and ebb tides can be assumed symmetrical with respect to volume, within the resolution of the particular model application.
Daily and tidal components
in the persistent activity rhythms of the crab Sesarma.