Lyttelton Harbour Waves

In the figure to the left, the upper panel shows:

• the residual (blue), which is the raw tide-gauge signal with the tide removed, and
• the smoothed residual (red), which is the residual with the harbour waves removed.

The lower panels show the three components of the harbour waves:

• Pegasus Bay seiche - 3.4 hour period - oscillation of Pegasus Bay at its natural frequency
• Harbour seiche - 1st (99 min) and 2nd (48 min) modes - longitudunal oscillation of the harbour
• Long waves - 3 to 24 min periods - far infra gravity (FIG) waves associated with swell waves

Some examples of harbour waves with commentary are presented here