2), at approximately 100 m from the shore (Offshore Tripod Location, hereafter TPL-1) and at about 20 m from the shore (Onshore Tripod Location, hereafter TPL-2).
Because TPL-1 was located about 90 m west-southwest of TPL-2, the waves approached the measurement site at an angle with respect to the line between the tripod locations.
As the tripod at TPL-2 was deployed later, the echosounder at that location started recording on 29 June 2013.
It is also visible for all three events that the vertical structure corresponding to the leading wave packet becomes more prominent at the TPL-2 location.
The top panel shows the original spectrograms at the TPL-1 and TPL-2 locations, whereas the bottom panels show the parts of the spectrogram where the PSD values are larger at TPL-1 than at TPL-2 (left-hand side), and vice versa (right-hand side panel).
Table 1 shows the potential energy for two wake events, measured at TPL-1 and TPL-2, and the relative contribution of different wake components as percentage of the total.
The wake from the Superstar shows a similar reduction in divergent waves, whereas the contribution from the transverse waves was conserved from TPL-1 to TPL-2 (at about 3.9 x [10.sup.3] J x s/[m.sup.2]).
where [d.sub.TPL-1] and [d.sub.TPL-2] are water depths at the TPL1 and TPL-2 locations, respectively.
The reduction in the potential energy for the divergent waves between TPL-1 and TPL-2 can probably be attributed to a combination of spilling wave breaking and wave reflection.