Here we show the process as described in Section 2.3 for the BRIG transmitter only. Panel A is the Lomb-Scargle periodogram performed on the CODAR-derived virtual heights. Panel B is the CODAR-derived virtual heights (black dots) with the reconstructed waveform based on the dominant 8-hour period of oscillation plotted over top (red curve). Panel C is the CODAR-derived virtual heights with the dominant 8-hour trend removed and the reconstructed waveform plotted over top (red curve). Panel D is the Lomb-Scargle periodogram based on the data shown in panel C. The dashed line refers to a significance level of 0.01.