Green’s function retrieval in a field of random water waves

• Water wave interferometry is described theoretically and investigated experimentally.
• Simulations and wave tank measurements are in agreement with theoretical predictions.
• Ocean-based measurements are not in agreement with theoretical predictions.
• Probable reasons for failure of the ocean-measurement-based analysis are discussed.

It has recently been demonstrated using a variety of wave types that cross-correlating time series of apparently random waves measured at two locations yields an estimate of the Green’s function that describes the wave field generated at one of those locations and measured at the other. This procedure can be described as random wave interferometry. In this paper random surface gravity wave interferometry is described theoretically, demonstrated using numerical simulations, and investigated experimentally using both wavetank measurements and ocean wave measurements. Simulations and wavetank measurements are in good agreement with theoretical predictions, but the ocean-measurement-based cross correlations do not yield the predicted structure. Possible explanations are discussed.