Influence of vertically shearing currents on surface wave spectra

The potential approach has been considered a reliable standard in computing wave directional spectra from instrumental measurements. However, by definition, it neglects ambient shearing currents. We present a proof that this oversight can lead to significant deviations of first-order in wave directional spectra estimates (height and direction), and propose a methodology based on rotational theory. The study demonstrates that shearing currents must not be neglected in wave data processing. A comparison of the rotational and potential approaches using the Acoustic Doppler Current Profiler (ADCP) dataset reveals notable and consistent differences in wave parameter estimation for $i\phantom{\rule{0}{0ex}}n$ $s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ data.