Video Based Estimation of Surface Currents in a Tidal Inlet

Abstract Oceanic surface currents are estimated from analysis of short duration video obtained by a nadir facing camera installed on a bridge over a tidal inlet. Data analyzed consisted of 13 two-minute video clips captured approximately every 40 min over a period of 8 hr, covering a significant portion of the tidal cycle. Surface current speed and direction estimates are obtained from each collected video using (i) a method originally developed for analysis of imagery from drones (CopterCurrents) and (ii) a particle tracking method. The horizontal (u, v) surface current velocity components and total horizontal velocity magnitude, obtained from the two methods, were in very good agreement with each other ( R 2 = .96 and Root Mean Square (RMS) differences of 0.12 m/s or less). Our analysis suggests that video cameras from stationary structures can provide surface flow measurements over inland waters and navigational channels where deployment of in-situ sensors is not feasible.