Figure 5

Time evolution of observed and modeled fronts of internal waves in the vicinity of the IORS. Time series of directional (subsampled) measures of distance D in meters (y-axis), from the topographic sill (origin) to the internal wave fronts as functions of time t (x-axis) and direction θ in degrees rotated counterclockwise from the east (numbers labeled in the right of filled circle symbols in the upper plots) for cases of (a) September 10, 2014, (b) June 3, (c) June 5, and (d) June 12, 2015. In the lower panel, surface expressions of leading internal wave fronts ((a) from ‘A’ to ‘H’ in September 8–10, 2014; (b) ‘J’ in June 3, 2015; (c) ‘K’ in June 5, 2015; (d) ‘L’ and ‘M’ in June 12, 2015) observed by the SAR images (pink for 2014 and orange for 2015) and estimated (cyan and green for successive but distinct waves; (a) and (e), and blue for a single wave; (b) and (c)) are compared in the polar coordinate. In (a) and (d), multiple local origins (arbitrarily shifted) are used for better comparisons. Thick green shaded lines in (a) denote the cases in which free wave speeds c _i are doubled to show the sensitivity of the estimation to density stratification. In each panel, hodographs of horizontal current vectors at the IORS reproduced by the ROMS are shown above. They correspond to absolute horizontal (tidal plus subtidal) current vectors (u _i , v _i ) at the four layers (centered at 5, 15, 25, and 35 m) of the station (a) from 22:00 UTC September 9 to 22:00 UTC September 10, 2014, (b) from 22:00:00 UTC June 2 to 22:00:00 UTC June 3, 2015, (c) from 22:00:00 UTC June 4 to 22:00:00 UTC June 5, 2015, and (d) from 22:00:00 UTC June 11 to 22:00:00 UTC June 12, 2015. Here, the surface layer current vectors (u₁, v₁) at the starting time, time of wave generation, and the SAR image acquisition time are remarked with blue circles, red arrows, and orange arrows, respectively.