Double peak-flood current asymmetry in a shallow-water-constituent dominated embayment with a macro-tidal flat

摘要

Tide and tidal current distortions were examined in Hampyung Embayment, a shallow, semidiurnal tide-dominated bay with large tidal flats, via in situ monitoring. Harmonic analyses reveal that the shallow-water constituents of the tides and tidal currents are strong in this restricted setting relative to on the open coast. In particular, the amplitudes of the shallow-water currents constituents (M-4, MS4, M-6, 2MS(6)) are three times greater than those of the diurnal constituents (K-1, O-1). The quarter-diurnal (M-4 + MS4) and sexta-diurnal (M-6 + 2MS(6)) current amplitudes account for >35% and >17% of the semi-diurnal current (M-2 + S-2) amplitudes, which account for >42% of total amplitude. The MS4 current amplitude is as important as that of the M-4 amplitude in the middle of the bay. Such strong generation of shallow-water velocity constituents induced by non-linear processes leads to an ebb-dominated tidal regime with double-flood current-velocity peaks.