Tidal evolution in the Yellow and East China Sea during holocene

The impact of the sea level (SL) change on the propagation of tides in the Bohai Sea, Yellow Sea and East China Sea (BYECS) during Holocene was investigated by a 3D numerical model with SL of -60, -30, -15, 0 and +2 m, respectively. Same amplitude and phase of tidal constituents M2, S2, K1 and O1 were applied along the open boundaries in all the cases. The results showed that the number of amphidromic points of M2 increased from 2 to 4 while that of K1 increased from 1 to 2 as the SL rising. Both M2 and K1 co-phase lines rotated anti-clockwise as sealevel rising. S2 shared similar evolution pattern with M2 while O1 evolved similarly with K1. The +2 m SL can have significant influence on the tide pattern. Mainly because the new basin area enlarged, especially the vast area around the Subei and Changjiang estuary, also very near the amphidromes in the south Yellow Sea, which dissipated large amount of tide energy. The new coastline and bathymetry changed the propagation pattern of M2, the tide energy decreased significantly at the north Yellow Sea and Bohai Sea while increased along the Yangtze estuary and Korea west coast. The strong tidal current area corresponded well with the sand ridges during Holocene while weaker tidal current area corresponded with finer muddy deposit, indicating tide force is the dominate factor controlling the bedform generation and sediment distribution in BYECS.