Vertical displacement loading tides and self-attraction and loading tides in the Bohai, Yellow, and East China Seas

Abstract

The loading tides are calculated by means of the Green’s function method based on a high-resolution regional ocean tide model, the TOPO7.0 global ocean tide model, and the Gutenberg-Bullen A Earth model. The results show that the maximal amplitude of M₂ vertical displacement loading (VDL) tide in the Bohai, Yellow, and East China Seas exceeding 28 mm appears 150 km off the Zhejiang coast; the second maximum exceeding 20 mm appears in Inchon Bay; and the third maximum exceeding 14 mm is located in the northeast of the North Yellow Sea. The maximal amplitudes of S₂ VDL tide at the above three locations exceed 10, 8, and 4 mm, respectively. The maximal amplitudes of the K₁ and O₁ VDL tides, exceeding 13 and 10 mm respectively, appear near the central and north Ryukyu Islands; the amplitudes tend to decease toward the inward areas. The phases of semidiurnal VDL tides are basically opposite to those of corresponding ocean tides. The phases of diurnal VDL tides are basically opposite to those of corresponding ocean tides in the most part of the East China Sea and the eastern part of the South Yellow Sea. This anti-phase relationship generally does not hold in the rest parts of the Bohai and Yellow Seas. The distribution patterns of self-attraction and loading (SAL) tides are very similar to those of VDL tides. The SAL tides have amplitudes about 1.2–1.7 times of the corresponding VDL tides and their phases are basically opposite to the corresponding VDL tides. The maximal amplitude of M₂ SAL tide also appears off the Zhejiang coast, with a magnitude exceeding 42 mm.