Monday, 10 January 2005
Modeling Bering Sea Tides
Tides provide important driving force in the Bering Sea, and play an important role in such oceanographic processes as transportation of nutrients, sediment resuspension, the distribution of benthic and intertidal organisms. We focus on modeling five tidal constituents: two semidiurnal components (M2, N2) and three diurnal components (K1, O1, Q1). The POM (Princeton Ocean Model) is used to simulate tides. The modeling area covers from 157° E to 218° E, and from 48° N to 70° N. The space resolution along latitude is 5 minutes (9.26 km), and along longitude is 10 minutes (about 9.26 km). The total grid size is 366 x 264 x 16. Two semidiurnal components (M2, N2) show similar pattern in amplitude, phase, velocity and energy flux, so do three diurnal components (K1, O1, Q1). The amplitude of the M2 tide shows obviously unchanged at the shelf break area in both the Bering Sea and south of the Aleutian Islands of the North Pacific Ocean, whereas the amplitude of the K1 tide increases in the same area. In the deep basin of the Bering Sea, the amplitude of the K1 tide is higher than that of the M2 tide, whereas in the most shelf areas and bays in the Bering Sea, the amplitude of the K1 tide is less than that of the M2 tide. K1 tidal current shows a stronger tendency in interaction with the bathymetry than that of M2 tidal current. M2 tidal velocity tends to be increased in shallow water and around Islands. K1 tidal velocity increases not only in shallow water and around Islands, but also in the shelf break. Simulation results show that K1 tidal velocity obtains its maximum value in Aleutian Islands and off Cape Navarin. Energy flux patterns of semidiurnal and diurnal tides are quite different. There is more energy flux from north to south in K1 tide than that in M2 tide in Bering Sea. Around Aleutian Islands, divergent K1 energy flux results in divergent K1 current and decrease in K1 sea level or K1 amplitude in several areas. Based on magnitude of amplitude, velocity, and energy flux, M2 is a dominant tidal component in the Bering Sea, nevertheless, both K1 and O1 components also play a comparable important role.
Investigation of interaction among five tidal constituents, harmonic analysis and residual tidal currents in the Bering Sea is also conducted.