Numerical Simulation Of Hydrodynamics And Eco-dynamics Applied To The Jiaozhou Bay

In this paper, a one-year baroclinic current numerical simulation is applied for theJiaozhou Bay and its adjacent sea, implementing an unstructured grid，Finite-VolumeCoastal Ocean Model(FVCOM)，with wind and heat fluxes as atmospheric forcing. Atopen boundary, the model is driven by elevation from prediction including8mainpartial tides. Harmonic analysis provides co-tidal chart and iso-amplitude line toillustrate the propagation property of M2, S2, O1and K1, as well as current ellipsedistribution map. Euler residual current vector graph and sea surface temperaturedistribution map show the temporal and special variability. Then，an appropriateeco-dynamics box model composed by the dominant species in the Jiaozhou Bay isconstructed in order to explore the seasonal variations of the state variables in theecosystem. On this basis, a three-dimensional physical-biological coupled model forqualitatively studying the spatial and temporal variations of primary productivity inthe Jiaozhou Bay is developed, followed by the analysis and discussion. Significantresults and useful conclusions have been achieved in the following aspects:1) FVCOM is applied to study the tidal currents and circulation patters in the JiaozhouBay, in order to provide physical background for the transport of substances. Thesimulation recovers the hydrodynamics of the Jiaozhou Bay, indicating that stationarywaves are dominant in the tidally-driven system. Tidal currents in most areas flowback and forth, with eddy-structure especially near the mouth of the bay. Affected bycoastal line and topography, Euler residual current is featured by the4main eddies.2) The water temperature of the Jiaozhou Bay has distinct seasonal variation.Generally, in the offshore area outside the Jiaozhou Bay, the isothermals lie in thedirection of northeast-southwest, with a mild inter-annual fluctuation in values, whilewithin the Bay, isothermals mostly go parallel to the isobaths. The amplitude contourof temperature variation also approximately parallels to the shoreline, with smallranges at the mouth and in the middle of the Bay and large variations in the coastal seas, which reflects the impact by solar radiation and the intrusion water from theYellow Sea on the annual variation.3) A zero-dimensional biological model FBM (Flexible Biological Module) isemployed to simulate the seasonal variations of main ecological variables (i.e.,large-phytoplankton, small-phytoplankton, zooplankton, inorganic nitrogen, inorganicphosphorus and detritus) in the Jiaozhou Bay. Seasonal characteristics of theecosystem are depicted and the relationships between different ecological variablesare analyzed. Numerical results show that the biomass of phytoplankton has abimodal distribution annually, with two algal blooms occurring in March andSeptember, respectively. Nutrients and phytoplankton are in negative correlation.4) One-way coupling of FBM with FVCOM is performed to carry out thethree-dimensional numerical simulation of the ecosystem dynamics in the JiaozhouBay. The biological model FBM is simplified (i.e., only phytoplankton, zooplankton,nutrients and detritus) to highlight the effect of the physical mechanism on biologicalmodels. The temporal and spatial distribution patterns of phytoplankton and nutrientsare analyzed and the relationship between them is interpreted consequently.