Numerical Simulation Of Tidal Wave In The Sea Area Around Taiwan Island And The Expansion Of Minjiang River Diluted Water In Winter

At first, Three-dimensional model POM(Princeton Ocean Model) was tested for its feasibility and effectiveness in the Numerical simulation for tide and tidal current in the sea area around Taiwan Island, and then by using the field data and the reanalysis monthly mean data, the influence of Minjiang runoff and sea surface wind were analysed in the model, in order to understand the characteristics and dynamic mechanism of Minjiang river diluted water in winter.Research area includes southern East China sea, Taiwan strait, northeastern South China sea, east of Taiwan and Luzon strait. To validate the results of tide and tidal current numerical simulation, the calculated tidal harmonic constants were compared with the observed ones at thirty eight tide gauge stations, the calculated tidal level and tidal current data were compared with tide table data and ADCP measured data respectively. The results showed that,the mean absolute error of M2 constituent between the computed and the observed harmonic constants are 5.8cm and 5. 1°for amplitudes and phase lags respectively, the computed tidal level and tidal current results were very near to the observed ones too.Impacted by the sea surface wind, Minjiang runoff, climatic factors in winter, Minjiang river diluted water have characteristics as follows: the diluted water extended along the Fujian coast and towards the South direction under the effect of northeaster, the diluted water might extended southward to 25. 15°N and extended eastward to 120.2°E hereabout at low tide.Halocline was obvious in Minjiang estuary. Depth of halocline inceases gradually from nearshore to open sea. Intensity of halocline in neap tide exceeds that in spring tide, depth of halocline in neap tide is deeper than in spring tide too. In one tidal cycle, Intensity of halocline in low tide exceeds that in high tide, depth of halocline in low tide is deeper than in high tide.Minjiang runoff and sea surface wind change from year to year. If annual mean Minjiang runoff was used (annual mean runoff is about 2. 5 times monthly mean runoff in January) , the Minjiang river diluted water might extend southward to 25°N hereabout and extend eastward to east of 120. 2°E at low tide. Intensity of halocline was enhanced when Minjiang runoff inceased. While the sea surface wind was increased to 1. 5 times the climatic value of January, the diluted water might extended southward to Shenhu bay hereabout and extended eastward to 120°E hereabout at low tide. Intensity of halocline was weekened when surface wind force increased.