以往对渤、黄、东海潮汐数值模拟中使用的摩擦系数大都采用不随地点变化的常数,即采用Chezy型摩擦。为了改善模拟效果,本文比较了Chezy型和广义Manning型摩擦关系,并选择与实测数据符合最好的参数,即最优参数。结果表明,采用广义Manning型摩擦系数所得结果更好。底摩擦系数在0.0009至0.0014之间,显著低于Proudman(1953)给出的0.0026,也比以往大多数已发表的值小。与原始的Manning公式不同(该公式的幂值为负数),本研究得到的幂值为正,表明在渤、黄、东海陆架区。总体上,水体越浅摩擦系数越小。本文给出了根据最优Manning型摩擦参数模拟得出的同潮图和能通量分布图,并描述了它们的特征。
Earlier numerical tidal simulations for Chinese eastern shelf seas(Bohai Sea, Yellow Sea, and East China Sea) often use a constant friction coefficient for all areas(the Chezy-type friction). We compared the Chezy-type with the generalized Manning-type friction, and chose the optimal parameters to fit best the observation. The results show that the modeling in the generalized Manning-type friction was more accurate than in the Chezy-type. In addition, the friction coefficients we recalculated for the study area range from 0.0009 to 0.0014, much smaller than 0.0026 given by Proudman in 1953 that often adopted previously. Different from the negative exponent in the original Manning formula, the exponent we obtained is positive, indicating that the shallower the water mass, the smaller the coefficient. In the generalized Manning-type, we reproduced cotidal charts and energy flux maps with new optimal parameters for the study area.