渤海M2分潮的伴随模式数值实验

根据渤海海域内M2潮汐调和常数的实测值,采用伴随方法来反演出开边界处的潮汐调和常数.为了取得较好的数值模拟结果,同时对给定的底摩擦系数进行了校正并对水深进行了微调.做了4个实验,并分别计算出调和常数的实测值与模拟值之差的绝对平均值:(1)只用19个验潮站的潮汐调和常数;振幅差为2.4cm,迟角差为5.0°.(2)只用37个观测点的高度计资料;振幅差为4.4cm,迟角差为5.7°.(3)同时利用19个验潮站的潮汐调和常数和37个观测点的高度计资料;振幅差为5.5cm,迟角差为8.5°.(4)同时利用19个验潮站的潮汐调和常数和14个观测点的高度计资料;振幅差为3.3cm,迟角差为5.6°.4个实验结果都较好地体现了渤海M₂潮波的特征.

Numerical experiments of the adjoint model for M2 tide in the Bohai Sea

Adjoint method was used to deduce M₂ tidal harmonic constants on the open boundary of the Bohai Sea by using M₂ tidal harmonic constants in the inter iorregion.To improve the results of numerical simulation,the prescribed bottom friction coefficients were also adjusted by adjoint assimilation.Four experiments were car ried out.Experiment 1 uses only har monic constats at 19 tidal stations;Experiment 2 uses harmonic constants at 37 points on the T/P Satellite Tracks;Experiment 3 uses all the above data;Experiment 4 uses har monic constants at 19 tidal stations and 14 selected points on the T/P Satellite Tracks.The averaged absolute differences between the simulated and the observed are as follows respectively.For Experiment 1 the averaged absolute difference of the amplitude is 2.4 cm and the averaged absolute difference of the phaselag is 5.0°.For Experiment 2 they are 4.4 cm and 5.7°respectively.Experiment 3 gives 5.5 cm and 8.5°respectively.And Experiment 4 gives 3.3 cm and 5.6°respectively.The results of the four experiments coincide with the observed M₂ tide in the Bohai Sea fairly well.