Tide assessment for the continental shelf situated in the southwestern Atlantic between the latitudes 19.8ºS and 21.2ºS

Abstract The astronomical tide was numerically simulated by the MOHID model for the South-Central Region of Espírito Santo State (Brazil), between latitudes 19.8ºS and 21.2ºS. The grid nesting technique was used to transpose the boundary conditions from the larger domain to a more refined local domain (spatial resolution around 450 m), with tidal harmonics provided by the TPXO tide inverse model as boundary conditions for the larger domain. Results from the numerical model were compared with both the pre-existing tide harmonics and the harmonics calculated from measured data. From the maps of phase, amplitude, tidal ellipses and residual currents the main tidal kinematic characteristics in the study area were described. On the continental shelf, the results showed that the physiography and bathymetry of the region play an important role in the distribution of tidal co-phases, co-amplitudes, ellipses and residual currents. The MOHID model was able to reproduce satisfactorily the astronomical tide and thus can be used to study the behaviour of the tidal propagation in continental shelf areas.

摘要 针对巴西圣埃斯皮里图州中南部区域（纬度范围19.8°S至21.2°S），采用MOHID模型（MOHID Model）对天文潮汐进行数值模拟。采用网格嵌套技术将大计算域的边界条件传递至精细化局域计算域（空间分辨率约450米），其中大计算域的边界条件由TPXO潮汐反演模型（TPXO Tide Inverse Model）提供的潮汐调和常数给出。将数值模型的模拟结果与已有的潮汐调和常数以及由实测数据计算得到的调和常数进行对比。通过相位、振幅、潮汐椭圆及余流分布图，对研究区域内的主要潮汐运动学特征进行了描述。在大陆架区域，模拟结果表明该区域的地形地貌与水深地形对潮汐同潮相位、同潮振幅、潮汐椭圆及余流的分布具有重要影响。MOHID模型能够较好地复现天文潮汐，因此可用于研究大陆架区域的潮汐传播特性。