当前位置: X-MOL 学术J. Geophys. Res. Oceans › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Estimation of Bottom Friction Coefficient in Multi‐Constituent Tidal Models Using the Adjoint Method: Temporal Variations and Spatial Distributions
Journal of Geophysical Research: Oceans ( IF 3.6 ) Pub Date : 2021-04-15 , DOI: 10.1029/2020jc016949
Daosheng Wang 1, 2, 3 , Jicai Zhang 4 , Ya Ping Wang 5
Affiliation  

The bottom friction coefficient (BFC) is critical for precisely determining hydrodynamic conditions and sediment transport rates, which are important for scientific research and coastal ocean engineering. The BFC varies spatially and temporally, as indicated by in situ observations, but it is difficult to accurately set this parameter in tidal models. In this study, based on a two‐dimensional multi‐constituent tidal model and its adjoint model, the harmonic constants of four principal tidal constituents (M2, S2, K1, and O1) obtained from TOPEX/Poseidon altimeter data were assimilated to estimate spatially and temporally varying BFCs using the adjoint method in the Bohai, Yellow, and East China Seas. The model performance was significantly improved after data assimilation, which was independently tested by harmonic constants at coastal tidal gauge stations. Through several sensitivity experiments, the spatial distributions of the temporally averaged BFCs were verified to be robust and not affected by model settings, while the temporal variations of the spatially averaged BFCs were also robust but related to the tidal constituents. The variations in the estimated BFCs with the current speed and water depth were nearly consistent with those in the observations. Overall, the temporal and spatial variations in the estimated BFCs are significantly correlated with the current speed and water depth, which is attributed to the erosion‐deposition of sediment on the seabed and the changes in seabed roughness under different current speeds. The results can be beneficial for determining reasonable parameters for the bottom stress and setting the BFC in multi‐constituent tidal models.

中文翻译:

使用伴随法估计多成分潮汐模型的底部摩擦系数:时间变化和空间分布

底部摩擦系数(BFC)对于精确确定流体动力条件和沉积物传输速率至关重要,这对于科学研究和沿海海洋工程至关重要。如原位观测所表明的,BFC在空间和时间上都会变化,但是很难在潮汐模型中准确设置此参数。在这项研究中,基于二维多成分潮汐模型及其伴随模型,确定了四个主要潮汐成分(M 2S 2K 1O 1)的谐波常数。从TOPEX / Poseidon高度计数据获得的)被同化,以在渤海,黄海和东海使用陪伴方法估算时空变化的BFC。数据同化后,模型性能得到了显着改善,这些数据已通过沿海潮汐测量站的谐波常数进行了独立测试。通过几次敏感性实验,验证了时间平均BFC的空间分布是稳健的,不受模型设置的影响,而空间平均BFC的时间变化也很健壮,但与潮汐成分有关。估计的BFC随当前速度和水深的变化与观测中的变化几乎一致。全面的,估计的BFCs的时空变化与当前速度和水深显着相关,这归因于在不同流速下海床上沉积物的侵蚀沉积和海床粗糙度的变化。该结果对于确定底部应力的合理参数以及在多分量潮汐模型中设置BFC可能是有益的。
更新日期:2021-04-29
down
wechat
bug