Dynamically Constrained Interpolation of the Sparsely Observed Suspended Sediment Concentrations in Both Space and Time: A Case Study in the Bohai Sea

Mao, Xinyan; Wang, Daosheng; Zhang, Jicai; Bian, Changwei; Lv, Xianqing

doi:10.1175/jtech-d-17-0149.1

Cited by 6 publications

(3 citation statements)

References 51 publications

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“…Owing to the Huanghe, Liaohe, Haihe, and Luanhe Rivers carrying large amounts of sediment into the Bohai Sea and the seawater having a poor exchange capacity, the suspended sediment concentration (SSC) in the Bohai Sea is higher than that in other East China seas (Bian et al, 2013;Wang et al, 2016). Consequently, in recent decades, the high SSC in the Bohai Sea has been widely studied, especially Mao et al (2018) and Zhao et al (2022) considered the entire Bohai Sea. Since the majority of previous studies have concentrated on the resuspension, transportation and final destination of Huanghe River-derived sediment and its seasonal variability, most researchers have focused on specific areas such as the Huanghe Estuary (Li et al, 2010;Qiao et al, 2010;Yang et al, 2011;Wang et al, 2014;Liu et al, 2020a), the Bohai Strait (Duan et al, 2020b;Liu et al, 2020b;Wang et al, 2020), and the Bohai Bay (Qiao et al, 2011), and paid minimal academic attention to other sea areas, such as the exceptional low SSC area off Qinhuangdao (Figure 1B).…”

Section: Introductionmentioning

confidence: 99%

Winter and summer sedimentary dynamic process observations in the sea area off Qinhuangdao in the Bohai Sea, China

et al. 2023

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Sedimentary processes in marginal seas play an important role in the biology, physics, and geochemistry as well as ecology of coastal environments and contain abundant information about the material transfer from land to ocean and the regional circulation. Due to the huge sediment discharge of the Yellow River, the Bohai Sea, China is one of the areas with the highest suspended sediment concentration (SSC) in the world. Interestingly, the SSC at the west of the Bohai Sea is low all year round. Thus, it is of great significance to examine the sedimentary dynamic process in this area for better understanding the circulation structure, material exchange and regional environment of the Bohai Sea. Using seabed base observation platform measurements obtained in February 2017 and August 2019, this study examines the winter and summer hydrography and suspended sediment concentration in the sea area off Qinhuangdao located to the west of the Bohai Sea. In summer, the relatively weak residual currents flowed northeastward and showed little correlation with the wind field, especially in the middle layer of the water column. In winter, the residual currents were strengthened, flowing to the northeast during strong wind periods, and predominantly to the southwest during intermittent periods. Moreover, driven by the pressure gradient force associated with the wind-induced sea surface height variations, the winter current was closely related to the wind speed, with correlation coefficients ranging from 0.4 to 0.6 and a time lag of 10 h. The summer SSC was lower and mainly controlled by the tidal current, whereas in winter, owing to the enhanced Reynolds stress and turbulent kinetic energy, strong wind bursts triggered significant sediment resuspension and led to a higher SSC. For the suspended sediment flux (SSF), the advection terms contributed more than 80% in the winter and summer, while the vertical circulation terms contributed 13% in winter, and approximately half that much in summer. Generally, the suspended sediment is transported back and forth, with a little net northward and northeastward motions in winter and summer, respectively. This may explain the low SSC sustaining in coastal Qinhuangdao all year round. These results provide a reference for sedimentary studies conducted in other coastal waters, especially in monsoon-dominating shelf seas.

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Section: Introductionmentioning

confidence: 99%

Winter and summer sedimentary dynamic process observations in the sea area off Qinhuangdao in the Bohai Sea, China

et al. 2023

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“…Considering the influences of wind on the distributions of PM 2.5 , Li et al (2021) used the PM 2.5 transport model as a dynamical constraint, and obtained high-accuracy national-scale distributions of PM 2.5 in China from August to November 2014. Based on the adjoint assimilation method and taking the sediment transport model as the constraint condition, Mao et al (2018) used a dynamically constrained interpolation method to obtain the SPM concentrations in the Bohai Sea. However, unconstrained interpolations weren't used in practical applications due to insufficient observations, and the higher accuracy of dynamically constrained interpolation than unconstrained interpolation had not been proved.…”

Section: Introductionmentioning

confidence: 99%

Application of interpolation methodology with dynamical constraint to the suspended particulate matter in the Liaodong Bay

Geng

Peng²,

Shi³

et al. 2022

Front. Mar. Sci.

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IntroductionSuspended Particulate Matter (SPM) influences the primary production and the distributions of pollutants in the ocean. Besides, the regulation mechanisms of SPM in the Liaodong Bay were complicated.MethodTo analyze the distributions and influencing factors of SPM, based on the adjoint assimilation method, an interpolation method with dynamical constraint was established in the Liaodong Bay.ResultIn two ideal experiments, the cost function, Mean Absolute Error (MAE) and Normalized Mean Error (NME) all had reduced by more than 90%, which proved the accuracy of the interpolation method. Based on conventional observations of SPM, the distributions of dynamically constrained, Kriging and radial basis function (RBF) interpolations in March, May, August and October of 2015 were obtained.DiscussionThe cross-validation was carried out to compare the dynamically constrained interpolation and the unconstrained interpolations. Among seven unconstrained interpolation methods, the averaged MAE of RBF interpolation was the lowest, which was 10.976 mg/L. The averaged MAE of dynamically constrained interpolation was 7.703 mg/L, reduced by 29.8% compared with the RBF interpolation. It was indicated that RBF interpolation was the most accurate among the seven unconstrained interpolations and dynamically constrained interpolation was more accurate than unconstrained interpolations at the observation stations. The distributions of dynamically constrained and RBF interpolations were compared with Korean Geostationary Ocean Color Imager (GOCI) satellite-derived distributions of SPM concentrations in the Liaodong Bay. Fully considering the influences of the hydrodynamic processes, the dynamically constrained interpolation provided distributions more consistent with the satellite-derived distributions. However, due to the lack of observations in some areas and ignoring the influences of currents, some high values of SPM concentration were not captured by the distributions of RBF interpolation. Moreover, in accordance with the results of dynamically constrained interpolation, it was found that the SPM concentrations in the bay were affected by the SPM discharge from the Liao River Basin.

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“…A three-dimensional cohesive sediment transport model with the adjoint assimilation method was established in Wang et al [24] to get better simulation results of parameters. Furthermore, Mao et al [25] developed the dynamically constrained interpolation methodology (DCIM), where the dynamic constraints were combined with the statistical information of observations to interpolate the suspended sediment concentrations. In this paper, DCIM will be applied to interpolate the surface nitrogen concentration in the Bohai Sea.…”

Section: Introductionmentioning

confidence: 99%

Application of Dynamically Constrained Interpolation Methodology to the Surface Nitrogen Concentration in the Bohai Sea

Zheng

2019

IJERPH

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Observations of ocean pollutants are usually spatiotemporally dispersive, while it is of great importance to obtain continuous distribution of ocean pollutants in a certain area. In this paper, a dynamically constrained interpolated methodology (DCIM) is proposed to interpolate surface nitrogen concentration (SNC) in the Bohai Sea. The DCIM takes the pollutant transport advection diffusion equation as a dynamic constraint to interpolate SNCs and optimizes the interpolation results with adjoint method. Feasibility and validity of the DCIM are testified by ideal twin experiments. In ideal experiments, mean absolute gross errors between interpolated observations and final interpolated SNCs are all no more than 0.03 mg/L, demonstrating that the DCIM can provide convincing results. In practical experiment, SNCs are interpolated and the final interpolated surface nitrogen distribution is acquired. Correlation coefficient between interpolated and observed SNCs is 0.77. In addition, distribution of the final interpolated SNCs shows a good agreement with the observed ones.

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Dynamically Constrained Interpolation of the Sparsely Observed Suspended Sediment Concentrations in Both Space and Time: A Case Study in the Bohai Sea

Cited by 6 publications

References 51 publications

Winter and summer sedimentary dynamic process observations in the sea area off Qinhuangdao in the Bohai Sea, China

Winter and summer sedimentary dynamic process observations in the sea area off Qinhuangdao in the Bohai Sea, China

Application of interpolation methodology with dynamical constraint to the suspended particulate matter in the Liaodong Bay

Application of Dynamically Constrained Interpolation Methodology to the Surface Nitrogen Concentration in the Bohai Sea

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