Quantitative Assessment on Multiple Timescale Features and Dynamics of Sea Surface Suspended Sediment Concentration Using Remote Sensing Data

Abstract

Wind‐waves, tidal currents, and some other dynamic factors dominate the suspended sediment concentration (SSC) variations in shallow seas and it is difficult to quantitatively evaluate the effects of individual dynamic factors on SSC modulation. This work used the long‐term Moderate Resolution Imaging Spectroradiometer (MODIS) and the high temporal‐resolution Geostationary Ocean Color Imager (GOCI) remote sensing data to quantify the sea surface SSC variations on multiple timescales (intratidal, spring‐neap, seasonal, and long‐term timescales) in the Bohai Sea, and further quantitatively evaluated the effects of corresponding dynamic factors on the SSC modulation. The results indicated that the monsoon associated wind‐waves and stratification played the most important role in modulating SSC, with seasonal SSC variation of 8.1 mg/L in the Bohai Sea. The intratidal current variations played the secondary important role, causing SSC variation of 5.8 mg/L. The spring‐neap tidal current variations led to SSC variation of 3.1 mg/L in the Bohai Sea. In the long run (2003–2014), the SSC of the Bohai Sea decreased slightly with SSC variation of 2.8 mg/L (decline rate: 0.23 mg/L/year), which may be caused by the weakening wind, decreasing sediment load from the Yellow River or the massive reclamation in recent decades. Probably due to the topography, sea bed sediment grain size and river plume, SSC variations in the southern Bohai Sea were more pronounced than those in the northern Bohai Sea.

Multiscale Superposition and Decomposition of Field‐Measured Suspended Sediment Concentrations: Implications for Extending 1DV Models to Coastal Oceans With Advected Fine Sediments

“…Recently, spectral analysis is still adopted to qualitatively judge the existence of HA (Zhong et al, 2020). Zhou et al (2017) evaluated the contributions of various mechanisms to the modulation of surface sediment concentrations from remote sensing data at subtidal time scales. However, to the best of the authors' knowledge, quantitative evaluations of C(t) component contributions using multiscale information in the oceans (where hydrodynamics are much more complicated than rivers) and their decomposition from subtidal (period of storm events) to supratidal (tidal constituents) time scales have been scarcely explored.…”

Holocene vegetation dynamics in response to climate change and hydrological processes in the Bohai region

“…The prevailing northerly winds are much stronger in winter than the dominant southerly winds in summer. Strong winter winds cause strong wind waves and thus strong bottom shear stresses that readily erode seabed sediment into water (Yang et al, 2011;Wang et al, 2014;Zhou et al, 2017).…”

Impacts of Insufficient Observations on the Monitoring of Short- and Long-Term Suspended Solids Variations in Highly Dynamic Waters, and Implications for an Optimal Observation Strategy

“…Moreover, the ongoing satellite ocean color missions call for thorough consideration of the trade-offs between requirements of water resource monitoring and instrument design, including the time and frequency for water quality observation. Although there were some time series stations to monitor the physical, biological, and chemical parameters of water quality-for instance, in the southern North Sea [28], Bohai Sea [29], and in the tidal inlet between the East Frisian islands of Langeoog and Spiekeroog, southern North Sea [30]-high frequency measurements are still rare.…”