Drivers of suspended sediment dynamics along the shorelines of the Yellow River Delta detected from satellite data

Abstract

Total suspended solids (TSS) can be a useful indicator of environmental change in nearshore coastal environments. Understanding the mechanisms of TSS variations in response to environmental drivers is of broad interest for ecology and geomorphology. The Yellow River Delta (YRD) in China is a fragile coastal region that has been affected by human activities and climate change. Here, we investigated TSS along the YRD shoreline over two decades with time‐series satellite data (2002–2020). We observed that TSS concentration decreased significantly in nearshore waters (5‐m isobath) surrounding the YRD, especially in the LaiZhou Bay. During the same time period, wave height (WH) along the deltaic shoreline and sediment load from the Yellow River have decreased, while sea surface height (SSH) has displayed a positive trend. Our results indicate that WH and SSH play a major role in sediment resuspension and dispersion, while the YSD mildly affected TSS variability along the coast. Monthly bed shear stress triggered by waves was then computed using WH, wave period (WP), and SSH. Bed shear stress and TSS displayed a positive correlation. We concluded that seasonal oscillations in SSH in conjunction with wind waves are responsible for TSS variability in the shallow waters in front of the YRD.

Monitoring Suspended Sediment Concentration in the Yellow River Estuary and Its Vicinity Waters on the Basis of SDGSAT-1 Multispectral Imager

“…Previous research findings have consistently demonstrated that the dispersion patterns of suspended sediments are influenced by the dynamics of tidal currents [37,38]. Variations in suspended sediment concentrations are primarily induced by seasonal oscillations in sea surface elevation and wind-induced waves [39], with tidal level fluctuations regarded as short-term variations in sea surface elevation. Similarly, the distribution range of high SSC areas in this study may be related to tidal levels and wind speeds.…”

Particle Size Distribution Slope Changes along the Yellow River Delta Observed from Sentinel 3A/B OLCI Images

“…Here, we used estimates of SPM obtained by the ratio of red and green wavelengths in the Sentinel-3 A/B OLCI images. The SPM was derived using the following equation: log(SPM) = 4.289 × R rs (670)/R rs (555) + 0.0667 [56]. The SPM spatial pattern changes significantly in different seasons, and it is often specular to the particle size distribution (Figure 9a).…”