Temporal variations of fine suspended sediment concentration in the Changjiang River estuary and adjacent coastal waters, China

Chen, Shen-Liang; Zhang, Guoan; Yang, S.L.; Shi, John Z.

doi:10.1016/j.jhydrol.2006.05.013

Cited by 89 publications

(40 citation statements)

References 30 publications

(41 reference statements)

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“…From the view of the cross-section shown in Figure 14 turbidity zone of the Yangtze Estuary that leads to resuspension of bottom sediments [49]. The exchange of materials and waters between the channels and tidal flats was strong under complex hydrodynamic conditions [48,50]. This implies a need for the observation with both of the high spatial and temporal resolution data.…”

Section: The Spatiotemporal Variations Of [Spm]mentioning

confidence: 99%

Fusion of Landsat-8/OLI and GOCI Data for Hourly Mapping of Suspended Particulate Matter at High Spatial Resolution: A Case Study in the Yangtze (Changjiang) Estuary

2018

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Suspended particulate matter (SPM) concentrations ([SPM]) in the Yangtze estuary, which has third-order bifurcations and four outlets, exhibit large spatial and temporal variations. Studying the characteristics of these variations in [SPM] is important for understanding sediment transport and pollutant diffusion in the estuary as well as for the construction of port and estuarine engineering structures. The 1-h revisit frequency of the Geostationary Ocean Color Imager (GOCI) sensor and the 30-m spatial resolution of the Landsat 8 Operational Land Imager (L8/OLI) provide a new opportunity to study the large spatial and temporal variations in the [SPM] in the Yangtze estuary. In this study, [SPM] images with a temporal resolution of 1 h and a spatial resolution of 30 m are generated through the product-level fusion of [SPM] data derived from L8/OLI and GOCI images using the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM). The results show that the details and accuracy of the spatial and temporal variations are maintained well in the [SPM] images that are predicted based on the fused images. Compared to the [SPM] observations at fixed field stations, the mean relative error (MRE) of the predicted SPM is 17.7%, which is lower than that of the GOCI-derived [SPM] (27.5%). In addition, thanks to the derived high-resolution [SPM] with high spatiotemporal dynamic changes, both natural phenomena (dynamic variation of the maximum turbid zone) and human engineering changes leading to the dynamic variability of SPM in the channel are observed.

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Section: The Spatiotemporal Variations Of [Spm]mentioning

confidence: 99%

Fusion of Landsat-8/OLI and GOCI Data for Hourly Mapping of Suspended Particulate Matter at High Spatial Resolution: A Case Study in the Yangtze (Changjiang) Estuary

2018

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“…Previous studies on SSC in the Yangtze Estuary have focused on intertidal, spring-neap, and seasonal and vertical changes (e.g., Milliman et al 1985;Chen et al 2006); for the most part, however, these studies have lacked temporal or spatial perspectives. For example, the Chen et al (2006) study of surface SSC variations in the Yangtze Estuary and northern Hangzhou Bay relied on data from eight gauging stations, but measured in different years; moreover, the absence of a gauging station seaward of the mouth bar prevented Chen et al (2006) from documenting any seaward trend in SSC.…”

Section: Introductionmentioning

confidence: 99%

“…For example, the Chen et al (2006) study of surface SSC variations in the Yangtze Estuary and northern Hangzhou Bay relied on data from eight gauging stations, but measured in different years; moreover, the absence of a gauging station seaward of the mouth bar prevented Chen et al (2006) from documenting any seaward trend in SSC.…”

Section: Introductionmentioning

confidence: 99%

Spatial, Temporal, and Human-Induced Variations in Suspended Sediment Concentration in the Surface Waters of the Yangtze Estuary and Adjacent Coastal Areas

Yang

Milliman

et al. 2012

Estuaries and Coasts

107

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To delineate temporal and spatial variations in suspended sediment concentration (SSC) in the Yangtze (Changjiang) Estuary and adjacent coastal waters, surfacewater samples were taken twice daily from 10 stations over periods ranging from 2 to 12 years (total number of samples >28,000). Synoptic measurements in 2009 showed an increase in surface SSC from 0.058 g/l in the upper sections of the estuary to ∼0.6 g/l at the Yangtze River turbidity maximum at the river mouth, decreasing seaward to 0.057 g/l. Annual periodicities reflect variations in the Yangtze discharge, which affect the horizontal distribution and transport of SSC, and seasonal winds, which result in vertical resuspension and mixing. Over the past 10-20 years, annual surface SSC in the lower Yangtze River and the upper estuary has decreased by 55%, due mainly to dam construction in the upper and middle reaches of the river. The 20-30% decrease in mean surface SSC in the lower estuary and adjacent coastal waters over the same period presumably reflects sediment resuspension, in part due to erosion of the subaqueous Yangtze Delta. SSCs in the estuary and adjacent coastal waters are expected to continue to decline as new dams are constructed in the Yangtze basin and as erosion of the subaqueous delta slows in coming decades.

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“…The SSC value in the inner estuary is higher in summer than in winter, whereas the SSC value in the outer estuary is lower in summer than in winter. The demarcation line between the inner and the outer estuary is around the upper port of Changxing Island (Chen et al, 2004).…”

Section: Study Areamentioning

confidence: 99%

Response of the turbidity maximum zone to fluctuations in sediment discharge from river to estuary in the Changjiang Estuary (China)

Jiang

2013

Estuarine, Coastal and Shelf Science

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In the Changjiang Estuary, interactions between the sea and the river result in the development of a turbidity maximum zone (TMZ). Riverine sediments are an important source for TMZ formation. Since the 1960s, sediment discharge from the river basin to the estuary has decreased due to dam construction, water and soil conservation, and water diversion projects. Thirty-two Landsat images of the estuary, covering the period from 1979 to 2008, were collected to identify the TMZ response to sediment decline. A threshold value of suspended sediment concentration (SSC) of 0.7 kg/m 3 , corresponding to a spectrum reflectance of 5% of Landsat MSS band 7 and 7% of Landsat TM/ETM band 4, was used to identify the Changjiang Estuary TMZ. The TMZ area was then extracted from each image to investigate its temporal and spatial variations during the past 30 years. The images were grouped into five time series; the average TMZ area of each series was estimated. The results show that the TMZ area declined 23% from series (a) to series (e), responding to a 77% reduction in riverine sediment discharge. In addition, the TMZ had strong seasonal and tidal variations; it was generally larger during flood seasons than during dry seasons and during spring tides compared to neap tides. The spring / neap tidal cycle played a more important role in TMZ change than did the seasonal cycle. Due to the continued reduction of sediment discharge to the estuary resulting from dams already constructed and to those that will be constructed upstream in the Changjiang River, it is predicted that the TMZ area will continue decreasing and that the re-suspension of local sediments will play a more important role in the formation of the TMZ.

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Temporal variations of fine suspended sediment concentration in the Changjiang River estuary and adjacent coastal waters, China

Cited by 89 publications

References 30 publications

Fusion of Landsat-8/OLI and GOCI Data for Hourly Mapping of Suspended Particulate Matter at High Spatial Resolution: A Case Study in the Yangtze (Changjiang) Estuary

Fusion of Landsat-8/OLI and GOCI Data for Hourly Mapping of Suspended Particulate Matter at High Spatial Resolution: A Case Study in the Yangtze (Changjiang) Estuary

Spatial, Temporal, and Human-Induced Variations in Suspended Sediment Concentration in the Surface Waters of the Yangtze Estuary and Adjacent Coastal Areas

Response of the turbidity maximum zone to fluctuations in sediment discharge from river to estuary in the Changjiang Estuary (China)

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