scholarly journals 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 ◽  
Vol 10 (2) ◽  
pp. 158 ◽  
Author(s):  
Yanqun Pan ◽  
Fang Shen ◽  
Xiaodao Wei
2020 ◽  
Author(s):  
Jin Li ◽  
Yanling Hao ◽  
Zhuangzhuang Zhang ◽  
Zhipeng Li ◽  
Ruihong Yu ◽  
...  

Abstract Yellow River Estuary (YRE) as well as its adjacent coastal areas are famous for its high concentration of Suspended Particulate Matter (SPM). The distribution of SPM and its variations in the estuary area promoted the carbon, oxygen and nutrient cycles in coastal areas and nearby sea areas. This study took advantage of Landsat 8 Operational Land Imager (Landsat 8 OLI) data to estimate SPM in the YRE from 2013 to 2019. Remote sensing reflectance (R rs ) measured by Landsat 8 OLI has been proved to be effective through cross-validate with Geostationary Ocean Color Imager (GOCI). A simple empirical alogrithm (NIR band ratio green band and add red band) was developed to map the SPM distribution and concentration, with the APD 33.12% and R 2 0.93 based on in-situ data. Annual average distribution of SPM shows that highy turbid areas with SPM greater than 10 3 mg/L are mostly found surrounding the estuary of Yellow River, in the northwest part of the Laizhou Bay and south part of Bohai bay. High variations of SPM distributions are consistent with high SPM, and vice versa. The influences of river runoff is mainly concentrated in the estuary area, and outside 4.5 km the variability of SPM effected by river discharge is not ovbious. Significant difference is observed in seasonal SPM distribution. Higher SPM in winter is observed both in range and intensity compared to summer. Significant seasonal variations are mainly controlled by sediment resuspension processes driven by wind-wave forces. The results of this study indicate that Landsat8 OLI is an effective mean to retrieve SPM in YRE and its adjcent areas.


2018 ◽  
Vol 10 (11) ◽  
pp. 1733 ◽  
Author(s):  
Noelia Abascal Zorrilla ◽  
Vincent Vantrepotte ◽  
Erwan Gensac ◽  
Nicolas Huybrechts ◽  
Antoine Gardel

The coast of French Guiana is characterised by the northwestward migration of large mud banks alongshore and by high concentrations of suspended particulate matter (SPM) resulting from the strong influence of the Amazon River outflow. Surface OLI SPM concentration, linked to the footprint of the subtidal part of mud banks due to resuspension and migration processes, was used to develop a method to estimate the location of this footprint. A comparison of the results from this method with those obtained by locating the limit of the wave damping, which characterises muddy coasts, revealed good performance of the method based on recurring SPM values. The migration rates of the mud banks in French Guiana were calculated according to the delimitation of their subtidal parts, and showed slightly higher values (2.31 km/year) than suggested by earlier studies. In comparison with other methods, the migration rate estimated using the method proposed within the framework of this study takes into account the variability of the shape of the subtidal part for the first time. It was also shown that the mud banks existing on the coastal area of French Guiana present two different shapes. Our results clearly demonstrate the advantage of ocean colour data to describe mud banks according to their subtidal part, delimited using the assessment of SPM temporal variability.


Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4186 ◽  
Author(s):  
Dinghui Shang ◽  
Huiping Xu

The suspended particulate matter (SPM) in Changjiang Estuary is characterized by a high concentration of significant diurnal dynamics. With a higher temporal resolution (eight images obtained per day), Geostationary Ocean Color Imager (GOCI) was selected as the primary remote sensor for the dynamics monitoring in this paper, instead of other satellite sensor working in polar orbit. Based on the characteristics of the field spectra measured in the estuary, an empirical model was established with the band ratio of Rrs745 divided by Rrs490 and proven effective in Suspended Particulate Matter (SPM) estimation (R2 = 0.9376, RMSE = 89.32 mg/L). While, Validation results showed that the model performed better in coastal turbid waters than offshore clear waters with higher chlorophyll-a concentration, stressing the importance of partitioning SPM into its major components and doing separate analysis. The hourly observations from GOCI showed that the diurnal variation magnitudes exhibited clear regional characteristics, with a maximum in the turbidity belt near the mouth and a minimum in the offshore deeper areas. In addition, comparing the monthly averaged SPM distribution with the amount of sediment discharged into the estuary, the variation in estuarine turbidity maximum zone is more likely contributed by the sediments resuspended from the sea bed that has already accumulated in the estuarine delta.


1995 ◽  
Vol 30 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Chen Jingsheng ◽  
Tang Fei ◽  
Wang Feiyue

Abstract Trace metal concentrations in suspended particulate matter in estuaries are dependent on the extent of mixing between river and seawater. Superimposed on this physical mixing, chemical mobilization from the particulates may take place. This paper presents the behavior of mercury in the Yalujiang estuary, northeast China. It deals with (i) field observations on the variations of mercury concentrations in the estuarine suspended material and (ii) the experimental mobilization of mercury from contaminated estuarine sediment by exposure to artificial seawater. Three stations on two cross sections in the upper and lower Yalujiang estuary were sampled over at least two or three complete tidal cycles. The field observations show that there is a clear mobilization of mercury from the suspended material during the maximum mixing of river and seawater. The experimental mobilization suggests that mobilization of mercury from the suspended particulates in seawater is caused not only by complexing with CI’ and ion-exchanging with the alkali and alkaline earth cations in seawater, but also by the dissolution of humic substances in the particles by seawater and the release of associated mercury.


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