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Characteristics of the transport and fate of the waterborne materials (e.g., pollutants, sediments, organisms, and nutrients) between an estuary and the adjacent coastal ocean depend significantly on the strength of estuarine exchange flow (

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Wave parameters, e.g., wave height, near-bed wave orbital velocity, and wave-induced shear stresses, are important hydrodynamic parameters for sediment processes in coastal oceans. Wave orbital velocity is particularly critical in sediment resuspension. Several algorithms to calculate wave orbital velocity have been proposed, including linear wave theory, spectrum, and Joint North Sea Wave Project methods, but the validity of these algorithms in relatively shallow waters is not well understood. In this study, we compared the wave parameters obtained by different instruments and algorithms at four sites, one within the intertidal zone with a mean depth of 1 m and the remainder three in deeper offshore water with mean depths of 15-30 m. We found a high consistency of the estimated wave height, peak wave period, and wave orbital velocity among different datasets and different algorithms at the offshore sites, while there were significant discrepancies at the shoreline site. Using Ursell number, our study suggests that it is reliable to apply any of the three algorithms and different instruments (acoustic Doppler velocimeter and buoy) in deeper water. However, for very shallow water, it is recommended to use the measured highfrequency velocity and spectrum method to calculate wave orbital velocity, and use wave gauge instrument or zero-crossing algorithm to obtain wave height and period information. Finally, the effect of turbulence and bedform morphology on wave-induced shear stress is discussed: without removing the turbulence or taking onto account bedforms (e.g., ripples), the orbital velocity will be remarkably over-estimated or under-estimated.

Coastal saltern and aquaculture are vital components of human-made coastal areas and they have immense influence on the coastal water environment in China. Hyperspectral space-borne remote sensing is a significant technology in remote sensing, enabling in-depth identification and discrimination of the spectra from water features on shore. The study uses CHRIS/PROBA images to identify water-bodies and classify six optical water types from artificial and natural water in three sites across regions along China’s coastline. Most of the offshore waters are affected by the inflow of land source materials. The fluorescence peaks appearing at 675 nm can be observed by 5 water types. In addition to Class 1 water which is far from the shore and the Class 4 water whose signals are mainly affected by the algae at its bottom, the other 4 kinds of water show backscattering peak after 800 nm, suggesting that particles are playing an important role in coastal water. For coastal waters in Liushagang, the mangrove forest will transfer the water body signal received by the satellite into the vegetation signal; pools in coastal saltern have rather shallow water during production period when the benthic signal will seriously interfere the reflected signal. In the intertidal area, the hyperspectral characteristics in the same sample also change periodically due to the ebb and flow. The Class 2 and Class 3 water bodies alternately occur in the intertidal zone in the Lianyungang research area. Therefore, it is concluded that optical classification approaches reflect the advantages of remote sensing from Satellite-bone, and our study can be helpful and conductive for follow-up sensors.