The impact of sea bottom effects on the retrieval of water constituent concentrations from MERIS and OLCI images in shallow tidal waters supported by radiative transfer modeling

Integration of in-situ and multi-sensor satellite observations for long-term water quality monitoring in coastal areas

“…On the other hand, these results confirm the previous studies in the area (Doerffer and Fischer, 1994;Doerffer and Murphy, 1989;Dube, 2012;Garaba et al, 2014;Hommersom et al, 2010aHommersom et al, , 2010b. However, the effect of tide and sea-bottom should be considered into the model's retrievals to generate more accurate maps in these shallow coastal waters (Eleveld et al, 2014;van der Wal et al, 2010;Arabi et al, 2019), although this does not apply for the location of the NJS where the sea-bottom effect does not contribute to the sensor's measurements (water depth > 5 m).…”

“…The two-stream RT model, 2SeaColor (Salama and Verhoef, 2015), has already shown a high accuracy for the retrieval of water optical properties in the turbid waters of the Dutch Wadden Sea and other coastal areas in previous studies (e.g., Arabi et al, 2016Arabi et al, , 2018Arabi et al, , 2019Salama and Verhoef, 2015;Yu et al, 2016a, 2016b, Doxaran et al, 2014a, 2014bPalmer et al, 2015;Wu, 2015). To invert the 2SeaColor model against in-situ R rs measurements, we used a spectral optimization technique by minimizing the differences between in-situ R rs measurements and the 2SeaColor-R rs simulations.…”

“…Effective monitoring of this area needs continuous tracking of the spatio-temporal variations of WCCs in order to capture information on dynamic events, which might have a substantial impact on ecosystems, such as changes caused by storms or unexpected phytoplankton blooms (Zevenboom et al, 1991). However, the climatological conditions of the Dutch Wadden Sea, characterized by frequent cloudiness, various combinations of three WCCs, besides the tide-modulated shallowness of the water, make this region a complex case study for water quality monitoring using remote sensing approaches (Arabi et al, 2019;Hommersom et al, 2010aHommersom et al, , 2010bMisdorp et al, 1989;Müller et al, 2016).…”

Two decades water quality monitoring using time-series of multispectral satellite images over the Wadden Sea supported by radiative transfer modelling

“…The Dutch Wadden Sea encompasses numerous regions with extremely shallow water depths, as depicted in Figure 3. It has been demonstrated in prior work by Arabi et al (2020) 29 that many water pixels in satellite images, particularly those situated over shallow areas of the Dutch Wadden Sea, are affected by the sea-bottom effect. This effect leads to contamination of water pixel measurements, resulting in an overestimation of the retrieved WCCs.…”

“…In accordance with the methodology proposed by Arabi et al in 2020 29 , we executed the NIBEI calculations on each MERIS and OLCI image, respectively, while excluding OSWs based on individually established thresholds for each image. For a comprehensive understanding of the NIBEI calculation, interested readers are encouraged to refer to the detailed description in Arabi et al 2020 29 . The ultimate WCCs, aerosol type, and visibility maps, following the exclusion of OSWs, are depicted in Figure 3.…”