Underwater light field changes in Pärnu Bay influenced by weather phenomena and captured by Sentinel-3

2020 ◽  
Author(s):  
Kristi Uudeberg ◽  
Mirjam Randla ◽  
Age Arikas ◽  
Tuuli Soomets ◽  
Kaire Toming ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Coastal Waters ◽  
Light Field ◽  
Suspended Sediments ◽  
Quality Parameters ◽  
The Baltic Sea ◽  
Underwater Light Field ◽  
Underwater Light ◽  
The Baltic

<p>Climate change is expected to continue in the 21st century, but the magnitude of change depends on future actions. In the Baltic Sea, specifically in the Pärnu Bay region, this is predicted to mean warmer temperatures, less ice cover, more precipitations and a slight increase in average wind speed, furthermore extreme climatic events such as heavy rains, strong winds and storms will be more intense and frequent. The coastal waters play a central role in humans and nature's everyday lives as providing food, living and recreational opportunities. Since Pärnu Bay is one of the most eutrophied area in the Baltic Sea and provides living hood more the 800 fishermen, then regular monitoring is strongly recommended, but with traditional methods often unfeasible. The availability of free Sentinel satellites data with good spectral, spatial and temporal resolution has generated wide interest in how to use remote sensing capabilities to monitor coastal waters water quality, which affects the underwater light field and can lead even to changes in fish composition. However, these waters are optically complex and influenced independently by coloured dissolved organic matter, phytoplankton and an amount of suspended sediments. Therefore, the remote sensing of optically complex waters is more challenging, and standard remote sensing products often fail. In this study, we use satellite Sentinel-3 data to investigate weather phenomena as strong wind and precipitations effect to Pärnu Bay water quality parameters. We study the spatial and temporal scope of change of water quality parameters after the event. For that, we use optical water type classification based chlorophyll-a, suspended sediments and coloured dissolved organic matter algorithms on Sentinel-3 images and estimate underwater light field changes. Furthermore, we also use in situ data to analyses the frequency and the strength of weather events. Finally, we look at the composition of fish based on literature and we investigate the possible effects of the change of the underwater light field on fish composition.</p>

scholarly journals A Semi-Analytical Optical Remote Sensing Model to Estimate Suspended Sediment and Dissolved Organic Carbon in Tropical Coastal Waters Influenced by Peatland-Draining River Discharges off Sarawak, Borneo

2020 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Nagur Cherukuru ◽  
Patrick Martin ◽  
Nivedita Sanwlani ◽  
Aazani Mujahid ◽  
Moritz Müller
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Suspended Sediment ◽  
Coastal Water ◽  
Coastal Waters ◽  
Suspended Sediments ◽  
Optical Remote Sensing ◽  
Coastal Water Quality

Coastal water quality degradation is a global challenge. Marine pollution due to suspended sediments and dissolved matter impacts water colour, biogeochemistry, benthic habitats and eventually human populations that depend on marine resources. In Sarawak (Malaysian Borneo), peatland-draining river discharges containing suspended sediments and dissolved organic carbon influence coastal water quality at multiple locations along the coast. Optical remote sensing is an effective tool to monitor coastal waters over large areas and across remote geographic locations. However, the lack of regional optical measurements and inversion models limits the use of remote sensing observations for water quality monitoring in Sarawak. To overcome this limitation, we have (1) compiled a regional spectral optical library for Sarawak coastal waters, (2) developed a new semi-analytical remote sensing model to estimate suspended sediment and dissolved organic carbon in coastal waters, and (3) demonstrated the application of our remote sensing inversion model on satellite data over Sarawak. Bio-optical data analysis revealed that there is a clear spatial variability in the inherent optical properties of particulate and dissolved matter in Sarawak. Our optical inversion model coupled with the Sarawak spectral optical library performed well in retrieving suspended sediment (bias = 3% and MAE = 5%) and dissolved organic carbon (bias = 3% and MAE = 8%) concentrations. Demonstration products using MODIS Aqua data clearly showed the influence of large rivers such as the Rajang and Lupar in discharging suspended sediments and dissolved organic carbon into coastal waters. The bio-optical parameterisation, optical model, and remote sensing inversion approach detailed here can now help improve monitoring and management of coastal water quality in Sarawak.

scholarly journals CoastColour Round Robin datasets: a database to evaluate the performance of algorithms for the retrieval of water quality parameters in coastal waters

2015 ◽  
Vol 8 (1) ◽  
pp. 173-258 ◽  
Author(s):  
B. Nechad ◽  
K. Ruddick ◽  
T. Schroeder ◽  
K. Oubelkheir ◽  
D. Blondeau-Patissier ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Coastal Waters ◽  
Quality Parameters ◽  
Round Robin ◽  
Water Quality Parameters ◽  
Quality Data ◽  
Ocean Colour ◽  
Water Quality Data

Abstract. The use of in situ measurements is essential in the validation and evaluation of the algorithms that provide coastal water quality data products from ocean colour satellite remote sensing. Over the past decade, various types of ocean colour algorithms have been developed to deal with the optical complexity of coastal waters. Yet there is a lack of a comprehensive inter-comparison due to the availability of quality checked in situ databases. The CoastColour project Round Robin (CCRR) project funded by the European Space Agency (ESA) was designed to bring together a variety of reference datasets and to use these to test algorithms and assess their accuracy for retrieving water quality parameters. This information was then developed to help end-users of remote sensing products to select the most accurate algorithms for their coastal region. To facilitate this, an inter-comparison of the performance of algorithms for the retrieval of in-water properties over coastal waters was carried out. The comparison used three types of datasets on which ocean colour algorithms were tested. The description and comparison of the three datasets are the focus of this paper, and include the Medium Resolution Imaging Spectrometer (MERIS) Level 2 match-ups, in situ reflectance measurements and data generated by a radiative transfer model (HydroLight). These datasets are available from doi.pangaea.de/10.1594/PANGAEA.841950. The datasets mainly consisted of 6484 marine reflectance associated with various geometrical (sensor viewing and solar angles) and sky conditions and water constituents: Total Suspended Matter (TSM) and Chlorophyll a (CHL) concentrations, and the absorption of Coloured Dissolved Organic Matter (CDOM). Inherent optical properties were also provided in the simulated datasets (5000 simulations) and from 3054 match-up locations. The distributions of reflectance at selected MERIS bands and band ratios, CHL and TSM as a function of reflectance, from the three datasets are compared. Match-up and in situ sites where deviations occur are identified. The distribution of the three reflectance datasets are also compared to the simulated and in situ reflectances used previously by the International Ocean Colour Coordinating Group (IOCCG, 2006) for algorithm testing, showing a clear extension of the CCRR data which covers more turbid waters.

scholarly journals Implementation of Trophic Status Index in Brackish Water Quality Assessment of Baltic Coastal Waters

2008 ◽  
Vol 62 (3) ◽  
pp. 115-119 ◽  
Author(s):  
Elmīra Boikova ◽  
Uldis Botva ◽  
Vita Līcīte
Keyword(s):  
Water Quality ◽  
Baltic Sea ◽  
Quality Assessment ◽  
Coastal Waters ◽  
Brackish Water ◽  
Trophic Status ◽  
Water Quality Assessment ◽  
The Baltic Sea ◽  
The Baltic ◽  
Status Index

Implementation of Trophic Status Index in Brackish Water Quality Assessment of Baltic Coastal Waters The assessment of the trophic state of marine coastal waters is one of the leading initiatives declared in the European Water Framework Directive (WFD). The Baltic Sea is a semi-enclosed ecosystem which consists of subregions with wide salinity and seasonality gradients. Anthropogenic impact results in eutrophication processes on different scales. Efficient eutrophication control and environmental management in the Baltic Sea, according to WFD, requires a prerequisite of common and sensitive indicators for the European coastal waters including the Baltic Sea. In this article the Trophic Status Index TRIX, recently succcesfully implemented in Mediterranean and Northern European sea coastal waters as a holistic approach indicator, was implemented for the Gulf of Rīga and Latvian Baltic Sea coastal water quality assessment between 1999 and 2005.

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