Steef Peters

Water Insight BV

It is common in estuarine waters to place fixed monitoring stations, with the advantages of easy maintenance and continuous measurements. These two features make fixed monitoring stations indispensable for understanding the optical complexity of estuarine waters and enable an improved quantification of uncertainties in satellite-derived water quali...

Satellite data from the Climate Change Initiative (CCI) lakes project were used to examine the influence of climate on chlorophyll-a (Chl-a). Nonparametric multiplicative regression and machine learning were used to explain Chl-a concentration trend and dynamics. The main parameters of importance were seasonality, interannual variation, lake level,...

The frequency of heatwave events in Europe is increasing as a result of climate change. This can have implications for the water quality and ecological functioning of aquatic systems. We deployed three spectroradiometer WISPstations at three sites in Europe (Italy, Estonia, and Lithuania/Russia) to measure chlorophyll-a at high frequency. A heatwav...

The Earth-observation based products are in the CoastObs portal: https://coastobs.lizard.net. Login details to the portal will be provided after finalising the CoastObs training materials: https://coastobs.eu/e-training Products in the portal include demonstration products of the following parameters: Basic products: Chl-a Suspended matter Turbi...

Atmospheric correction over inland and coastal waters is one of the major remaining challenges in aquatic remote sensing, often hindering the quantitative retrieval of biogeochemical variables and analysis of their spatial and temporal variability within aquatic environments. The Atmospheric Correction Intercomparison Exercise (ACIX-Aqua), a joint...

Accurate habitat mapping methods are urgently required for the monitoring, conservation, and management of blue carbon ecosystems and their associated services. This study focuses on exposed intertidal seagrass meadows, which play a major role in the functioning of nearshore ecosystems. Using Sentinel-2 (S2) data, we demonstrate that satellite remo...

This study presents a first assessment of the Top-Of-Atmosphere (TOA) radiances measured in the visible and near-infrared (VNIR) wavelengths from PRISMA (PRecursore IperSpettrale della Missione Applicativa), the new hyperspectral satellite sensor of the Italian Space Agency in orbit since March 2019. In particular, the radiometrically calibrated PR...

Lake water quality monitoring has the potential to be improved through integrating detailed spatial information from new generation remote sensing satellites with high frequency observations from in situ optical sensors (WISPstation). We applied this approach for Lake Trasimeno with the aim of increasing knowledge of phytoplankton dynamics at diffe...

Executive summary and recommendations The EU Water Framework Directive 1 (WFD) is an ambitious legislation framework to achieve good ecological and chemical status for all surface waters and good quantitative and chemical status for groundwater by 2027. A total of 111,062 surface waterbodies are presently reported on under the Directive, 46% of whi...

Evaluation of Sentinel-2 and -3 water quality products over European coastal and transitional waters, including chlorophyll-a, seagrass density, primary productivity, phytoplankton size classes, and harmful algal bloom detection.

This study presents the work developed as a CEOS action for which CSIRO and DLR taken the lead on a feasibility assessment to determine the benefits and technological difficulties of designing an Earth observing satellite mission focused on the aquatic (non-oceanic) ecosystems. I n fact, many Earth observing sensors have been designed, built and la...

A new autonomous above water radiometer system (WISPstation) was developed based on the experience with the handheld WISP-3 system. The instrument records radiance and irradiance with an extended wavelength range of 350 to 1100 nm in two viewing directions, which enables continuous and autonomous high-quality measurements for water quality monitori...

Remote sensing has the potential to provide long-term, global monitoring but for marine plastics it is still in its early stages. We present a reflectance model of sunlight interacting with a sea surface littered with macro plastics in the visible (VIS) to near infrared (NIR) to short wave infrared (SWIR). The model is based on geometrical optics a...

6IMDC (Sixth International Marine Debris Conference), SAN DIEGO, CALIFORNIA, USA • MARCH 12-16, 2018

There is growing global concern over the chemical, biological and ecological impact of plastics in the ocean. Remote sensing has the potential to provide long-term, global monitoring but for marine plastics it is still in its early stages. Some progress has been made in hyperspectral remote sensing of marine macroplastics in the visible (VIS) to sh...

Many Earth observing sensors have been designed, built and launched with primary objectives of either terrestrial or ocean remote sensing applications. Often the data from these sensors are also used for freshwater, estuarine and coastal water quality observations, bathymetry and benthic mapping. However, such land and ocean specific sensors are no...

Many Earth observing sensors have been designed, built and launched with primary objectives of either terrestrial or ocean remote sensing applications. Often the data from these sensors are also used for freshwater, estuarine and coastal water quality observations, bathymetry and benthic mapping. However, such land and ocean specific sensors are no...

Sky reflectance R sky ( λ ) is used to correct in situ reflectance measurements in the remote detection of water color. We analyzed the directional and spectral variability in R sky ( λ ) due to adjacency effects against an atmospheric radiance model. The analysis is based on one year of semi-continuous R sky ( λ ) observations that were recorded i...

A three-component reflectance model (3C) is applied to above-water radiometric measurements to derive remote-sensing reflectance Rrs (λ). 3C provides a spectrally resolved offset Δ(λ) to correct for residual sun and sky radiance (Rayleigh- and aerosol-scattered) reflections on the water surface that were not represented by sky radiance measurements...

The H2020 project EOMORES will develop operational monitoring and reporting services for inland and coastal water quality based on a combination of the most up-to-date satellite data, innovative in situ instruments and ecological models. Lakes, reservoirs and coastal water bodies constitute essential components of the hydrological and biogeochemica...

The Committee on Earth Observation Satellites (CEOS) response to the Group on Earth Observations System of Systems (GEOSS) Water Strategy developed under the auspices of the Water Strategy Implementation Study Team was endorsed by CEOS at the 2015 Plenary. As one of the actions, CSIRO has taken the lead on recommendation C.10: A feasibility assessm...

Shallow and deep lakes receive and recycle organic and inorganic substances from within the confines of these lakes, their watershed and beyond. Hence, a large range in absorption and scattering and extreme differences in optical variability can be found between and within global lakes. This poses a challenge for atmospheric correction and bio-opti...

Many Earth observing sensors have been designed, built and launched with primary objectives of either terrestrial or ocean remote sensing applications. Often the data from these sensors are also used for freshwater, estuarine and coastal water quality observations and bathymetry and benthic mapping. However, such land and ocean specific sensors are...

Phytoplankton spring bloom phenology was derived from a 15-year time series (2000–2014) of ship-of-opportunity chlorophyll a fluorescence observations collected in the Baltic Sea through the Alg@line network. Decadal trends were analysed against inter-annual variability in bloom timing and intensity, and environmental drivers (nutrient concentratio...

The scope of this document is to show how satellite data, especially GLaSS products, can be used to detect mine tailing ponds in Azerbaijan, Finland and Mongolia.

The GLaSS training material (10 lesson) builds on the global lakes use cases of FP7 project GLaSS. It allows students (((Bsc), Msc, PhD) and professionals in fields as aquatic ecology, environmental technology, remote sensing and GIS to learn about the possibilities of optical remote sensing of water quality, by using the Sentinel-2 and Sentinel-3...

Phytoplankton spring bloom phenology was derived from a 15-year time-series (2000-2014) of ship-of-opportunity chlorophyll-a fluorescence observations in the Baltic Sea. Decadal trends were analysed against inter-annual variability in bloom timing and intensity, and environmental drivers (nutrient concentration, temperature, radiation level, wind s...

To demonstrate the applicability of the system developed in the project and to assess changing of the trophic status impacting water uses, EO data were used for selected deep waters. EO data provides in fact a synoptic vision and a good sampling frequency suitable for the evaluation not only of the trophic state but also of changes in trophic state...

The European collaborative project GLaSS aims to prepare for the use of the data streams from Sentinel 2 and Sentinel 3. Its focus is on inland waters, since these are considered to be sentinels for land-use- and climate change and need to be monitored closely. One of the objectives of the project is to compare existing water quality algorithms and...

The North-Western part of the Black Sea is highly affected by eutrophication due to nutrient and sediment load inflow from the Danube River, which is the second largest delta in Europe. To get a general spatial picture of the water quality of the Romanian coast, it is not only time consuming, but also hard to measure with traditional in situ sampli...

The GlaSS consortium has an excellent working knowledge on how to apply MERIS RR and The GlaSS consortium has an excellent working knowledge on how to apply MERIS RR and The GlaSS consortium has an excellent working knowledge on how to apply MERIS RR and The GlaSS consortium has an excellent working knowledge on how to apply MERIS RR and The GlaSS...

Cyanobacterial bloom detection from flow-through optical sensors on ships-of-opportunity (’ferryboxes’) is challenging in periods of strong stratification and due to varying cell physiology and phytoplankton community composition. Wavelet coherence analysis between ferrybox parameters (chlorophyll-a fluorescence, phycocyanin fluorescence, turbidity...

Optical close-range instruments can be applied to derive water quality parameters for monitoring purposes and for validation of optical satellite data. In situ radiometers are often difficult to deploy, especially from a small boat or a remote location. The water insight spectrometer (WISP-3) is a new hand-held radiometer for monitoring water quali...

Coastal areas of the North Sea are commercially important for fishing and tourism, and are subject to the increasingly adverse effects of harmful algal blooms, eutrophication and climate change. Monitoring phytoplankton in these areas using Ocean Colour Remote Sensing is hampered by the high spatial and temporal variations in absorption and scatter...

Current protocols prescribe 0.2 µm filters for absorption measurements of Coloured Dissolved Organic Matter (a (CDOM)). However, a large historical dataset of a (CDOM) was obtained over 0.7 µm filters. Since small particles may pass 0.7 µm filters, a (CDOM) was prob-ably overestimated because of residual scattering. Furthermore, current protocols r...

Ocean colour-based monitoring of water masses is a promising alternative to monitoring concentrations in heterogeneous coastal seas. Fuzzy methods, such as spectral unmixing, are especially well suited for recognition of water masses from their remote sensing reflectances. However, such models have not yet been applied for water classification and...

Phaeocystis blooms in the Southern Bight of the North Sea may cause damage to the aquatic ecosystem and to commercial mussel cultures at the entrance of the Oosterschelde estuary. In this paper the potential for early detection of Phaeocystis blooms in Dutch coastal waters is studied, using a combination of field data, satellite observations and hy...

Phaeocystis blooms in the Southern Bight of the North Sea may cause damage to the aquatic ecosystem and to commercial mussel cultures at the entrance of the Oosterschelde estuary. In this paper the potential for early detection of Phaeocystis blooms in Dutch coastal waters is studied, using a combination of field data, satellite observations and hy...

Een uitgebreide meetinspanning op de Noordzee, in combinatie met wiskundige en statistische modellering, laat zien dat de klimaatveranderingen in de vorm van een verandering in de overheersende windrichting, een toename van de windsnelheid, een toename van de zeewatertemperatuur, als wel als een toenemende CO2 concentratie van de atmosfeer, niet al...

In this study, the inverse bio-optical model HYDROPT was calibrated with regional specific inherent optical properties (SIOPs) and various local SIOPs to examine the effect of these calibrations on the retrievals. The study area, the Wadden Sea, is an estuary and tidal flat area with very high concentrations of chlorophyll a (Chl a), suspended part...

Suspended matter in inland waters is related to total primary production and fluxes of heavy metals and micropollutants such as PCBs. Synoptic information on suspended matter cannot be obtained from an in situ monitoring network since suspended matter is a spatially inhomogeneous parameter. This problem can be solved by the integrated use of remote...

Physically based numerical modelling follows from the basic understanding of the underlying mechanisms and is often represented by a set of (partial differential) equations. It is one of the main approaches in population dynamics modelling. The emphasis of the model introduced in this paper is on the simulation of short-term spatial and temporal dy...

The interpretation of optical remote sensing data of estuaries and tidal flat areas is hampered by optical complexity and often extreme turbidity. Extremely high concentrations of suspended matter, chlorophyll and dissolved organic matter, local differences, seasonal and tidal variations and resuspension are important factors influencing the optica...

With its 500 km length the Wadden Sea is the largest mudflat area in the world. Discharges from various rivers mix here with water from the North Sea. Due to surfacing tidal flats during low tide, the variation in source water, resuspension and extremely high concentrations of Chlorophyll-a (Chl-a), Suspended Particulate Matter (SPM), and Coloured...

The Wadden Sea, a shallow coastal area bordering the North Sea, is optically a complex area due to its shallowness, high turbidity and fast changes in concentrations of optically active substances. This study gathers information from the area on concentrations of suspended particulate matter (SPM), Chlorophyll-a (Chl-a), and Coloured Dissolved Orga...

Accurate and reliable flow forecasting form an important basis for efficient real-time river management, including flood control, flood warning and so on. In order to improve the accuracy of flow forecasting, gain matrix of Kalman filter was applied to real-time correction of hydraulic model for spatial distributing the system deviation (called “ex...

MarCoast (Marine und Coastal Environmental Information Services)is the GMES Service Element Project (2005-2008) addressing the marine environment and is funded by the European Space Agency. MarCoast is delivering on a regular basis a wide array of products to support the monitoring of European Seas in terms of water quality, alga bloom and oil spil...

The Wadden Sea is a shallow coastal sea, interesting because it is a Particular Sensitive Sea Area. It is also optically an interesting area because of mudflats, tidal inlets from the North Sea, discharges from various rivers, great variation in time and space of optically active substances, very high concentrations of optically active substances....

Optical remote sensing in the North Sea is reviewed with a focus on applications supporting environmental management. Optical remote sensing provides estimates of Chlorophyll a, total suspended matter and diffuse attenuation coefficient and related parameters. These are used for harmful algal bloom detection, eutrophication assessment, ecosystem an...

Atmospheric correction of MERIS images of inland lakes is difficult due to a number of reasons: topographic altitude and viewing geometry needs to be accounted for; the adjacency effect may have to be removed and realistic settings for atmospheric optical properties have to be chosen. Atmospheric heterogeneity may pose problems as well. Earlier exp...

An extensive field campaign was carried out for the validation of a previously published reflectance ratio-based algorithm for quantification of the cyanobacterial pigment phycocyanin (PC). The algorithm uses band settings of the Medium Resolution Imaging Spectrometer (MERIS) onboard ENVISAT, and should accurately retrieve the PC concentration in t...

An extensive field campaign was carried out for the validation of a previously published reflectance ratio-based algorithm for quantification of the cyanobacterial pigment phycocyanin (PC). The algorithm uses band settings of the Medium Resolution Imaging Spectrometer (MERIS) onboard ENVISAT, and should accurately retrieve the PC concentration in t...

In this paper spectral reflectances as measured by MERIS in Dutch coastal waters together with observations of Chlorophyll-a (as the algal2 product) are validated. In order to evaluate the effects of the upgrade of MERIS processing from MEGS7.0 to MEGS7.4 match-up stations of 2003 were revisited. To validate the performance of the algal2 product, i...

This is a conference proceedings. For the full paper please see: "Optical signatures of the filamentous cyanobacterium Leptolyngbya boryana during mass viral lysis" by S.G.H. Simis, M. Tijdens, H.L. Hoogveld, H.J. Gons. Limnology and Oceanography. 01/2007; 52(1). On researchgate: https://www.researchgate.net/publication/215493153_Optical_signatures...

This paper reports on the validation of bio-optical models in estuarine and nearshore (case 2) waters of New Jersey–New York to retrieve accurate water leaving radiance spectra and chlorophyll concentration from the NASA Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data complemented with in situ measurements. The study area—Hudson/Rarita...

ISBN 90-5192-026-1 This atlas of the North Sea contains maps of Chlorophyll-a concentrations based on remote sensing images. Chlorophyll-a is one of the main photosynthetic pigments in phytoplankton and can be used to assess the degree of eutrophication of the water. The concentration of Chlorophyll-a is derived from the sea surface, at about the f...

The pigment phycocyanin (PC) is a marker for cyanobacterial presence in eutrophic inland water. We present a reflectance band–ratio algorithm for retrieval of cyanobacterial PC. The model conforms to the band settings of the Medium Resolution Imaging Spectrometer. The parameters of the algorithm were optimized using reflectance and absorption data...

The pigment phycocyanin (PC) is a marker for cyanobacterial presence in eutrophic inland water. We present a reflectance band–ratio algorithm for retrieval of cyanobacterial PC. The model conforms to the band settings of the Medium Resolution Imaging Spectrometer. The parameters of the algorithm were optimized using reflectance and absorption data...

Reliable chlorophyll-a (CHL) algorithms are still far from well established for turbid coastal waters. The development and validation of these algorithms has so far been limited by the lack of knowledge on natural variations in optical properties and concentrations due to many coastal processes. In fact, the confidence in the relation between one s...

This paper reports on the validation of bio-optical models in estuarine and nearshore (case 2) waters of New Jersey-New York to retrieve accurate water-leaving radiance spectra and chlorophyll concentration from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) imaging spectrometer data. MODTRAN-4 was applied to remove the effects of the...