Category: news

On Saturday 25 January 2020, a hiker was very surprised when he found a peculiar animal skull along the road, with meat and fat remains still on it. The scene of the event was Braine-le-Château, a small green community in the province of Brabant wallon.

Not special? Yes, as it appeared to be the skull of a dolphin, and the hiker happened to be someone with knowledge on the subject. It is the skull of a Common dolphin (Delphinus delphis) or a Striped dolphin (Stenella coeruleoalba), two species whose skulls are not easily distinguishable from each other. These species only rarely end up in the North Sea, their normal Atlantic range extending only to the western part of the English Channel.

How did this skull end up along a small road close to the E19 between Nivelles and Brussels? Wild speculation … That the animal swam up the Scheldt, and then reached the site via tributaries, through locks, can be excluded. That the animal was dragged to the site after being stranded by, for example, a fox, seems equally unlikely.

All information that can contribute to solving this mystery is welcome at kmoreau@naturalsciences.be.

On Wednesday evening 15 January a Sowerby’s beaked whale washed ashore in Ostend. An autopsy showed that the animal was probably still alive when it got into trouble in our coastal waters, no clear cause of death could be determined. Since shallow coastal waters are an unsuitable habitat for beaked whales, reports of the species have always been rare in Belgium. To date, only five previous cases of strandings of beaked whales in Belgium are known.

In the evening of 15 January 2020, late beachgoers found a stranded beaked whale near the eastern breakwater of Ostend. Unfortunately, the animal (which was first reported as a harbour porpoise, and later as a bottlenose dolphin) was already dead, and thanks to an efficient cooperation with the Ostend police, fire brigade and technical services, the carcass could quickly be transferred to the buildings of the Royal Belgian Institute of Natural Sciences (RBINS) in Ostend. From there, on Thursday morning 16 January, it left for the Faculty of Veterinary Medicine of Ghent University, where an autopsy was performed around noon. Meanwhile it was clear that it was an immature female of the Sowerby’s beaked whale (Mesoplodon bidens), with a length of 2.88 m and a weight of 240 kg.

Beaked Whales in Belgium

It is not often that pointed beaked dolphins are observed in the North Sea or washed ashore along the North Sea coast, which is not surprising. After all, beaked whales prefer the deep sea, and stay far away from coasts. A large water depth is more important than the absence of land, as the diet of beaked whales consists of all kinds of deep-sea organisms (mainly cephalopods, but also deep-sea fish and crustaceans). Thus, around islands in deep-sea areas, where water depths increase rapidly with distance from the coast, beaked whales can be observed relatively close to the coast. However, the shallow waters of the North Sea (especially the southern part) cannot be considered their familiar habitat.

In Belgium only five previous strandings of Sowerby’s beaked whales are known (and no observations of live animals at sea). In two cases these were mother-calf pairs: in August 1835 in Ostend, in August 1933 in Wenduine (mother + calf), in August 1954 in De Panne (pregnant female), in February 1969 in Heist and in October 1972 in Bredene (mother + calf). All these animals washed ashore alive, but died shortly afterwards (the calf of 1972 at Bredene survived a few days in the Harderwijk dolphinarium, in the Netherlands).

Cause of death?

« The autopsy found no evidence of a recent trauma that could be cited as cause of death (e.g. collision, drowning in a net), and confirmed that the animal was healthy until shortly before death ». explains Jan Haelters, marine biologist and marine mammal expert at RBINS. « It therefore seems plausible that the Ostend beaked whale was still alive when it got into trouble in the coastal waters, and that the grazes on the animal were caused by scraping of the body against the stones of the breakwater. However, nothing was found in the stomach (not even plastic or other items), which illustrates that the animal had not found food for a while and that it had no bright future anyway. All beaked whales on the Belgian list probably underwent the same fate ».

Some of the skulls of Belgian beaked whales are stored at RBINS, which also has an extensive collection of fossil remains of beaked whales. Here they remain available for scientific research (e.g. https://www.naturalsciences.be/en/news/item/2880), and occasional exhibition (e.g. https://www.naturalsciences.be/en/news/item/17771/). The skeleton of the new Ostend beaked whale will be used at the University of Ghent as didactic material in the veterinary training.

Since 2008, 318 offshore wind turbines have been installed in the Belgian part of the North Sea. Both the construction technology and the environmental impact monitoring have changed a lot during the past decade. In a new report, the scientific partners in the monitoring programme summarise what we have learned so far about the longer-term effects onto a variety of ecosystem components, from benthic invertebrates to birds and marine mammals. As time series grow longer, our ability to detect impacts increases. Some striking results include that artificial hard substrata such as wind turbine foundations cannot be considered to be equivalent alternatives for species-rich natural hard substrata, that wind farms deter some bird species but attract others, that the number of stranded harbour porpoises correlates with periods of high intensity underwater sound and that offshore wind farms only subtly changed fishing activity without creating lower catch rates of the main target species.

Evolving construction practices and monitoring programme

From 2008 to 2018, 318 offshore wind turbines with a total installed capacity of 1556 MW have been constructed in the Belgian part of the North Sea. The technology and construction practices have drastically changed during this decade. These changes include an evolution in foundation types (from gravity-based foundations and jacket-foundations to XL monopile wind turbines), an expansion of the geographical area for wind farm construction (towards more offshore waters) and an increase in the size and capacity of the wind turbines (from 3 MW turbines with a 72 m rotor diameter to 8.4 MW turbines with a 164 m rotor diameter).

The monitoring programme WinMon.BE has documented and evaluated the environmental impact of the construction and operational phases of the wind farms during this entire period. It evolved to be the basis for an in depth understanding of longer-term effects onto a variety of ecosystem components, from benthic invertebrates over fish to birds and marine mammals. The new report takes stock of what we have learned so far and zooms into a selection of innovative monitoring and impact mitigation techniques.

Ecosystem impacts

Sediment sampling revealed consistent impacts on the sediment composition and macrobenthic communities (invertebrates living in and on the sea floor, such as worms, shellfish, crustaceans and starfish). Sediment fining was only observed very close to the jacket foundations, while no conclusive results were found in terms of organic enrichment. Higher densities and diversity (species richness) of macrobenthic organisms were found in closer vicinity of the wind turbines. The phenomenon was most pronounced at the Thornton Bank. This confirms the hypothesis that impacts are specific to sites, foundation-types or even individual turbines, which highlights the importance of a continued monitoring of the macrobenthos at the different turbine types.

With respect to the macrofauna that is living/growing on the foundations, a decade of monitoring revealed three succession stages. In a first, relatively short, pioneer stage (~2 years), the installation of the turbine foundations was followed by rapid colonization which differed between locations and foundation types. This was followed by a more diverse intermediate stage characterized by large numbers of suspension feeders (such as Jassa herdmani, a small amphipod crustacean). A third, and possibly climax stage, with a lower species diversity and frilled anemone Metridium senile and blue mussel Mytilus edulis as the dominant species, was reached after nine to ten years. Earlier reports on offshore wind turbines as biodiversity hotspots generally refer to the species-rich second stage of succession, so these should be read with caution as the rich biodiversity now appears to be short-lived and disappears again in a later stage (after about six years in this study). This underlines that artificial hard substrata cannot be considered as an alternative for the species-rich natural hard substrata.

Birds and mammals

Comparing pre-construction seabird distribution data with post-construction distribution data showed a significant avoidance of the wind farm area by northern gannet Sula bassana (-98%), common guillemot Uria aalge (-60-63 %) and razorbill Alca torda (-75-80%). In contrast, attraction to the wind farm could be demonstrated for great cormorants Phalacrocorax carbo, herring gulls Larus argentatus and greater black-backed gulls Larus marinus. Importantly, most of these effects were no longer noticeable at distances over 0.5 km away from the wind farm edges. How these effects impact individual fitness, reproductive success and survival of the birds remains yet unknown.

It is demonstrated that the Belgian offshore wind farms are visited by migrating Nathusius’ pipistrelles Pipistrellus nathusii. The study sheds a preliminary light on the meteorological conditions that favour bat activity in the southern North Sea and the possible risk of colliding with offshore wind turbines. Wind speed (most detections at wind speed of maximally 5 m/s), wind direction (peak in occurrence for east- and southeasterly winds), temperature and barometric pressure seem to influence bat activity in the wind farms. Wind speed seems to have the largest influence on bat activity at sea. These insights offer the possibility to reduce the risk of collision for bats, for example by curtailing the turbines when certain weather conditions occur during the migration season.

The high impulsive sound levels produced during offshore wind farm construction (pile driving) result in displacement and disturbance of harbour porpoises Phocoena phocoena, the most common cetacean in the Southern North Sea. Our analysis reveals a higher occurrence of harbour porpoises strandings on Belgian beaches during months with a high intensity of impulsive sound. This preliminary analysis suggests an increased mortality of harbour porpoise during periods of wind farm construction and will be subject to future in-depth analysis. In the past few years, sound mitigation techniques hence have received a lot of attention and various techniques are now commercially available. In this report, we quantify how Big Bubble Curtains and stationary resonator systems (AdBm Noise Mitigation System) were applied to lower the sound pressure during wind farm construction in Belgian waters.

Impact on fisheries

Because fishing is prohibited within the Belgian offshore wind farms (ca. 140 km² operational), the overall surface area available for fisheries is decreasing as offshore wind farms are proliferating. It was demonstrated that the offshore wind farms only subtly changed the fishing activity (effort, landings and catch rate of the top 10 species, including the main target species sole Solea solea and plaice Pleuronectes platessa of the Belgian and Dutch beam trawl fleet in Belgian waters over the period 2006-2017. Evidently, a remarkable decrease in fishing effort was however observed inside the offshore wind farms, suggesting that local fishermen have adopted efforts to adapt to the exclusion of the wind farm zone from their fishing grounds and have increased their fishing effort at the edges. While catch rates of sole in the vicinity of the operational offshore wind farms remained comparable to catch rates in the wider area, catch rates of plaice were higher around some operational wind farms.

 

The Monitoring Programme WinMon.BE is a cooperation between the Royal Belgian Institute of Natural Sciences (RBINS), the Research Institute Nature and Forest (INBO), the Research Institute for Agriculture, Fisheries and Food (ILVO) and the Marine Biology Research Group of Ghent University, and is coordinated by the Marine Ecology and Management team (MARECO) of the Royal Belgian Institute of Natural Sciences.

The complete report, as well as the older monitoring reports, can be consulted at http://odnature.naturalsciences.be/mumm/en/windfarms/.

« Dear Michael, it is my great pleasure to inform you that you have been selected to receive the 2019 JJ Mehta Award for outstanding contributions to the study of cohesive sediment dynamics at the upcoming INTERCOH 2019 meeting in Istanbul, Turkey. » These were the words with which Carl T. Friedrichs, Professor, Research Coordinator & Associate Director of CBNERR-VA at the Virginia Institute of Marine Science, United States, announced the great news to our colleague Michael Fettweis.

The Mehta Award is a given to an individual who has made significant contributions to the advancement in the theory or application of cohesive sediment transport in the marine or aquatic environment. The award, which carries a plaque and a financial prize, is named in the memory of Jayant J. Mehta (1916-1996) by his son Ashish J. Mehta. Jayant J. Mehta (MS, MIT, 1938) was a pioneer in the inception and growth of the petrochemical industry in India, contributing significantly to the country’s industrial expansion starting in the 1970s.”

The selection committee was especially impressed by Michael’s record of combining diverse field observations and innovative analyses to successfully characterize naturally complex cohesive sediment processes while recognizing and quantifying the inherent uncertainties involved. As an awardee, Michael was asked to present an extended keynote lecture during the conference.

The award was presented at the INTERCOH 2019 conference banquet on the evening of Tuesday October 15^th, 2019.

Congratulations on this well-deserved recognition of your work, Michael!

With the construction of the new Belgian Ocean Class RV that is currently ongoing, Belgium is well preparing for a bright ocean science future.

In a new Position Paper, the European Marine Board together with the European Research Vessel Operators (ERVO) group provide a comprehensive look at the European research vessel fleet. The publication presents an overview of the current fleet, its capabilities, equipment and management. It also looks to the future, highlighting what will be needed to ensure that the European fleet can continue to provide the same high level of support to science, in particular in specialized areas such as the deep-sea and Polar regions. It also goes beyond the fleet itself, to consider the training of fleet personnel, fleet management, and the role of research vessels in the wider context of ocean observations.

The further development of our understanding of the ocean is fundamental to address many of the global challenges that society faces today, such as climate change and food security. Although new and autonomous data collection platforms (fixed and mobile continuous measuring equipment and satellites) are increasingly used to investigate, monitor and evaluate the marine environment, research vessels (RVs) remain a key infrastructure that enable scientists to gather data and conduct the research required to expand our knowledge for the purpose of both fundamental understanding and policy support. Physical sampling of the seabed, water column and marine fauna, as well as multi-beam mapping of the seabed, are examples of activities for which RVs remain critical. Also deploying and recovering tools such as moorings, remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs) and gliders, often relies on RVs.

However, research vessels and their equipment are large and sophisticated, and inevitably costly, infrastructures. It is therefore critical that their importance and indispensable role is clear and that appropriate investments are made to ensure the ongoing provision of scientific support. On November 6^th 2019, the European Marine Board (EMB, a strategic pan-European Forum of 33 Member Organizations, including key marine research performing institutes, funding agencies and university consortia) launched a new Position Paper that provides an overview of the current European research vessel fleet and its capabilities, and recommends ways in which it should evolve to meet future science needs. The Position Paper #25 is titled « Next generation European research vessels: Current status and foreseeable evolution » and is the result of a collaboration with the European Research Vessel Operators  (ERVO) group. ERVO is a European platform where RV operators discuss their national activities, projects, problems and plans for the maintenance, modifications and renewal of their research vessels.

Research vessels to address future science needs

The Position Paper describes the current fleet to be highly capable and leading on the world stage. However, with a typical life expectancy of a research vessel of 30 years, the fleet is ageing and urgently requires (re)investment to continue to be as efficient and capable as the scientific community and an effective policy require. Meantime also technology is developing fast and new research arises in specialized areas such as the deep-sea and Polar regions, and research vessels need to keep up the pace. Besides looking to the future needs, the Position Paper also goes beyond the fleet itself, and considers the training of fleet personnel, fleet management, and the role of research vessels in the wider context of ocean observations and the European Ocean Observing System (EOOS).

General recommendations

• Information and data on the capabilities and equipment of the European research vessel fleet should be kept up to date and be periodically reviewed by the infrastructure owners with support from the European Research Vessel Operators (ERVO) group
• For the European research vessel fleet to remain capable and fit-for-purpose, both the fleet and its scientific equipment and instruments should be renewed and developed as a matter of urgency
• The research vessel community should continue on its path towards greater collaboration in order to aim for equal access to research vessel time based on excellent science and not (constrained by) the country of origin of the scientist, for more effective use of resources, for appropriate training for all parties, and for strategic planning of the research
• Funding agencies should engage in discussions with the research vessel and marine science communities as well as other relevant stakeholders to identify key funding needs
• The research vessel operator community should continue to look forward to the emerging science and technological developments (e.g. towards real-time data delivery, new autonomous systems, new science frontiers) and work together with relevant parties to ensure that the fleet is ready to support these

Belgian contribution

Belgium is represented in the EMB by the Fonds National de la Recherche Scientifique (FNRS), het Fonds voor Wetenschappelijk Onderzoek – Vlaanderen (FWO), en the Belgian Science Policy Office (BELSPO). BELSPO works closely with the Operational Directorate Natural Environment of the Royal Belgian Institute of Natural Sciences (RBINS) in support of selected EMB Position Papers and for communication aspects. Dr. Lieven Naudts, coordinator of the « Measurement Service Ostend & RV Belgica » group (part of RBINS-OD Nature), was one of the work package leaders in the EMB Expert Working Group on Next Generation European Research Vessels (WG Research Vessels) and is a contributing author of the resulting Position Paper. In June 2019, Dr. Naudts also was elected chairman of the European Research Vessel Operators (ERVO) group during their annual meeting in Hamburg, Germany. « Apart from exchanging experiences, the focus of ERVO in the following years will go to exploring collaboration opportunities to promote common interests and improve the service of RVs to the scientific community, policy makers, funding agencies and even private companies. Requesting the EMB to prepare a new Position Paper on RVs, was a logical thing to do », says Naudts. « With the construction of the new Belgian Ocean Class RV that is currently ongoing at Freire Shipyard (Vigo, Spain), in collaboration with Rolls-Royce Marine AS (now Kongsberg Maritime CM AS), Belgium is well on its way to be prepared for a bright RV future. The new RV Belgica will be technologically cutting edge and ensures the continuation of the Belgian contribution to the much-needed data collection in the marine environment, not only in the North Sea but also in the deep-sea and polar regions. » he adds.

On Friday 11 October 2019, the North Sea countries celebrated the 50th anniversary of their Bonn Agreement cooperation in Bonn (Germany). Under this agreement, Belgium, the Netherlands, Germany, the United Kingdom, France, Denmark, Ireland, Sweden and Norway are fighting pollution of the North Sea together with the EU. This regional agreement was founded to combat the pollution of the North Sea by ships and other maritime activities. At the 2019 meeting, Belgium took the initiative to extend the scope of the agreement to include the prevention of illegal air pollution by shipping.

Evolution of the agreement

In 1967 the oil tanker ‘Torrey Canyon’ lost 117.000 tons of oil after being shipwrecked. Shortly after this first major oil spill, in 1969, the countries bordering the North Sea joined forces and concluded to the Bonn Agreement. In this way they help each other in the fight against pollution caused by disasters at sea, chronic pollution from ships and offshore installations. Moreover, they work together in exercising supervision and control.

Oil pollution in the North Sea has fallen sharply over the years, mainly due to the fact that nowadays, illegal oil discharges at sea are rare. This is the result of thirty years of coordinated efforts within the framework of the agreement to detect illegal discharges and to prosecute the polluters caught. However, it is still important to be able to act quickly and collectively in the event of an environmental disaster.

Results of the meeting

The Bonn meeting took a number of important decisions for the future of the agreement, which were adopted at a ministerial meeting. A new ambitious Strategic Action Plan of the Accord for the next six years was completed. Spain’s accession to the agreement – resulting in the extension of the agreement’s zone to the Bay of Biscay – was formally approved. Another important decision is the extension of the scope of the agreement to include emissions of polluting gases from ships. This was done at the suggestion of Belgium, which is in charge of the organisation of these new activities.

North Sea Minister Philippe De Backer: “This is an international recognition of Belgium’s expertise and pioneering role in protecting the seas and oceans. There is no doubt that this expertise will ensure even more effective controls on compliance with the standards for emissions of gaseous pollutants from ships in the North Sea”.

Implementation in Belgium

In Belgium, the Bonn Agreement is implemented by MUMM (Management Unit of the Mathematical Model of the North Sea) of the KBIN and the Marine Environment Service of the FPS Public Health. With the new action on the control of emissions from ships, the DG for Maritime Affairs of the FPS Mobility is now also actively involved. They jointly monitor marine pollution with aircraft and patrol vessels and control on board the vessels in the port.

Belgium is internationally regarded as a blue leader in the field of the protection of the seas and oceans. Our country was a pioneer in the field of marine spatial planning, the construction of offshore wind turbines and the fight against plastic waste in the sea. It has also taken international action to halve the CO₂ emissions of ships by 2050, and Belgian shipowners are working hard to achieve zero-emission shipping. Moreover, one third of the Belgian part of the North Sea is protected as a Natura 2000 area and Minister De Backer recently confirmed to the United Nations the ambitious ’30×30′ plan to protect 30% of the ocean by 2030. The initiative to extend the scope of the Bonn Agreement in order to better protect the North Sea once again illustrates Belgium’s pioneering role.

More information: www.bonnagreement.org

The European Marine Board has recently launched a publication, titled ‘Navigating the Future V’, which will provide European governments with robust, independent scientific advice and expert opinion on future seas and ocean research to 2030 and beyond. To achieve this, leading ocean experts have identified the key areas of marine science where there are still gaps in knowledge.

 

The European Marine Board (EMB) is a leading European think tank in marine science policy. It is an independent non-governmental advisory network with a membership comprising more than 10,000 marine scientists from the major national marine/oceanographic institutes, research funding agencies and national networks of universities from countries across Europe. The Board provides a platform for its member organizations to develop common priorities, to advance marine research, and to bridge the gap between science and policy to meet future marine science challenges and opportunities.

Navigating the Future V

The knowledge gaps that Navigating the Future V (NFV) advises to prioritise in the research agenda is critical in understanding the four-dimensional ocean, to predict tsunamis and the impact of multiple stressors on biogeochemistry and biology, and to understand the impact of the future blue economy on our marine ecosystems. NFV shows that we need transdisciplinary science and sustainability science to address the management of a holistic four-dimensional ocean. It also highlights the technological advances and modelling needed for a possible future virtual ocean that would enhance public engagement and understanding of the ocean.

NFV proposes the science we need for the forthcoming United Nations Decade for Ocean Science for Sustainable Development (2021-2030), the next European Framework Programme, Horizon Europe, and its Mission on Healthy Oceans, Seas, Coastal and Inland Waters. The report was officially launched on 11 June 2019 in Paris, France, at the EurOCEAN 2019 Conference (High-level science-policy conference co-organised by European Marine Board, the European Commission and the Intergovernmental Oceanographic Commission of UNESCO).

Key Messages

Specifically, the report recommends a solutions-oriented marine research agenda, co-designed with all stakeholders, and with the governance of sustainability at its core. It should address the following key knowledge gaps:

• The four-dimensional ocean (changes in the three-dimensional ocean over space and time) and functional links between the components of the marine system, i.e. physics, chemistry, biology, ecology and humans;
• The impact of multiple stressors (e.g. climate change, pollution, overfishing) on the functioning of marine ecosystems, their interactions, evolution and adaptation over time, and the ecosystem services they provide;
• The characteristics, probability and impacts of climate-related extreme events and geohazards (e.g. marine heat waves, meteotsunamis and submarine earthquakes, landslides, volcanic eruptions and their associated tsunamis) and how these might change under climate change; and
• Ocean technologies, modelling, data and artificial intelligence needed for sustainable ocean observations to understand, predict and manage human impacts on the ocean.

Key actions include the development of a business model ensuring the long-term economic sustainability of ocean observations. We also need to develop a new generation of sustainability scientists and establish a sustainability forum within Europe bringing together all actors including industry and civil society.

The key messages and actions are also explained in a set of infographics (see below).

The report has been a collaborative effort starting in November 2017 with a planning meeting of 19 leading European experts in the field of marine science and related disciplines to decide on the high-level content. Larger collaborative working groups with representatives from 13 European countries then worked to identify knowledge gaps and draft the recommendations of the report.

The Belgian Federal Government is represented in the European Marine Board by the Belgian Science Policy Office (BELSPO). A scientific communicator from RBINS is delegated for communication aspects and membership of the European Marine Board Communications Panel (EMBCP).

Over the past four decades, different satellites have been circling Earth whilst collecting numerous data. However, technology evolved during this time, creating the need for a unified processing method. A newly developed algorithm and software now make it possible to consistently process all these data and obtain unified image series for parameters such as water reflectance and turbidity.

Since the launch of Landsat 5 in 1984 the earth’s landmass and coastal zones have been imaged every 16 days. Landsat 5 provided regular imagery for over 25 years and was disabled fully in 2013. Its mission is being continued by Landsat 7 (launched in 1999) and Landsat 8 (2013). The Landsat missions are complemented by two Sentinel-2 missions, launched in 2015 (S2A) and 2017 (S2B) which image the earth every 5 days. The data from the Landsat missions has been open access since 2008, and those of Sentinel-2 since their launch. Combining the data streams allows the study of long time series, but due to differences in sensor design and image formats of these satellites, it was difficult to align these data over time. More precisely, an atmospheric correction algorithm and processing software for the automated and consistent processing of these images was needed.

Unified processing

In a recent publication in the journal ‘Remote Sensing of Environment’, Quinten Vanhellemont of the Remote Sensing team (REMSEM) of our institute, describes a method for unified processing of these data in order to retrieve water reflectance and derived parameters, such as water turbidity. These products have been validated with a long time series of in situ measurements from around the globe (Figure 1). This method has been the default in the ACOLITE software since April 2018 that can process imagery from Sentinel-2A/B and Landsat 5/7/8. ACOLITE was also developed by Quinten at the Royal Belgian Institute of Natural Sciences.

Images of long time series

The unified processing of data collected by the different satellites provides standardized, easily interpretable (and also beautiful) data series and images series. In the Belgian coastal zone, we can for example observe the impact of the extension of the ports of Zeebrugge and Oostende on the sedimentation on both sides of the port walls. The image series in Figure 2 show an accumulation of sand on the beaches to the east and west of the extended ports. Water turbidity is also retrieved and is in the Belgian coastal zone mainly dominated by resuspension of bottom material in superimposed cycles: an annual cycle of winter-high, summer-low turbidity and cycles of ebb-flood and neap-spring tidal resuspension.

Vanhellemont, Quinten. “Adaptation of the dark spectrum fitting atmospheric correction for aquatic applications of the Landsat and Sentinel-2 archives.” Remote Sensing of Environment 225 (2019): 175-192. https://doi.org/10.1016/j.rse.2019.03.010

 

ACOLITE processor https://odnature.naturalsciences.be/remsem/software-and-data/acolite

ACOLITE forum https://odnature.naturalsciences.be/remsem/acolite-forum/

ACOLITE source code https://github.com/acolite/acolite