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Article Reference Atmospheric correction of Sentinel-3/OLCI data for mapping of suspended particulate matter and chlorophyll-a concentration in Belgian turbid coastal waters
The performance of different atmospheric correction algorithms for the Ocean and Land Colour Instrument (OLCI) on board of Sentinel-3 (S3) is evaluated for retrieval of water-leaving radiance reflectance, and derived parameters chlorophyll-a concentration and turbidity in turbid coastal waters in the Belgian Coastal Zone (BCZ). This is performed using in situ measurements from an autonomous pan-and-tilt hyperspectral radiometer system (PANTHYR). The PANTHYR provides validation data for any satellite band between 400 and 900 nm, with the deployment in the BCZ of particular interest due to the wide range of observed Near-InfraRed (NIR) reflectance. The Dark Spectrum Fitting (DSF) atmospheric correction algorithm is adapted for S3/OLCI processing in ACOLITE, and its performance and that of 5 other processing algorithms (L2-WFR, POLYMER, C2RCC, SeaDAS, and SeaDAS-ALT) is compared to the in situ measured reflectances. Water turbidities across the matchups in the Belgian Coastal Zone are about 20–100 FNU, and the overall performance is best for ACOLITE and L2-WFR, with the former providing lowest relative (Mean Absolute Relative Difference, MARD 7–27\%) and absolute errors (Mean Average Difference, MAD -0.002, Root Mean Squared Difference, RMSD 0.01–0.016) in the bands between 442 and 681 nm. L2-WFR provides the lowest errors at longer NIR wavelengths (754–885 nm). The algorithms that assume a water reflectance model, i.e. POLYMER and C2RCC, are at present not very suitable for processing imagery over the turbid Belgian coastal waters, with especially the latter introducing problems in the 665 and 709 nm bands, and hence the chlorophyll-a and turbidity retrievals. This may be caused by their internal model and/or training dataset not being well adapted to the waters encountered in the BCZ. The 1020 nm band is used most frequently by ACOLITE/DSF for the estimation of the atmospheric path reflectance (67\% of matchups), indicating its usefulness for turbid water atmospheric correction. Turbidity retrieval using a single band algorithm showed good performance for L2-WFR and ACOLITE compared to PANTHYR for e.g. the 709 nm band (MARD 15 and 17\%), where their reflectances were also very close to the in situ observations (MARD 11\%). For the retrieval of chlorophyll-a, all methods except C2RCC gave similar performance, due to the RedEdge band-ratio algorithm being robust to typical spectrally flat atmospheric correction errors. C2RCC does not retain the spectral relationship in the Red and RedEdge bands, and hence its chlorophyll-a concentration retrieval is not at all reliable in Belgian coastal waters. L2-WFR and ACOLITE show similar performance compared to in situ radiometry, but due to the assumption of spatially consistent aerosols, ACOLITE provides less noisy products. With the superior performance of ACOLITE in the 490–681 nm wavelength range, and smoother output products, it can be recommended for processing of S3/OLCI data in turbid waters similar to those encountered in the BCZ. The ACOLITE processor for OLCI and the in situ matchup dataset used here are made available under an open source license.
Located in Library / RBINS Staff Publications 2021
Techreport Reference Attraction of harbour porpoises to offshore wind farms: what can be expected? In: S. Degraer, R. Brabant and B. Rumes (Eds.) Environmental impacts of the offshore windfarms in the Belgian part of the North Sea: learning from the past to optimize future m
Located in Library / RBINS Staff Publications
Conference Reference Au nord, deuil dans les corons. Analyse anthropologique des victimes non identifiées de la catastrophe du Bois du Cazier (1956, Belgique).
Le 8 août 1956, la catastrophe minière la plus meurtrière de Belgique se produisit au charbonnage du Bois du Cazier à Marcinelle : 262 mineurs de nationalités diverses (belge, italienne, allemande, algérienne, grecque, …) périrent à la suite d’une erreur humaine. Tous furent identifiés à l’exception de 17 d’entre eux. En octobre 2021, à la demande d’un descendant des victimes non identifiées, la Cellule d’Identification des Victimes de Catastrophes de la Police Fédérale a lancé une grande opération afin d’exhumer les restes des inconnus et de procéder à leur identification. Les analyses ont été réalisées par une équipe composée d’experts en pathologie médico-légale, en odontologie, en anthropologie, en archéologie et en ADN. Nous présentons ici les résultats de l’analyse anthropologique. Après l’inventaire des restes, le profil biologique de chaque individu a été reconstitué. La DSP a été utilisée pour déterminer le sexe et sept méthodes différentes ont été appliquées pour estimer l’âge au décès, y compris la cémentochronologie. La stature a été estimée à l’aide des équations de Raxter et d’Oliver, tandis que l’origine bio-géographique a été évaluée avec AncesTrees. La confrontation des registres ante-mortem (stature, âge, pathologies et particularités physiques) avec les données post-mortem nous a permis de proposer une identification pour huit individus. Quatre d’entre elles ont été confirmées par l’ADN. Au-delà de l’identification permettant de mener à bien ce devoir de mémoire envers les familles des victimes, cette mission nous a donné l’opportunité d’enregistrer des données précieuses pour d’autres domaines de recherche comme les traumatismes péri-mortem et les marqueurs d’activité résultant des pénibles conditions de travail des mineurs de fond.
Located in Library / RBINS Staff Publications 2024
Article Reference Australian Cleotychini planthoppers: review of the genus Cleotyche Emeljanov, 1997 with three new species (Hemiptera: Fulgoromorpha: Dictyopharidae)
Located in Library / RBINS Staff Publications 2022
Inproceedings Reference Authenticating fish and seafood products for sale on the Belgian market
Located in Library / RBINS Staff Publications 2017
Article Reference Authorship and date of five family-series nomina in Oligochaeta (Annelida): Lumbricidae, Naididae, Enchytraeidae, Tubificidae and Lumbriculidae
Located in Library / RBINS Staff Publications 2021
Article Reference Automated water surface temperature retrieval from Landsat 8/TIRS
Satellite remote sensing of Land and Water Surface Temperature (L/WST) has many applications in studies of terrestrial and aquatic ecology. Retrieval of L/WST requires a well calibrated radiometer and an accurate atmospheric correction. In the present study, the performance of the Thermal InfraRed Sensor (TIRS) on board Landsat 8 is evaluated for the retrieval of L/WST. libRadtran is used to retrieve atmospheric correction parameters based on atmospheric profiles of relative humidity and temperature from three global atmospheric models. Performance of single band retrievals is compared to typical MODTRAN results from the Atmospheric Correction Parameter Calculator (ACPC) and a split-window approach. A multi-temporal land masking method using imagery from the Operational Land Imager (OLI) on board Landsat 8 is demonstrated, and is used to automatically classify imagery in the matchup dataset in three classes of cloud cover. Two sources of in situ data covering the Belgian Coastal Zone (BCZ) are used for validation of the L/WST product: (1) fixed locations in the Flemish Banks measurement network and (2) underway data from regular RV Belgica campaigns. In the present study the single band methods outperformed the split-window approach, and consistent retrievals are found for the MODTRAN and libRadtran simulations. Typical single band surface temperature retrievals in quasi cloud-free conditions have Root Mean Squared Differences (RMSD) of 0.7 K and 1 K for Bands 10 and 11 with low bias, depending on the method and atmospheric profile source. For imagery with scattered clouds, RMSD values increase to 1 K and 2 K respectively with an approximately 0.5 K cold bias, likely caused by cloud proximity. The calibration efforts combined into Collection 1 allows for accurate absolute surface temperature retrievals from B10 on Landsat 8/TIRS for homogeneous targets with known emissivity, such as liquid water. The method is adapted to global processing and can be used for Land Surface Temperature retrieval with a suitable source of emissivity data.
Located in Library / RBINS Staff Publications 2020
Inproceedings Reference Backscatter stability and influence of water column conditions: estimation by multibeam echosounder and repeated oceanographic measurements, Belgian part of the North Sea
The European Union Marine Strategy Framework Directive requires Member States to monitor and assess the health status of their marine habitats. Belgium put forward that the spatial extent and distribution of the major habitats (sandy mud to mud, muddy sands to sands and coarse-grained sediments), as well as that of gravel beds may only fluctuate within a margin that is limited to the accuracy of the current sediment distribution maps. Due to their ability to provide simultaneous bathymetry and backscatter strength (BS), reflecting seabed nature, multibeam echosounder systems (MBES) provide a time- and costefficient solution to anticipate on this legal obligation. However, as there is no formal quality level scale for the BS and consequently no level of reliability of the final decibel values, evaluating the BS quantitative capabilities to monitor habitat changes remains challenging. In a monitoring context, it is absolutely necessary to investigate to what extent the mean MBES-measured BS variation -from one cruise to another- actually represents a significant change in seabed properties and not only a change in the conditions of the water column (e.g., variation in near-bed suspensions, biological effects, increased occurrence of micro bubbles in the sea surface due to wind) at the time of the measurement. In order to evaluate the relative accuracy and the repeatability of MBES BS and to examine the external sources of variance in acoustic signatures, repeated measurements combining MBES with an Acoustic Doppler current Profiler (ADP) have been performed during tidal cycles on reference areas in the Belgian part of the North Sea. Currents and BS in the water column and vertical profiling of oceanographic parameters have been investigated allowing studying the influence of water column conditions on the BS. Measurements were conducted using two MBES systems to evaluate repeatability between echosounders. Ultimate goal is to arrive at seabed mapping and analyses protocols to obtain harmonized data products from a collaborative seabed mapping community.
Located in Library / RBINS Staff Publications
Article Reference Barcoding and traditional health practitioner perspectives are informative to monitor and conserve frogs and reptiles traded for traditional medicine in urban South Africa
Previous literature suggests that Indigenous cultural practices, specifically traditional medicine, are commonplace among urban communities contrary to the general conception that such practices are restricted to rural societies. We reviewed previous literature for records of herptiles (frog and reptile species) sold by traditional health practitioners in urban South Africa, then used visual confirmation surveys, DNA barcoding and folk taxonomy to identify the herptile species that were on sale. Additionally, we interviewed 11 IsiZulu and SePedi speaking traditional health practitioners to document details of the collection and pricing of herptile specimens along with the practitioners' views of current conservation measures for traditional medicine markets. The 34 herptile species recorded in previous literature on traditional medicine markets included endangered and non-native species. Spectrophotometry measurements of the DNA we extracted from the tissue of herptiles used in traditional medicine were an unreliable predictor of whether those extractions would be suitable for further experimental work. From our initial set of 111 tissue samples, 81 sequencing reactions were successful and 55 of those sequences had species-level matches to COI reference sequences on the NCBI GenBank and/or BOLD databases. Molecular identification revealed that traditional health practitioners correctly labelled 77% of the samples that we successfully identified with DNA barcoding in this study. Our mixed methodology approach is useful for conservation planning as it updates knowledge of animal use in Indigenous remedies and can accurately identify species of high conservation priority. Furthermore, this study highlights the possibility of collaborative conservation planning with traditional health practitioners.
Located in Library / RBINS Staff Publications 2023 OA
Article Reference Barcoding Earthworms from Ecotoxicological Test Laboratories
Located in Library / RBINS Staff Publications