Clémence Goyens

Clémence Goyens
Ghent University | UGhent · Department of Biology

PhD

About

32
Publications
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590
Citations

Publications

Publications (32)
Article
Full-text available
The LANDHYPERNET and WATERHYPERNET networks (which together make up the HYPERNETS network) consist of a set of autonomous hyperspectral spectroradiometers (HYPSTAR ® ) acquiring fiducial reference measurements of surface reflectance at various sites covering a wide range of surface types (both land and water) for use in satellite Earth observation...
Article
Full-text available
Satellites are now routinely used for measuring water and land surface reflectance and hence environmentally relevant parameters such as aquatic chlorophyll a concentration and terrestrial vegetation indices. For each satellite mission, radiometric validation is needed at bottom of atmosphere for all spectral bands and covering all typical conditio...
Article
Full-text available
A Match-up Database (MDB) file structure and tools were developed to ease the validation analysis of satellite water products and to improve the exchange and processing of match-up data from different sites, missions and atmospheric correction processors. In situ remote sensing reflectance ( Rrs ) measurements were available from the HYPSTAR ® (HYp...
Article
Full-text available
Since 2021, two autonomous HYPERNETS (A new hyperspectral radiometer integrated in automated networks of water and land bidirectional reflectance measurements for satellite validation) stations are operated in contrasted French coastal waters: one in the center of an optically complex coastal lagoon and one at the mouth of a highly turbid estuary....
Article
Full-text available
The standard above-water protocol for measurement of water reflectance uses a measurement of wind speed to estimate the air–water interface reflectance factor and, thus, remove reflected skylight from upwelling radiance. This aerodynamic wind speed measurement may be a poor proxy for the local wave slope distribution in cases such as fetch-limited...
Article
Full-text available
At the Blankaart Water Production Center, a reservoir containing 3 million m3 of raw surface water acts as a first biologic treatment step before further processing to drinking water. Over the past decade, severe algal blooms have occurred in the reservoir, hampering the water production. Therefore, strategies (e.g., the injection of algaecide) hav...
Article
Full-text available
The Green Edge project was designed to investigate the onset, life, and fate of a phytoplankton spring bloom (PSB) in the Arctic Ocean. The lengthening of the ice-free period and the warming of seawater, amongst other factors, have induced major changes in Arctic Ocean biology over the last decades. Because the PSB is at the base of the Arctic Ocea...
Article
Full-text available
Deriving sea ice albedo from spaceborne platforms is of interest to model the propagation of the photosynthetically available radiation (PAR) through Arctic sea ice. We show here that use of the Moderate Resolution Imaging Spectroradiometer (MODIS) operational surface reflectance satellite product to derive albedo in the PAR spectral range is possi...
Preprint
The Green Edge project was designed to investigate the onset, life and fate of a phytoplankton spring bloom (PSB) in the Arctic Ocean. The lengthening of the ice-free period and the warming of seawater, amongst other factors, have induced major changes in arctic ocean biology over the last decades. Because the PSB is at the base of the Arctic Ocean...
Technical Report
Full-text available
Article
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The Green Edge initiative was developed to investigate the processes controlling the primary productivity and fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Qikiq...
Article
Full-text available
Nutrient deficiency in forest stands has a negative impact on timber production. Although there are numerous studies investigating nutrient deficiency in forests using remote sensing, research has usually focused on extracting nutrient/ pigment concentrations using hyperspectral imagery. Results of studies using this method of assessment are uncert...
Article
Full-text available
Water pixel extraction and correction of the atmospheric signal represent prerequisite steps prior to applying algorithms dedicated to the assessment of water quality of natural surface water bodies. The recent multiplication of medium spatial resolution sensors (10–60 m) provides the required constellation to monitoring bio-optical and biogeochemi...
Article
Full-text available
The Green Edge initiative was developed to investigate the processes controlling the primary productivity and the fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Q...
Article
Full-text available
We introduce a new method to determine the anisotropy of reflectance of sea ice and snow at spatial scales from 1 m2 to 80 m2 using a multispectral circular fish-eye radiance camera (CE600). The CE600 allows measuring radiance simultaneously in all directions of a hemisphere at a 1°angular resolution. The spectral characteristics of the reflectance...
Data
This dataset includes the data published in Goyens et al. (2018, DOI:10.1002/2017EA000332). available from SEANOE. http://doi.org/10.17882/55352
Data
Dans le contexte 1) de la fonte du pergélisol et le relargage de carbone organique, 2) du verdissement de l'Arctique, et 3) de l'accélération des processus d'érosion des berges, on s'attend à une augmentation progressive de l'export de nutriments et matière organique dissoute et particulaire vers les systèmes aquatiques de l'Arctique. Les conséquen...
Thesis
Full-text available
L'acquisition de paramètres marins à partir des données spatiales de la couleur de l'eau nécessite l'élimination de la contribution de l'atmosphère au signal mesuré par le capteur. En effet, la majorité du rayonnement solaire mesuré par les instruments optiques dans les longueurs d'ondes qui intéressent la couleur de l'eau provient de la diffusion...
Article
Full-text available
The present study provides an extensive overview of red and near infra-red (NIR) spectral relationships found in the literature and used to constrain red or NIR-modeling schemes in current atmospheric correction (AC) algorithms with the aim to improve water-leaving reflectance retrievals, ρw(λ), in turbid waters. However, most of these spectral rel...
Article
Full-text available
Spectral relationships, reflecting the spectral dependence of water-leaving reflectance, ρw(λ), can be easily implemented in current AC algorithms with the aim to improve ρw(λ) retrievals where the algorithms fail. The present study evaluates the potential of spectral relationships to improve the MUMM [Ruddick et al., 2006, Limnol. Oceanogr. 51, 11...
Article
Full-text available
The use of satellites to monitor the color of the ocean requires effective removal of the atmospheric signal. This can be performed by extrapolating the aerosol optical properties to the visible from the near-infra-red (NIR) spectral region assuming that seawater is totally absorbent in this latter part of the spectrum, the so-called black pixel as...
Article
Full-text available
Although mesoscale convective systems (MCSs) are the main source of precipitation in the semi-arid Sahel region, the relationship between MCS characteristics and their generated precipitation remain unclear. However, a thorough understanding of this relation is essential to work towards a classification scheme for MCSs and eventually to improve qua...
Article
Located in the semi-arid African Sahel, Lake Chad has shrunk from a surface area of 25000 km2 in 1960 to about 1350 km2 due to a series of droughts and anthropogenic influences. The disappearance of such a large open-water body can be expected to have a noticeable effect on the meteorology in the surroundings of the lake. The impact could extend ev...
Article
Full-text available
Abstract The role of tropical cyclones in structuring tropical rainforests has long been recognized in the Americas and northern Australia. However, their role in the dynamics of Australian savannas has received little attention compared with the effects of fire and drought. In April 2006, Tropical Cyclone Monica caused trees to be snapped or uproo...

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