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1. Canopy Structure Stratification in Mature Mediterranean Cork Oak Forest Ecosystems and Its Impact on the Water Balance

Author

Ben Yahia, Kaouther, Delpierre, Nicolas, Hasnaoui, Brahim, Soudani, Kamel, Pisello, Anna Laura, Editorial Board Member, Hawkes, Dean, Editorial Board Member, Bougdah, Hocine, Editorial Board Member, Rosso, Federica, Editorial Board Member, Abdalla, Hassan, Editorial Board Member, Boemi, Sofia-Natalia, Editorial Board Member, Mohareb, Nabil, Editorial Board Member, Mesbah Elkaffas, Saleh, Editorial Board Member, Bozonnet, Emmanuel, Editorial Board Member, Pignatta, Gloria, Editorial Board Member, Mahgoub, Yasser, Editorial Board Member, De Bonis, Luciano, Editorial Board Member, Kostopoulou, Stella, Editorial Board Member, Pradhan, Biswajeet, Editorial Board Member, Abdul Mannan, Md., Editorial Board Member, Alalouch, Chaham, Editorial Board Member, Gawad, Iman O., Editorial Board Member, Nayyar, Anand, Editorial Board Member, Amer, Mourad, Series Editor, Ksibi, Mohamed, editor, Negm, Abdelazim, editor, Hentati, Olfa, editor, Ghorbal, Achraf, editor, Sousa, Arturo, editor, Rodrigo-Comino, Jesus, editor, Panda, Sandeep, editor, Lopes Velho, José, editor, El-Kenawy, Ahmed M., editor, and Perilli, Nicola, editor

Published
2024
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6. Phenology across scales: an intercontinental analysis of leaf-out dates in temperate deciduous tree communities

Author

Delpierre, Nicolas, primary, Garnier, Suzon, additional, Treuil-Dussouet, Hugo, additional, Hufkens, Koen, additional, Lin, Jianhong, additional, Beier, Colin, additional, Bell, Michael, additional, Berveiller, Daniel, additional, Cuntz, Matthias, additional, Curioni, Giulio, additional, Dahlin, Kyla, additional, Denham, Sander O, additional, Desai, Ankur R, additional, Domec, Jean-Christophe, additional, Hart, Kris M, additional, Ibrom, Andreas, additional, Joetzjer, Emilie, additional, King, John, additional, Klosterhalfen, Anne, additional, Koebsch, Franziska, additional, McHale, Peter, additional, Morfin, Alexandre, additional, Munger, J. William, additional, Noormets, Asko, additional, Pilegaard, Kim, additional, Pohl, Felix, additional, Rebmann, Corinna, additional, Richardson, Andrew D, additional, Rothstein, David, additional, Schwartz, Mark D, additional, Wilkinson, Matthew, additional, and Soudani, Kamel, additional

Published
2023
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10. Investigating the responses of sun-induced chlorophyll fluorescence, gross primary production and their inter-relationship to abiotic factors changes in a temperate deciduous forest.

Author

Balde, Hamadou, Hmimina, Gabriel, Goulas, Yves, Latouche, Gwendal, Ounis, Abderrahmane, Berveiller, Daniel, and Soudani, Kamel

Subjects
CHLOROPHYLL spectra, DECIDUOUS forests, TEMPERATE forests, SATELLITE-based remote sensing, NORMALIZED difference vegetation index, EXTREME weather, HELIOSEISMOLOGY
Abstract

Far-red Sun-Induced chlorophyll Fluorescence (SIF) is increasingly used as a proxy of vegetation Gross Primary Production (GPP) across different ecosystems and at spatiotemporal resolutions going from proximal to satellite-based remote sensing measurements. However, the use of SIF to probe variations in GPP in forests is challenged by (1) confounding factors such as canopy structure and sun-canopy geometry, and by (2) leaf physiological and biochemical properties along with abiotic factors (light intensity, temperature, soil water content, atmospheric vapour pressure deficit, etc.) that can influence SIF and GPP in a different way. To provide insights into understanding the complex drivers of GPP and SIF variations and of their relationships, we examined how SIF and GPP changed at daily and seasonal scales and how canopy structure and environmental conditions affected SIF and GPP relationships in a deciduous oak forest. To do so, we combined canopy scale SIF measurements, spectral vegetation indices, environmental variables measurements, including diffuse and direct radiations in the spectral range of the Photosynthetically Active Radiation (PAR), air and canopy temperature, soil water content (SWC), atmospheric Vapour Pressure Deficit (VPD), and GPP estimated from eddy covariance measurements. Canopy chlorophyll fluorescence was also measured using an active system with an artificial light source, referred to as LIF (LED Induced chlorophyll Fluorescence) hereafter. Further, Random Forest (RF) models were used to predict SIF and GPP and to analyse the responses of SIF and GPP to environmental drivers. The results show that both SIF and GPP variations and their relationships were dependent on the temporal scale considered. At the seasonal scale, The data show that leaf and canopy properties variations, seasonal cycle of PAR, and other abiotic factors such as VPD and SWC control not only SIF and GPP variations, but also their relationships. Further, during extreme weather conditions (heatwaves observed in 2022 in: mid-June (DOY: 166-169), mid-July (DOY: 196-199), and early August (DOY: 218-224)), we observed that SIF and reflectance-based Vegetation Indices (VIs), such as Normalized Difference Vegetation Index (NDVI) and Near-Infrared Reflectance of vegetation index (NIRv), and also SIF and PAR are uncorrelated, while GPP, SIF, passive SIF yield (SIFy) and active chlorophyll fluorescence yield (FyieldLIF) strongly decreased. This indicates that during these severe abiotic conditions SIF stayed a usable proxy of GPP, while VIs cannot be used to track changes in vegetation physiology. This specific response of SIF compared to VIs underlined the interest of SIF to monitor GPP under severe abiotic conditions. At the diurnal timescale, the results also revealed that the saturation of the relationship between GPP and SIF was not only dependent on PAR, but also on the fraction of diffuse to total PAR, as well as on VPD, SWC, and air and canopy temperature. The other key finding was that sun geometry angles had strong effects on GPP and SIF variations. This result highlights that using ground-based SIF measurements to validate satellite measurements at coarse spatial and temporal resolutions can therefore be very difficult, due to confounding factors whose effects are significant and may vary from one site to another, especially in forest canopies. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Data-based investigation of the effects of canopy structure and shadows on chlorophyll fluorescence in a deciduous oak forest.

Author

Balde, Hamadou, Hmimina, Gabriel, Goulas, Yves, Latouche, Gwendal, Ounis, Abderrahmane, and Soudani, Kamel

Subjects
CHLOROPHYLL spectra, DECIDUOUS forests, NORMALIZED difference vegetation index, FLUORESCENCE yield, FOREST canopies, ZENITH distance, OAK
Abstract

Data from satellite, aircraft, drone, and ground-based measurements have already shown that canopy-scale sun-induced chlorophyll fluorescence (SIF) is tightly related to photosynthesis, which is linked to vegetation carbon assimilation. However, our ability to effectively use those findings are hindered by confounding factors, including canopy structure, fluctuations in solar radiation, and sun–canopy geometry that highly affect the SIF signal. Thus, disentangling these factors has become paramount in order to use SIF for monitoring vegetation functioning at the canopy scale and beyond. Active chlorophyll fluorescence measurements (FyieldLIF), which directly measures the apparent fluorescence yield, have been widely used to detect physiological variation of the vegetation at the leaf scale. Recently, the measurement of FyieldLIF has become feasible at the canopy scale, opening up new opportunities to decouple structural, biophysical, and physiological components of SIF at the canopy scale. In this study, based on top-of-canopy measurements above a mature deciduous forest, reflectance (R), SIF, SIF normalized by incoming photosynthetically active radiation (SIF y), FyieldLIF , and the ratio between SIF y and FyieldLIF (named Φk) were used to investigate the effects of canopy structure and shadows on the diurnal and seasonal dynamics of SIF. Further, random forest (RF) models were also used to not only predict FyieldLIF and Φk , but also provide an interpretation framework by considering additional variables, including the R in the blue, red, green, red-edge, and near-infrared bands; SIF; SIF y ; and solar zenith angle (SZA) and solar azimuth angle (SAA). Results revealed that the SIF signal is highly affected by the canopy structure and sun–canopy geometry effects compared to FyieldLIF. This was evidenced by the weak correlations obtained between SIF y and FyieldLIF at the diurnal timescale. Furthermore, the daily mean SIF‾y captured the seasonal dynamics of daily mean F‾yieldLIF and explained 58 % of its variability. The findings also revealed that reflectance in the near-infrared (R -NIR) and the NIR v (the product of R -NIR and normalized difference vegetation index (NDVI)) are good proxies of Φk at the diurnal timescale, while their correlations with Φk decrease at the seasonal timescale. With FyieldLIF and Φk as outputs and the abovementioned variables as predictors, this study also showed that the RF models can explain between 86 % and 90 % of FyieldLIF , as well as 60 % and 70 % of Φk variations under clear-sky conditions. In addition, the predictor importance estimates for FyieldLIF RF models revealed that R at 410, 665, 740, and 830 nm; SIF; SIF y ; SZA; and SAA emerged as the most useful and influential factors for predicting FyieldLIF , while R at 410, 665, 705, and 740 nm; SZA; and SAA are crucial for predicting Φk. This study highlighted the complexity of interpreting diurnal and seasonal dynamics of SIF in forest canopies. These dynamics are highly dependent on the complex interactions between the structure of the canopy, the vegetation biochemical properties, the illumination angles (SZA and SAA), and the light conditions (ratio of diffuse to direct solar radiation). However, such measurements are necessary to better separate the variability in SIF attributable to radiation and measurement conditions from the subtler variability attributable to plant physiological processes. [ABSTRACT FROM AUTHOR]

Published
2024
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13. Data-based investigation of the effects of canopy structure and shadows on chlorophyll fluorescence in a deciduous oak forest.

Author

Balde, Hamadou, Hmimina, Gabriel, Goulas, Yves, Latouche, Gwendal, Ounis, Abderrahmane, and Soudani, Kamel

Subjects
CHLOROPHYLL spectra, DECIDUOUS forests, NORMALIZED difference vegetation index, FLUORESCENCE yield, FOREST canopies, RADIATION measurements, OAK
Abstract

Data from satellite, aircraft, drone, and ground-based measurements have already shown that canopy scale sun-induced chlorophyll fluorescence (SIF) is tightly related to photosynthesis, which is linked to vegetation carbon assimilation. However, our ability to effectively use those findings are hindered by confounding factors, including canopy structure, fluctuations in solar radiation and in sun-canopy-geometry that highly affect the SIF signal. Thus, disentangling these factors has become paramount in order to use SIF for monitoring vegetation functioning at canopy scale and beyond. Active chlorophyll fluorescence measurements (FyieldLIF), which directly measures the apparent fluorescence yield, have been widely used to detect physiological variation of the vegetation at leaf scale. Recently, the measurement of FyieldLIF has become feasible at the canopy scale, opening up new opportunities to decouple structural, biophysical, and physiological components of SIF at the canopy scale. In this study, based on top-of-canopy measurements above a mature deciduous forest, reflectance (R), SIF, SIF normalized by incoming photosynthetically active radiation (SIFy), FyieldLIF, and the ratio between SIFy and FyieldLIF (named Φk) were used to investigate the effects of canopy structure and shadows on the diurnal and seasonal dynamics of SIF. Further, random forest (RF) models were also used to not only predict FyieldLIF and Φk, but also provide an interpretation framework by considering additional variables, including the R in the blue, red, green, red-edge, and near-infrared bands, SIF, SIFy, and sun zenith (SZA) and azimuth (SAA) angles. Results revealed that the SIF signal is highly affected by the canopy structure and sun-canopy geometry effects compared to FyieldLIF. This was evidenced by the weak correlations obtained between SIFy and FyieldLIF at the diurnal timescale. Furthermore, the daily mean SIF y captured the seasonal dynamics of daily mean FyieldLIF and explained 58 % of its variability. The findings also revealed that reflectance in the near-infrared (R-NIR) and the NIRv (the product of NIR by the normalized difference vegetation index) are good proxies of Φk at the diurnal timescale, while their correlations with Φk decrease at the seasonal timescale. With FyieldLIF and Φk as outputs and the abovementioned variables as predictors, this study also showed that the RF models can explain between 86 % and 90 % of FyieldLIF, and 60 % and 70 % of Φk variations under clear sky conditions. In addition, the predictor importance estimates for FyieldLIF RF models revealed that R at 410, 665, 740, and 830 nm, SIF, SIFy, SZA, and SAA emerged as the most useful and influential factors for predicting FyieldLIF, while R at 410, 665, 705, and 740 nm, SZA, and SAA are crucial for predicting Φk. This study highlighted the complexity of interpreting diurnal and seasonal dynamics of SIF in forest canopies. These dynamics are highly dependent on the complex interactions between the structure of the canopy, the vegetation biochemical properties, the illumination angles (SZA and SAA) and the light conditions (ratio of diffuse to direct solar radiation). However, such measurements are necessary to better separate the variability in SIF attributable to radiation and measurement conditions from the subtler variability attributable to plant physiological processes. [ABSTRACT FROM AUTHOR]

Published
2023
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16. BIODIVERSITY – A new space mission to monitor Earth ecosystems at fine scale

Author

BRIOTTET, Xavier, primary, BAJJOUK, Touria, additional, CHAMI, Malik, additional, DELACOURT, Christophe, additional, FERET, Jean-Baptiste, additional, JACQUEMOUD, Stephane, additional, MINGHELLI, Audrey, additional, SHEEREN, David, additional, WEBER, Christiane, additional, FABRE, Sophie, additional, ADELINE, Karine, additional, VAUDOUR, Emmanuelle, additional, LUQUE, Sandra, additional, DEVILLE, Yannick, additional, SOUDANI, Kamel, additional, and VERPOOTER, Charles, additional

Published
2022
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18. BIODIVERSITY – Une Nouvelle Mission Spatiale Pour Le Suivi Des Ecosystèmes A Une Echelle Fine

Author

Briottet, Xavier, Bajjouk, Touria, Chami, Malik, Delacourt, Christophe, Feret, Jean-baptiste, Jacquemoud, Stephane, Minghelli, Audrey, Sheeren, David, Weber, Christiane, Fabre, Sophie, Adeline, Karine, Vaudour, Emmanuelle, Luque, Sandra, Deville, Yannick, Soudani, Kamel, and Verpooter, Charles

Subjects
critical zone, zone critique, milieu urbain, imaging spectroscopy, space mission, biodiversité, coastal ecosystems, écosystèmes côtiers, hyperspectral, vegetation, mission spatiale, soil quality, imagerie hyperspectrale, végétation, qualité des sols, biodiversity, urban area
Abstract

Imaging spectroscopy has demonstrated its interest in characterizing the biochemical, biophysical and structural properties of vegetation, natural and agricultural soils, as well as artificial surfaces. Following the Hyperion mission, new space missions have emerged (PRISMA, EnMap), or are under study (CHIME, SBG). However, one of their main limitations lies in their spatial resolution that induces a large number of mixed pixels reducing their potential for discrimination for very heterogeneous areas. The BIODIVERSITY mission aims to complement these space missions with better GSD acquisitions (typically 8-10 m) with a 5-day revisit on targeted reference sites with identified and well-located characteristics. It will thus make it possible, in particular, to answer two scientific issues that will design the instrument. The first issue concerns the spatial and temporal distribution of vegetation traits in species assemblages; these traits are associated with the resilience of terrestrial ecosystems, anthropogenic influences, and the biodiversity of ecosystems in terms of species composition and assemblages. The second issue relates to improving our knowledge of coastal areas and inland waters in terms of biodiversity, water quality and bathymetry, in order to assess the impact of human activity on their ecosytems. The scientific challenges as well as the user requirements for such a mission are presented for each application., L’imagerie hyperspectrale a démontré son intérêt pour la caractérisation des propriétés biochimiques, biophysiques et structurelles de la végétation, des sols naturels et agricoles ainsi que des surfaces artificialisées. A la suite de la mission Hyperion, de nouvelles missions spatiales ont vu le jour (PRISMA, EnMAP), ou sont en phase d’étude (SBG, CHIME). Ces spectro-imageurs ont une résolution spatiale au sol de l’ordre de 30 m, un large champ de vue et peuvent couvrir de vastes zones du globe terrestre afin de caractériser les écosystèmes terrestres et océaniques avec un temps de revisite variant de 4 à 16 jours. Néanmoins, leur résolution spatiale est limitée ce qui induit un nombre important de pixels mixtes réduisant leur potentiel de discrimination pour des zones hétérogènes. La mission BIODIVERSITY a pour objectif de compléter ces missions par des acquisitions de meilleure résolution spatiale (typiquement 8-10 m) avec une revisite de l’ordre de 5 jours sur des sites de référence ciblés possédant des caractéristiques identifiées et bien localisées. Elle permettra ainsi de répondre à deux problématiques scientifiques qui vont dimensionner l’instrument. La première problématique porte sur la distribution spatiale et temporelle des traits de la végétation dans les assemblages d’espèces ; ces traits sont associés à la résilience des écosystèmes terrestres, aux influences anthropiques et à la biodiversité des écosystèmes en termes de composition et d’assemblages en espèces. La seconde problématique porte sur l’amélioration de nos connaissances des zones côtières et des eaux continentales en termes de biodiversité, de qualité des eaux et de bathymétrie, pour ensuite évaluer l’impact de l’activité anthropique sur leurs écosystèmes. Enfin, ces deux applications qui déterminent les spécifications de l’instrument seront complétées par l’étude, à fine résolution spatiale, de l’impact des pratiques de gestion des sols dans un processus environnemental tels que le stockage du carbone dans les sols, l’infiltration et la rétention d’eau en surface ou l’érosion des sols. Elles ouvrent également de nouvelles voies pour évaluer comment les matériaux urbains influencent notre environnement proche et pour caractériser les pollutions urbaine et industrielle. Les défis scientifiques ainsi que les exigences-utilisateurs pour une telle mission sont présentés pour chaque application.

Published
2022

20. Warming does not delay the start of autumnal leaf coloration but slows its progress rate

Author

Jiang, Nan, primary, Shen, Miaogen, additional, Ciais, Philippe, additional, Campioli, Matteo, additional, Peñuelas, Josep, additional, Körner, Christian, additional, Cao, Ruyin, additional, Piao, Shilong, additional, Liu, Licong, additional, Wang, Shiping, additional, Liang, Eryuan, additional, Delpierre, Nicolas, additional, Soudani, Kamel, additional, Rao, Yuhan, additional, Montagnani, Leonardo, additional, Hörtnagl, Lukas, additional, Paul‐Limoges, Eugénie, additional, Myneni, Ranga, additional, Wohlfahrt, Georg, additional, Fu, Yongshuo, additional, Šigut, Ladislav, additional, Varlagin, Andrej, additional, Chen, Jin, additional, Tang, Yanhong, additional, and Zhao, Wenwu, additional

Published
2022
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23. Synergy between TROPOMI sun-induced chlorophyll fluorescence and MODIS spectral reflectance for understanding the dynamics of gross primary productivity at Integrated Carbon Observatory System (ICOS) ecosystem flux sites.

Author

Balde, Hamadou, Hmimina, Gabriel, Goulas, Yves, Latouche, Gwendal, and Soudani, Kamel

Subjects
SPECTRAL reflectance, CHLOROPHYLL spectra, SHRUBLANDS, BIOSPHERE, NORMALIZED difference vegetation index, PHYSIOLOGICAL adaptation, BROADLEAF forests, OBSERVATORIES
Abstract

An accurate estimation of vegetation gross primary productivity (GPP), which is the amount of carbon taken up by vegetation through photosynthesis for a given time and area, is critical for understanding terrestrial–atmosphere CO 2 exchange processes and ecosystem functioning, as well as ecosystem responses and adaptations to climate change. Prior studies, based on ground, airborne, and satellite sun-induced chlorophyll fluorescence (SIF) observations, have recently revealed close relationships with GPP at different spatial and temporal scales and across different plant functional types (PFTs). However, questions remain regarding whether there is a unique relationship between SIF and GPP across different sites and PFTs and how we can improve GPP estimates using solely remotely sensed data. Using concurrent measurements of daily TROPOspheric Monitoring Instrument (TROPOMI) SIF (daily SIFd); daily MODIS Terra and Aqua spectral reflectance; vegetation indices (VIs, notably normalized difference vegetation index (NDVI), near-infrared reflectance of vegetation (NIRv), and photochemical reflectance index (PRI)); and daily tower-based GPP across eight major different PFTs, including mixed forests, deciduous broadleaf forests, croplands, evergreen broadleaf forests, evergreen needleleaf forests, grasslands, open shrubland, and wetlands, the strength of the relationships between tower-based GPP and SIF d at 40 Integrated Carbon Observation System (ICOS) flux sites was investigated. The synergy between SIF d and MODIS-based reflectance (R) and VIs to improve GPP estimates using a data-driven modeling approach was also evaluated. The results revealed that the strength of the hyperbolic relationship between GPP and SIF d was strongly site-specific and PFT-dependent. Furthermore, the generalized linear model (GLM), fitted between SIF d , GPP, and site and vegetation type as categorical variables, further supported this site- and PFT-dependent relationship between GPP and SIF d. Using random forest (RF) regression models with GPP as output and the aforementioned variables as predictors (R , SIF d , and VIs), this study also showed that the spectral reflectance bands (RF- R) and SIF d plus spectral reflectance (RF-SIF- R) models explained over 80 % of the seasonal and interannual variations in GPP, whereas the SIF d plus VI (RF-SIF-VI) model reproduced only 75 % of the tower-based GPP variance. In addition, the relative variable importance of predictors of GPP demonstrated that the spectral reflectance bands in the near-infrared, red, and SIF d appeared as the most influential and dominant factors determining GPP predictions, indicating the importance of canopy structure, biochemical properties, and vegetation functioning on GPP estimates. Overall, this study provides insights into understanding the strength of the relationships between GPP and SIF and the use of spectral reflectance and SIF d to improve estimates of GPP across sites and PFTs. [ABSTRACT FROM AUTHOR]

Published
2023
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26. Site Characteristics Mediate the Relationship Between Forest Productivity and Satellite Measured Solar Induced Fluorescence

Author

Yazbeck, Theresia, primary, Bohrer, Gil, additional, Gentine, Pierre, additional, Ye, Luping, additional, Arriga, Nicola, additional, Bernhofer, Christian, additional, Blanken, Peter D., additional, Desai, Ankur R., additional, Durden, David, additional, Knohl, Alexander, additional, Kowalska, Natalia, additional, Metzger, Stefan, additional, Mölder, Meelis, additional, Noormets, Asko, additional, Novick, Kim, additional, Scott, Russell L., additional, Šigut, Ladislav, additional, Soudani, Kamel, additional, Ueyama, Masahito, additional, and Varlagin, Andrej, additional

Published
2021
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27. Method comparison of indirect assessments of understory leaf area index (LAIu): A case study across the extended network of ICOS forest ecosystem sites in Europe

Author

George, Jan-Peter, primary, Yang, Wei, additional, Kobayashi, Hideki, additional, Biermann, Tobias, additional, Carrara, Arnaud, additional, Cremonese, Edoardo, additional, Cuntz, Matthias, additional, Fares, Silvano, additional, Gerosa, Giacomo, additional, Grünwald, Thomas, additional, Hase, Niklas, additional, Heliasz, Michael, additional, Ibrom, Andreas, additional, Knohl, Alexander, additional, Kruijt, Bart, additional, Lange, Holger, additional, Limousin, Jean-Marc, additional, Loustau, Denis, additional, Lukeš, Petr, additional, Marzuoli, Riccardo, additional, Mölder, Meelis, additional, Montagnani, Leonardo, additional, Neirynck, Johan, additional, Peichl, Matthias, additional, Rebmann, Corinna, additional, Schmidt, Marius, additional, Serrano, Francisco Ramon Lopez, additional, Soudani, Kamel, additional, Vincke, Caroline, additional, and Pisek, Jan, additional

Published
2021
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28. Synergy between TROPOMI sun-induced chlorophyll fluorescence and MODIS spectral reflectance for understanding the dynamics of gross primary productivity at integrated carbon observatory system (ICOS) ecosystem flux sites.

Author

Balde, Hamadou, Hmimina, Gabriel, Goulas, Yves, Latouche, Gwendal, and Soudani, Kamel

Subjects
CHLOROPHYLL spectra, PHOTOSYNTHESIS, CLIMATE change, CARBON dioxide, FORESTS & forestry
Abstract

An accurate estimation of vegetation Gross Primary Productivity (GPP), which is the amount of carbon taken up by vegetation through photosynthesis for a given time and area, is critical for understanding terrestrial-atmosphere CO2 exchange processes, ecosystem functioning, and as well as ecosystem responses and adaptations to climate change. Earliest studies, based on ground, airborne and satellite Sun-Induced chlorophyll Fluorescence (SIF) observations have recently revealed close relationships with GPP at different spatial and temporal scales and across different plant functional type (PFT). However, questions remain regarding whether there is a unique relationship between SIF and GPP across different sites and PFT and how can we improve GPP estimates using solely remotely sensed data. Using concurrent measurements of daily TROPOMI (TROPOspheric Monitoring Instrument) SIF (daily SIFd), daily MODIS Terra and Aqua spectral reflectance, and vegetation indices (VIs, notably NDVI (normalized difference vegetation index), NIRv (near-infrared reflectance of vegetation) and PRI (photochemical reflectance index)) and daily tower-based GPP across eight major different PFT, including mixed forests, deciduous broadleaf forests, croplands, evergreen broadleaf forests, evergreen needleleaf forests, grassland, open shrubland, and wetland, the strength of the linear relationships between tower-based GPP and SIFd at 40 ICOS (Integrated Carbon Observation Systems) flux sites was investigated, and the synergy between these variables to improve GPP estimates using a data-driven modelling approach was evaluated. The results revealed that the strength of the linear relationship between GPP and SIFd was strongly site-specific and PFT-dependent. Furthermore, the GLM (Generalized Linear Model) model, fitted between SIFd, GPP, site and vegetation type as categorical variables, further supported this site-and PFT-dependent relationship between GPP and SIFd. This study also showed that the spectral reflectance bands (RF-R), SIFd plus spectral reflectance (RF-SIF-R) models explained over 80 % of the seasonal and interannual variations in GPP, whereas the SIFd plus VIs (RF-SIF-VI) model reproduced only 75 % of the tower-based GPP variance. In addition, the relative importance results demonstrated that the spectral reflectance bands in the near-infrared, red and SIFd appeared as the most influential and dominant factors determining GPP predictions, indicating the importance of canopy structure, biochemical properties and vegetation functioning on GPP estimates. Overall, this study provides insights into understanding the strength of the relationships between GPP and SIF and the use of the spectral reflectance and SIFd to improve GPP across sites and PFT. [ABSTRACT FROM AUTHOR]

Published
2022
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35. Retrieval and validation of forest background reflectivity from daily Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF) data across European forests

Author

Pisek, Jan, primary, Erb, Angela, additional, Korhonen, Lauri, additional, Biermann, Tobias, additional, Carrara, Arnaud, additional, Cremonese, Edoardo, additional, Cuntz, Matthias, additional, Fares, Silvano, additional, Gerosa, Giacomo, additional, Grünwald, Thomas, additional, Hase, Niklas, additional, Heliasz, Michal, additional, Ibrom, Andreas, additional, Knohl, Alexander, additional, Kobler, Johannes, additional, Kruijt, Bart, additional, Lange, Holger, additional, Leppänen, Leena, additional, Limousin, Jean-Marc, additional, Serrano, Francisco Ramon Lopez, additional, Loustau, Denis, additional, Lukeš, Petr, additional, Lundin, Lars, additional, Marzuoli, Riccardo, additional, Mölder, Meelis, additional, Montagnani, Leonardo, additional, Neirynck, Johan, additional, Peichl, Matthias, additional, Rebmann, Corinna, additional, Rubio, Eva, additional, Santos-Reis, Margarida, additional, Schaaf, Crystal, additional, Schmidt, Marius, additional, Simioni, Guillaume, additional, Soudani, Kamel, additional, and Vincke, Caroline, additional

Published
2021
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36. Retrieval and validation of forest background reflectivity from daily MODIS bidirectional reflectance distribution function (BRDF) data across European forests

Author

Pisek, Jan, Erb, Angela, Korhonen, Lauri, Biermann, Tobias, Carrara, Arnaud, Cremonese, Edoardo, Cuntz, Matthias, Fares, Silvano, Gerosa, Giacomo, Grünwald, Thomas, Hase, Niklas, Heliasz, Michal, Ibrom, Andreas, Knohl, Alexander, Kobler, Johannes, Kruijt, Bart, Lange, Holger, Leppänen, Leena, Jean-Marc Limousin, Ramon, Francisco, Lopez Serrano, Loustau, Denis, Lukeš, Petr, Lundin, Lars, Marzuoli, Riccardo, Mölder, Meelis, Montagnani, Leonardo, Neirynck, Johan, Peichl, Matthias, Rebmann, Corinna, Rubio, Eva, Santos-Reis, Margarida, Schaaf, Crystal, Schmidt, Marius, Simioni, Guillaume, Soudani, Kamel, and Vincke, Caroline

Published
2020
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37. Coupling high-frequency measurements and predictive modelling for monitoring and an early warning system of cyanobacteria blooms

Author

Vinçon-Leite, Brigitte, Piccioni, Francesco, Hong, Yi, Tran Khac, Viet, Lemaire, Bruno J., Furstenau Plec, Denis, Li, Chenlu, Dubois, Philippe, Saad, Mohamed, Hmimina, Gabriel, Soudani, Kamel, Quiblier, Catherine, Tambosco, Kevin, Six, Gonzague, Freissinet, Catherine, Decencière, Beatriz, Humbert, Jean-François, Laboratoire Eau Environnement et Systèmes Urbains (LEESU), École des Ponts ParisTech (ENPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Ecologie Systématique et Evolution (ESE), AgroParisTech-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Molécules de Communication et Adaptation des Micro-organismes (MCAM), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Gustave Eiffel, Artelia Eau & Environnement [Echirolles], Artelia Eau & Environnement [Lyon], CEREEP-Ecotron Ile de France (UMS 3194), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Philipp Hess, ANR-13-ECOT-0001,OSS-CYANO,Développement d'un capteur optique et d'un système drone pour la surveillance spatiale des cyanobactéries dans les écosystèmes aquatiques continentaux(2013), Vinçon-Leite, Brigitte, EcoTechnologies & EcoServices - Développement d'un capteur optique et d'un système drone pour la surveillance spatiale des cyanobactéries dans les écosystèmes aquatiques continentaux - - OSS-CYANO2013 - ANR-13-ECOT-0001 - ECO-TS - VALID, Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre National de la Recherche Scientifique (CNRS)-Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
urban lakes, web platform, [SDE.IE]Environmental Sciences/Environmental Engineering, forecasting, [SDE.IE] Environmental Sciences/Environmental Engineering, [SDU.STU.OC] Sciences of the Universe [physics]/Earth Sciences/Oceanography, 3D modelling, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

International audience; In urban watersheds, anthropogenic activities have major impacts on the ecological quality of water bodies. The degradation of water quality can result in toxic cyanobacteria blooms, which in turn may cause serious health risks to people in contact with water, e.g. when doing water sports. Due to the complexity of natural processes in water bodies, physically-based and spatially distributed models are valuable tools for better understanding the interactions between variables driving cyanobacteria blooms, as well as for helping stakeholders determine management strategies. However, traditional in situ measurements are limited by temporal and spatial resolution to make such numerical models reliable. Continuous in situ measurements provided by automated high-frequency monitoring can significantly improve adaptive decision-making. The main objectives of this work were to (i) set up a full-scale experimental site for high-frequency monitoring of cyanobacteria biomass in an urban lake; (ii) couple the high-frequency measurements and a physicallybased three-dimensional hydro-ecological model for predicting cyanobacteria blooms; (iii) implement atransfer platform for real-time data management; and (iv) develop a web platform for communicating information to lake managers, other stakeholders and the public. These steps were conducted in the framework of the OSS-cyano project, funded by the French Research Agency (ANR). The study site is Lake Champs-surMarne (0.12 km2 surface, 3.5 m maximum depth), located in Greater Paris. The field monitoring includesmeasurements of water temperature, dissolved oxygen, chlorophyll-a fluorescence and phycocyanin fluorescence at 10 min time steps, and regular vertical profiles of temperature and fluorescence of the main phytoplankton groups. The Delft3D hydrodynamic and ecological modules, Flow and Bloom respectively, were implemented. Using continuous measurements and short-term meteorological forecast, a predictive modelling of the cyanobacteria biomass evolution over four days was performed. Simulation results can then be communicated to the lake manager and the public through a web platform for health risk warning.

Published
2020

38. Tree Phenology

Author

Vilhar, Urša, primary, Beuker, Egbert, additional, Mizunuma, Toshie, additional, Skudnik, Mitja, additional, Lebourgeois, François, additional, Soudani, Kamel, additional, and Wilkinson, Matthew, additional

Published
2013
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41. Retrieval and validation of forest background reflectivity from daily MODIS bidirectional reflectance distribution function (BRDF) data across European forests

Author

Pisek, Jan, primary, Erb, Angela, additional, Korhonen, Lauri, additional, Biermann, Tobias, additional, Carrara, Arnaud, additional, Cremonese, Edoardo, additional, Cuntz, Matthias, additional, Fares, Silvano, additional, Gerosa, Giacomo, additional, Grünwald, Thomas, additional, Hase, Niklas, additional, Heliasz, Michal, additional, Ibrom, Andreas, additional, Knohl, Alexander, additional, Kobler, Johannes, additional, Kruijt, Bart, additional, Lange, Holger, additional, Leppänen, Leena, additional, Limousin, Jean-Marc, additional, Serrano, Francisco Ramon Lopez, additional, Loustau, Denis, additional, Lukeš, Petr, additional, Lundin, Lars, additional, Marzuoli, Riccardo, additional, Mölder, Meelis, additional, Montagnani, Leonardo, additional, Neirynck, Johan, additional, Peichl, Matthias, additional, Rebmann, Corinna, additional, Rubio, Eva, additional, Santos-Reis, Margarida, additional, Schaaf, Crystal, additional, Schmidt, Marius, additional, Simioni, Guillaume, additional, Soudani, Kamel, additional, and Vincke, Caroline, additional

Published
2020
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42. Towards long-term standardised carbon and greenhouse gas observations for monitoring Europe's terrestrial ecosystems : a review

Author

Franz, Daniela, Acosta, Manuel, Altimir, Nuria, Arriga, Nicola, Arrouays, Dominique, Aubinet, Marc, Aurela, Mika, Ayres, Edward, Lopez-Ballesteros, Ana, Barbaste, Mireille, Berveiller, Daniel, Biraud, Sebastien, Boukir, Hakima, Brown, Timothy, Bruemmer, Christian, Buchmann, Nina, Burba, George, Carrara, Arnaud, Cescatti, Allessandro, Ceschia, Eric, Clement, Robert, Cremonese, Edoardo, Crill, Patrick, Darenova, Eva, Dengel, Sigrid, D'Odorico, Petra, Filippa, Gianluca, Fleck, Stefan, Fratini, Gerardo, Fuss, Roland, Gielen, Bert, Gogo, Sebastien, Grace, John, Graf, Alexander, Grelle, Achim, Gross, Patrick, Gruenwald, Thomas, Haapanala, Sami, Hehn, Markus, Heinesch, Bernard, Heiskanen, Jouni, Herbst, Mathias, Herschlein, Christine, Hortnagl, Lukas, Hufkens, Koen, Ibrom, Andreas, Jolivet, Claudy, Joly, Lilian, Jones, Michael, Kiese, Ralf, Klemedtsson, Leif, Kljun, Natascha, Klumpp, Katja, Kolari, Pasi, Kolle, Olaf, Kowalski, Andrew, Kutsch, Werner, Laurila, Tuomas, de Ligne, Anne, Linder, Sune, Lindroth, Anders, Lohila, Annalea, Longdoz, Bernhard, Mammarella, Ivan, Manise, Tanguy, Maranon Jimenez, Sara, Matteucci, Giorgio, Mauder, Matthias, Meier, Philip, Merbold, Lutz, Mereu, Simone, Metzger, Stefan, Migliavacca, Mirco, Molder, Meelis, Montagnani, Leonardo, Moureaux, Christine, Nelson, David, Nemitz, Eiko, Nicolini, Giacomo, Nilsson, Mats B., Op de Beeck, Maarten, Osborne, Bruce, Lofvenius, Mikaell Ottosson, Pavelka, Marian, Peichl, Matthias, Peltola, Olli, Pihlatie, Mari, Pitacco, Andrea, Pokorny, Radek, Pumpanen, Jukka, Ratie, Celine, Rebmann, Corinna, Roland, Marilyn, Sabbatini, Simone, Saby, Nicolas P. A., Saunders, Matthew, Schmid, Hans Peter, Schrumpf, Marion, Sedlak, Pavel, Serrano Ortiz, Penelope, Siebicke, Lukas, Sigut, Ladislav, Silvennoinen, Hanna, Simioni, Guillaume, Skiba, Ute, Sonnentag, Oliver, Soudani, Kamel, Soule, Patrice, Steinbrecher, Rainer, Tallec, Tiphaine, Thimonier, Anne, Tuittila, Eeva-Stiina, Tuovinen, Juha-Pekka, Vestin, Patrik, Vincent, Gaelle, Vincke, Caroline, Vitale, Domenico, Waldner, Peter, Weslien, Per, Wingate, Lisa, Wohlfahrt, Georg, Zahniser, Mark, Vesala, Timo, Institute for Atmospheric and Earth System Research (INAR), INAR Physics, Micrometeorology and biogeochemical cycles, Ecosystem processes (INAR Forest Sciences), Department of Agricultural Sciences, Environmental Soil Science, Methane and nitrous oxide exchange of forests, Viikki Plant Science Centre (ViPS), University Management, and Faculty of Agriculture and Forestry

Subjects
GHG exchange, MEASUREMENT NETWORK, CO2 EXCHANGE, 4111 Agronomy, FOREST ECOSYSTEMS, DIOXIDE EXCHANGE, ICOS, standardised monitoring, 1.5 DEGREES-C, carbon cycle, CLIMATE EXTREMES, observational network, CH4 EMISSIONS, INTERANNUAL VARIABILITY, NET CARBON, 1172 Environmental sciences, PRIMARY PRODUCTIVITY
Abstract

Research infrastructures play a key role in launching a new generation of integrated long-term, geographically distributed observation programmes designed to monitor climate change, better understand its impacts on global ecosystems, and evaluate possible mitigation and adaptation strategies. The pan-European Integrated Carbon Observation System combines carbon and greenhouse gas (GHG; CO2, CH4, N2O, H2O) observations within the atmosphere, terrestrial ecosystems and oceans. High-precision measurements are obtained using standardised methodologies, are centrally processed and openly available in a traceable and verifiable fashion in combination with detailed metadata. The Integrated Carbon Observation System ecosystem station network aims to sample climate and land-cover variability across Europe. In addition to GHG flux measurements, a large set of complementary data (including management practices, vegetation and soil characteristics) is collected to support the interpretation, spatial upscaling and modelling of observed ecosystem carbon and GHG dynamics. The applied sampling design was developed and formulated in protocols by the scientific community, representing a trade-off between an ideal dataset and practical feasibility. The use of open-access, high-quality and multi-level data products by different user communities is crucial for the Integrated Carbon Observation System in order to achieve its scientific potential and societal value.

Published
2018

43. Development of a low cost optical sensor and of a drone system for the monitoring of cyanobacteria in freshwater ecosystems

Author

Humbert, Jean-François, Soudani, Kamel, Hmimina, Gabriel, Audebert, Louise, Buttigieg, Stéphane, Chatellier, Patrice, Chollet, Simon, Decencière, Beatriz, Derkx, François, Freissinet, Catherine, Hong, Yi, Hulot, Florence D., Lemaire, Bruno J., Millot, Alexis, Perrin, Aurélien, Quiblier, Catherine, Six, Gonzague, Sorin, Jean-Luc, Tambosco, Kevin, Tran Khac, Viet, Vinçon-Leite, Brigitte, Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Ecologie Systématique et Evolution (ESE), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Laboratoire Instrumentation, Simulation et Informatique Scientifique (IFSTTAR/COSYS/LISIS), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Communauté Université Paris-Est, CEREEP-Ecotron Ile de France (UMS 3194), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Artelia Eau & Environnement [Echirolles], Artelia Eau & Environnement [Lyon], laboratoire Eau Environnement et Systèmes Urbains (LEESU), AgroParisTech-École des Ponts ParisTech (ENPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Molécules de Communication et Adaptation des Micro-organismes (MCAM), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Département Composants et Systèmes (IFSTTAR/COSYS), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université de Lyon-PRES Université Nantes Angers Le Mans (UNAM)-PRES Université Lille Nord de France, Laboratoire Géophysique et évaluation non destructive (IFSTTAR/GERS/GeoEND), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Nantes Angers Le Mans (UNAM), ANR-13-ECOT-0001,OSS-CYANO,Développement d'un capteur optique et d'un système drone pour la surveillance spatiale des cyanobactéries dans les écosystèmes aquatiques continentaux(2013), Institut d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) ), Communauté Université Paris-Est-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS), PRES Université Lille Nord de France-PRES Université Nantes Angers Le Mans (UNAM)-Université de Lyon-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Lemaire, Bruno J., EcoTechnologies & EcoServices - Développement d'un capteur optique et d'un système drone pour la surveillance spatiale des cyanobactéries dans les écosystèmes aquatiques continentaux - - OSS-CYANO2013 - ANR-13-ECOT-0001 - ECO-TS - VALID, and ISSHA

Subjects
[SDE] Environmental Sciences, [SDE]Environmental Sciences
Abstract

International audience; Cyanobacteria blooms frequently disturb the functioning of freshwater ecosystems and their uses, due to the toxins dangerous to health that cyanobacteria are able to synthesize. Therefore, many countries have implemented monitoring programs aimed at reducing the risk of human exposure to these toxins. The main limitation is related to the heterogeneity of the spatial distribution of cyanobacteria. In the vertical dimension, these organisms can stay in different layers in the water column and in the horizontal scale, the cells may accumulate in some a rea of the water body, under the action of winds or currents. In an attempt to improve monitoring, many research projects have been undertaken in order to develop new tools, like buoys equipped with various underwater sensors. This tool is highly relevant but it does not allow assessing the horizontal distribution of cyanobacteria and its cost remains expensive. Moreover, if satellite remote sensing can be considered very useful for estimating biomass and horizontal distribution of cyanobacteria in a water body, the cost of this technology and the lack of satellite availability make it unaffordable for routine monitoring. In this context, our project named OSS-CYANO (Development of optical sensors and drone system for the survey of cyanobacteria) project aims in a first time to develop and validate a new, low-cost aerial sensor. In this goal, we developed a framework for performing high-throughput measurements of the absorbance and reflectance of small volumes of controlled mixtures of phytoplankton species and studied the potential of this framework to validate remote-sensing proxies of cyanobacteria concentration. A systematic test of every possible two-band and three-band normalized difference between optical indices was then performed, and the coincidental correlation with chlorophyll-b (absent in cyanobacteria) was used as an indicator of non-specificity. Two-band indices were shown to suffer from non-specificity issues and could not yield strong and specific relationships with phycocyanin or phycoerythrin (maximum R² 0.8). The second part of our program aimed to couple the high-frequency measurements and a physically-based three-dimensional hydro-ecological model for predicting cyanobacteria blooms. Finally, the third part of our program aimed to implement a drone capable of carrying the sensor to perform spatial measurements on large water bodies, and other instruments for water sampling or for performing underwater measurements. Six public research laboratories and one private company have been involved in this project.

Published
2018

44. Coupling high-frequency measurements and predictive modelling in a monitoring and early warning system of cyanobacteria blooms

Author

Vinçon-Leite, Brigitte, Hong, Yi, Tran Khac, Viet, Plec, Denis, Li, Chenlu, DUBOIS, Philippe, Saad, Mohamed, Lemaire, Bruno J., Hmimina, Gabriel, Soudani, Kamel, Quiblier, Catherine, Tambosco, Kevin, Six, Gonzague, Freissinet, Catherine, Decencière, Beatriz, Humbert, Jean-François, laboratoire Eau Environnement et Systèmes Urbains (LEESU), AgroParisTech-École des Ponts ParisTech (ENPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Université libre de Bruxelles (ULB), Ecologie Systématique et Evolution (ESE), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Paris-Sud - Paris 11 (UP11), Molécules de Communication et Adaptation des Micro-organismes (MCAM), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Institut d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) ), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Département Composants et Systèmes (IFSTTAR/COSYS), PRES Université Lille Nord de France-PRES Université Nantes Angers Le Mans (UNAM)-Université de Lyon-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Artelia Eau & Environnement [Echirolles], Artelia Eau & Environnement [Lyon], CEREEP-Ecotron Ile de France (UMS 3194), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), ANR-13-ECOT-0001,OSS-CYANO,Développement d'un capteur optique et d'un système drone pour la surveillance spatiale des cyanobactéries dans les écosystèmes aquatiques continentaux(2013), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université de Lyon-PRES Université Nantes Angers Le Mans (UNAM)-PRES Université Lille Nord de France, Université Libre de Bruxelles [Bruxelles] (ULB), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDE]Environmental Sciences, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation
Abstract

International audience; Anthropogenic activities have major impacts on the ecological quality of downstream water bodies. The degradation of the water quality can lead to toxic cyanobacteria blooms, which in turn may cause serious health risks to people doing water sports. Due to the complexity of natural processes in water bodies, physically-based and spatially distributed models are valuable tools for a better understanding of the interactions between variables driving cyanobacteria blooms, as well as for helping stakeholders determine their management strategies. However, traditional in situ measurements have too limited temporal and spatial resolution to make such a numerical model reliable. Efforts must be made to use innovative monitoring to overcome these limitations. Continuous in situ measurements provided by automated high-frequency monitoring can decisively improve model performances.Therefore, the main objectives of the study were to (i) set up a full-scale experimental site for high-frequency monitoring of cyanobacteria biomass in an urban lake; (ii) couple the high-frequency measurements and a physically-based three-dimensional hydro-ecological model for predicting cyanobacteria blooms; (iii) establish a transfer platform for real-time data management; and (iv) develop a web platform for communicating information with lake managers, other stakeholders and the public. In the framework of the OSS-cyano project, the study site is Lake Champs-sur-Marne (0.12 km2 surface, 3.5 m maximum depth), located in Greater Paris. The field monitoring includes measurements of water temperature, dissolved oxygen, chlorophyll fluorescence and phycocyanin fluorescence every fifth minute, and fortnightly vertical profiles of temperature and of the fluorescence of the main phytoplankton groups. The Delft3D hydrodynamic and ecological models, respectively Flow and Bloom, were implemented. Using continuous measurements and short-term meteorological forecast, a predictive modelling of the cyanobacteria biomass evolution over a week was performed. Simulation results were then communicated to the lake manager and the public through a web platform for sanitary risk warning.

Published
2018

46. Assimilating phenology datasets automatically across ICOS ecosystem stations

Author

Hufkens, Koen, Filippa, Gianluca, Cremonese, Edoardo, Migliavacca, Mirco, D'Odorico, Petra, Peichl, Matthias, Gielen, Bert, Hörtnagl, Lukas, Soudani, Kamel, Papale, Dario, Rebmann, Corinna, Brown, Tim, Wingate, Lisa, Interactions Sol Plante Atmosphère (UMR ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), Climate Change Unit, Environmental Protection Agency of Aosta Valley, Max Planck Institute of Biochemistry (MPIB), Max-Planck-Gesellschaft, Department of Biology, Northern Arizona University [Flagstaff], Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), University of Antwerp (UA), Institute of Agricultural Sciences, Ecole Polytechnique Fédérale de Zurich, Université Paris-Sud - Paris 11 (UP11), Tuscia University, Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ), Research School of Biology, and Australian National University (ANU)

Subjects
[SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, Biology, ICOS, near-surface remote sensing, proximal sensing, digital repeat photography, phenology, protocol
Abstract

The presence or absence of leaves within plant canopies exert a strong influence on the carbon, water and energy balance of ecosystems. Identifying key changes in the timing of leaf elongation and senescence during the year can help to understand the sensitivity of different plant functional types to changes in temperature. When recorded over many years these data can provide information on the response of ecosystems to long-term changes in climate. The installation of digital cameras that take images at regular intervals of plant canopies across the Integrated Carbon Observation System ecosystem stations will provide a re- liable and important record of variations in canopy state, colour and the timing of key phenological events. Here, we detail the procedure for the implementation of cameras on Integrated Carbon Observation System flux towers and how these images will help us understand the impact of leaf phenology and ecosystem function, distinguish changes in canopy structure from leaf physiology and at larger scales will assist in the validation of (future) remote sensing products. These data will help us improve the representation of phenological responses to climatic variability across Integrated Carbon Observation System stations and the terrestrial biosphere through the improvement of model algorithms and the provision of validation datasets. ISSN:0236-8722 ISSN:2300-8725

Published
2018

48. The within-population variability of leaf spring and autumn phenology is influenced by temperature in temperate deciduous trees

Author

Denéchère, Rémy, primary, Delpierre, Nicolas, additional, Apostol, Ecaterina Nicoleta, additional, Berveiller, Daniel, additional, Bonne, Fabrice, additional, Cole, Ella, additional, Delzon, Sylvain, additional, Dufrêne, Eric, additional, Gressler, Eliana, additional, Jean, Frédéric, additional, Lebourgeois, François, additional, Liu, Guohua, additional, Louvet, Jean-Marc, additional, Parmentier, Julien, additional, Soudani, Kamel, additional, and Vincent, Gaëlle, additional

Published
2019
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50. Ancillary vegetation measurements at ICOS ecosystem stations

Author

Gielen, Bert, primary, Acosta, Manuel, additional, Altimir, Nuria, additional, Buchmann, Nina, additional, Cescatti, Alessandro, additional, Ceschia, Eric, additional, Fleck, Stefan, additional, Hörtnagl, Lukas, additional, Klumpp, Katja, additional, Kolari, Pasi, additional, Lohila, Annalea, additional, Loustau, Denis, additional, Marańon-Jimenez, Sara, additional, Manise, Tanguy, additional, Matteucci, Giorgio, additional, Merbold, Lutz, additional, Metzger, Christine, additional, Moureaux, Christine, additional, Montagnani, Leonardo, additional, Nilsson, Mats B., additional, Osborne, Bruce, additional, Papale, Dario, additional, Pavelka, Marian, additional, Saunders, Matthew, additional, Simioni, Guillaume, additional, Soudani, Kamel, additional, Sonnentag, Oliver, additional, Tallec, Tiphaine, additional, Tuittila, Eeva-Stiina, additional, Peichl, Matthias, additional, Pokorny, Radek, additional, Vincke, Caroline, additional, and Wohlfahrt, Georg, additional

Published
2018
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