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... a , Chung-Yen Kuo b * , Hong-Zeng Tseng b , Alexander Braun c , Stéphane Calmant d , Naziano Filizola e & Frederique Seyler f pages 3913-3929. ... 20055. Berry, PAM, Garlick, JD, Freeman, JA... more
... a , Chung-Yen Kuo b * , Hong-Zeng Tseng b , Alexander Braun c , Stéphane Calmant d , Naziano Filizola e & Frederique Seyler f pages 3913-3929. ... 20055. Berry, PAM, Garlick, JD, Freeman, JA and Mathers, EL 2005. Global inland water monitoring from multi-mission altimetry. ...
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Le secteur agricole, au coeur d'un tissu d'interactions liant de maniere etroite les enjeux de securite alimentaire, de pauvrete, de sante, de justice environnementale et climatique, d'acces a l'eau, de production durable,... more
Le secteur agricole, au coeur d'un tissu d'interactions liant de maniere etroite les enjeux de securite alimentaire, de pauvrete, de sante, de justice environnementale et climatique, d'acces a l'eau, de production durable, de climat et de lutte contre la degradation des terres, est central pour l'Agenda 2030. Il represente a ce titre un levier d'action puissant. Pour illustrer cela, les auteurs analysent d'une part le nexus "Securite alimentaire - Eau Production durable", d'autre part le nexus "Securite alimentaire - Actions pour le climat Degradation des terres". Les exemples montrent combien les cibles de l'ODD 2 sont indissociables de celles des autres ODD. Ils permettent d'affirmer le potentiel de transformation que porte le secteur agricole pour la sante de la planete, de l'humanite et pour la stabilite politique, pour autant qu'une revolution des systemes alimentaires se dessine. Et pour autant qu'une plur...
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ABSTRACT We present a study conducted in the Amazon basin to compute distributed discharge with ENVISAT and JASON-2 altimetry in the one hand and the rain/discharge MGB model in the other hand. The MGB model is run over the 1998-2008... more
ABSTRACT We present a study conducted in the Amazon basin to compute distributed discharge with ENVISAT and JASON-2 altimetry in the one hand and the rain/discharge MGB model in the other hand. The MGB model is run over the 1998-2008 period with TRMM rain input. The altimetry data of ~500 series throughout the basin are used to determine rating curves that enable to tune the model parameters such as the depth and slope of small contributors still un-monitored, or the variations in Manning coefficient; and to make discharge series exceeding the time window of the model runs. With this case study, we show that the measurements collected today by conventional altimetry missions can be used to prepare SWOT in two directions: get geophysical values that will be necessary for the discharge algorithms of SWOT and compute discharge time series which will constitute an archive to be continued by SWOT.
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Rating curve estimation (height-stream relation) made by hydrometric stations representing cross-sections of a river is one of hydrometrics’ fundamental tasks due to the fact that it leads to deducing a river’s average daily flow on that... more
Rating curve estimation (height-stream relation) made by hydrometric stations representing cross-sections of a river is one of hydrometrics’ fundamental tasks due to the fact that it leads to deducing a river’s average daily flow on that particular section. This information is fundamental in any attempt at hydrological modelling. However, the number of hydrological control stations monitoring large hydrological basins has been reduced worldwide. Space hydrology studies during the last five years have shown that satellite radar altimetry means that hydrological monitoring networks’ available information can be densified due to the introduction of so-called virtual stations and the joint use of such information along with in-situ measured flow records for estimating expenditure curves at these stations.
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Research Interests: Environmental Engineering, Civil Engineering, Environmental Science, Methodology, Linear models, and 15 moreParameter estimation, Optimization, Linear Model, Sampling, Noise, Multi objective optimization, Satellite Altimetry, Accuracy, Random Noise, Interpolation, River Basin, Least Squares, Missing Values, Precision, and Amazon basin
Research Interests: Environmental Engineering, Civil Engineering, Environmental Science, Hydrology, Time Series, and 11 moreComparative Study, Image Classification, Land Cover, River water, Large River Ecology, Root-Mean Square Error, Digital Elevation Model, Satellite Radar Altimeter, Amazon basin, Large Scale, and Root mean square
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Gravity Recovery and Climate Experiment (GRACE) mission is dedicated to measuring temporal variations of the Earth's gravity field. In this study, the Stokes coefficients made available by Groupe de Recherche en Géodésie Spatiale... more
Gravity Recovery and Climate Experiment (GRACE) mission is dedicated to measuring temporal variations of the Earth's gravity field. In this study, the Stokes coefficients made available by Groupe de Recherche en Géodésie Spatiale (GRGS) at a 10-day interval were converted into equivalent water height (EWH) for a ~4-year period in the Amazon basin (from July-2002 to May-2006). The seasonal amplitudes of EWH signal are the largest on the surface of Earth and reach ~ 1250mm at that basin's center. Error budget represents ~130 mm of EWH, including formal errors on Stokes coefficient, leakage errors (12 ~ 21 mm) and spectrum truncation (10 ~ 15 mm). Comparison between in situ river level time series measured at 233 ground-based hydrometric stations (HS) in the Amazon basin and vertically-integrated EWH derived from GRACE is carried out in this paper. Although EWH and HS measure different water bodies, in most of the cases a high correlation (up to ~80%) is detected between the HS...
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The combined use of remote sensing and radar altimetry is offering entirely new perspectives for the monitoring of water resources in large tropical trans-boundary basins. Based on a study conducted mostly in the region of the Llanos de... more
The combined use of remote sensing and radar altimetry is offering entirely new perspectives for the monitoring of water resources in large tropical trans-boundary basins. Based on a study conducted mostly in the region of the Llanos de Mojos, a large complex of wetlands located within the southernmost extension of the Amazon Basin, at the Brazilian border with Bolivia and Peru, but also based on previous studies, we give some results that will illustrate this point of view. First, the results are showing the current limitations of the radar altimetric missions, which were designed primarily for ocean level or ice caps studies: essentially the revisit time, the size of the water bodies that can be monitored, and the lack of reliable data in presence of relief. Nevertheless, they also show that the data processing and the tools we developed to select appropriately the data, allow retrieving quite accurately the seasonal variability of the water elevation within the basin selected. Se...
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ABSTRACT The Gabonese Agency for Space Studies and Observations (AGEOS) was set up in 2010 with one of its aims to develop a national forest monitoring capability. In addition, the European Space Agency (ESA) has developed its activities... more
ABSTRACT The Gabonese Agency for Space Studies and Observations (AGEOS) was set up in 2010 with one of its aims to develop a national forest monitoring capability. In addition, the European Space Agency (ESA) has developed its activities in the Congo basin through the REDD extension of its GMES Service Element on Forest Monitoring program (GSE FM). The ESA GSE FM REDD extension project is seen by the Gabonese authorities as a precursor to the establishment of the newly created AGEOS for the monitoring of forest cover. During this phase of the project the production of forest area maps and forest cover change maps for 1990, 2000 was initiated with a wall to wall approach for the total area of Gabon and about a third of the country for 2010. Initial results confirm the generally low level of deforestation expected in the Congo basin region and in Gabon in particular.
The Eastern Cordillera of the bolivian Andes is mainly composed of paleozoic sedimentary rocks. It overthursts the Subandean thrust and fold belt, which involves the Paleozoic basement and synorogenic Cenozoic sediments. This orographic... more
The Eastern Cordillera of the bolivian Andes is mainly composed of paleozoic sedimentary rocks. It overthursts the Subandean thrust and fold belt, which involves the Paleozoic basement and synorogenic Cenozoic sediments. This orographic ensemble is 200 to 300 km wide, and its height ranges from 150 to 200m height at the subandean-amazonian plain contact to more than 6000 m height
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Texture characterization aiming at landscape description was performed by multifractal analysis on radar images of the South Cameroon rain forest. The global characterization has been done with the Legendre spectrum. The local... more
Texture characterization aiming at landscape description was performed by multifractal analysis on radar images of the South Cameroon rain forest. The global characterization has been done with the Legendre spectrum. The local characterization has been done via the singularity maps of pointwise Holder exponents; then, multifractal spectra were obtained via a normalized estimator based upon the statistics of the singularity maps. The nature of local texture was therefore characterized by singularity spectra. Preliminary interpretations in terms of bio-geo-hydrological processes are given.
In this study, we propose to assess the use of MODIS images to monitor interannual variation of sediment flow by comparing surface reflectance data and field measurements of suspended sediment (SS) concentration collected every 10 days in... more
In this study, we propose to assess the use of MODIS images to monitor interannual variation of sediment flow by comparing surface reflectance data and field measurements of suspended sediment (SS) concentration collected every 10 days in surface waters of different locations of the Amazon River in Brazil. These data come from the HYBAM measurement network that measures the hydrology
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ABSTRACT The Gabonese Agency for Space Studies and Observations (AGEOS) was set up in 2010 with one of its aims being to develop a national forest monitoring capability. In addition, the European Space Agency (ESA) has developed its... more
ABSTRACT The Gabonese Agency for Space Studies and Observations (AGEOS) was set up in 2010 with one of its aims being to develop a national forest monitoring capability. In addition, the European Space Agency (ESA) has developed its activities in the Congo basin through the REDD extension of its GMES Service Element on Forest Monitoring program (GSE FM). The ESA GSE FM REDD extension project is seen by the Gabonese authorities as a precursor to the establishment of the AGEOS for the monitoring of forest cover. During this phase of the project, the production of forest area maps and forest cover change maps for 1990 and 2000 was initiated with a wall to wall approach for the total area of Gabon and about a third of the country for 2010. Initial results confirm the generally low level of deforestation expected in the Congo basin region and in Gabon in particular. However, these results cannot be used without a thorough and statistically sound assessment of thematic accuracy. Thus, a suitable sampling approach was developed to assess the accuracy and results show that these products exceed the requirements set by AGEOS with an overall accuracy above 95%.
The Amazon river basin has been recently affected by extreme climatic events, such as the exceptional drought of 2005, with significant impacts on human activities and ecosystems. In spite of the importance of monitoring freshwater stored... more
The Amazon river basin has been recently affected by extreme climatic events, such as the exceptional drought of 2005, with significant impacts on human activities and ecosystems. In spite of the importance of monitoring freshwater stored and moving in such large river basins, only scarce measurements of river stages and discharges are available and the signatures of extreme drought conditions on surface freshwater dynamics at the basin scale are still poorly known. Here we use continuous multisatellite observations of inundation extent and water levels between 2003 and 2007 to monitor monthly variations of surface water storage at the basin scale. During the 2005 drought, the amount of water stored in the river and floodplains of the Amazon basin was ˜130 km3 (˜70%) below its 2003-7 average. This represents almost a half of the anomaly of minimum terrestrial water stored in the basin as estimated using the Gravity Recovery and Climate Experiment (GRACE) data. Water stored in the aqui...
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Research Interests: Geology and Geochemistry
This paper presents an application of the TOPEX/Poseidon (T/P) satellite altimetry data to estimate river discharge at three sites along the Amazon River. We discuss the methodology to establish empirical relationships between... more
This paper presents an application of the TOPEX/Poseidon (T/P) satellite altimetry data to estimate river discharge at three sites along the Amazon River. We discuss the methodology to establish empirical relationships between satellite-derived water levels and daily estimations of river discharges based on rating curves and in situ level measurements at gauging stations. Three sites are chosen: Manacapuru (River Solimões),
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... Abridged English version 1. Introduction 2. Environmental settings and method 3. Weathering sequences in the Nyong Basin 4. Discussion and conclusion 1. Introduction 2. Objet, méthodes et données 3. Résultats 3.1. ... 3. Weathering... more
... Abridged English version 1. Introduction 2. Environmental settings and method 3. Weathering sequences in the Nyong Basin 4. Discussion and conclusion 1. Introduction 2. Objet, méthodes et données 3. Résultats 3.1. ... 3. Weathering sequences in the Nyong Basin. ...