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245 results on '"Mialon, Arnaud"'

1. Use of a new Tibetan Plateau network for permafrost to characterize satellite-based products errors: An application to soil moisture and freeze/thaw

Author

Zheng, Jingyao, Zhao, Tianjie, Lü, Haishen, Zou, Defu, Rodriguez-Fernandez, Nemesio, Mialon, Arnaud, Richaume, Philippe, Xiao, Jianshe, Ma, Jun, Fan, Lei, Song, Peilin, Zhu, Yonghua, Li, Rui, Yao, Panpan, Yang, Qingqing, Du, Shaojie, Wang, Zhen, Peng, Zhiqing, Xiong, Yuyang, Xing, Zanpin, Zhao, Lin, Kerr, Yann, and Shi, Jiancheng

Published
2024
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6. Comprehensive carbon footprint of Earth and environmental science laboratories: implications for sustainable scientific practice

Author

Marc, Odin, primary, Barret, maialen, additional, Biancamaria, Sylvain, additional, Dassas, Karin, additional, Firmin, Antoine, additional, Gandois, Laure, additional, Gheusi, François, additional, Kuppel, Sylvain, additional, Maisonobe, Marion, additional, Mialon, Arnaud, additional, Monnier, Loïs, additional, Pantillon, Florian, additional, and Toublanc, Florence, additional

Published
2024
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7. Impact of the 2015/2016 El Niño on the terrestrial carbon cycle constrained by bottom-up and top-down approaches

Author

Bastos, Ana, Friedlingstein, Pierre, Sitch, Stephen, Chen, Chi, Mialon, Arnaud, Wigneron, Jean-Pierre, Arora, Vivek K, Briggs, Peter R, Canadell, Josep G, Ciais, Philippe, Chevallier, Frédéric, Cheng, Lei, Delire, Christine, Haverd, Vanessa, Jain, Atul K, Joos, Fortunat, Kato, Etsushi, Lienert, Sebastian, Lombardozzi, Danica, Melton, Joe R, Myneni, Ranga, Nabel, Julia EMS, Pongratz, Julia, Poulter, Benjamin, Rödenbeck, Christian, Séférian, Roland, Tian, Hanqin, van Eck, Christel, Viovy, Nicolas, Vuichard, Nicolas, Walker, Anthony P, Wiltshire, Andy, Yang, Jia, Zaehle, Sönke, Zeng, Ning, and Zhu, Dan

Subjects
Climate Action, Atmosphere, Carbon Cycle, Carbon Sequestration, Ecosystem, El Nino-Southern Oscillation, Models, Theoretical, carbon cycle, El Nino/Southern Oscillation, land-surface models, atmospheric inversions, El Niño/Southern Oscillation, Biological Sciences, Medical and Health Sciences, Evolutionary Biology
Abstract

Evaluating the response of the land carbon sink to the anomalies in temperature and drought imposed by El Niño events provides insights into the present-day carbon cycle and its climate-driven variability. It is also a necessary step to build confidence in terrestrial ecosystems models' response to the warming and drying stresses expected in the future over many continents, and particularly in the tropics. Here we present an in-depth analysis of the response of the terrestrial carbon cycle to the 2015/2016 El Niño that imposed extreme warming and dry conditions in the tropics and other sensitive regions. First, we provide a synthesis of the spatio-temporal evolution of anomalies in net land-atmosphere CO2 fluxes estimated by two in situ measurements based on atmospheric inversions and 16 land-surface models (LSMs) from TRENDYv6. Simulated changes in ecosystem productivity, decomposition rates and fire emissions are also investigated. Inversions and LSMs generally agree on the decrease and subsequent recovery of the land sink in response to the onset, peak and demise of El Niño conditions and point to the decreased strength of the land carbon sink: by 0.4-0.7 PgC yr-1 (inversions) and by 1.0 PgC yr-1 (LSMs) during 2015/2016. LSM simulations indicate that a decrease in productivity, rather than increase in respiration, dominated the net biome productivity anomalies in response to ENSO throughout the tropics, mainly associated with prolonged drought conditions.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.

Published
2018

8. Above ground biomass dataset from SMOS L band vegetation optical depth and reference maps.

Author

Boitard, Simon, Mialon, Arnaud, Mermoz, Stéphane, Rodríguez-Fernández, Nemesio J., Richaume, Philippe, Salazar-Neira, Julio César, Tarot, Stéphane, and Kerr, Yann H.

Subjects
*BIOMASS, *SEAWATER salinity, *TIME series analysis, *CARBON cycle, *BRIGHTNESS temperature
Abstract

The Above Ground Biomass (AGB) is an essential component of the Earth carbon cycle. Yet, large uncertainties remain on its spatial distribution and temporal evolution. Improving the accuracy of the AGB estimates requires precise and regular monitoring. Satellite remote sensing offers such capabilities. In particular, the L-Band (1.41 GHz) Vegetation Optical Depth (VOD) derived from the SMOS (Soil Moisture and Ocean Salinity mission) multi-angle brightness temperatures is a good AGB proxy. Averaging the SMOS L-VOD over a year and linking it to a pre-existing AGB map is a well-established method to derive a spatial relationship between both quantities. After temporal extrapolation of this relation, global AGB time series are derived from the L-VOD, allowing to retrieve vegetation biomass values up to 300 Mg ha-1 from 2011 onwards. This study focuses on this protocol to produce a harmonized AGB dataset from the L-VOD and analyses the impact of three factors on the AGB/VOD calibration. First, the influence of the orbit type (ascending or descending) on the estimation is quantified. Second, the relevance of using a single global spatial calibration or several regional ones is thoroughly discussed for the first time. Third, the AGB time series from this new dataset are compared against other published AGB time series to assess the validity of extrapolating a spatial relationship over time. These comparisons highlight that the produced dataset has more inter-annual variability than the other available time series and presents globally lower AGB estimates, particularly over the equatorial part of Africa. These two limitations are inherent to the input data and method used. Overall, the resulting AGB is coherent with the AGB map from the CCI Biomass version 4 and can be used in AGB studies. The freely accessible AGB dataset has been produced from the level 2 SMOS products, mixing ascending and descending orbits altogether and using a single global relationship between the AGB and the VOD. The spatial bias associated with the AGB estimates is also provided in the files. The AGB dataset is open access and the NetCDF files are available at: https://doi.org/10.12770/95f76ff0-5d89-430d-80db-95fbdd77f543 (Boitard et al., 2024). [ABSTRACT FROM AUTHOR]

Published
2024
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13. Satellite-observed pantropical carbon dynamics

Author

Fan, Lei, Wigneron, Jean-Pierre, Ciais, Philippe, Chave, Jérôme, Brandt, Martin, Fensholt, Rasmus, Saatchi, Sassan S., Bastos, Ana, Al-Yaari, Amen, Hufkens, Koen, Qin, Yuanwei, Xiao, Xiangming, Chen, Chi, Myneni, Ranga B., Fernandez-Moran, Roberto, Mialon, Arnaud, Rodriguez-Fernandez, N. J., Kerr, Yann, Tian, Feng, and Peñuelas, Josep

Published
2019
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17. Satellite passive microwaves reveal recent climate-induced carbon losses in African drylands

Author

Brandt, Martin, Wigneron, Jean-Pierre, Chave, Jerome, Tagesson, Torbern, Penuelas, Josep, Ciais, Philippe, Rasmussen, Kjeld, Tian, Feng, Mbow, Cheikh, Al-Yaari, Amen, Rodriguez-Fernandez, Nemesio, Schurgers, Guy, Zhang, Wenmin, Chang, Jinfeng, Kerr, Yann, Verger, Aleixandre, Tucker, Compton, Mialon, Arnaud, Rasmussen, Laura Vang, Fan, Lei, and Fensholt, Rasmus

Published
2018
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18. How to reduce the carbon footprint of Earth and Space Science? Potential strategies based on a comprehensive greenhouse gas budget for five French labs

Author

Pantillon, Florian, primary, Kuppel, Sylvain, additional, Biancamaria, Sylvain, additional, Derrien, Solene, additional, Gheusi, François, additional, Knödlseder, Jürgen, additional, Maisonobe, Marion, additional, Marc, Odin, additional, Mialon, Arnaud, additional, Martin, Pierrick, additional, Tibaldo, Luigi, additional, and Toublanc, Florence, additional

Published
2023
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19. Analyzing the reliability of in situ soil moisture measurements for satellite product validation: What makes fiducial reference measurements fiducial?

Author

Himmelbauer, Irene, primary, Gruber, Alexander, additional, Aberer, Daniel, additional, Preimesberger, Wolfgang, additional, Stradiotti, Pietro, additional, Dorigo, Wouter A., additional, Boresch, Alexander, additional, Tercjak, Monika, additional, Gibon, Francois, additional, Mialon, Arnaud, additional, Richaume, Philippe, additional, Kerr, Yann, additional, Diez Garcia, Raul, additional, Crapolicchio, Raffaele, additional, Sabia, Roberto, additional, Scipal, Klaus, additional, and Goryl, Philippe, additional

Published
2023
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21. QA4SM: a service for transparent and reproducible evaluation of satellite soil moisture products

Author

Aberer, Daniel, primary, Preimesberger, Wolfgang, additional, Stradiotti, Pietro, additional, Scherrer, Samuel, additional, Tercjak, Monika, additional, Gruber, Alexander, additional, Dorigo, Wouter, additional, Boresch, Alexander, additional, Himmelbauer, Irene, additional, Gibon, François, additional, Richaume, Philippe, additional, Mialon, Arnaud, additional, Kerr, Yann, additional, Mahmoodia, Ali, additional, Crapolicchio, Raffaele, additional, Sabia, Roberto, additional, Garcia, Raul, additional, Goryl, Philippe, additional, and Scipal, Klaus, additional

Published
2023
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22. Fiducial Reference Measurements for Soil Moisture (FRM4SM): Toward a better understanding of (satellite) soil moisture uncertainties 

Author

Gibon, François, primary, Boresch, Alexander, additional, Himmelbauer, Irene, additional, Aberer, Daniel, additional, Crapolicchio, Raffaele, additional, Díez-García, Raúl, additional, Dorigo, Wouter, additional, Goryl, Philippe, additional, Gruber, Alexander, additional, Kerr, Yann, additional, Mialon, Arnaud, additional, Preimesberger, Wolfgang, additional, Richaume, Philippe, additional, Rodriguez-Fernandez, Nemesio, additional, Sabia, Roberto, additional, Scipal, Klaus, additional, Stradiotti, Pietro, additional, and Tercjak, Monika, additional

Published
2023
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23. The share of research infrastructure in comprehensive greenhouse gas budget for five French Earth and Space Science laboratories

Author

Marc, Odin, primary, Biancamaria, Sylvain, additional, Derrien, Solene, additional, Gheusi, François, additional, Knödleser, Jürgen, additional, Kuppel, Sylvain, additional, Maisonobe, Marion, additional, Mialon, Arnaud, additional, Martin, Pierrick, additional, Pantillon, Florian, additional, Tibaldo, Luigi, additional, and Toublanc, Florence, additional

Published
2023
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27. Suivi du cycle de l’eau et de la biomasse des surfaces continentales au moyen des données SMOS

Author

Mialon, Arnaud, Centre d'études spatiales de la biosphère (CESBIO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Toulouse III Paul Sabatier, and Jean-Philippe Gastellu Etchegorry

Subjects
[SDE.IE]Environmental Sciences/Environmental Engineering, SURFACE SOIL MOISTURE, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, SMOS MISSION, TÉLÉDÉTECTION SATELLITAIRE, HUMIDITÉ DU SOL, REMOTE SENSING, MICRO-ONDES PASSIVES
Published
2022

31. COSMOS-Europe: a European network of cosmic-ray neutron soil moisture sensors

Author

Bogena, Heye Reemt, primary, Schrön, Martin, additional, Jakobi, Jannis, additional, Ney, Patrizia, additional, Zacharias, Steffen, additional, Andreasen, Mie, additional, Baatz, Roland, additional, Boorman, David, additional, Duygu, Mustafa Berk, additional, Eguibar-Galán, Miguel Angel, additional, Fersch, Benjamin, additional, Franke, Till, additional, Geris, Josie, additional, González Sanchis, María, additional, Kerr, Yann, additional, Korf, Tobias, additional, Mengistu, Zalalem, additional, Mialon, Arnaud, additional, Nasta, Paolo, additional, Nitychoruk, Jerzy, additional, Pisinaras, Vassilios, additional, Rasche, Daniel, additional, Rosolem, Rafael, additional, Said, Hami, additional, Schattan, Paul, additional, Zreda, Marek, additional, Achleitner, Stefan, additional, Albentosa-Hernández, Eduardo, additional, Akyürek, Zuhal, additional, Blume, Theresa, additional, del Campo, Antonio, additional, Canone, Davide, additional, Dimitrova-Petrova, Katya, additional, Evans, John G., additional, Ferraris, Stefano, additional, Frances, Félix, additional, Gisolo, Davide, additional, Güntner, Andreas, additional, Herrmann, Frank, additional, Iwema, Joost, additional, Jensen, Karsten H., additional, Kunstmann, Harald, additional, Lidón, Antonio, additional, Looms, Majken Caroline, additional, Oswald, Sascha, additional, Panagopoulos, Andreas, additional, Patil, Amol, additional, Power, Daniel, additional, Rebmann, Corinna, additional, Romano, Nunzio, additional, Scheiffele, Lena, additional, Seneviratne, Sonia, additional, Weltin, Georg, additional, and Vereecken, Harry, additional

Published
2022
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32. Considering Combined or Separated Roughness and Vegetation Effects in Soil Moisture Retrievals

Author

Parrens, Marie, Wigernon, Jean-Pierre, Richaume, Philippe, Al Bitar, Ahmad, Mialon, Arnaud, Fernandez-Moran, Roberto, Al-Yarri, Amen, O'Neill, Peggy, and Kerr, Yann

Subjects
Earth Resources And Remote Sensing
Abstract

For more than six years, the Soil Moisture and Ocean Salinity (SMOS) mission has provided multi angular and full-polarization brightness temperature (TB) measurements at L-band. Geophysical products such as soil moisture (SM) and vegetation optical depth at nadir (tau(sub nad)) are retrieved by an operational algorithm using TB observations at different angles of incidence and polarizations. However, the quality of the retrievals depends on several surface effects, such as vegetation, soil roughness and texture, etc. In the microwave forward emission model used in the retrievals (L-band Microwave Emission Model, L-MEB),soil roughness is modeled with a semi-empirical equation using four main parameters (Q(sub r), H(sub r), N(sub rp), with p = H or V polarizations). At present, these parameters are calibrated with data provided by airborne studies and in situ measurements made at a local scale that is not necessarily representative of the large SMOS footprints (43 km on average) at global scale. In this study, we evaluate the impact of the calibrated values of N(sub rp) and H(sub r) on the SM and tau(sub nad) retrievals based on SMOS TB measurements (SMOS Level 3 product) over the Soil Climate Analysis Network (SCAN) network located in North America over five years (2011-2015). In this study, Qr was set equal to zero and we assumed that N(sub rH)= N(sub rV). The retrievals were performed by varying N(sub rp) from −1 to 2 by steps of 1 and H(sub r) from 0 to 0.6 by steps of 0.1. At satellite scale, the results show that combining vegetation and roughness effects in a single parameter provides the best results in terms of soil moisture retrievals, as evaluated against the in situ SM data. Even though our retrieval approach was very simplified, as we did not account for pixel heterogeneity, the accuracy we obtained in the SM retrievals was almost systematically better than those of the Level 3 product. Improved results were also obtained in terms of optical depth retrievals. These new results may have key consequences in terms of calibration of roughness effects within the algorithms of the SMOS (ESA) and the SMAP (NASA) space missions.

Published
2016
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34. COSMOS-Europe: A European Network of Cosmic-Ray Neutron Soil Moisture Sensors

Author

Bogena, Heye, primary, Schrön, Martin, additional, Jakobi, Jannis, additional, Ney, Patrizia, additional, Zacharias, Steffen, additional, Andreasen, Mie, additional, Baatz, Roland, additional, Boorman, David, additional, Duygu, Berk M., additional, Eguibar-Galán, Miguel A., additional, Fersch, Benjamin, additional, Franke, Till, additional, Geris, Josie, additional, González Sanchis, María, additional, Kerr, Yann, additional, Korf, Tobias, additional, Mengistu, Zalalem, additional, Mialon, Arnaud, additional, Nasta, Paolo, additional, Nitychoruk, Jerzy, additional, Pisinaras, Vassilios, additional, Rasche, Daniel, additional, Rosolem, Rafael, additional, Said, Hami, additional, Schattan, Paul, additional, Zreda, Marek, additional, Achleitner, Stefan, additional, Albentosa-Hernández, Eduardo, additional, Akyürek, Zuhal, additional, Blume, Theresa, additional, del Campo, Antonio, additional, Dimitrova-Petrova, Katya, additional, Evans, John G., additional, Frances, Felix, additional, Güntner, Andreas, additional, Herrmann, Frank, additional, Iwema, Joost, additional, Jensen, Karsten Høgh, additional, Kunstmann, Harald, additional, Lidón, Antonio, additional, Looms, Majken Caroline, additional, Oswald, Sascha, additional, Panagopoulos, Andreas, additional, Patil, Amol, additional, Power, Daniel, additional, Rebmann, Corinna, additional, Romano, Nunzio, additional, Scheiffele, Lena M., additional, Seneviratne, Sonia, additional, Weltin, Georg, additional, and Vereecken, Harry, additional

Published
2021
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37. In-situ multifrequency dielectric measurements to improve soil permittivity models for radiometric observations of soil in the high latitudes

Author

Demontoux Francois, Bonnaudin Fabrice, Mialon Arnaud, Tsague King Junior, Bircher Simone, Kerr Yann, Wigneron Jean-Pierre, Ruffie Gilles, Laboratoire de l'intégration, du matériau au système (IMS), Université Sciences et Technologies - Bordeaux 1-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Interactions Sol Plante Atmosphère (UMR ISPA), and Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
Permittivity, gradients, L band, Topsoil, Moisture, 0211 other engineering and technologies, 0207 environmental engineering, Context (language use), Soil science, 02 engineering and technology, Dielectric, Soil, remote sensing, Environmental science, Radiometric dating, dielectric profile, 020701 environmental engineering, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Microwave, 021101 geological & geomatics engineering
Abstract

International audience; In the context of soil monitoring from microwave radiometric observations, the knowledge of the soil permittivity is an important factor in order to guarantee the accuracy of models inversions. Previous studies have showed the impact of temperature and moisture gradients in the top soil layer on remote sensing monitoring of soil. So, we aim here to investigate a way to increase our knowledge of the permittivity profile of the top soil layer, in particular at the P and L band. The solution we selected is based on a new equipment for continuous in-situ measurements of dielectric soil profiles. First measurement results over a sandy soil after rainfall are presented.

Published
2020

38. Flagging the topographic impact on the SMOS signal

Author

Mialon, Arnaud, Coret, Laurent, Kerr, Yann H., Secherre, Francois, and Wigneron, Jean-Pierre

Subjects
Soil moisture -- Analysis, Soil moisture -- Observations, Salinity -- Observations, Salinity -- Analysis, Topographical drawing -- Analysis, Business, Earth sciences, Electronics and electrical industries
Abstract

Soil moisture retrieval models from the Soil Moisture and Ocean Salinity (SMOS) mission, which is an L-band microwave interferometer, are based on multiangular measurements and make use of the emissivity angular signature. Mountainous areas modify local incidence angles, implying significant impacts on brightness temperatures and, consequently, on soil moisture retrievals. The purpose of this paper is to establish a criterion in quantifying the relevance of topographic impacts at the SMOS scale (~40 km). The goal is thus to define a method of flagging the pixels according to the relative impact of topography on the brightness temperature. The proposed method uses the variogram of digital elevation model images. As a result, a map of the pixels to be flagged is produced to ensure that no soil moisture retrievals are carried out on pixels that are affected by strong topographic effects. As validation, a model was also used to simulate differences between brightness temperature variations between mountainous areas and flat surfaces. Index Terms--L-band, passive microwave, Soil Moisture and Ocean Salinity (SMOS), topography impacts.

Published
2008

41. SMOS L1C and L2 Validation in Australia

Author

Rudiger, Christoph, Walker, Jeffrey P, Kerr, Yann H, Mialon, Arnaud, Merlin, Olivier, and Kim, Edward J

Subjects
Earth Resources And Remote Sensing
Abstract

Extensive airborne field campaigns (Australian Airborne Cal/val Experiments for SMOS - AACES) were undertaken during the 2010 summer and winter seasons of the southern hemisphere. The purpose of those campaigns was the validation of the Level 1c (brightness temperature) and Level 2 (soil moisture) products of the ESA-led Soil Moisture and Ocean Salinity (SMOS) mission. As SMOS is the first satellite to globally map L-band (1.4GHz) emissions from the Earth?s surface, and the first 2-dimensional interferometric microwave radiometer used for Earth observation, large scale and long-term validation campaigns have been conducted world-wide, of which AACES is the most extensive. AACES combined large scale medium-resolution airborne L-band and spectral observations, along with high-resolution in-situ measurements of soil moisture across a 50,000km2 area of the Murrumbidgee River catchment, located in south-eastern Australia. This paper presents a qualitative assessment of the SMOS brightness temperature and soil moisture products.

Published
2012

43. SMOS L-VOD shows that post-fire recovery of dense forests is slower than what is depicted with X- and C-VOD and optical indices.

Author

Bousquet, Emma, Mialon, Arnaud, Rodriguez-Fernandez, Nemesio, Mermoz, Stéphane, and Henry Kerr, Yann

Subjects
FIRE management, EFFECT of human beings on climate change, TREE trunks, TREE branches
Abstract

Anthropogenic climate change is now considered to be one of the main factors causing an increase in both frequency and severity of wildfires. These fires are prone to release substantial quantities of CO2 in the atmosphere and to destroy natural ecosystems while reducing biodiversity. Depending on the ecosystem and climate regime, fires have distinct triggering factors and impacts. To better analyse and describe fire impact on different biomes, we investigated pre and post fire vegetation anomalies at global scale. The study was performed using several remotely sensed quantities ranging from optical vegetation indices (the enhanced vegetation index (EVI)) to vegetation opacities obtained at several microwave wavelengths (X-band, C-band, and L-band vegetation optical depth (X-VOD, C-VOD, and L-VOD)), ranging from 2 to 20 cm. It was found that C- and X-VOD are mostly sensitive to fire over low vegetation areas (grass and small bushes) or over tree leaves; while L-VOD depicts better the fire impact on tree trunks and branches. As a consequence, L-VOD is probably a better way of assessing fire impact on biomass. The study shows that L-VOD can be used to monitor fire affected areas as well as post-fire recovery, especially over densely vegetated areas. [ABSTRACT FROM AUTHOR]

Published
2021
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44. COSMOS-Europe: A European Network of Cosmic-Ray Neutron Soil Moisture Sensors.

Author

Bogena, Heye, Schrön, Martin, Jakobi, Jannis, Ney, Patrizia, Zacharias, Steffen, Andreasen, Mie, Baatz, Roland, Boorman, David, Duygu, Berk M., Eguibar-Galán, Miguel A., Fersch, Benjamin, Franke, Till, Geris, Josie, Sanchis, María González, Kerr, Yann, Korf, Tobias, Mengistu, Zalalem, Mialon, Arnaud, Nasta, Paolo, and Nitychoruk, Jerzy

Subjects
SOIL moisture, NEUTRONS, SOIL moisture measurement, REMOTE sensing, DETECTORS, DROUGHTS
Abstract

Human-caused climate change increases the occurrence and severity of droughts due to increasing temperatures, altered circulation patterns and reduced snow occurrence. For example, Europe has suffered from drought events in the last decade like never since the beginning of weather recording. Here we present soil moisture data from 65 Cosmic-ray neutron sensors (CRNS) in Europe (COSMOS-Europe for short) covering recent drought events. The CRNS sites are distributed across Europe and cover all major land use types and climate zones in Europe. The raw neutron count data from the CRNS stations were provided by 23 research institutions and processed using state-of-the-art methods. The harmonised processing included correction of the raw neutron counts, and a harmonised methodology for the conversion into soil moisture based on available in-situ information. In addition, information on the data uncertainty is provided with the dataset, information that is particularly useful for remote sensing and modelling applications. This paper presents the current spatiotemporal coverage of CRNS stations in Europe and describes the protocols for data processing from raw measurements to consistent soil moisture products as well as first results on how the recent drought events have been captured by the CRNS network. This harmonised European soil moisture dataset will help both hydrologists and climate scientists to study individual drought events, to understand their causes, to evaluate and improve their modelling, and to estimate the extremity of current events. The dataset, entitled “Dataset of COSMOS-Europe: A European network of Cosmic-Ray Neutron Soil Moisture Sensors”, is shared via Forschungszentrum Jülich: https://doi.org/10.34731/x9s3-kr48 (Bogena and Ney, 2021). [ABSTRACT FROM AUTHOR]

Published
2021
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45. An evaluation of SMOS L-band vegetation optical depth (L-VOD) data sets:high sensitivity of L-VOD to above-ground biomass in Africa

Author

Rodríguez-Fernández, Nemesio J., Mialon, Arnaud, Mermoz, Stephane, Bouvet, Alexandre, Richaume, Philippe, Al Bitar, Ahmad, Al-Yaari, Amen, Brandt, Martin Stefan, Kaminski, Thomas, Le Toan, Thuy, Kerr, Yann H., and Wigneron, Jean-Pierre

Abstract

The vegetation optical depth (VOD) measured at microwave frequencies is related to the vegetation water content and provides information complementary to visible/infra-red vegetation indices. This study is devoted to the characterisation of a new VOD data set obtained from SMOS (Soil Moisture and Ocean Salinity) satellite observations at L-band (1.4 GHz). Three different SMOS L-band VOD (L-VOD) data sets (SMOS Level 2, Level 3 and SMOS-IC) were compared with data sets on tree height, visible/infra-red indexes (NDVI, EVI), cumulated precipitation, and above ground biomass (AGB) for the African continent. For all relationships, SMOS-IC showed the lowest dispersion and highest correlation. Overall, we found a strong (R > 0.85) correlation with no clear sign of saturation between L-VOD and four AGB data sets. The relationship linking L-VOD to tree height (R = 0.87) and Baccini's AGB (R = 0.94) was strong and linear. The relationships between L-VOD and three other AGB data sets were linear per land cover class, but with a changing slope depending on the land cover type. For low vegetation classes, the annual mean of L-VOD spans a range from 0 to 0.7 and it is linearly correlation with the amount of the average annual precipitations. SMOS L-VOD showed a higher sensitivity to AGB as compared to NDVI and K/X/C-VOD (VOD measured, respectively, at 19, 10.7, and 6.9 GHz). The results showed that although the spatial resolution of L-VOD is coarse (~ 40 km), the high temporal frequency and sensitivity to AGB makes SMOS L-VOD a very promising index for large scale monitoring of the vegetation status, in particular biomass.

Published
2018

46. Le nouveau produit Smos-IC : humidité du sol et indice de végétation L-VOD

Author

Wigneron, Jean-Pierre, Mialon, Arnaud, Al-Yaari, Amen, Kerr, Yann H., 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), Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
[SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2018

47. SMOS-HR: A High Resolution L-Band Passive Radiometer for Earth Science and Applications

Author

Rodriguez-Fernandez, Nemesio J., primary, Mialon, Arnaud, additional, Merlin, Olivier, additional, Suere, Christophe, additional, Cabot, Francois, additional, Khazaal, Ali, additional, Costeraste, Josiane, additional, Palacin, Baptiste, additional, Rodriguez-Suquet, Raquel, additional, Tournier, Thierry, additional, Decoopman, Thibaut, additional, Anterrieu, Eric, additional, Colom, Miguel, additional, Morel, Jean-Michel, additional, Kerr, Yann H., additional, Rouge, Bernard, additional, Boutin, Jaqueline, additional, Picard, Ghislain, additional, Pellarin, Thierry, additional, Escorihuela, Maria Jose, additional, Al Bitar, Ahmad, additional, and Richaume, Philippe, additional

Published
2019
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48. After Almost 10 Years in Orbit: First Glance at Synergisms and New Results

Author

Kerr, Yann H., primary, Al-Yaari, Amen, additional, Fan, Lei, additional, Wigneron, Jean-Pierre, additional, Mialon, Arnaud, additional, Al Bitar, Ahmad, additional, Bousquet, Emma, additional, Richaume, Philippe, additional, Rodriguez-Fernandez, Nemesio, additional, Cabot, Francois, additional, and Miernecki, Maciej, additional

Published
2019
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50. SMOS-IC: an alternative SMOS soil moisture and 3 vegetation optical depth product

Author

Fernandez-Moran, Roberto, Al-Yaari, Amen, Mialon, Arnaud, Mahmoodi, Ali, Al Bitar, Ahmad, De Lannoy, Gabrielle, López-Baeza, Ernesto, Kerr, Yann, and Wigneron, Jean-Pierre

Subjects
SMOS, L-band, Level 3, ECMWF, SMOS-IC, soil moisture, vegetation optical depth, MODIS, NDVI
Abstract

The main goal of the Soil Moisture and Ocean Salinity (SMOS) mission over land surfaces is the production of global maps of soil moisture (SM) and vegetation optical depth (τ) based on multi-angular brightness temperature (TB) measurements at L-band. The operational SMOS Level 2 and Level 3 soil moisture algorithms account for different surface effects, such as vegetation opacity and soil roughness at 4 km resolution, in order to produce global retrievals of SM and τ. In this study, we present an alternative SMOS product which was developed by INRA (Institut National de la Recherche Agronomique) and CESBIO (Centre d’Etudes Spatiales de la BIOsphère). This SMOS-INRA-CESBIO (SMOS-IC) product provides daily SM and τ at the global scale and differs from the operational SMOS Level 3 (SMOSL3) product in the treatment of retrievals over heterogeneous pixels. Specifically, SMOS-IC is much simpler and does not account for corrections associated to the antenna pattern and the complex SMOS viewing angle geometry. It considers pixels as homogeneous to avoid uncertainties and errors linked to inconsistent auxiliary data sets which are used to characterize the pixel heterogeneity in the SMOS L3 algorithm. SMOS-IC also differs from the current SMOSL3 product (Version 300, V300) in the values of the effective vegetation scattering albedo (ω) and soil roughness parameters. An inter-comparison is presented in this study based on the use of ECMWF (European Center for Medium range Weather Forecasting) SM outputs and NDVI (Normalized Difference Vegetation Index) from MODIS (Moderate-Resolution Imaging Spectroradiometer). A 6 year (2010-2015) inter-comparison of the SMOS products SMOS-IC and SMOSL3 SM (V300) with ECMWF SM yielded higher correlations and lower ubRMSD (unbiased root mean square difference) for SMOS-IC over most of the pixels. In terms of τ, SMOS-IC τ was found to be better correlated to MODIS NDVI in most regions of the globe, with the exception of the Amazonian basin and of the northern mid-latitudes.

Published
2017

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