José Darrozes

• Phd
• Maître de Conférences at Université Toulouse III - Paul Sabatier

The ongoing global warming threatens the Greenland Ice Sheet (GIS). The GIS exhibits an overall mass loss since 1990. This ice mass loss varies annually and interannually, reflecting the intricate interactions between the ice sheet and the atmospheric and oceanic circulations. In this study, we look at the temporal variations of the GIS mass balanc...

Numerical tesseroid and radial-type approaches are presented and compared in terms of their efficiency for deriving the regional geoid height, vertical gravity, and gradiometric anomalies from sea floor topography grids. The vertical gradient function is particularly suitable for representing shorter wavelengths of gravity, typically less than 10 k...

Extreme hydrological events, such as tsunamis, high tides, or storm surges, present a formidable threat to coastal communities, leading to consequences such as flooding, property damage, loss of life, and enduring economic and social impacts. Therefore, monitoring, detecting, and predicting extreme hydrological events have significant implications...

In this study, we present the feasibility of using gravity measurements made with a small inertial navigation system (INS) during in situ experiments, and also mounted on an unmanned aerial vehicle (UAV), to recover local gravity field variations. The INS operated is the SPATIAL one developed by Advanced Navigation, which has three-axis acceleromet...

Mining areas and in particular those containing massive sulfides have left a heavy environmental legacy with soils and hydrographic networks highly contaminated with metals and metalloids as for example in the Iberian Pyrite Belt (Huelva, Spain). Here, we present new data on copper (Cu) isotopic composition of waters and solids collected along a co...

Microorganisms play a role in the construction or modulation of various types of landforms. They are especially notable for forming microbially induced sedimentary structures (MISS). Such microbial structures have been considered to be among the most likely biosignatures that might be encountered on the martian surface. Twenty-nine algorithms have...

With population growth, water will increase in the following decades tremendously. The optimization of water allocation for agriculture requires accurate soil moisture (SM) monitoring. Recent Global Navigation Satellite System Reflectometry (GNSS-R) studies take advantage of continuously emitted navigation signals by the Global Navigation Satellite...

The monitoring of flood and wetland dynamics at global scale is hampered by several limitations, including a reduced data availability in tropical areas due to the presence of clouds affecting visible and infrared imagery, or low spatial and/or temporal resolutions affecting passive and active microwave Earth Observation (EO) data. As a consequence...

There was an error in the original article [...]

We propose to derive local sea level variations by using the Signal-to-Noise Ratio (SNR) of the GNSS reflected signals at four GNSS single antenna sites (ILDG, TAR0, FFT2, LYTT) located at different latitudes. For these sites representing various ocean conditions (waves, tides, storm surges, etc…), tides estimates by SNR are highly consistent to ti...

It is of particular importance for structural geology, geophysical exploration and also obvious economical purposes to retrieve structures possibly hidden below salt domes. And these domes could trap hydrocarbon or gas. We thus propose a sensitivity analysis of seismic data in salt tectonic areas to identify different wavelengths associated with th...

This study uses the observations from the Cyclone GNSS (CYGNSS) mission to analyze their potential for a global mapping of the floods dynamics in the pan-tropical area using Global Navigation Satellite System (GNSS) Reflectometry (GNSS-R). We base our analysis on the coherent reflectivity derived from CYGNSS observations. We show that the CYGNSS mi...

An iterative Extended Kalman Filter (EKF) approach is proposed to recover a regional set of topographic heights composing an undersea volcanic mount by the successive combination of large numbers of gravity measurements at sea surface using altimetry satellite-derived grids and taking the error uncertainties into account. The integration of the non...

This article aims to attempt to increase the number of satellites that can be used for monitoring soil moisture to obtain more precise results using GNSS-IR (Global Navigation Satellite System-Interferometric Reflectometry) technology to estimate soil moisture. We introduce a soil moisture inversion model by using GPS SNR (Signal-to-Noise Ratio) da...

Surface water storage in floodplains and wetlands is poorly known from regional to global scales, in spite of its importance in the hydrological and the carbon balances, as the wet areas are an important water compartment which delays water transfer, modifies the sediment transport through sedimentation and erosion processes, and are a source for g...

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and mo...

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and mo...

Signal-to-noise ratio (SNR) time series acquired by a geodetic antenna were analyzed to retrieve water heights during asymmetric tides on a narrow river using the Interference Pattern Technique (IPT) from Global Navigation Satellite System Reflectometry (GNSS-R). The dynamic SNR method was selected because the elevation rate of the reflecting surfa...

GRACE spherical harmonics are well-adapted for representation of hydrological signals in river drainage basins of large size such as the Amazon or Mississippi basins. However, when one needs to study smaller drainage basins, one comes up against the low spatial resolution of the solutions in spherical harmonics. To overcome this limitation, we prop...

Radar backscattering coefficients from synthetic aperture radars and scatterometers are commonly used to characterize the land surface properties and monitor their temporal evolution. Radar altimetry is mostly used, over land, to provide time series of water stage of lakes, rivers and wetlands and the topography of the ice sheets. Very few studies...

We demonstrate a new approach to recover water mass changes from GRACE satellite data at a daily temporal resolution. Such a product can be beneficial in monitoring extreme weather events that last a few days and are missing by conventional monthly GRACE data. The determination of the distribution of these water mass sources over networks of juxtap...

In Southern Europe, soil contamination by heavy metals (HM) due to mining and industrial activities is a long-known problem. Yet, despite soils being widely contaminated through decades, some plants are still able to grow. Some of these plants, like giant reed (Arundo donax) or common reed (Phragmites australis) are capable of accumulating substant...

Geological evidence shows that life on Earth evolved in line with major concomitant changes in Earth surface processes and landforms. Biogeomorphological characteristics, especially those involving microorganisms, are potentially important facets of biosignatures on Mars and are generating increasing interest in astrobiology. Using Earth as an anal...

Nowadays, atmospheric pollution has a major impact on the human health and the environment, encouraging the development of biomonitors of the air quality over a wide zone. In this study, the relevance of the epiphyte plants Tillandsia usneoides is studied to estimate the transfer of metal(loid)s from a former Zn and Pb mining zone in the Southeast...

Nowadays, air pollution has a major impact on the environment and human health. Owen gauges allow the sampling of atmospheric depositions in polluted sites for further characterisation. This paper shows the study of the air particles of an old mining zone in Cartagena-La Unión (South-east of Spain) in order to quantify their potential risk on human...

In this study, three months of records (January–March 2010) that were acquired by a geodetic Global Navigation Satellite Systems (GNSS) station from the permanent network of RGP (Réseau GNSS Permanent), which was deployed by the French Geographic Institute (IGNF), located in Socoa, in the south of the Bay of Biscay, were used to determine the tide...

Lakes and reservoirs have been identified as sentinels of climate change. Tonle Sap is the largest lake in both the Mekong Basin and Southeast Asia and because of the importance of its ecosystem, it is has been described as the “heart of the lower Mekong”. Its seasonal cycle depends on the annual flood pulse governed by the flow of the Mekong River...

This work presents the results of an experimental program performed to study the effect of long series of moderate thermal cycles on the mechanical response of a limestone rock. Samples were exposed to more than 1000 temperature cycles from 10° to 50°C in dry conditions. Rock degradation was followed by measuring axial and radial strains, elastic w...

In the Sahelian region, the West African Monsoon (WAM) is an important phenomenon for land water storage evolution, as demonstrated by The Gravity Recovery and Climate Experiment (GRACE) estimations. The Monsoon leads to an annual increase of the water mass. However, GRACE data also displays the existence of a semi-annual cycle whose its origin is...

In continental and oceanic conditions, clay-rich deposits are characterised by the development of polygonal fracture systems (PFS). PFS can increase the vertical permeability of clay-rich deposits (mean permeability ≤10⁻¹⁶ m²) and are pathways for fluids. On continents, the width of PFS ranges from centimeters to hundreds of meters, while in oceani...

Long-term deformation often occurs in lava fields at volcanoes after flow emplacements. The investigation and interpretation of deformation in lava fields is one of the key factors for the assessment of volcanic hazards. As a typical Hawaiian volcano, Piton de la Fournaise volcano’s (La Réunion Island, France) main eruptive production is lava. Char...

This work assesses the estimation of surface volumetric soil moisture (VSM) using the global navigation satellite system interferometric reflectometry (GNSS-IR) technique. Year-round observations were acquired from a grassland site in southwestern France using an antenna consecutively placed at two contrasting heights above the ground surface (3.3...

Monitoring changes in coastal sea levels is necessary given the impacts of climate change. Information on the sea level and its changes are important parameters in connection to climate change processes. In this study, radar altimetry data from successive satellite missions, European Remote Sensing-2 (ERS-2), Jason-1, Envisat, Jason-2, and Satellit...

Since its launch in 2002, the Gravity Recovery And Climate Experiment (GRACE) has been measured the tiny variations of the gravity field due to redistributions of water mass in the surface envelops of Earth. At a spatial resolution of 400 km, these satellite data offer a unique perspective to understand the evolution of continental water storage at...

This work aims to assess the estimation of surface volumetric soil moisture (VSM) using the Global Navigation Satellite System Interferometric Reflectometry (GNSS-IR) technique. Year-round observations were acquired from a grassland site in southwestern France using an antenna consecutively placed at two contrasting heights above the ground surface...

Copper (Cu) based pesticides are widely used in viticulture and are permitted in organic viticulture. Due to its extensive long term use, Cu accumulates in vineyard soils and ecotoxicological implications are growing. In this study, the cycling of Cu based pesticides was investigated in vineyard environments using copper mass balance, electron para...

The ZA PYGAR project aims at studying the spatial dynamics of socio-ecological systems (SES) in South-Western France, going from the Pyrenees mountains to the plains of the Garonne river basin. PYGAR tries to answer three main scientific questions: 1/ What are the respective contributions of climate change and local anthropogenic disturbances to ec...

This work aims to estimate soil moisture and vegetation height from Global Navigation Satellite System (GNSS) Signal to Noise Ratio (SNR) data using direct and reflected signals by the land surface surrounding a ground-based antenna. Observations are collected from a rainfed wheat field in southwestern France. Surface soil moisture is retrieved bas...

Fluid circulation in sedimentary basins is responsible for the transformation and cementation of mineral grains during diagenesis. Concretions and pipe chimneys are obvious features resulting from such circulation but some transformations in the matrix of rocks, if less spectacular, may lead to pervasive transformations of the sediments. Inherited...

Monitoring ground surface displacement of volcanoes over a long period of time helps improve understanding of the volcano structure, dynamics and mechanisms. In this paper, we investigate the spatio-temporal behavior of the long-term displacement field at Piton de la Fournaise volcano (La Réunion Island) by means of X-band InSAR and GNSS time serie...

This work aims to estimate soil moisture and vegetation characteristics from Global Navigation Satellite System (GNSS) Signal to Noise Ratio (SNR) data using direct and reflected signals by the land surface surrounding a ground-based antenna. Observations are collected over a rainfed wheat field in southwestern France. The retrievals are compared w...

tSelf potential (SP) anomalies over Piton de La Fournaise volcano (La Réunion Island) are generally inter-preted as resulting from meteoritic water porous flow. However, there is no clear evidence that thesubsurface is permanently saturated. Recently, a convective subsurface airflow has been evidenced withina quiescent cone at Piton de La Fournaise...

The floods are an annual phenomenon on the Pacific Coast of Ecuador and can become devastating during El Niño years, especially in the Guayas watershed (32,300 km²), the largest drainage basin of the South American western side of the Andes. As limited information on flood extent in this basin is available, this study presents a monitoring of the s...

This paper aims to propose a new coastal observable based on the computation of the ratio between the coherent and incoherent averaging as an alternative to the coherent time and the effectiveness of incoherent averaging proposed by previous works. Experimental data have been processed to develop the relationship between wind speed and the proposed...

An open-source GNSS software receiver allows to have full access to the signal processing and to make add-ons to the source code in order to obtain the desired GNSS reflectometry processing. The direct signal is processed in the standard way, its tracking loops replica are tapped to have a robust processing of the reflected signal in a master-slave...

If we consider all remote sensing systems, the system that has the largest constellation, which is the most used in the world, is undoubtedly the global positioning system (GNSS: Global Navigation Satellite System). Indeed, anyone using a GNSS positioning system (GPS, Galileo, GLONASS, BEIDOU/COMPASS etc.) uses it. This system has shown a high leve...

Copper (Cu) based fungicides have been applied in European vineyards from the appearance of mildew in the late 19th century to the present day, particularly in organic viticulture. Even though its application is foliar, most of the Cu reaches the soil after being washed off or following leaf fall. As Cu accumulates in soils, the use of Cu based fun...

Si l’on regarde l’ensemble des systèmes de télédétection, le système qui présente la plus importante constellation et qui est le plus utilisé au monde est sans nul doute le système de Positionnement Global par Satellite (GNSS : Global Navigation Satellite System). En effet, il est utilisé par toute personne utilisant un système de localisation GNSS...

Global Navigation Satellite System-Reflectometry (GNSS-R) has emerged as a remote sensing tool, which is complementary to traditional monostatic radars, for the retrieval of geophysical parameters related to surface properties. In the present paper, we describe a new polarimetric GNSS-R system, referred to as the GLObal navigation satellite system...

In the Lake Chad basin, the quaternary phreatic aquifer (named hereafter QPA) presents large piezometric anomalies referred to as domes and depressions whose depths are ~15 and ~60 m, respectively. A previous study (Leblanc et al. in Geophys Res Lett, 2003, doi:10. 1029/ 2003GL018094) noticed that brightness temperatures from METEOSAT infrared imag...

Populations of the riparian pioneer species Populus nigra L. which establish on alluvial bars within river channels modulate sediment dynamics and fluvial landforms. Dense cohorts of P. nigra have colonized gravel point bars along the channelized River Garonne, France, during the last 20 years and have enhanced the vertical, lateral and longitudina...

We propose a Global Navigation Satellite System-Reflectometry (GNSS-R) interference pattern technique method to estimate the temporal variations of the soil moisture content of the ground surrounding a single geodetic antenna. Three parameters can be inverted from GNSS signal-to-noise ratio (SNR) acquisitions: amplitude/phase of the multipath contr...

In this study, a new high-level remote sensing image product is generated by exploiting Global Navigation Satellite System-Reflectometry (GNSS-R) measurements collected by the TechDemoSat-1 (TDS-1) mission. This product consists of normalized radar cross-section (NRCS) measurements arranged in a gridded format. The product is obtained reconstructin...

In the Lake Chad basin, the quaternary phreatic aquifer (named hereafter QPA) presents large piezometric anomalies referred to as domes and depressions whose depths are ~15 and ~60 m, respectively. A previous study (Leblanc et al. in Geophys Res Lett, 2003, doi:10. 1029/ 2003GL018094) noticed that brightness temperatures from METEOSAT infrared imag...

In the Lake Chad basin, the quaternary phreatic aquifer (named hereafter QPA) presents large piezometric anomalies referred to as domes and depressions whose depths are * 15 and * 60 m, respectively. A previous study (Leblanc et al. in Geophys Res Lett, 2003, doi: 10.1029/2003GL018094) noticed that brightness temperatures from METEOSAT infrared ima...

In Lake Chad basin, the Quaternary phreatic Aquifer (named hereafter QPA) is impacted by large closed piezometric anomalies as depressions (with a water table depth of ~60 m) and domes, which have a depth of ~15 m [1]. The classic hypothesis to explain the formation of these piezometric depressions is that the water deficit generated by evapotransp...

Clay-rich deposits are characterised by the development of polygonal fractures systems (PFS) in terrestrial [1] and marine conditions [2]. On continents, PFS with a size ranging from centimetre to hundred meters large are described. They form by tensile stresses due to the deposit contraction during dehydration. PFS are also observed in sub-marine...

Ocean altimetric applications of GNSS-R have particularly been developed through the last decades. Interference Pattern Technique (IPT) based on the analysis of the Signal-to-Noise Ratio (SNR) of a classical GNSS antenna presents the main advantage of being applicable everywhere by using a single geodetic antenna and a classical GNSS receiver, tran...

1. INTRODUCTION Piton de la Fournaise (2632 m a.s.l.), located on the south-eastern side of Réunion island (21°14′33″S, 55°42′32″E) in the Indian Ocean, is a hotspot oceanic basaltic shield volcano whose activity began more than 500,000 years ago [1]. It is one of the most active volcanoes in the world with a high eruptive frequency on average on...

Ocean altimetric applications of GNSS-R have particularly been developed through the last decades. Interference Pattern Technique (IPT) based on the analysis of the Signal-to-Noise Ratio (SNR) of a classical GNSS antenna presents the main advantage of being applicable everywhere by using a single geodetic antenna and a classical GNSS receiver, tran...

As multipaths still represent a major problem for reaching precise GNSS positioning, the mitigation of their influence has been widely investigated. However, previous studies have lately proposed to use these interferences of GNSS electromagnetic waves to estimate parameters related to the reflecting surface (e.g., antenna heights, rugosity,.. .)....

Ocean altimetric applications of GNSS-R have particularly been developed through the last decades. Interference Pattern Technique (IPT) based on the analysis of the Signal-to-Noise Ratio (SNR) of a classical GNSS antenna presents the main advantage of being applicable everywhere by using a single geodetic antenna and a classical GNSS receiver, tran...

Ocean altimetric applications of GNSS-R have particularly been developed through the last decades. Interference Pattern Technique (IPT) based on the analysis of the Signal-to-Noise Ratio (SNR) of a classical GNSS antenna presents the main advantage of being applicable everywhere by using a single geodetic antenna and a classical GNSS receiver, tran...

El sistema GNSS aparece en los años 70 con la constelación GPS ya que el sistema ha evolucionado considerablemente con el advenimiento, a bordo de los satélites, de relojes atómicos más precisos y la implementación de estaciones terrestres para guiar nuestros coches / aviones y barcos o que sea para aplicaciones científicas como la convergencia de...

Understanding the influence of soil composition in wine taste is of great economic and environmental interest in France and around the world. Nevertheless the impact of soil composition on wine taste is still controversially discussed. Since inorganic soil components do not have a proper taste and do not enter the plant anyway, their influence need...

The floods are an annual phenomenon on the Pacific coast of Ecuador and can become devastating during El Nino years, especially in the Guayas watershed (32,300 km(2)), the largest drainage basin on the South American western side of the Andes. In this study, we used ENVISAT ASAR GM SAR images with a spatial resolution of 1 km to map the flooded are...