A5051120098- Ocean Waves and Remote Sensing
- Oceanographic and Atmospheric Processes
- Arctic and Antarctic ice dynamics
- Meteorological Phenomena and Simulations
- Climate variability and models
- Precipitation Measurement and Analysis
- Cryospheric studies and observations
- Soil Moisture and Remote Sensing
- Tropical and Extratropical Cyclones Research
- Geophysics and Gravity Measurements
- Climate change and permafrost
- Marine and coastal ecosystems
- Marine and fisheries research
- Methane Hydrates and Related Phenomena
- Underwater Acoustics Research
- Geology and Paleoclimatology Research
- Coastal and Marine Dynamics
- Maritime Navigation and Safety
- Maritime Transport Emissions and Efficiency
- Vehicle emissions and performance
- Spacecraft Design and Technology
- Wind and Air Flow Studies
- Atmospheric chemistry and aerosols
- Marine animal studies overview
- Ocean Acidification Effects and Responses
Laboratory for Ocean Physics and Satellite Remote Sensing
2018-2023
Centre National de la Recherche Scientifique
2017-2023
Institut de Recherche pour le Développement
2018-2023
Université de Bretagne Occidentale
2017-2023
Ifremer
2014-2023
Laboratoire d’Études en Géophysique et Océanographie Spatiales
2012-2021
Institut Universitaire Européen de la Mer
2019
Université Bretagne Loire
2017-2018
Institut Français
1993-2009
A quantitative assessment of observed and projected environmental changes in the Southern Ocean (SO) with a potential impact on marine ecosystem shows: (i) large proportions SO are will be affected by one or more climate change processes; areas to future larger than that already under stress, (ii) sea-ice past likely much ocean warming. The smallest (<1% area SO) glacier retreat warming deeper euphotic layer. In future, decrease is expected widespread. Changes iceberg resulting from further...
Abstract Marine ecosystems are under increasing anthropogenic pressures from marine and terrestrial activities. Ship traffic, the major cause of change in open ocean, its temporal evolution still largely unknown because lack data. Altimeter data provide a new powerful tool to detect monitor ship traffic through method analysis echo waveform. The archive seven altimeter missions has been processed create two decade database locations. estimated annual density maps compare well with ones...
Unprecedented views of surface wind fields in tropical cyclones (hereafter TCs) are provided by the European Remote Sensing Satellite (ERS) C band scatterometer. Scatterometer measurements at able to penetrate convective storms clouds, observing with good accuracy. However resolution (50×50 km 2 ) limits interpretation scatterometer signals such mesoscale events. The strong gradients existing scales a few kms smoothed measured features as intensity and location maxima, position center....
Abstract Basal melting of floating ice shelves and iceberg calving constitute the two almost equal paths freshwater flux between Antarctic cap Southern Ocean. The largest icebergs (>100 km 2 ) transport most volume but their basal is small compared to breaking into smaller that thus major vector freshwater. archives nine altimeters have been processed create a database (<8 within open water containing positions, sizes, volumes spanning 1992–2014 period. intercalibrated monthly from...
Interest for icebergs and their possible impact on southern ocean circulation biology has increased during the recent years. While large tabular are routinely tracked monitored using scatterometer data, distribution of smaller (less than some km) is still largely unknown as they difficult to detect operationally conventional satellite data. In a study, Tournadre et al. (2008) showed that small can be detected, at least in open water, high resolution (20 Hz) altimeter waveforms. present...
Ocean models show an annual cycle in the Agulhas Current transport which has not yet been confirmed analyses of in‐situ or satellite observations. A cross‐stream coordinate approach is used to study variability from 18 years along‐track altimetry and merged close 7 high frequency Sea Surface Temperature (SST) While position width Current's dynamical core do display cycle, geostrophic current speed at current's exhibits distinct seasonal variations, with a stronger flow observed austral...
We address the lack of temporal information on ship emissions, and report rapid short-term variations satellite-derived NOx emissions between 2005 2012 over European seas. Our inversion is based OMI observed tropospheric NO2 columns GEOS-Chem simulations. Average increased by ∼15% from to 2008. This increase was followed a reduction ∼12% in 2009, direct result global economic downturn 2008–2009, steady 2009 2012. Observations passages through Suez Canal satellite altimeter derived densities...
Abstract Large uncertainties exist on the volume of ice transported by Southern Ocean large icebergs, a key parameter for climate studies, because paucity information, especially iceberg thickness. Using icebergs tracks from National Ice Center (NIC) and Brigham Young University (BYU) databases to select altimeter data over method analysis waveforms, database 5366 freeboard elevation, length, backscatter covering 2002–2012 period has been created. The is analyzed in terms distributions...
The India–France SARAL/AltiKa mission is the first Ka-band altimetric dedicated primarily to oceanography. objectives were firstly observation of oceanic mesoscales but also global and regional sea level monitoring, including coastal zone, data assimilation, operational proved be a great opportunity for inland waters applications, observing ice sheet or icebergs, as well geodetic investigations. ended its nominal phase after three years in orbit began new (drifting orbit) July 2016....
The two scatterometers currently in operation, the Ku‐band NASA Seawinds on QuikScat satellite and C‐band AMI‐Wind ERS‐2 satellite, are designed to infer ocean wind vectors from sea surface radar backscatter measurements. They provide excellent coverage of ocean, their products great value for meteorological communities. However, presence rain within scatterometer cells can significantly modify coefficient hence alter vector retrieval. These perturbations hamper analysis fields atmospheric...
Abstract In late 2007, two massive icebergs, C19a and B15a, drifted into open water slowly disintegrated in the southernmost Pacific Ocean. Archived acoustic records show that high‐intensity underwater sounds accompanying this breakup increased ocean noise levels at mid‐to‐equatorial latitudes over a period of ∼1.5 years. More typically, seasonal variations noise, which are characterized by austral summer‐highs winter‐lows, appear to be modulated annual cycle Antarctic iceberg drift...
Abstract. The SEMAPHORE (Structure des Echanges Mer-Atmosphère, Propriétés Hétérogénéités Océaniques: Recherche Expérimentale) experiment has been conducted from June to November 1993 in the Northeast Atlantic between Azores and Madeira. It was centered on study of mesoscale ocean circulation air-sea interactions. experimental investigation achieved at using moorings, floats, ship hydrological survey, a smaller scale by one dedicated ship, two instrumented aircraft, surface drifting buoys,...
Small icebergs (edge lengths <1 km) are difficult to detect and track. In a recently published study, it was demonstrated that small targets (ships, islets,…) emerging from the sea can be detected by analysis of high‐rate altimeter waveforms. The Jason data revealed also have detectable signature in thermal noise part waveforms for open water. These signatures very similar transponders almost deterministic. An automated method based on detection parabolic shapes convolution product with...
Microwave Sea Surface Salinity (SSS) measurements can be performed by isolating the emissivity response to salinity changes from numerous geophysical effects, including surface temperature and wind waves. At L‐band frequencies (1 2 GHz), sensitivity SSS is sufficient but it falls off quickly as frequency increased. Nevertheless, methods using higher microwave with much lower than at L band, already tested. In particular, combining 6 10 GHz data in vertical polarization efficiently minimizes...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The AltiKa project, developed by the French Centre National d'Etudes Spatiales, is based on a wideband Ka-band altimeter (35.75 GHz). technical characteristic of instrument will offer higher performance both in terms spatial and vertical resolutions that lead to improved observation ice, coastal areas, inland waters, wave height. An Indian Space Research Organization satellite, called Satellite...
Abstract. The evolution of the thickness and area two large Southern Ocean icebergs that have drifted in open water for more than a year is estimated through combined analysis altimeter data visible satellite images. observed compared with iceberg melting predictions from commonly used formulations, allowing us to test their validity icebergs. first formulation, based on fluid dynamics approach, tends underestimate basal melt rates, while second which considers thermodynamic budget, appears...
Observations of the downstream evolution an oceanic zonal horizontal shear flow at a Reynolds number about 10 11 , formed as westward North Equatorial Current passes island Hawai‘i, reveal finite-amplitude anticyclonic vortices resulting from instability shear. The initial orbital period is exactly one pendulum day (3.1 days this latitude), centrifugal presumably inhibiting stronger forming. As they move downstream, appear to pair and merge into successively larger vortices, in geometric...
The presence of rain in the sub-satellite track can significantly degrade altimeter measurements by causing an attenuation backscattered signal, a change its path length through atmosphere and mean square slope sea surface. This cause errors, not only measurement satellite altitude, but also determination wind speed wave height. TOPEX/Poseidon dual-frequency data (cycles 3 8) were searched for instances where possibly degraded over North inter-Tropical Atlantic. A subjective analysis data,...
The “flux, etat de la mer, et télédétection en conditions fetch variable” (FETCH) was aimed at studying the physical processes associated with air–sea exchanges and mesoscale oceanic circulation in a coastal region dominated by frequent strong offshore winds. experiment took place March–April 1998 northwestern Mediterranean Sea (Gulf of Lion). Observations were collected R/V L'Atalante , an interaction spar (ASIS) buoy, waverider buoys, research aircraft equipped for situ remote sensing...
Abstract. Variability of surface water masses the Laptev and East Siberian seas in August–September 2018 is studied using situ satellite data. In data were collected during ARKTIKA-2018 expedition then complemented with satellite-derived sea temperature (SST), salinity (SSS), height, wind speed, ice concentration. The estimation SSS fields challenging high-latitude regions, precision soil moisture ocean (SMOS) retrieval improved by applying a threshold on weekly error. For first time this...
Extreme weather events such as tropical cyclones are difficult to observe with conventional means. Satellite‐based observations provide essential measurements of key parameters governing cyclones. They critical for short‐term forecasting. Radiometers onboard the Defense Meteorological Satellite Program satellite series, WindSat and Tropical Rainfall Measuring Mission satellites, scatterometers ERS, ADEOS, QuikScat satellites offer unprecedented synoptic surface wind atmospheric liquid water...
About 5% of Ku‐band altimeter ocean data are degraded by the occurrence high radar return cross sections (σ 0 ), usually called σ blooms. During blooms, which occur during no or low wind conditions, mean waveform can significantly depart from expected shape. In about 60% cases waveforms distorted to such an extent that either range tracker loses lock off‐nadir angle estimate becomes unrealistic. The analysis rate bloom events reveals presence V‐shaped patterns similar ones observed rain...