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| Registros recuperados: 44 | |
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| Tran, Ngan; Chapron, Bertrand; Vandemark, D. |
| This letter uses a large ocean satellite data set to document relationships between Ku-band radar backscatter (sigma-0) of the sea surface, near-surface wind speed (U), and ocean wave height (SWH). The observations come from satellite crossovers of the Tropical Rainfall Mapping Mission (TRMM) Precipitation Radar (PR) and two satellite altimeters, namely: 1) Jason-1 and 2) ENVISAT. At these nodes, we obtain TRMM clear-air normalized radar cross-section data along with coincident altimeter-derived significant wave height. Wind speed estimates come from the European Centre for Medium-Range Weather Forecast. TRMM PR is the first satellite to measure low incidence Ku-band ocean backscatter at a continuum of incidence angles from 0 degrees to 18 degrees. This... |
| Tipo: Text |
Palavras-chave: Space borne radar; Scattering; Radar cross section; Altimetry. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3299.pdf |
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| Tournadre, Jean; Bouhier, Nicolas; Girard-ardhuin, Fanny; Remy, F.. |
| Basal melting of floating ice shelves and iceberg calving constitute the two almost equal paths of freshwater flux between the Antarctic ice cap and the Southern Ocean. The largest icebergs (>100 km2) transport most of the ice volume but their basal melting is small compared to their breaking into smaller icebergs that constitute thus the major vector of freshwater. The archives of nine altimeters have been processed to create a database of small icebergs (<8 km2) within open water containing the positions, sizes, and volumes spanning the 1992–2014 period. The intercalibrated monthly ice volumes from the different altimeters have been merged in a homogeneous 23 year climatology. The iceberg size distribution, covering the 0.1–10,000 km2 range,... |
| Tipo: Text |
Palavras-chave: Iceberg; Altimetry; Southern Ocean. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00307/41863/41114.pdf |
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| Verron, Jacques; Bonnefond, Pascal; Aouf, Lofti; Birol, Florence; Bhowmick, Suchandra A.; Calmant, Stephane; Conchy, Taina; Cretaux, Jean-francois; Dibarboure, Gerald; Dubey, A. K.; Faugere, Yannice; Guerreiro, Kevin; Gupta, P. K.; Hamon, Mathieu; Jebri, Fatma; Kumar, Raj; Morrow, Rosemary; Pascual, Ananda; Pujol, Marie-isabelle; Remy, Elisabeth; Remy, Frederique; Smith, Walter H. F.; Tournadre, Jean; Vergara, Oscar. |
| The India-France SARAL/AltiKa mission is the first Ka-band altimetric mission dedicated primarily to oceanography. The mission objectives were firstly the observation of the oceanic mesoscales but also global and regional sea level monitoring, including the coastal zone, data assimilation, and operational oceanography. SARAL/AltiKa proved also to be a great opportunity for inland waters applications, for observing ice sheet or icebergs, as well as for geodetic investigations. The mission ended its nominal phase after three years in orbit and began a new phase (drifting orbit) in July 2016. The objective of this paper is to highlight some of the most remarkable achievements of the SARAL/AltiKa mission in terms of scientific applications. Compared to the... |
| Tipo: Text |
Palavras-chave: Altimetry; Ka-band; Oceanography; Hydrology; Ice; Geodesy. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00600/71248/69623.pdf |
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| Raj, R. P.; Halo, I.; Chatterjee, S.; Belonenko, T.; Bakhoday‐paskyabi, M.; Bashmachnikov, I.; Fedorov, A.; Xie, J.. |
| The interaction between the mesoscale eddies and the cyclonic gyre circulation of the Lofoten Basin is studied using a suite of satellite altimeters, a regional coupled ocean‐sea‐ice data assimilation system (the TOPAZ reanalysis) and Argo float data. An automated method identified 5,373/5,589 individual anticyclonic/cyclonic eddies in the Lofoten Basin from more than 65,000 altimeter‐based eddy observations, of which 70–85% are found to be nonlinear. The nonlinearity of eddies is estimated from its translational and rotational velocities. The study found clustering of highly intense nonlinear eddies on either side of the Lofoten Basin. Further, we show the distinct cyclonic drift of the anticyclonic and cyclonic eddies, both confined to the western side... |
| Tipo: Text |
Palavras-chave: Mesoscale eddies; Lofoten vortex; Lofoten basin; Gyre circulation; Altimetry; Argo floats. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00635/74707/74651.pdf |
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| Ardhuin, Fabrice; Brandt, Peter; Gaultier, Lucile; Donlon, Craig; Battaglia, Alessandro; Boy, François; Casal, Tania; Chapron, Bertrand; Collard, Fabrice; Cravatte, Sophie; Delouis, Jean Marc; De Witte, Erik; Dibarboure, Gerald; Engen, Geir; Johnsen, Harald; Lique, Camille; Lopez-dekker, Paco; Maes, Christophe; Martin, Adrien; Marié, Louis; Menemenlis, Dimitris; Nouguier, Frederic; Peureux, Charles; Rampal, Pierre; Ressler, Gerhard; Rio, Marie-helene; Rommen, Bjorn; Shutler, Jamie D.; Suess, Martin; Tsamados, Michel; Ubelmann, Clement; Van Sebille, Erik; Van Den Oever, Martin; Stammer, Detlef. |
| The Sea surface KInematics Multiscale monitoring (SKIM) satellite mission is designed to explore ocean surface current and waves. This includes tropical currents, notably the poorly known patterns of divergence and their impact on the ocean heat budget, and monitoring of the emerging Arctic up to 82.5°N. SKIM will also make unprecedented direct measurements of strong currents, from boundary currents to the Antarctic circumpolar current, and their interaction with ocean waves with expected impacts on air-sea fluxes and extreme waves. For the first time, SKIM will directly measure the ocean surface current vector from space. The main instrument on SKIM is a Ka-band conically scanning, multi-beam Doppler radar altimeter/wave scatterometer that includes a... |
| Tipo: Text |
Palavras-chave: Ocean current; Tropics; Arctic; Doppler; Altimetry; Sea state; Remote sensing; Ocean waves. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00498/60964/64372.pdf |
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| Dibarboure, G.; Le Traon, Pierre-yves; Galin, N.. |
| Sea surface height (SSH) measurements provided by pulse-limited radar altimeters are one-dimensional profiles along the satellite's nadir track, with no information whatsoever in the cross-track direction. The anisotropy of resulting SSH profiles is the most limiting factor of mesoscale SSH maps that merge the 1D profiles.This paper explores the potential of the cross-track slope derived from the Cryosphere Satellite-2 (CryoSat-2)'s synthetic aperture radar interferometry (SARin) mode to increase the resolution of mesoscale fields in the cross-track direction. Through idealized 1D simulations, this study shows that it is possible to exploit the dual SARin measurement (cross-track slope and SSH profile) in order to constrain mesoscale mapping in the... |
| Tipo: Text |
Palavras-chave: Altimetry; Remote sensing; Sampling; Satellite observations; Interpolation schemes; Inverse methods. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00152/26305/24575.pdf |
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| Louis, Gilles; Lequentrec-lalancette, Marie-françoise; Royer, Jean-yves; Rouxel, Didier; Géli, Louis; Maïa, Marcia; Faillot, Mathilde. |
| Over the past 3 decades, satellite altimetry has been a key tool for dynamic ocean studies and for accurately estimating sea surface heights. The geodetic reference surface—the “geoid”—can be approximated as the mean sea surface height of an ocean corrected for dynamic terms such as tides and currents. It is an equipotential surface of the gravity field; and variations of this field are quantified as free‐air anomalies, from which density heterogeneities of the oceanic basement can be inferred. Using such data in combination with other geophysical data, scientists have improved their knowledge of the nature of submarine relief and underlying structures. In solid Earth geophysics, major breakthroughs came from the development of high‐resolution marine... |
| Tipo: Text |
Palavras-chave: Altimetry; High resolution; SWAT soil and water assessment tool. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00451/56260/57829.pdf |
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| Le Cann, Bernard; Assenbaum, Michel; Gascard, Jean-claude; Reverdin, Gilles. |
| Lagrangian instruments and altimetry data are used to investigate the upper ( 0 to similar to 500 m) mean and mesoscale circulations in a region of the midlatitude northeast Atlantic (36 degrees - 47 degrees N, 13 degrees - 23 degrees W), a formation and subduction area of Subpolar Mode Water. Lagrangian data were collected between September 2000 and September 2001 with isobaric subsurface floats, totaling 34.0 float years, and surface drifting buoys, totaling 27.9 buoy years. The near-surface ( 0 - 100 m) mean circulation is dominated by two weak ( similar to 5 cm/s) eastward currents which veer southward in the domain. In the 100- to 500-m-deep layer, these eastward mean currents retroflect westward and form two anticyclonic circulation cells, opened to... |
| Tipo: Text |
Palavras-chave: Altimetry; Drifting buoys; Acoustic floats; Lagrangian circulation; Mesoscale eddies; Northeastern Atlantic. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-745.pdf |
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| Qiu, Bo; Chen, Shuiming; Klein, Patrice; Torres, Hector; Wang, Jinbo; Fu, Lee-lueng; Menemenlis, Dimitris. |
| Reconstructability of upper ocean vertical velocity (w) and vorticity (ζ) fields from high-resolution sea surface height (SSH) data is explored using the global 1/48° horizontal-resolution MITgcm output in the context of the forth-coming Surface Water and Ocean Topography (SWOT) mission. By decomposing w with an omega equation of the primitive-equation system and by taking into account the measurement design of the SWOT mission, this study seeks to reconstruct the subinertial, balanced w and ζ signals. By adopting the effective surface quasi-geostrophic (eSQG) framework and applying to the Kuroshio Extension region of the North Pacific, we find that the target and reconstructed fields have a spatial correlation of ~0.7 below the mixed layer for w and 0.7 ~... |
| Tipo: Text |
Palavras-chave: Eddies; Mesoscale processes; Ocean dynamics; Vertical motion; Altimetry. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00593/70561/68744.pdf |
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| Golubkin, Pavel A.; Chapron, Bertrand; Kudryavtsev, Vladimir N.. |
| Wind-generated waves in the Kara, Laptev, and East-Siberian Seas are investigated using altimeter data from Envisat RA-2 and SARAL-AltiKa. Only isolated ice-free zones had been selected for analysis. Wind seas can be treated as pure wind-generated waves without any contamination by ambient swell. Such zones were identified using ice concentration data from microwave radiometers. Altimeter data, both significant wave height (SWH) and wind speed, for these areas were further obtained for the period 2002-2012 using Envisat RA-2 measurements, and for 2013 using SARAL-AltiKa. Dependencies of dimensionless SWH and wavelength on dimensionless wave generation spatial scale are compared to known empirical dependencies for fetch-limited wind wave development. We... |
| Tipo: Text |
Palavras-chave: Altimetry; Remote sensing; Satellite altimeter; Significant wave height; Wind speed. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00302/41330/40642.pdf |
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| Caballero, Ainhoa; Ferrer, Luis; Rubio, Anna; Charria, Guillaume; Taylor, Benjamin H.; Grima, Nicolas. |
| The presence of a quasi-stationary anticyclonic eddy within the southeastern Bay of Biscay (centred around 44°30′N-4°W) has been reported on various occasions in the bibliography. The analysis made in this study for the period 2003–2010, by using in situ and remote sensing measurements and model results shows that this mesoscale coherent structure is present almost every year from the end of winter-beginning of spring, to the beginning of fall. During this period it remains in an area limited to the east by the Landes Plateau, to the west by Le Danois Bank and Torrelavega canyon and to the northwest by the Jovellanos seamount. All the observations and analysis made in this contribution, suggest that this structure is generated between Capbreton and... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Eddies; SWODDIES; Topographic effects; Vortex; Mesoscale; Altimetry; Satellite oceanography; Drifters; ROMS. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00161/27260/25469.pdf |
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| Qiu, Bo; Chen, Shuiming; Klein, Patrice; Sasaki, Hideharu; Sasai, Yoshikazu. |
| Located at the center of the western North Pacific Subtropical Gyre, the Subtropical Countercurrent (STCC) is not only abundant in mesoscale eddies, but also exhibits prominent submesoscale eddy features. Output from a 1/30 degrees high-resolution OGCM simulation and a gridded satellite altimetry product are analyzed to contrast the seasonal STCC variability in the mesoscale versus submesoscale ranges. Resolving the eddy scales of >150 km, the altimetry product reveals that the STCC eddy kinetic energy and rms vorticity have a seasonal maximum in May and April, respectively, a weak positive vorticity skewness without seasonal dependence, and an inverse (forward) kinetic energy cascade for wavelengths larger (shorter) than 250 km. In contrast, the... |
| Tipo: Text |
Palavras-chave: Circulation/ Dynamics; Eddies; Instability; Mesoscale processes; Observational techniques and algorithms; Altimetry; Models and modeling; Ocean models; Variability; Seasonal variability. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00245/35588/34142.pdf |
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| Artana, Camila; Ferrari, Ramiro; Koenig, Zoe; Sennechael, Nathalie; Saraceno, Martin; Piola, Alberto R.; Provost, Christine. |
| We combined altimetric data and the in situ data sets from three 10 years apart mooring deployments to compute a coherent and accurate volume transport time series of the Malvinas Current (MC) at 41 degrees S. We used a method developed in Koenig et al. (2014) and explored three types of geostrophic shear to estimate the uncertainty derived from the lack of velocity data in the upper 300 m. The mean MC transport over 24 years in the upper 1,500 m is 37.12.6 Sv and the standard deviation 6.61 Sv. Since 1993, annual mean transports have varied from 32 to 41 Sv and the three in situ records corresponded to low annual mean transports. The MC transport time series is not stationary, its spectral content evolves with time showing significant energy at the 30-110... |
| Tipo: Text |
Palavras-chave: Malvinas Current; Transport; Time series; Altimetry; Moorings; Argentine Basin. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00481/59315/62076.pdf |
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| Registros recuperados: 44 | |
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