Consulta: subjectFacets:"Satellite observations"
Registros recuperados: 10
Data/hora: 01/06/2024 18:31:31

Variabilité de la salinité de surface d'après un modèle global de couche mélangée océanique
Provedor de dados: 5
Autores: Michel, Sylvain.
Sea surface salinity (SSS) influences numerous oceanic phenomena, for instance surface water ventilation, deep water formation and thermohaline circulation. SSS also controls some ocean-atmosphere coupled processes, such as the intensity of freshwater flux and the penetration of heat flux and turbulence. Salinity is more difficult to measure than temperature from in situ surveys, which results in 20 times less data being currently available. Moreover, sea surface temperature (SST) is routinely estimated from satellites, which is not possible yet for SSS. Two space missions will fill this gap soon: SMOS from the European Space Agency and Aquarius/SAC-D from NASA and CONAE.  To contribute to the SMOS project, we propose a method for estimating SSS from...
Tipo: Text
Palavras-chave: SMOS; SSS; SST; MLD; Heat balance; Vertical entrainment; Geostrophic current; Air sea fluxes; Satellite observations; Mixed layer; Salinity; SMOS; SSS; SST; MLD; Bilan de chaleur; Entraînement vertical; Courants géostrophiques; Flux air mer; Observations satellitaires; Couche mélangée; Salinité.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/these-2302.pdf

Ocean Climate Observing Requirements in Support of Climate Research and Climate Information
Provedor de dados: 5
Autores: Stammer, Detlef; Bracco, Annalisa; Achutarao, Krishna; Beal, Lisa; Bindoff, Nathaniel L.; Braconnot, Pascale; Cai, Wenju; Chen, Dake; Collins, Matthew; Danabasoglu, Gokhan; Dewitte, Boris; Farneti, Riccardo; Fox-kemper, Baylor; Fyfe, John; Griffies, Stephen M.; Jayne, Steven R.; Lazar, Alban; Lengaigne, Matthieu; Lin, Xiaopei; Marsland, Simon; Minobe, Shoshiro; Monteiro, Pedro M. S.; Robinson, Walter; Roxy, Mathew Koll; Rykaczewski, Ryan R.; Speich, Sabrina; Smith, Inga J.; Solomon, Amy; Storto, Andrea; Takahashi, Ken; Toniazzo, Thomas; Vialard, Jerome.
Natural variability and change of the Earth's climate have significant global societal impacts. With its large heat and carbon capacity and relatively slow dynamics, the ocean plays an integral role in climate, and provides an important source of predictability at seasonal and longer timescales. In addition, the ocean provides the slowly evolving lower boundary to the atmosphere, driving, and modifying atmospheric weather. Understanding and monitoring ocean climate variability and change, to constrain and initialize models as well as identify model biases for improved climate hindcasting and prediction, requires a scale-sensitive, and long-term observing system. A climate observing system has requirements that significantly differ from, and sometimes are...
Tipo: Text
Palavras-chave: Ocean observing system; Ocean climate; Earth observations; In situ measurements; Satellite observations; Ocean modeling; Climate information.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00675/78724/80996.pdf

Influence of Tropical Instability Waves on Phytoplankton Biomass near the Marquesas Islands
Provedor de dados: 5
Autores: Martinez, Elodie; Raapoto, Hirohiti; Maes, Christophe; Maamaatuaihutapu, Keitapu.
The Marquesas form an isolated group of small islands in the Central South Pacific where quasi-permanent biological activity is observed. During La Niña events, this biological activity, shown by a net increase of chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass), is particularly strong. It has been hypothesized that this strong activity is due to iron-rich waters advected from the equatorial region to the Marquesas by tropical instability waves (TIWs). Here we investigate this hypothesis over 18 years by combining satellite observations, re-analyses of ocean data, and Lagrangian diagnostics. Four La Niña events ranging from moderate to strong intensity occurred during this period, and our results show that the Chl plume within the...
Tipo: Text
Palavras-chave: Tropical instability waves; La Nina; Chlorophyll-a concentration variability; Ocean colour; Island mass effect; Marquesas islands; Oceanography; Satellite observations.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00437/54858/56346.pdf

Partitioning ocean motions into balanced motions and internal gravity waves: A modeling study in anticipation of future space missions
Provedor de dados: 5
Autores: Torres, Hector S.; Klein, Patrice; Menemenlis, Dimitris; Qiu, Bo; Su, Zhan; Wang, Jinbo; Chen, Shuiming; Fu, Lee-lueng.
Internal gravity waves (IGWs) and balanced motions (BMs) with scales &lt; 100‐km capture most of the vertical velocity field in the upper ocean. They have, however, different impacts on the ocean energy budget, which explains the need to partition motions into BMs and IGWs. One way is to exploit the synergy of using different satellite observations, the only observations with global coverage and a reasonable spatial and temporal resolution. But we need first to characterize and understand their signatures on the different surface oceanic fields. This study addresses this issue by using an ocean global numerical simulation with high‐resolution (1/48o). Our methodology is based on the analysis of the 12,000 frequency‐wavenumber spectra to discriminate these...
Tipo: Text
Palavras-chave: Oceanic surface motions; Satellite observations; Balanced motions; Internal gravity waves.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00464/57568/59746.pdf

Quantifying Tidal Fluctuations in Remote Sensing Infrared SST Observations
Provedor de dados: 5
Autores: González-haro, Cristina; Ponte, Aurelien; Autret, Emmanuelle.
The expected amplitude of fixed-point sea surface temperature (SST) fluctuations induced by barotropic and baroclinic tidal flows is estimated from tidal current atlases and SST observations. The fluctuations considered are the result of the advection of pre-existing SST fronts by tidal currents. They are thus confined to front locations and exhibit fine-scale spatial structures. The amplitude of these tidally induced SST fluctuations is proportional to the scalar product of SST frontal gradients and tidal currents. Regional and global estimations of these expected amplitudes are presented. We predict barotropic tidal motions produce SST fluctuations that may reach amplitudes of 0.3 K. Baroclinic (internal) tides produce SST fluctuations that may reach...
Tipo: Text
Palavras-chave: Sea surface temperature; Satellite observations; Tidal currents; Internal tides.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00589/70075/68048.pdf

SST subseasonal variability in the central Benguela upwelling system as inferred from satellite observations (1999-2009)
Provedor de dados: 5
Autores: Goubanova, Katerina; Illig, Serena; Machu, Eric; Garcon, Veronique; Dewitte, Boris.
Subseasonal variability of Sea Surface Temperature (SST) in the central Benguela upwelling system is investigated using TMI satellite-derived data over the period 1999-2009. Spatial patterns and time-frequency characteristics of subseasonal variability are documented based on Empirical Orthogonal Functions (EOF) decomposition and wavelet analysis. Despite the land contamination of the TMI satellite data within approximately 100 km off the coast the first EOF of SST anomalies allows characterizing the coastal upwelling variability at the subseasonal scale. Two regimes of variability are evidenced: a submonthly (2-30 days) regime with a dominant 11 days oscillation and a lower frequency intraseasonal (30-90 days) regime with a dominant 61 days oscillation....
Tipo: Text
Palavras-chave: Benguela upwelling; Satellite observations; Intraseasonal variability; Wind-SST relationship; Mean vertical stratification; Antarctic oscillation.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00164/27565/25928.pdf

Whitecap and Wind Stress Observations by Microwave Radiometers: Global Coverage and Extreme Conditions
Provedor de dados: 5
Autores: Hwang, Paul A.; Reul, Nicolas; Meissner, Thomas; Yueh, Simon H.
Whitecaps manifest surface wave breaking that impacts many ocean processes, of which surface wind stress is the driving force. For close to a half century of quantitative whitecap reporting, only a small number of observations are obtained under conditions with wind speed exceeding 25 m/s. Whitecap contribution is a critical component of ocean surface microwave thermal emission. In the forward solution of microwave thermal emission, the input forcing parameter is wind speed, which is used to generate the modeled surface wind stress, surface wave spectrum, and whitecap coverage necessary for the subsequent electromagnetic (EM) computation. In this respect, microwave radiometer data can be used to evaluate various formulations of the drag coefficient,...
Tipo: Text
Palavras-chave: Wave breaking; Wind stress; Wind waves; Severe storms; Microwave observations; Satellite observations.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00506/61757/65730.pdf

Exploring the Benefits of Using CryoSat-2's Cross-Track Interferometry to Improve the Resolution of Multisatellite Mesoscale Fields
Provedor de dados: 5
Autores: 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

Observed atlantification of the Barents Sea causes the Polar Front to limit the expansion of winter sea ice
Provedor de dados: 5
Autores: Barton, Benjamin I.; Lenn, Yueng-djern; Lique, Camille.
Barents Sea Water (BSW) is formed from Atlantic Water that is cooled through atmospheric heat loss and freshened through seasonal sea ice melt. In the eastern Barents Sea, the BSW and fresher, colder Arctic Water meet at the surface along the Polar Front (PF). Despite its importance in setting the northern limit of BSW ventilation, the PF has been poorly-documented, mostly eluding detection by observational surveys that avoid seasonal sea ice. In this study, satellite sea surface temperature (SST) observations are used in addition to a temperature and salinity climatology to examine the location and structure of the PF, and characterise its variability over the period 1985 – 2016. It is shown that the PF is independent of the position of the sea ice edge...
Tipo: Text
Palavras-chave: Arctic; Sea ice; Fronts; Sea surface temperature; Satellite observations.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00448/56003/57509.pdf

Studies of Sub-Mesoscale Variability of the Ocean Upper Layer Based on Satellite Observations Data
Provedor de dados: 5
Autores: Chapron, Bertrand; Kudryavtsev, V. N.; Collard, Fabrice; Rascle, Nicolas; Kubryakov, A. A.; Stanichny, S. V.
Purpose. The approach represented in the article is applied to analysis of satellite scanner optical images of high spatial resolution for identifying and quantitative determining the characteristics of the sub-mesoscale dynamic processes in the ocean upper layer. Methods and Results. The Envisat AATSR and MERIS SAR-images are used as the satellite data, which permit to determine the ocean surface temperature and surface brightness in the visible range, respectively. Variations in the sea surface glitter contrasts are associated with modulations of the sea surface roughness (rms slope of short waves) on the currents. It is shown that the surface roughness contrasts correlate with the spatial inhomogeneities of the ocean surface temperature, tracing...
Tipo: Text
Palavras-chave: Satellite observations; Air-sea interaction; Ocean upper layer dynamics; Temporal and spatial variability.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00682/79420/82002.pdf