Sabiia Seb
PortuguêsEspañolEnglish
Embrapa
        Busca avançada

Botão Atualizar


Botão Atualizar

Ordenar por: RelevânciaAutorTítuloAnoImprime registros no formato resumido
Registros recuperados: 8
Primeira ... 1 ... Última
Imagem não selecionada

Imprime registro no formato completo
A unified directional spectrum for long and short wind-driven waves ArchiMer
Elfouhaily, Tanos; Chapron, Bertrand; Katsaros, Kristina; Vandemark, D.
Review of several recent ocean surface wave models finds that while comprehensive in many regards, these spectral models do not satisfy certain additional, but fundamental, criteria. We propose that these criteria include the ability to properly describe diverse fetch conditions and to provide agreement with in situ observations of Cox and Munk [1954] and Jahne and Riemer [1990] and Hara et al. [1994] data in the high-wavenumber regime. Moreover, we find numerous analytically undesirable aspects such as discontinuities across wavenumber limits, nonphysical tuning or adjustment parameters, and noncentrosymmetric directional spreading functions. This paper describes a two-dimensional wavenumber spectrum valid over all wavenumbers and analytically amenable to...
Tipo: Text
Ano: 1997 URL: http://archimer.ifremer.fr/doc/00091/20226/17877.pdf
Imagem não selecionada

Imprime registro no formato completo
Differences between two estimates of air-sea turbulent heat fluxes over the Atlantic Ocean ArchiMer
Santorelli, A.; Pinker, R. T.; Bentamy, Abderrahim; Katsaros, Kristina; Drennan, W. M.; Mestas-nunez, A. M.; Carton, J. A..
Uncertainties in turbulent ocean-atmosphere heat flux estimates, both among the estimates and between them and ground truth, suggest that further comparisons are needed. We analyze estimates from the French Research Institute for Exploitation of the Sea (IFREMER) and the Woods Hole Oceanographic Institution's Objectively Analyzed air-sea Fluxes (WHOI OAFlux). The IFREMER products are based on satellite observations and the WHOI OAFlux ones on data from satellites, buoys, and ships assimilated into numerical analyses. We focus on the Atlantic sector (70 degrees W-30 degrees E, 45 degrees S-45 degrees N) during 1996-2005, where the variables that enter the bulk formulae for computing fluxes (wind speed, sea surface and air temperature, and specific humidity)...
Tipo: Text
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00048/15915/13344.pdf
Imagem não selecionada

Imprime registro no formato completo
Estimates of net heat fluxes over the Atlantic Ocean ArchiMer
Pinker, R. T.; Bentamy, Abderrahim; Katsaros, Kristina; Ma, Y.; Li, C..
Many studies have been undertaken to evaluate turbulent heat fluxes at the ocean-atmosphere interface; less was done on the total net heat flux. We will compare heat budgets at the ocean-atmosphere interface as derived from satellites and from blended products, compare them to in situ observations, identify the location of largest differences, and attempt to explain reasons for these differences. The results over the Atlantic Sector (50 degrees S-50 degrees N) for a 3 year period show that differences in the turbulent fluxes among two widely used approaches are overshadowed by differences in the radiative fluxes. While the maximum difference in sensible and latent heat fluxes can be about 30 W/m(2), the mean values for latent heat fluxes are -2.27 W/m(2)...
Tipo: Text Palavras-chave: Oceanic heat fluxes; Oceanic net heat fluxes; Ocean-atmosphere interface.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00186/29713/28119.pdf
Imagem não selecionada

Imprime registro no formato completo
Global oceanic precipitation: A joint view by TOPEX and the TOPEX microwave radiometer ArchiMer
Chen, Ge; Chapron, Bertrand; Tournadre, Jean; Katsaros, Kristina; Vandemark, Douglas.
The TOPEX/POSEIDON mission offers the first opportunity to observe rain cells over the ocean by a dual-frequency radar altimeter (TOPEX) and simultaneously observe their natural radiative properties by a three-frequency radiometer (TOPEX microwave radiometer (TMR)). This work is a feasibility study aimed at understanding the capability and potential of the active/passive TOPEX/TMR system for oceanic rainfall detection. On the basis of past experiences in rain flagging, a joint TOPEX/TMR rain probability index is proposed. This index integrates several advantages of the two sensors and provides a more reliable rain estimate than the radiometer alone. One year's TOPEX/TMR TMR data are used to test the performance of the index. The resulting rain frequency...
Tipo: Text
Ano: 1997 URL: http://archimer.ifremer.fr/doc/00336/44719/44883.pdf
Imagem não selecionada

Imprime registro no formato completo
Improvement in airsea flux estimates derived from satellite observations ArchiMer
Bentamy, Abderrahim; Grodsky, Semyon A.; Katsaros, Kristina; Mestas-nunez, Alberto M.; Blanke, Bruno; Desbiolles, Fabien.
A new method is developed to estimate daily turbulent airsea fluxes over the global ocean on a 0.25 degrees grid. The required surface wind speed (w(10)) and specific air humidity (q(10)) at 10m height are both estimated from remotely sensed measurements. w(10) is obtained from the SeaWinds scatterometer on board the QuikSCAT satellite. A new empirical model relating brightness temperatures (T-b) from the Special Sensor Microwave Imager (SSM/I) and q(10) is developed. It is an extension of the author's previous q(10) model. In addition to T-b, the empirical model includes sea surface temperature (SST) and airsea temperature difference data. The calibration of the new empirical q(10) model utilizes q(10) from the latest version of the National Oceanography...
Tipo: Text
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00137/24825/23575.pdf
Imagem não selecionada

Imprime registro no formato completo
Inertial dissipation method applied to derive turbulent fluxed over the ocean during the Surface of the Ocean, Fluxes and Interactions with the Atmosphere Atlantic Stratocumulus Transition Experiment (SOFIA/ASTEX) and Structure des Echanges Mer-Atmosphere, Proprietes des Heterogeneites Oceaniques: Recherche Experimentale (SEMAPHORE) experiments with low to moderate wind speed ArchiMer
Dupuis, Hélène; Taylor, Peter K; Weill, Alain; Katsaros, Kristina.
The transfer coefficients for momentum and heat have been determined for 10 m neutral wind speeds (U-10n) between 0 and 12 m/s using data from the Surface of the Ocean, Fluxes and Interactions with the Atmosphere (SOFIA) and Structure des Echanges Mer-Atmosphere, Proprietes des Heterogeneites Oceaniques: Recherche Experimentale (SEMAPHORE) experiments. The inertial dissipation method was applied to wind and pseudo virtual temperature spectra from a sonic anemometer, mounted on a platform (ship) which was moving through the turbulence held. Under unstable conditions the assumptions concerning the turbulent kinetic energy (TKE) budget appeared incorrect. Using a bulk estimate for the stability parameter, Z/L (where Z is the height and L is the Obukhov...
Tipo: Text
Ano: 1997 URL: http://archimer.ifremer.fr/doc/00336/44669/45113.pdf
Imagem não selecionada

Imprime registro no formato completo
Observation of tropical cyclones by high-resolution scatterometry ArchiMer
Quilfen, Yves; Chapron, Bertrand; Elfouhaily, Tanos; Katsaros, Kristina; Tournadre, Jean.
Unprecedented views of surface wind fields in tropical cyclones thereafter TCs) are provided by the European Remote Sensing Satellite (ERS) C band scatterometer. Scatterometer measurements at C band are able to penetrate convective storms clouds, observing the surface wind fields with good accuracy. However the resolution of the measurements (50x50 km(2)) limits the interpretation of the scatterometer signals in such mesoscale events. The strong gradients of the surface wind existing at scales of a few kms are smoothed in the measured features such as the intensity and location of the wind maxima, and the position of the center. Beyond the ERS systems, the scatterometers on-board the ADEOS and METOP satellites, designed by the Jet Propulsion Laboratory and...
Tipo: Text
Ano: 1998 URL: http://archimer.ifremer.fr/doc/00251/36257/34805.pdf
Imagem não selecionada

Imprime registro no formato completo
Satellite Air - Sea fluxes ArchiMer
Bentamy, Abderrahim; Katsaros, Kristina; Queffeulou, Pierre.
This chapter addresses the estimation of global surface winds, surface wind stress, latent heat flux, and sensible heat flux over the oceans with high spatial and temporal resolution using satellite radar and radiometer measurements. An overview of the physics of remotely sensed data, of methods and algorithms used to retrieve surface fluxes is provided. The retrievals are used to estimate regular in space and time surface parameters, requested for oceanic forcing function, over global ocean. The characteristics of the former are investigated at global and regional scales.
Tipo: Text
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00030/14101/11333.pdf
Registros recuperados: 8
Primeira ... 1 ... Última
 

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Embrapa
Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC: https://www.embrapa.br/fale-conosco

Valid HTML 4.01 Transitional