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| Bentamy, Abderrahim; Mouche, Alexis; Grouazel, Antoine; Moujane, Abderrahim; Mohamed, Ait Ahmed. |
| Scatterometer surface wind speed and direction observations in combination with radiometer wind speeds allow to generate surface wind analyses with high space and time resolutions over global as well as at regional scales. Regarding scatterometer sampling schemes and physics, the resulting surface wind analyses suffer from lack of accuracy in areas near coasts. The use of the synthetic aperture radar (SAR) onboard the Sentinel-1A satellite attempts to address the enhancement of surface wind analyses issues. In this study, SAR wind speeds and directions retrieved from backscatter coefficients acquired in interferometric wide (IW) swath mode are used. Their accuracy is determined through comprehensive comparisons with moored buoy wind measurements. SAR and... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00464/57611/59848.pdf |
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| Bentamy, Abderrahim; Piolle, Jean-francois; Grouazel, Antoine; Danielson, R.; Gulev, S.; Paul, Frederic; Azelmat, Hamza; Mathieu, P. P.; Von Schuckmann, Karina; Sathyendranath, S.; Evers-king, H.; Esau, I.; Johannessen, J. A.; Clayson, C. A.; Pinker, R. T.; Grodsky, S. A.; Bourassa, M.; Smith, S. R.; Haines, K.; Valdivieso, M.; Merchant, C. J.; Chapron, Bertrand; Anderson, A.; Hollmann, R.; Josey, S. A.. |
| For over a decade, several research groups have been developing air-sea heat flux information over the global ocean, including latent (LHF) and sensible (SHF) heat fluxes over the global ocean. This paper aims to provide new insight into the quality and error characteristics of turbulent heat flux estimates at various spatial and temporal scales (from daily upwards). The study is performed within the European Space Agency (ESA) Ocean Heat Flux (OHF) project. One of the main objectives of the OHF project is to meet the recommendations and requirements expressed by various international programs such as the World Research Climate Program (WCRP) and Climate and Ocean Variability, Predictability, and Change (CLIVAR), recognizing the need for better... |
| Tipo: Text |
Palavras-chave: Ocean Heat Flux; Latent heat flux; Sensible heat flux; Ocean heat content; Scatterometer; Surface wind; Specfic air humidity; OceanSites; Remotely sensed data. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00403/51403/53729.pdf |
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| Cabanes, Cecile; Grouazel, Antoine; Von Schuckmann, Karina; Hamon, Michel; Turpin, Victor; Coatanoan, Christine; Paris, Francois; Guinehut, Stephanie; Boone, C.; Ferry, N.; De Boyer Montegut, Clement; Carval, Thierry; Reverdin, Gilles; Pouliquen, Sylvie; Le Traon, Pierre-yves. |
| The French program Coriolis, as part of the French operational oceanographic system, produces the COriolis dataset for Re-Analysis (CORA) on a yearly basis. This dataset contains in-situ temperature and salinity profiles from different data types. The latest release CORA3 covers the period 1990 to 2010. Several tests have been developed to ensure a homogeneous quality control of the dataset and to meet the requirements of the physical ocean reanalysis activities (assimilation and validation). Improved tests include some simple tests based on comparison with climatology and a model background check based on a global ocean reanalysis. Visual quality control is performed on all suspicious temperature and salinity profiles identified by the tests, and quality... |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00117/22799/20606.pdf |
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| Kitidis, Vassilis; Shutler, Jamie D.; Ashton, Ian; Warren, Mark; Brown, Ian; Findlay, Helen; Hartman, Sue E.; Sanders, Richard; Humphreys, Matthew; Kivimae, Caroline; Greenwood, Naomi; Hull, Tom; Pearce, David; Mcgrath, Triona; Stewart, Brian M.; Walsham, Pamela; Mcgovern, Evin; Bozec, Yann; Gac, Jean-philippe; Van Heuven, Steven M. A. C.; Hoppema, Mario; Schuster, Ute; Johannessen, Truls; Omar, Abdirahman; Lauvset, Siv K.; Skjelvan, Ingunn; Olsen, Are; Steinhoff, Tobias; Koertzinger, Arne; Becker, Meike; Lefevre, Nathalie; Diverres, Denis; Gkritzalis, Thanos; Cattrijsse, Andre; Petersen, Wilhelm; Voynova, Yoana G.; Chapron, Bertrand; Grouazel, Antoine; Land, Peter E.; Sharples, Jonathan; Nightingale, Philip D.. |
| Shelf seas play an important role in the global carbon cycle, absorbing atmospheric carbon dioxide (CO2) and exporting carbon (C) to the open ocean and sediments. The magnitude of these processes is poorly constrained, because observations are typically interpolated over multiple years. Here, we used 298500 observations of CO2 fugacity (fCO(2)) from a single year (2015), to estimate the net influx of atmospheric CO2 as 26.2 +/- 4.7 Tg C yr(-1) over the open NW European shelf. CO2 influx from the atmosphere was dominated by influx during winter as a consequence of high winds, despite a smaller, thermally-driven, air-sea fCO(2) gradient compared to the larger, biologically-driven summer gradient. In order to understand this climate regulation service, we... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00607/71869/70566.pdf |
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| Land, Peter E.; Findlay, Helen S.; Shutler, Jamie D.; Ashton, Ian; Holding, Thomas; Grouazel, Antoine; Ardhuin, Fanny; Reul, Nicolas; Piolle, Jean-francois; Chapron, Bertrand; Quilfen, Yves; Bellerby, Richard G.j.; Bhadury, Punyasloke; Salisbury, Joseph; Vandemark, Douglas; Sabia, Roberto. |
| Improving our ability to monitor ocean carbonate chemistry has become a priority as the ocean continues to absorb carbon dioxide from the atmosphere. This long-term uptake is reducing the ocean pH; a process commonly known as ocean acidification. The use of satellite Earth Observation has not yet been thoroughly explored as an option for routinely observing surface ocean carbonate chemistry, although its potential has been highlighted. We demonstrate the suitability of using empirical algorithms to calculate total alkalinity (AT) and total dissolved inorganic carbon (CT), assessing the relative performance of satellite, interpolated in situ, and climatology datasets in reproducing the wider spatial patterns of these two variables. Both AT and CT in situ... |
| Tipo: Text |
Palavras-chave: Carbonate chemistry; Earth observation; Ocean acidification; Total alkalinity; Dissolved inorganic carbon; SMOS; Aquarius; CORA; HadGEM2-ES. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00591/70267/68368.pdf |
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| Hauser, Daniele; Tourain, Cedric; Hermozo, Laura; Alraddawi, D.; Aouf, L.; Chapron, Bertrand; Dalphinet, A.; Delaye, L.; Dalila, M.; Dormy, E.; Gouillon, F.; Gressani, Victor; Grouazel, Antoine; Guitton, Gilles; Husson, R.; Mironov, Alexey; Mouche, Alexis; Ollivier, A.; Oruba, L.; Piras, E.; Suquet, R. Rodriguez; Schippers, P.; Tison, C.; Tran, Ngan. |
| This article describes the first results obtained from the Surface Waves Investigation and Monitoring (SWIM) instrument carried by the China France Oceanography Satellite (CFOSAT), which was launched on October 29, 2018. SWIM is a Ku-band radar with a near-nadir scanning beam geometry. It was designed to measure the spectral properties of surface ocean waves. First, the good behavior of the instrument is illustrated. It is then shown that the nadir products (significant wave height, normalized radar cross section, and wind speed) exhibit an accuracy similar to standard altimeter missions, thanks to a new retracking algorithm, which compensates a lower sampling rate compared to standard altimetry missions. The off-nadir beam observations are analyzed in... |
| Tipo: Text |
Palavras-chave: Spaceborne radar; Radar cross-sections; Surface waves; Sea surface; Instruments; Altimeter; Ocean wave spectra; Radar measurements; Scatterometer; Sea surface; Spaceborne radar; Speckle noise. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00677/78869/81168.pdf |
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| Bentamy, Abderrahim; Grodsky, Semyon A; Cambon, Gildas; Tandeo, Pierre; Capet, Xavier; Roy, Claude; Herbette, Steven; Grouazel, Antoine. |
| More than twelve satellite scatterometers have operated since 1992 through the present, providing the main source of surface wind vector observations over global oceans. In this study, these scatterometer winds are used in combination with radiometers and synthetic aperture radars (SAR) for the better determination and characterization of high spatial and temporal resolution of regional surface wind parameters, including wind speed and direction, wind stress components, wind stress curl, and divergence. In this paper, a 27-year-long (1992–2018) 6-h satellite wind analysis with a spatial resolution of 0.125° in latitude and longitude is calculated using spatial structure functions derived from high-resolution SAR data. The main objective is to improve... |
| Tipo: Text |
Palavras-chave: Satellite scatterometer; Surface wind; Upwelling systems; Long time series. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79416/81989.pdf |
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| Woolf, D.k.; Shutler, J.d.; Goddijn‐murphy, L.; Watson, A.j.; Chapron, Bertrand; Nightingale, P.d.; Donlon, C.j.; Piskozub, J.; Yelland, M.j.; Ashton, Ian; Holding, T.; Schuster, U.; Girard-ardhuin, Fanny; Grouazel, Antoine; Piolle, Jean-francois; Warren, M.; Wrobel‐niedzwiecka, I.; Land, P.e.; Torres, R.; Prytherch, J.; Moat, B.; Hanafin, J.; Ardhuin, Fabrice; Paul, Frederic. |
| The contemporary air‐sea flux of CO2 is investigated by the use of an air‐sea flux equation, with particular attention to the uncertainties in global values and their origin with respect to that equation. In particular, uncertainties deriving from the transfer velocity and from sparse upper ocean sampling are investigated. Eight formulations of air‐sea gas transfer velocity are used to evaluate the combined standard uncertainty resulting from several sources of error. Depending on expert opinion, a standard uncertainty in transfer velocity of either ~5% or ~10% can be argued and that will contribute a proportional error in air‐sea flux. The limited sampling of upper ocean fCO2 is readily apparent in the Surface Ocean CO2 Atlas (SOCAT) databases. The effect... |
| Tipo: Text |
Palavras-chave: Carbon dioxide; Air-sea flux; Uncertainty; Transfer velocity; Sampling. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00513/62450/66754.pdf |
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