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| Ninove, Floriane; Le Traon, Pierre-yves; Remy, E.; Guinehut, S.. |
| Argo observations from 2005 to 2013 are used to characterize spatial scales of temperature and salinity variations from the surface down to 1300 m. Simulations are first performed to analyze the sensitivity of results to Argo sampling; they show that several years of Argo observations are required to estimate spatial scales of ocean variability over 20 degrees x 20 degrees boxes. Spatial scales are then computed over several large-scale areas. Zonal and meridional spatial scales (L-x and L-y which are zero crossing of covariance functions) vary as expected with latitudes. Scales are of about 100 km at high latitudes and more of 700 km in the Indian and Pacific equatorial-tropical regions. Zonal and meridional scales are similar except in... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00317/42845/42257.pdf |
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| Ablain, M.; Cazenave, A.; Valladeau, G.; Guinehut, S.. |
| A new error budget assessment of the global Mean Sea Level (MSL) determined by TOPEX/Poseidon and Jason-1 altimeter satellites between January 1993 and June 2008 is presented using last altimeter standards. We discuss all potential errors affecting the calculation of the global MSL rate. We also compare altimetry-based sea level with tide gauge measurements over the altimetric period. Applying a statistical approach, this allows us to provide a realistic error budget of the MSL rise measured by satellite altimetry. These new calculations highlight a reduction in the rate of sea level rise since 2005, by similar to 2 mm/yr. This represents a 60% reduction compared to the 3.3 mm/yr sea level rise (glacial isostatic adjustment correction applied) measured... |
| Tipo: Text |
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| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32920/31405.pdf |
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| Balmaseda, M. A.; Hernandez, F.; Storto, A.; Palmer, M. D.; Alves, O.; Shi, L.; Smith, G. C.; Toyoda, T.; Valdivieso, M.; Barnier, B.; Behringer, D.; Boyer, T.; Chang, Y-s.; Chepurin, G. A.; Ferry, N.; Forget, Gael; Fujii, Y.; Good, S.; Guinehut, S.; Haines, K.; Ishikawa, Y.; Keeley, S.; Koehls, A.; Lee, T.; Martin, M. J.; Masina, S.; Masuda, S.; Meyssignac, B.; Mogensen, K.; Parent, L.; Peterson, K. A.; Tang, Y. M.; Yin, Y.; Vernieres, G.; Wang, X.; Waters, J.; Wedd, R.; Wang, O.; Xue, Y.; Chevallier, M.; Lemieux, J-f.; Dupont, F.; Kuragano, T.; Kamachi, M.; Awaji, T.; Caltabiano, A.; Wilmer-becker, K.; Gaillard, Fabienne. |
| Uncertainty in ocean analysis methods and deficiencies in the observing system are major obstacles for the reliable reconstruction of the past ocean climate. The variety of existing ocean reanalyses is exploited in a multi-reanalysis ensemble to improve the ocean state estimation and to gauge uncertainty levels. The ensemble-based analysis of signal-to-noise ratio allows the identification of ocean characteristics for which the estimation is robust (such as tropical mixed-layer-depth, upper ocean heat content), and where large uncertainty exists (deep ocean, Southern Ocean, sea ice thickness, salinity), providing guidance for future enhancement of the observing and data assimilation systems. |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00280/39090/37655.pdf |
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| Dhomps, A. -l.; Guinehut, S.; Le Traon, Pierre-yves; Larnicol, Gilles. |
| Differences, similarities and complementarities between Sea Level Anomalies (SLA) deduced from altimeter measurements and dynamic height anomalies (DHA) calculated from Argo in situ temperature (T) and salinity (S) profiles are globally analyzed. SLA and DHA agree remarkably well and, compared to previous studies, Argo dataset allows an improvement in the coherence between SLA and DHA. Indeed, Argo data provides a much better spatial coverage of all oceans and particularly the Southern Ocean, the use of an Argo mean dynamic height, the use of measured salinity profiles (versus climatological salinity), and the use of a deeper reference level (1000 m versus 700 m). The large influence of Argo salinity observations on the consistency between altimetry and... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00035/14630/11930.pdf |
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