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Las series temporales de los satélites altimétricos son, con las de los mareógrafos, una de las dos fuentes principales de información sobre la evolución del nivel del mar. Sus principales ventajas sobre las series de los mareógrafos estriban en que permiten acceder a información espacialmente continua, en registrar cambios absolutos, y en una contrastada precisión. Algunos problemas anteriormente existentes en áreas costeras, como el problema del píxel mixto o aparentes errores en la calibración, han sido superados, o filtrados por la principal fuente de información de este tipo de registros, el Sea Level Research Group de la Universidad de Colorado. Sin embargo, el problema de la escasa duración de las series temporales (empezaron a funcionar en julio de 1992) no ha sido aún resuelto. En este trabajo se propone una metodología que permite alargar la serie hacia el pasado basándose en un análisis de correlación múltiple con datos procedentes de los registros de los mareógrafos, existentes desde décadas antes del lanzamiento de los satélites. Los resultados obtenidos indican que con cierto margen de error es posible interpretar la evolución del nivel del mar en cada celdilla de los satélites altimétricos desde los años 40 en el caso del litoral mediterráneo peninsular. The time series of the altimetric satellites are of the two main sources of information on the evolution of the level of the sea. Its main advantages over the series of tide gauges are that they allow access to information spatially continuous, recording absolute changes. Some problems previously encountered in coastal areas, such as the mixed pixel problem or apparent calibration errors, have been overcome or filtered by the University of Colorado's Sea Level Research Group's main source of information. However, the problem of the short duration of the time series (which began to operate in July 1992) has not yet been solved. This paper proposes a methodology that allows extending the series to the past based on a multiple correlation analysis with data from the records of the gauges, which had existed for decades before the launch of the satellites. The obtained results indicate that it is possible to interpret the evolution of sea level in each cell of the altimetric satellites since the 1940s in the case of the peninsular Mediterranean littoral.

© 2015 Elsevier Ltd. This work studies the wave energy availability in the Western Mediterranean Sea using wave simulation from January 1983 to December 2011. The model implemented is the WAM, forced by the ECMWF ERAInterim wind fields. The Advanced Scatterometer (ASCAT) data from MetOp satellite and the TOPEX-Poseidon altimetry data are used to assess the quality of the wind fields and WAM results respectively. Results from the hindcast are the starting point to analyse the potentiality of obtaining wave energy around the Balearic Islands Archipelago. The comparison of the 29 year hindcast against wave buoys located in Western, Central and Eastern basins shows a high correlation between the hindcasted and the measured significant wave height (Hs), indicating a proper representation of spatial and temporal variability of Hs. It is found that the energy flux at the Balearic coasts range from 9.1 kW/m, in the north of Menorca Island, to 2.5 kW/m in the vicinity of the Bay of Palma. The energy flux is around 5 and 6 times lower in summer as compared to winter, GS is supported from the Spanish Government through the Ramon y Cajal program

Significant wave height (Hs) is a measure of the variability of the ocean surface. Benefits from knowing the spatial and temporal characteristics of this field are multiple: It is useful to size offshore structures, to foresee the fatigue of the ship's hull depending on its route and season, to compute probabilities of risks associated with marine operations. In this paper, we describe a method for modeling the Hs in space. The method is based on the Gaussian hypothesis for the logarithms of Hs and consists of estimating the mean and the covariance structure of log(Hs) using the information provided by the total variation. We then use the estimated parameters of every area in the world to construct maps of the median and the correlation structure. These maps are used to compute the probability of Hs exceeding a predefined level, and the distribution of the length of a storm. The data used are those of the TOPEX-Poseidon satellite. Copyright © by The International Society of Offshore and Polar Engineers. 18 1 1 7 Cited By :7

The work carried out during this thesis consisted in examining a broad range of processes related to the continental branch of the water cycle using the land surface model ORCHIDEE (ORganising Carbon and Hydrology In Dynamic EcosystEms), and in situ and satellite observations. By using data from the altimetry mission Topex/Poséidon and the gravimetric mission GRACE (Gravity Recovery And Climate Experiment), I showed that the ORCHIDEE model was able to reproduce the seasonal and interannual variations of water reservoirs on the continents. I provided, for the first time, a validation at global scale of water assessment estimated in this model. The important role of the tropical areas in the variability of the climate was also underlined. During the thesis, to study low frequency variations (decadal/multi-decadal), I built a new, long-period atmospheric forcing data set, called NCC (National Centers for Environmental Prediction/National Center for Atmospheric Research Corrected by Climate Research Unit), for land surface models. NCC extends from 1948 to 2000 with a spatial resolution of 1°x1° and a 6-hourly temporal resolution. The NCC data set was validated by discharges of the world's largest rivers and proved to be very useful in the study of the evolution of continental water storage during the past 50 years. One of the applications of NCC was to study the contribution of continental water to sea level variations. I showed that an increase in ocean temperature led to more water stored on the continents, leading to a negative feedback on sea level changes., Le travail effectué au cours de cette thèse a consisté à examiner une large gamme de processus liés à la branche continentale du cycle de l'eau à l'aide du modèle de surface ORCHIDEE (ORganising Carbon and Hydrology In Dynamic EcosystEms), des observations in situ et satellites. En utilisant les données de l'altimétrie spatiale Topex/Poséidon et de la mission gravimétrique GRACE (Gravity Recovery And Climate Experiment), j'ai montré que le modèle ORCHIDEE était capable de reproduire les variations saisonnières et interannuelles des réservoirs d'eau sur les continents. J'ai fourni, pour la première fois, une validation à l'échelle globale du bilan d'eau estimé dans ce modèle. Le rôle important des régions tropicales dans la variabilité du climat a aussi été souligné. Au cours de la thèse, dans le but d'étudier les variations lentes (décennales/multi-décennales), j'ai construit une base de données de forçage atmosphérique de longue période, appelé NCC (National Centers for Environmental Prediction/National Center for Atmospheric Research Corrected by Climate Research Unit), pour les modèles de surface. NCC s'étend de 1948 à 2000 avec une résolution spatiale de 1°x1° et une résolution temporelle de 6 heures. Cette base de données a été validée par les débits des plus grands fleuves du monde et s'est montrée un élément important pour la compréhension de l'évolution des processus continentaux au cours des 50 dernières années. Une des applications de NCC était l'étude de la contribution de l'eau continentale au changement du niveau de la mer. J'ai montré qu'une augmentation de température de l'océan menait à plus d'eau stockée sur les continents, menant à une rétroaction négative sur le niveau de la mer.