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Étude des propriétés physiques des vagues océaniques à partir d'observations par radar aéroporté à ouverture réelle

Abstract : Understanding and forecasting waves is very important for economic and societal issues because they have an impact on the navigation, oil industry and littoral activities. Moreover, waves are the principal actor in air sea exchange processes which have an important impact on climate. Wave observations with in situ measurements and remote sensing observations allow to improve the representation of wave physical processes in the models. However, improvement of instrumental concept and the improvement of the wave representation in the models still need to pursue the work in the understand of the radar measurement over oceans. The SWIM radar, onboard the CFOSAT mission, is a new concept dedicated to the measurement of wave spectra at the global scale. This system provides detailed information about waves (height, frequency, direction, spread…). In order to prepare the CFOSAT mission, the CNRS-LATMOS developed an airborne radar with the help of the French space agency (CNES). This radar named KuROS uses measurement geometry and principle similar to the ones of SWIM. The objective of the thesis is twofold: firstly, to characterize and understand the performances and the limits of the KuROS airborne radar and secondly, to identify the complementary information provided by the spectral measurements of waves at the regional scale in the study of wave physics and modelling. The first part of the thesis is about the comparison of the wave parameters measured by KuROS during two field campaigns with data from wave models. We show that conditions with wavelengths lower than 200 m and significant wave heights lower than 4 m are the most appropriated situations for the wave spectrum measurements with KuROS. A simulator has been developed in order to evaluate the measurement performances with respect to the sea surface state and the observation geometry. The results of the simulations, compared to the observations, allow us to confirm in which conditions wave spectral parameters are obtained with a good accuracy with KuROS and to specify the factors which impact the most the measurement accuracy in some sea state conditions.
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  • HAL Id : tel-02537212, version 1

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Eva Le Merle. Étude des propriétés physiques des vagues océaniques à partir d'observations par radar aéroporté à ouverture réelle. Physique Atmosphérique et Océanique [physics.ao-ph]. Université Paris-Saclay, 2019. Français. ⟨NNT : 2019SACLV084⟩. ⟨tel-02537212⟩

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