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Laurent Dezileau

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Présentation

**Spécialités** : Géochimie, radiochimie, géochronologie, sédimentologie, géomorphologie. **Thématiques** : Paléoclimatologie, paléohydrologie, paléotempestologie, paléoenvironnement, paléocéanographie. **Chantiers** : Maroc, Tunisie, Algérie, Taiwan, Chili, Espagne, France, Océan Austral, Océan Pacifique **Compétences analytiques et techniques** : Nomination Personne Compétente en Radioprotection (PCR) option sources scellées, appareils électriques émettant des rayons X et accélérateurs de particules ; Radiochimie (U,Th, Po). **Instruments et laboratoires** : Spectrométrie nucléaire, FluoX portable, granulométrie laser, laboratoire de radiochimie, laboratoire de sédimentologie/géochimie/granulométrie **Recherche actuelle: Paleotempestology, Paleohydrology (Paleomex)** In the context of future climate change, there is an increasing concern that extreme climatic events may be changing in frequency and intensity. Storms and floods have been for long a threat for the western Mediterranean coast even if their link with climate variability is still misunderstood. This is in partly due to the fact that extreme events are inherently rare and difficult to observe in the period of a human life and to the lack of long-term observations or paleo-reconstructions. Understanding causes of their occurrence both in past and present climate, i.e. under different forcings, is an crucial issue for future predictions considering the growing number of people living in the coastal Mediterranean in high-risk areas and therefore enhanced exposure. Natural systems are highly sensitive to intense climate episodes but impact assessment strongly depends on the resiliency and capability for adaptation and mitigation of each system. In order to place such events in the broader context of climate change, it is essential to document their occurrence, both in space and time, over period of several centuries or millennium. One of the PALEOMEX projects intend to combine paleo-data and model simulations to (i) document the occurrence of extreme events (floods and storms) that have impacted the western Mediterranean coastal region during the last millennium, high resolution bio- and geo-proxies will be compared with historical sources in order to illustrate, quantify, date and test the reliability and frequency of past disastrous events, (ii) investigate the relationship between these events and climate variability and trends (iii) cross-compare reconstructed climatic series to simulations realized on the coupled climatic models (ARPEGE-NEMO, IPSL) in order to answer the fundamental scientific questions : Are the mechanisms triggering those extreme events governed by internal feedbacks of the climate system ? Which ones ?, What will be the climate variability in the Mediterranean basin ?, What kind of change the region will be the most vulnerable to (trend and / or extreme events) ?, and to develop future scenarios simulations to tentatively assess the extreme floods and storms probabilities in the future. We will focus on the western Mediterranean coastal region (i.e. Morocco, Algeria, Tunisia, Spain and France) that are particularly sensitive to erosion/submersion during storm events and have societal issues in terms of flood risks.

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