Objectif Greenland temperature is one of the most important variables when considering future climate change, as it has the potential to impact a significant percentage of the population through an increase of the global sea level resulting from the melting of the Greenland ice sheet. Therefore, it is critical to understand the mechanism of Greenland temperature variability over multidecadal to centennial time scales with societal relevance. A new method has been developed to reconstruct Greenland temperature variability using argon and nitrogen isotopes in occluded air in ice cores coupled with a firn densification heat diffusion model. The method is based upon the fact that gasses in the firn (unconsolidated snow layer) fractionate based on the depth and temperature gradient of the layer. In the proposed research, we plan to reconstruct temperature change in northern Greenland over the past 6000 years using the NGRIP ice core. The period from the middle Holocene to the present is considered similar to the preindustrial climate, so it is an important period for which to understand the natural climate variability because the future climate under increasing greenhouse gasses is expected to evolve with the natural variability. The NGRIP ice core will be analysed for the argon and nitrogen isotopes of occluded air in ice cores, and the firn densification models used to calculate the surface temperature will be improved by testing them with other models and data from other cores. A new firn model that is fully consistent with argon and nitrogen isotopes, the Ar/N2 ratio in occluded air, and the oxygen isotopes of ice will then be developed, which may provide information on past accumulation rate change. Finally, the reconstructed Greenland temperature changes will be investigated with climate models to constrain the past influences of North Atlantic Oscillation and Atlantic meridional overturning circulation. Champ scientifique natural scienceschemical sciencesinorganic chemistrynoble gasesnatural sciencesearth and related environmental sciencesatmospheric sciencesclimatologyclimatic changesnorth atlantic oscillation Programme(s) FP7-PEOPLE - Specific programme "People" implementing the Seventh Framework Programme of the European Community for research, technological development and demonstration activities (2007 to 2013) Thème(s) FP7-PEOPLE-2013-IIF - Marie Curie Action: "International Incoming Fellowships" Appel à propositions FP7-PEOPLE-2013-IIF Voir d’autres projets de cet appel Régime de financement MC-IIF - International Incoming Fellowships (IIF) Coordinateur UNIVERSITAET BERN Contribution de l’UE € 277 296,80 Adresse HOCHSCHULSTRASSE 6 3012 Bern Suisse Voir sur la carte Région Schweiz/Suisse/Svizzera Espace Mittelland Bern / Berne Type d’activité Higher or Secondary Education Establishments Contact administratif Markus Leuenberger (Prof.) Liens Contacter l’organisation Opens in new window Site web Opens in new window Coût total Aucune donnée