Mots-clé
(Anglais)
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climate change; marine carbon cycle; CO2
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Programme de recherche
(Anglais)
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COST-Action 735 - Tools for Assessing Global Air Sea Fluxes of Climate and Air Pollution Relevant Gases
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Description succincte
(Anglais)
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A prerequisite to project future atmospheric CO2 and global warming is to understand the role of the ocean This project aims to improve our quantitative understanding of the marine carbon cycle and to thoroughly assess uncertainties in projections of the uptake of anthropogenic CO2 by the ocean. First, we will quantify current, regional air-sea fluxes of carbon and related processes from observations using an Ensemble Kalman Filter approach in the cost-efficient Bern3D ocean model. Preparation of observational data sets and comparison of results will be coordinated with the sister project submitted by N. Gruber, ETH Zürich. Second, we will perform Monte Carlo simulations with the Bern3D climate-carbon cycle model to project anthropogenic carbon uptake and atmospheric CO2 under global warming. Model parameters will be systematically varied according to assigned prior uncertainties. Results will be used to estimate probability distributions for projected air-sea fluxes and atmospheric CO2.
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Partenaires et organisations internationales
(Anglais)
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BE, CH, CY, DE, DK, ES, FI, FR, GR, HU, IE, IT, NL, NO, PL, SE, TR, UK
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Résumé des résultats (Abstract)
(Anglais)
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This project aimed to improve our quantitative understanding of the marine carbon cycle and to thoroughly assess uncertainties in projections of the uptake of anthropogenic CO2 by the ocean. We quantified current natural and anthropogenic regional air-sea fluxes and meridional transport of carbon using an Ensemble Kalman Filter data assimilation approach in the Bern3D climate-carbon cycle model and published two manuscript describing results (Gerber et al., GBC, 2009, Gerber and Joos, GBC, 2010). We also assimilated fields of temperature, salinity, radiocarbon, and clorofluorocarbons in a sequential way into the Bern3D model to determine uncertain model paramteres for improved carbon cycle-climate projections. Results of this work are described in Gerber and Joos (submitted to GBC, 2011). Further, we contributed to a study addressing regional impacts of climate change and atmospheric CO2 on future ocean carbon uptake by applying a linear feedback analysis to the output of a multi-model ensemble (Roy et al., J.Clim., 2011). In preparation of probabilistic projections of air-sea carbon fluxes and carbon-climate feedbacks, a Dynamic Global Vegetation Model was coupled to the Bern3D ocean model and multi-gas scenario input was prepared to run the Representative Concentration Pathways in the Bern3D model. A first set of probabilistic runs including 1000 members were performed to test the general setup and procedure and first probability density functions were computed. Results were presented at national and international meetings and we held a workshop on the Ensemble Kalman Data Assimilation technique during the 8th International NCCR Climate Summer School in Grindelwald.
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Références bases de données
(Anglais)
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Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. +41 31 322 74 82 Swiss Project-Number: C07.0068
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