Untitled - The Future Ocean

hydrological cycle. Therefore, improved constraints on future changes in the hydrological cycle aswell as progress in modeling the various aspects of ocean-atmosphere-continent interactionsinvolved are essential for more accurate climate change predictions (Allen & Ingram 2002, Stocker& Raible 2005). Past linkages between ocean circulation changes, ocean-atmosphere waterexchange, and shifts in the hydrological regimes over the continents are qualitatively wellunderstood (e.g. Wang et al. 2005), but not much is known about the magnitudes of change. Theperformance of coupled ocean-atmosphere-continent models for simulating realistic water vapor,precipitation and evaporation balances has been explored to an even lesser extent (e.g. Clausenet al. 2003, Lorenz et al. 2006, cf. Figure).3. Previous and on-going work of the proponentsThe proponents combine profound levels of expertise in coupled ocean-atmosphere modeling (e.g.Latif et al. 2006) with experience in past climate reconstruction and potential forcing mechanismsas well as with applications of microfossil-based, geochemical, and isotopic paleoenvironmentalparameters (e.g. Schefuß et al. 2006). Currently, the ESF DECLAKES project provides well-datedhigh-resolution records of the isotopic composition of past precipitation derived from lakesediments within Europe. The EU 5 th framework MOTIF project is designed to create advancedpaleoclimate data and coupled climate model comparisons on a global scale for the warm and coldclimate states at 6 and 21 ka BP. The BMBF DEKLIM GHOST project has provided acomprehensive statistical analysis of Holocene temperature trends in comparison with transientAOGCM ensemble experiments on a global scale. In order to account for inherent uncertainties inmodels and proxies, new, probably stochastic, methods are required which can minimizeuncertainties and provide better constraints on the coherency between models and paleoclimatedata. Such new numerical tools for the computation of expected responses and the quantificationof the uncertainties involved are under development at the Interdisciplinary Center for NumericalSimulation (platform P1).4. ObjectivesBy pooling and extending existing scientific expertise as well as laboratory and computer facilitiesat Kiel University and associated research institutions, A4 seeks to reach an advanced level ofcooperation between climate research teams for the purpose of focusing on coupled oceanatmospheremodeling and paleoclimatic reconstructions based on paleoenvironmental parametersfrom marine climate archives. We aim to merge high-resolution time series of past oceancirculation and precipitation changes (the last Glacial and the Holocene) with those from historicaldata (the past 200 years) and to compare paleoclimate data with coupled ocean-atmospheregeneral circulation model (GCM) results on regional and global scales. The impacts of oceancirculation changes on continental precipitation and evapo-transpiration balances, as well as theirforcing mechanisms on decadal to centennial time scales may be more accurately assessed byseparating natural forcing from forcing induced by mankind. This will provide advanced estimatesfor past and future magnitudes of droughts, floods, vegetation changes, weathering and river runoff47