Palaeoclimate and Palaeoenvironmental Reconstructions Using a Computational Regional Environmental Modelling System (project E6)
Project E6 aims to provide reliable palaeoclimatic and environmental data for the CRC 806 study domain and focus areas, which are perceived to be important to the movement of Homo sapiens from Africa to Europe. The palaeo-descriptions include the quantifications of the mean climate state, its variability including extreme events, climate stability and uncertainty, as well as the closely related natural environmental parameters, such as water availability, primary production, and Aeolian dust. This project is significant in that it (i) generates the necessary understanding of the global and regional palaeoclimate conditions which drive and constrain human mobility, (ii) supports the palaeoclimatic interpretation of geoscientific and archaeological CRC 806 climate proxies, the extrapolation of proxy data, and palaeoenvironmental reconstructions, and (iii) supports the development of human mobility models.
The regional palaeoclimate modelling for the CRC 806 domain will be achieved through the dynamical downscaling of PMIP3 (Palaeoclimate Modelling Intercomparison Project, Phase III) and - in the second part of the funding period - own global palaeoclimate simulations using a regional climate and environmental modelling system. The PMIP3 global climate model runs for the Mid-Holocene (6 ka BP, and, if available, also a transient Holocene experiment, 8.5-2.5 ka BP), for the Last Glacial Maximum (LGM, 21 ka BP), and for the Eemian interglacial (120-125 ka BP) will be used. The regional climate model will be the CEMSYS (Computational Environmental Modelling System), being developed at the Institute for Geophysics and Meteorology, University of Cologne. The new version of CEMSYS couples the WRF (Weather Research and Forecast) model with modules necessary for regional climate simulation, including aeolian-dust processes, surface hydrological processes, and vegetation processes. CEMSYS will be nested in PMIP3 GCM (General Circulation Model) output and then run in a self-nesting mode for the selected domains centred over Europe and North Africa (including the Near East), with resolutions between 10 and 50 km, and integrated over time slices of up to 50 years. The following approach will be pursued to enhance the confidence in the model-simulated palaeoclimates: (a) Present-day integrations will be validated against state-of-the-art atmospheric re-analyses and (b) checked for the representation of meteorological processes known to govern present regional climate variability, (c) the palaeoclimate runs will be compared with the climate, vegetation, and dust proxies from the CRC 806 and other palaeo-databases, and (d) other palaeo-model results.
Experiments with perturbed initial and boundary conditions will be carried out with CEMSYS to assess the palaeoclimate stability and the range of climate variability. The palaeoclimate and palaeoenvironmental data will be fed into the CRC 806 database along with interpretations. The deliveries of the project will include the spatial patterns and time series of meteorological parameters for the CRC 806 study sites, including frequencies of droughts, floods, frost, snow, extreme temperatures, and dust storms. The simulated dust-climate link will facilitate the interpretation of palaeodust as an indicator of palaeoclimate and palaeoenvironmental change. In the second stage of the project, the global MPI-ESM-P (Max-Planck-Institute for Meteorology, Earth System Model-Paleo) will be implemented in a low-resolution and/or simplified physics mode with a dynamical ice sheet model for multi-centennial integrations for the CRC 806-relevant climate transition periods 40-36 ka BP and 200-190 ka BP. The regionalisation of the climate information will be conducted through a dynamic downscaling as described above.