Climate & Atmosphere
past and future climate change
data assimilation in palaeoclimatology
statistical downscaling for precipitation
Current / recent research
Transient GCM simulations of the mid-Holocene climate and comparison with palaeoclimate proxy data
Together with Sebastian Wagner (GKSS Research Centre, Geesthacht, Germany) and Julie Jones (University of Sheffield) I am investigating the climate response to orbital and solar forcing using transient simulations for the mid-Holocene (7.0-4.5 ka BP) with a coupled atmosphere-ocean general circulation model (project MIDHOL). In collaboration with colleagues from the universities of Bremen and Cologne we have also performed consistency tests between the statistically downscaled simulations and climate proxy data from North and South America. MIDHOL has been funded by the German climate research programme DEKLIM.
Southern Hemisphere atmospheric circulation
I work with Julie Jones (University of Sheffield) on reconstructions of the state of the Southern Hemisphere Annular Mode (the major mode of extratropical atmospheric circulation in the Southern Hemisphere, also known as the Antarctic Oscillation) from instrumental pressure measurements for the twentieth century, and from tree-ring width chronologies back to the 18th century. This work has been supported by the German climate research programme DEKLIM and the Helmholtz Society.
Correction of precipitation simulated by General Circulation Models using Model Output Statistics
Simulating precipitation realistically is still a major challenge in climate modelling, because the spatial scales involved are often smaller than the gridcell size used in General Circulation Models (GCMs). I work with Jonathan Eden (University of Birmingham) on developing a method for statistically estimating regional precipitation using GCM-simulated precipitation as a predictor. This is an example for a Model Output Statistics correction method, which is conceptually different from the perfect-prog downscaling usually used in climate change studies. As part of this project we run the ECHAM5 GCM on the BEAR Linux cluster at the University of Birmingham. Once the correction method is developed, it will be applied to GCM simulations for the 21st century.
Data assimilation for palaeoclimatic applications
I have developed a pattern nudging method that allows the specification of large-scale circulation anomalies in general circulation models. This work is conducted in collaboration with Hans von Storch (GKSS Research Centre, Geesthacht), Reiner Schnur (Max Planck Institute for Meteorology, Hamburg) and Ingo Kirchner (Free University Berlin) and aims at providing a tool for assimilating large-scale circulation estimates derived from proxy data in simulations with general circulation models. This work has been supported by the German climate research programme DEKLIM and the Helmholtz Society.
Stability of teleconnections and of scale relationships
Together with Nikolaus Groll (GKSS Research Centre, Geesthacht) I have compared temperature teleconnections in the Eemian (the last interglacial about 125 ka ago) and in the preindustrial climate using simulations with General Circulation Models. We have also analysed relationships between large-scale atmospheric circulation and regional temperatures in these simulations. This work shows how orbital forcing changes the mean climate and thus in turn teleconnections and relationships between large-scale and regional climate. It has been supported by the German climate research programme DEKLIM.
Regional climate modelling for the European Alps
In collaboration with Kerstin Prömmel, Beate Mueller (GKSS Research Centre, Geesthacht) and Julie Jones (University of Sheffield) I am involved in the analysis of a regional model simulation over the Alps. We are exploring whether the high-resolution simulation adds value compared to the ERA40 reanalysis. We also are investigating mesoscale climate variability patterns in the region. This work has been funded through the EU Framework 5 project ALP-IMP.
Key Publications since 2001
Eden, J.M., Widmann, M., Grawe, D, and Rast. S., 2010: Reassessing the skill of GCM-simulated precipitation. J. Climate, accepted subject to minor revisions.
Widmann, M., H. Goosse, G. van der Schrier, R. Schnur and Jan Barkmeijer, 2010: Using data assimilation to study extratropical Northern Hemisphere climate over the last millennium. Climate of the Past, 6, 627-644.
Maraun, D., A. Ireson, F. Wetterhall, R. Chandler, E. Kendon, M. Widmann, and 11 contributing authors, 2010: Precipitation downscaling under climate change: recent developments to bridge the gap between dynamical models and the end user. Reviews of Geophysics, 48, RG3003.
Baker, A., A. Asfawossen, I.J. Fairchild, M. Leng, L. Thomas, M. Widmann, C. Jex, B. Dong, P. van Calsteren, and C. Bryant, 2010: Decadal-scale rainfall variability in Ethiopian recorded in an annually laminated, Holocene-age Stalagmite. The Holocene, 20(6), 827-836.
Prömmel, K., B. Geyer, J.M. Jones, and M. Widmann, 2010: Evaluation of the skill and added value of a reanalysis-driven regional simulation for Alpine temperature. Int. J. Climatol., 30, 760-773
Widmann, M., 2009: Delayed Holocene warming. Nature Geoscience, 2, 380-381.
Jones, J.M., R.L. Fogt, M. Widmann, G. Marshall, P. Jones and M. Visbeck, 2009: Historical Southern Hemisphere Annular Mode Variability. Part I: Century Length Seasonal Reconstructions of the Southern Hemisphere Annular Mode. J. Clim., 22, 5319-5345
Wanner, H., Beer, J., Bütikofer, J. Crowley, T., Cubasch, U., Flückiger, J., Goosse, H., Grosjean, M., Joos, F., Kaplan, J.O., Küttel, M., Müller, S., Pentice, C. Solomina, O., Stocker, T., Tarasov, P., Wagner, M., and Widmann, M., 2008: Mid to late Holocene climate change - an overview, Quaternary Science Reviews, 27(19-20), 1791-1828.
Wagner, S., M. Widmann, J. Jones, T. Haberzettl, A. Lücke, C. Mayr, C. Ohlendorf, F. Schäbitz and B. Zolitschka, 2007: Transient simulations, empirical reconstructions and forcing mechanisms for the Mid-Holocene hydrological climate in Southern Patagonia. Climate Dynamics, 29(4), 333-355.
Widmann, M., N. Groll and J.M. Jones, 2007. Simulated teleconnections during the Eemian, the last glacial inception and the preindustrial period. In Sirocko, F., T. Litt and M. Claussen (eds.): The climate of past interglacials, Elsevier, ISSN 1571-0866, 622pp..
Le Treut, H., R. Sommerville, U. Cubasch, Y. Ding, C. Mauritzen, A. Mokssit, T. Peterson, M.Prather and contributing authors (including M. Widmann), 2007: Historical Overview of Climate Change Science. In: Climate Change 2007 – The Physical Science Basis. IPCC AR4 WG 1, Cambridge University Press.
Christensen, J.H., Hewitson B., Busuioc A., Chen, A., Gao., X., Jones, R., Kwon, W.-T., Laprise, R., Magana, V., Mearns, L. Menenedez, C., Raisaenen, J., Rinke, A., Kolli, R. K., Sarr, A., Whetton, P. and contributing authors (including M. Widmann), 2007: Regional Climate Projections. In: Climate Change 2007 – The Physical Science Basis. IPCC AR4 WG 1, Cambridge University Press.
Groll, N. and M. Widmann, 2006: Sensitivity of temperature teleconnections to orbital changes in AO-GCM simulations. Geophys. Res. Lett., 13(12), Art. No. L12705.
Groll, N., M. Widmann, J. M.Jones, F. Kaspar, and S. Lorenz, 2005: Simulated relationships between regional temperatures and large-scale circulation during the early Eemian interglacial (125 kyr BP) and the pre-industrial period. J. Clim, 18(19), 4035-4048 .
Widmann, M., 2005: One-dimensional CCA and SVD, and their relationship to regression maps. J. Clim., 18(14), 2785-2792.
Jones, J. M. and M. Widmann, 2004: Early peak in Antarctic Oscillation index. Nature, 432(7015), 290-291.
Jones, J. M. and M. Widmann, 2004: Reconstructing large-scale variability from palaeoclimatic evidence by means of Data Assimilation Through Upscaling and Nudging (DATUN). In: H. Fischer, T. Kumke, G. Lohmann, G. Flöser, H. Miller, H. von Storch and J. F. W. Negendank (eds.), 2004: The KIHZ project: towards a synthesis of Holocene proxy data and climate models. Springer, Heidelberg, Berlin, New York. ISSN 1437-028X, p171-193.
Jones, J. M. and M. Widmann, 2003: Instrument- and tree-ring-based estimates for the Antarctic Oscillation. J. Clim., 16(21), 3511-3524.
Widmann, M., C. S. Bretherton, and E. P. Salathé Jr., 2003: Statistical precipitation downscaling over the Northwestern United States using numerically simulated precipitation as a predictor. J. Clim, 16(5), 799-816.
Matulla, C., N. Groll, H. Kromp-Kolb, H. Scheifinger, M. J. Lexer, and M. Widmann, 2002: Climate change scenarios at Austrian National Forest Inventory sites. Clim. Res., 22(2), 161-173.
Giorgi, F., B. Hewitson, J. Christensen, C. Fu, M. Hulme, L. Mearns, H. von Storch, P. Whetton, and contributing authors (including M. Widmann), 2001: Regional Climate Simulation - Evaluation and Projections. In: Climate Change 2001: The Scientific Basis (IPCC WG1 Third Assessment Report). Cambridge University Press