Climate of the Past
www.clim-past.net
1814-9324
1814-9332
3
2
2007
10.5194/cp-3-355-2007
http://www.clim-past.net/3/355/2007/
http://www.clim-past.net/3/355/2007/cp-3-355-2007.html
http://www.clim-past.net/3/355/2007/cp-3-355-2007.pdf
355
366
2007-06-22
Historical droughts in Mediterranean regions during the last 500 years: a data/model approach
S. Brewer
brewer@cerege.fr
S. Alleaume
J. Guiot
A. Nicault
CEREGE, CNRS/Université Paul Cézanne UMR 6635, BP 80, 13545 Aix-en-Provence cedex, France
Centre d'Etudes Nordiques, Université Laval, Ste Foy, Québec GlK7P4, Canada
We present here a new method for comparing the output of General Circulation Models (GCMs)
with proxy-based reconstructions, using time series of reconstructed and simulated climate
parameters. The method uses <i>k</i>-means clustering to allow comparison between different periods
that have similar spatial patterns, and a fuzzy logic-based distance measure in order to take
reconstruction errors into account. The method has been used to test two coupled ocean-atmosphere
GCMs over the Mediterranean region for the last 500 years, using an index of drought stress, the
Palmer Drought Severity Index. The results showed that, whilst no model exactly
simulated the reconstructed changes, all simulations were an improvement over using the mean
climate, and a good match was found after 1650 with a model run that took into account changes in
volcanic forcing, solar irradiance, and greenhouse gases. A more detailed investigation of the
output of this model showed the existence of a set of atmospheric circulation patterns linked to the
patterns of drought stress: 1) a blocking pattern over northern Europe linked to dry conditions in the
south prior to the Little Ice Age (LIA) and during the 20th century; 2) a NAO-positive like pattern
with increased westerlies during the LIA; 3) a NAO-negative like period shown in the model
prior to the LIA, but that occurs most frequently in the data during the LIA. The results of the
comparison show the improvement in simulated climate as various forcings are included and
help to understand the atmospheric changes that are linked to the observed reconstructed climate changes.
Airey, M. and Hulme, M.: Evaluating climate model simulations of precipitation: Methods, problems and performance., Prog. Phys. Geog., 19, 427–448, 1995.
Bardossy, A. and Duckstein, L.: Fuzzy Rule-Based Modelling with Applica- tions to Geophysical, Biological, and Engineering Systems, CRC Press, Boca Raton, Florida, 1995.
Barriendos, M. and Rodrigo, F.: Seasonal rainfall variability in the iberian peninsula from the 16th century: preliminary results from historical documentary sources, Geophys. Res. Abstr., 7, 3533, 2005.
Bonfils, C., de Noblet-Ducoudre, N., Guiot, J., and Bartlein, P.: Some mechanisms of mid-Holocene climate change in Europe, inferred from comparing PMIP models to data, Clim. Dynam., 23, 79–98, 2004.
Bradley, R. and Jones, P.: Climate since A.D. 1500, Routledge, London, 679 pp., 1992.
Briffa, K., Jones, P., Bartholin, T., Eckstein, D., Schweingruber, F., Karlen, W., Zetterberg, P., and Eroren, M.: Fennoscandian summers from AD 500: temperature changes on short and long timescales, Clim. Dynam., 7, 111–119, 1992.
Briffa, K., Osborn, T., Schweingruber, F., Harris, I., Jones, P., Shiyatov, S., and Vaganov, E.: Low-frequency temperature variations from a northern tree ring density, J. Geophys. Res., 106, 2929–2941, 2001.
Crowley, T.: Causes of climate change over the past 1000 years, Science, 289, 270–277, 2000.
Crowley, T. and Lowery, T.: How warm was the Medieval Warm Period?, Ambio, 29, 51–54, 2000.
Cusbach, U., Voss, R., Hegerl, G., Waszkewitz, J., and Crowley, T.: Simulation of the influence of solar radiation variations on the global climate with an ocean-atmosphere general circulation model, Clim. Dynam., 13, 757–767, 1997.
Gonzalez-Rouco, F., von Storch, H., and Zorita, E.: Deep soil temperature as proxy for surface air-temperature in a coupled model simulation of the last thousand years, Geophys. Res. Lett., 30, 2116, doi:10.1029/2003GL018264, 2003.
Goosse, H. and Renssen, H.: Exciting natural modes of variability by solar and volcanic forcing: idealized and realistic experiments, Clim. Dynam., 21, 153–163, 2004.
Goosse, H., Renssen, H., Timmermann, A., and Bradley, R.: Internal and forced climate variability during the last millennium: a model-data comparison using ensemble simulations, Quaternary Sci. Rev., 24, 1345–1360, 2005.
Gordon, C., Cooper, C., Senior, C., Banks, H., Gregory, J., Johns, T., Mitchell, J., and Wood, R.: The simulation of SST, sea ice extents and ocean heat transports in a version of the Hadley Centre coupled model without flux adjustments, Clim. Dynam., 16, 147–168, 2000.
Guiot, J., Boreux, J J., Braconnot, P., Torre, F., and PMIP participating groups: Data-model comparisons using fuzzy logic in palaeoclimatology, Clim. Dynam., 15, 569–581, 1999.
Hartigan, J. and Wong, M.: A K-means clustering algorithm, Appl. Stat., 28, 100–108, 1979.
Hughes, M. and Diaz, H.: Was there a "Medieval Warm Period", and if so, where and when?, Clim. Change, 26, 109–142, 1994.
Hurrell, J.: Decadal trends in the North Atlantic oscillation: Regional temperatures and precipitation, Science, 269, 676–679, 1995.
Jones, P., Briffa, K., Barnett, T., and Tett, S.: High- resolution palaeoclimatic records for the last millennium: interpretation, integration and comparison with General Circulation Model control-run temperatures, The Holocene, 8, 455–471, 1998.
Joussaume, S. and Taylor, K.: Status of the Paleoclimate Modeling Intercomparison Project (PMIP), in: Proc. 1st Int. AMIP Scientific conference, WRCP Report, Vol 92, pp 425–430, Monterey, CA, 1995.
Lamb, H H.: Climate: present, past and future, Methuen, London, 825 pp., 1977.
Le~Roy~Ladurie, E.: Histoire du Climat depuis l'An Mil, Champs Flammarion, Paris, 531 pp., 1983.
Legutke, S. and Voss, R.: ECHO-G, the Hamburg atmosphere-ocean coupled circulation model, DKRZ technical report~18, DKRZ, Hamburg, 1999.
Liao, X., Street-Perrott, F., and Mitchell, J.: GCM experiments with different cloud parameterization: comparisons with palaeoclimatic reconstructions for 6000 years BP, Data Model., 1, 99–123, 1994.
Luterbacher, J.: Mediterranean Climate Variability, chap. Mediterranean Climate Variability Over the Last Centuries: A Review, Elsevier, Oxford, pp 27–143, 2006.
Luterbacher, J. and Xoplaki, E.: 500-Year Winter Temperature and Precipitation Variability over the Mediterranean Area and its Connection to the Large-Scale Atmospheric Circulation, Springer-Verlag, Berlin, Heidelberg, pp 133–153, 2003.
Luterbacher, J., Xoplaki, E., Dietrich, D., Rickli, R., Jacobeit, J., Beck, C., Gyalistras, D., Schmutz, C., and Wanner, H.: Reconstruction of sea level pressure fields over the Eastern North Atlantic and Europe back to 1500, Clim. Dynam., 18, 545–561, 2002.
Luterbacher, J., Dietrich, D., Xoplaki, E., Grosjean, M., and Wanner, H.: European seasonal and annual temperature variability, trends, and extremes since 1500, Science, 303, 1499–1503, 2004.
Mann, M., Bradley, R., and Hughes, M.: Northern Hemisphere temperatures during the past millennium: inferences, uncertainties, and limitations, Geophys. Res. Lett., 26, 759–762, 1999.
Masson, V., Cheddadi, R., Braconnot, P., Joussaume, S., Texier, D., and PMIP Participants: Mid-Holocene climate in Europe: what can we infer from PMIP model-data comparisons?, Clim. Dynam., 15, 163–182, 1998.
Mitchell, T., Carter, T., Jones, P., Hulme, M., and New, M.: A comprehensive set of high-resolution grids of monthly climate for Europe and the globe: the observed records (1901–2000) and 16 scenarios (2001–2100), Working Paper~55, Tyndall Centre for Climate Change Research, 25 pp., 2004.
Palmer, W.: Meteorological drought, Research Paper~45, U.S. Dept. Commerce, Washington, D.C., 58 pp., 1965.
Pauling, A., Luterbacher, J., Casty, C., and Wanner, H.: 500 years of gridded high-resolution precipitation reconstructions over Europe and the connection to large-scale circulation, Clim. Dynam., 26, 387–405, 2006.
Prentice, I., Harrison, S., Jolly, D., and Guiot, J.: The climate and biomes of europe at 6000 yr BP: comparison of model simulations and pollen-based reconstructions, Quaternary Sci. Rev., 17, 659–668, 1998.
Rind, D., Lean, J., and Healy, R.: Simulated time-dependent response to solar radiative forcing since 1600., J. Geophys. Res., 104, 1973–1990, 1999.
Rutherford, S., Mann, M., Delworth, T., and Stouffer, R.: Climate field reconstruction under stationary and nonstationary forcing, J. Climate, 16, 462–479, 2003.
Shindell, D., Schmidt, G., Mann, M., Rind, D., and Waple, A.: Solar forcing of regional climate change during the Maunder Minimum., Science, 294, 2149–2152, 2001.
Tett, S., Betts, R., Crowley, T., Johns, T., Jones, A., Osborn, T., Orstrom, E., Roberts, D., and Woodage, M.: The impact of natural and anthropogenic forcings on climate and hydrology since 1550, Clim. Dynam., 28, 3–34, 2007.
Texier, D., de Noblet, N., Harrison, S., Haxeltine, A., Jolly, D., Laarif, F., Prentice, I., and Tarasov, P.: Quantifying the role of biosphere-atmosphere feedbacks in climate change: coupled model simulations for 6000 years BP and comparison with paleodata for northern Eurasia and northern Africa, Clim. Dynam., 13, 865–882, 1997.
Till, C. and Guiot, J.: Reconstruction of precipitation in Morocco since 1100 AD based on Cedrus atlantica tree-ring widths, Quaternary Res., 33, 337–351, 1990.
Villalba, R.: Climatic fluctuations on Northern Patagonia during the last 1000 years as inferred from tree-ring records, Quaternary Res., 34, 346–360, 1990.
von Storch, H., Zorita, E., Jones, J., Dimitriev, Y., Gonzalez-Rouco, F., and Tett, S.: Reconstructing past climate from noisy data, Science, 306, 679–682, 2004.
Waple, A., Mann, M., and Bradley, R.: Long-term patterns of solar irradiance forcing in model experiments and proxy based surface temperature reconstructions, Clim. Dynam., 18, 563–578, 2002.
Wells, N., Goddard, S., and Hayes, M J.: A Self-Calibrating Palmer Drought Severity Index, J. Climate, 17, 2335–2351, 2004.
Widmann, M. and Tett, S.: Simulating the climate of the last millennium, PAGES News, 11, 21–23, 2003.
Yiou, P. and Nogaj, M.: Extreme climatic events and weather regimes over the North Atlantic: When and where?, Geophys. Res. Lett., 31, 1–10, 2004.
Zobler, L.: Global Soil Types, 1-Degree Grid (Zobler). Data set., Tech. rep., Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA, http://www.daac.ornl.gov, 1999.
Zorita, E., Gonzalez-Rouco, F., and Legutke, S.: Testing the Mann et al. (1998) approach to paleoclimate reconstructions in the context of a 1000-year control simulation with the ECHO-G coupled climate model, J. Climate, 16, 1368–1390, 2003.