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Internal variability in a regional climate model over West Africa

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Abstract

Sensitivity studies with regional climate models are often performed on the basis of a few simulations for which the difference is analysed and the statistical significance is often taken for granted. In this study we present some simple measures of the confidence limits for these types of experiments by analysing the internal variability of a regional climate model run over West Africa. Two 1-year long simulations, differing only in their initial conditions, are compared. The difference between the two runs gives a measure of the internal variability of the model and an indication of which timescales are reliable for analysis. The results are analysed for a range of timescales and spatial scales, and quantitative measures of the confidence limits for regional model simulations are diagnosed for a selection of study areas for rainfall, low level temperature and wind. As the averaging period or spatial scale is increased, the signal due to internal variability gets smaller and confidence in the simulations increases. This occurs more rapidly for variations in precipitation, which appear essentially random, than for dynamical variables, which show some organisation on larger scales.

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References

  • Bechtold P, Basile E, Guichard F, Mascart P, Richard E (2001) A mass flux convection scheme for regional and global models. Q J R Meteorol Soc 127:869–886

    Article  Google Scholar 

  • Caya D, Biner S (2004) Internal variability of RCM simulations over an annual cycle. Clim Dyn 22:33–46 doi: 10.1007/s00382-003-0360-2

    Article  Google Scholar 

  • Charney JG (1975) Dynamics of deserts and droughts in the Sahel. Q J R Meteorol Soc 101:193–202

    Article  Google Scholar 

  • Christensen OB, Gaertner MA, Prego JA, Polcher J (2001) Internal variability of regional climate models. Clim Dyn 17:875–887

    Article  Google Scholar 

  • De Ridder K, Schayes G (1997) The IAGL land surface model. J Appl Meteorol 36:167–183

    Article  Google Scholar 

  • Derive G (2003) Estimation de l’évapotranspiration en région Sahélienne. Synthèse des connaissances et évaluation de modélisations (SISVAT, RITCHIE). Application à la zone d’HAPEX-Sahel. Ph.D. thesis, Mechanical of the Geophysics Mediums and Environment, Institut National Polytechnique de Grenoble, Grenoble, pp 74

  • Douville H, Chauvin F, Broqua H (2001) Influence of soil moisture on the Asian and African monsoons. Part I: mean monsoon and daily precipitation. J Clim 14:2381–2403

    Article  Google Scholar 

  • Folland CK, Palmer TN, Parker DE (1986) Sahel rainfall and worldwide sea temperatures. Nature 320:602–607

    Article  Google Scholar 

  • Fouquart Y, Bonnel B (1980) Computations of solar heating of the Earth’s atmosphere: a new parameterization. Beitraege Phys Atmos 53:35–62

    Google Scholar 

  • Gallée H (1995) Simulation of the mesocyclonic activity in the Ross Sea, Antarctica. Mon Weather Rev 123:2051–2069

    Article  Google Scholar 

  • Gallée H, Schayes G (1994) Development of a three-dimensional meso-gamma primitive equation model: katabatic winds simulation in the area of Terra Nova bay, Antarctica. Mon Weather Rev 122:671–685

    Article  Google Scholar 

  • Gallée H, Moufouma-Okia W, Bechtold P, Brasseur O, Dupays I, Marbaix P, Messager C, Ramel R, Lebel T (2004) A high resolution simulation of a West African rainy season using a regional climate model. J Geophys Res 109 doi: 10.1029/2003JD004020

  • Giorgi F, Bi X (2000) A study of internal variability of a regional climate model. J Geophys Res 105:29503–29521

    Article  Google Scholar 

  • Janicot S, Moron V, Fontaine B (1996) Sahel droughts and ENSO dynamics. Geophys Res Lett 23:515–518, doi: 96GL00246

    Article  Google Scholar 

  • Kessler E (1969) On the distribution and continuity of water substance in atmospheric circulation. Meteorol Monogr 10:32 AMS

    Google Scholar 

  • Marbaix P, Gallée H, Brasseur O, van Ypersele JP (2003) Lateral boundary conditions in regional climate models: a detailed study of the relaxation procedure. Mon Weather Rev 131:461–479

    Article  Google Scholar 

  • Messager C, Gallée H, Brasseur O (2004) Precipitation sensitivity to regional SST in a regional climate simulation during the West African monsoon for two dry years. Clim Dyn 22:249–266, doi: 10.1007/s00382-003-0381-x

    Article  Google Scholar 

  • Morcrette J (1984) Sur la paramétrisation du rayonnement dans les modèles de la circulation générale atmosphérique. Ph.D. thesis, Université des Sciences et Techniques, Lille, France, 373 pp

  • Nicholson SE (1993) An overview of African rainfall fluctuations of the last decade. J Clim 6:1463–1466

    Article  Google Scholar 

  • Paeth H, Feichter J (2006) Greenhouse-gas versus aerosol forcing and African climate response. Clim Dyn 26:35–54

    Article  Google Scholar 

  • Paeth H, Born K, Jacob D, Podzun R (2005) Regional dynamic downscaling over West Africa: model validation and comparison of wet and dry years. Meteorologische Zeitschrift 14:349–367

    Article  Google Scholar 

  • Philippon N, Fontaine B (2002) The relationship between the Sahelian and the 2nd Guinean rainy seasons: a monsoon regulation by soil wetness? Anal Geophys 20:575–582

    Article  Google Scholar 

  • Ramel R (2006) Impacts des processus de surface sur le climat en Afrique de l’Ouest. Ph.D. thesis, Laboratoire d’étude des transferts en hydrologie et environnement, Université Joseph Fourier, Grenoble, 149 pp

  • Ramel R, Gallée H, Messager C (2006) On the northward shift of the West African monsoon. Clim Dyn 26:429–440

    Article  Google Scholar 

  • Rinke A, Marbaix P, Dethloff K (2004) Internal variability in Artic regional climate simulations: case study for the SHEBA year. Clim Res 27:197–209

    Article  Google Scholar 

  • Vizy EK, Cook KH (2002) Development and application of a mesoscale climate model for the tropics: influence of sea surface temperature anomalies on the West African monsoon. J Geophys Res 17, D3, 4023 doi: 10.1029/2001JD000686

  • Von Storch H, Zwiers FW (1999) Statistical analysis in climate research. Cambridge University Press, Cambridge, 494 pp ISBN 0 521 45071 3

  • Weisse R, Heyen H, von Storch H (2000) Sensitivity of a regional atmospheric model to a sea state-dependent roughness and the need for ensemble calculations. Mon Weather Rev 128:3631–3642

    Article  Google Scholar 

  • Wheeler M, Kiladis GN (1999) Convectively coupled equatorial waves: analysis of clouds and temperature in the wavenumber–frequency domain. J Atmos Sci 56:374–399

    Article  Google Scholar 

  • Zeng N, Neelin JD, Lau KM, Tucker CJ (1999) Enhancement of interdecadal climate variability in the Sahel by vegetation interaction. Science 286(5444):1537–1540

    Article  Google Scholar 

  • Zheng X, Eltahir EAB (1998) The role of the vegetation in the dynamics of West African monsoons. J Clim 11:2078–2096

    Google Scholar 

Download references

Acknowledgments

E. Vanvyve is sponsored by the Belgian National Fund for Industrial and Agricultural Research. N. Hall is supported by the CNRS. C. Messager is supported by NERC grant NE/B505538/1. S. Leroux is sponsored by the French Ministry of “Enseignement Supérieur et Recherche”. J.-P. van Ypersele is a professor at the Université catholique de Louvain. All model simulations were realised with the CNRS-IDRIS computing resources (Institut du Développement et des Ressources en Informatique Scientifique, France). The authors thank the European Centre for Medium-Range Weather Forecasts (United Kingdom) for its dataset used as driving fields for the model. This study forms part of the international African Monsoon Multidisciplinary Analysis (AMMA) project, see http://www.amma-international.org for details.

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Authors and Affiliations

  1. Institut d’astronomie et de géophysique Georges Lemaître, Université catholique de Louvain, 2 Chemin du Cyclotron, 1348, Louvain-la-Neuve, Belgium

    Emilie Vanvyve & Jean-Pascal van Ypersele

  2. Laboratoire d’Etudes en Géophysique et Océanographie Spatiales/Centre National d’Etudes Spatiales, 18 Avenue Edouard Belin, 31401, Toulouse Cedex 9, France

    Nicholas Hall

  3. Institute for Atmospheric Science, Environment, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK

    Christophe Messager

  4. Laboratoire d’étude des Transferts en Hydrologie et Environnement, Université Joseph Fourier, BP53, 38041, Grenoble Cedex 9, France

    Stéphanie Leroux

Authors
  1. Emilie Vanvyve
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  2. Nicholas Hall
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  3. Christophe Messager
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  4. Stéphanie Leroux
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  5. Jean-Pascal van Ypersele
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Correspondence to Emilie Vanvyve.

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Vanvyve, E., Hall, N., Messager, C. et al. Internal variability in a regional climate model over West Africa. Clim Dyn 30, 191–202 (2008). https://doi.org/10.1007/s00382-007-0281-6

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  • DOI: https://doi.org/10.1007/s00382-007-0281-6

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