Theoretical and Applied Climatology

, Volume 98, Issue 3–4, pp 293–314 | Cite as

High-resolution simulations of West African climate using regional climate model (RegCM3) with different lateral boundary conditions

  • M. B. Sylla
  • A. T. Gaye
  • J. S. Pal
  • G. S. Jenkins
  • X. Q. Bi
Original Paper


To downscale climate change scenarios, long-term regional climatologies employing global model forcing are needed for West Africa. As a first step, this work examines present-day integrations (1981–2000) with a regional climate model (RCM) over West Africa nested in both reanalysis data and output from a coupled atmospheric–ocean general circulation model (AOGCM). Precipitation and temperature from both simulations are compared to the Climate Research Unit observations. Their spatial distributions are shown to be realistic. Annual cycles are considerably correlated. Simulations are also evaluated with respect to the driving large-scale fields. RCM offers some improvements compared to the AOGCM driving field. Evaluation of seasonal precipitation biases reveals that RCM dry biases are highest on June–August around mountains. They are associated to cold biases in temperature which, in turn, are connected to wet biases in precipitation outside orographic zones. Biases brought through AOGCM forcing are relatively low. Despite these errors, the simulations produce encouraging results and show the ability of the AOGCM to drive the RCM for future projections.


Regional Climate Model Cold Bias Guinea Coast RegCM3 Simulation High Rain Rate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



These simulations have been done at the Abdus Salam International Centre for Theoretical Physics (Trieste, Italy). Therefore, the authors would like to thank the Physics of Weather and Climate Group scientists: Prof. Filippo Giorgi and Dr. Fred Kusharsky for providing the computing facilities. Thanks as well to Prof. William J. Gutowski, Jr. from Iowa State University and to the two anonymous reviewers for their helpful suggestions and comments.


  1. Adegoke JO, Lamptey BL (2000) Intraseasonal variability of summertime precipitation in the Guinea coastal region of West Africa. Proceedings of the Workshop on the West African Monsoon Variability and Predictability, WMO/TD No. 1003, pp 115–118Google Scholar
  2. Afiesimama EA, Pal JS, Abiodun BJ, Gutowski WJ, Adedoyin A (2006) Simulation of West African monsoon using the RegCM3. Part I: model validation and interannual variability. Theor Appl Climatol 86:23–37CrossRefGoogle Scholar
  3. Christensen OB, Christensen JH, Machenhauer B, Botzet M (1998) Very high resolution regional climate simulations over Scandinavia: present climate. J Clim 11:3204–3229CrossRefGoogle Scholar
  4. Cook KH (1999) Generation of the African Easterly Jet and its role in determining West African precipitation. J Climate 12:1165–1184CrossRefGoogle Scholar
  5. D’Amato N, Lebel T (1998) On the characteristics of the rainfall events in the Sahel with a view to the analysis of climatic variability. Int J Climatol 18:955–974CrossRefGoogle Scholar
  6. Dickinson RE, Henderson-Sellers A, Kennedy PJ (1993) Biosphere–atmosphere transfer scheme (BATS) version 1E as coupled to the NCAR community climate model. Technical Note NCAR/TN—387+STR, p 72Google Scholar
  7. Doherty R, Mearns LO (1999) A comparison of simulations of present climate from two coupled atmospheric-ocean AOGCMs against observations and evaluation of their future climates. Report to NIGEC National Office NCAR, p 47Google Scholar
  8. Fritsch JM, Chappell CF (1980) Numerical prediction of convectively driven mesoscale pressure systems. Part I: convective parameterization. J Atmos Sci 37:1722–1733CrossRefGoogle Scholar
  9. Gallée H, Moufouma-Okia W, Bechtold P, Brasseur O, Dupays I (2004) A high-resolution simulation of a West African rainy season using a regional climate model. J Geophys Res 109:D05108 doi: 10.1029/2003JD004020 CrossRefGoogle Scholar
  10. Gaye AT, Viltard A, De Felice P (2005) Lignes de grains et pluies en Afrique de l’Ouest: part des lignes de grains à la pluie totale des étés 1986 et 1987. Sécheresse 16:269–73Google Scholar
  11. Giannini A, Saravanan R, Chang P (2003) Oceanic forcing of Sahel rainfall on interannual to interdecadal time scales. Science 302:1027–1030CrossRefGoogle Scholar
  12. Giorgi F, Marinucci MR (1996a) An investigation of the sensitivity of simulated precipitation to model resolution and its implications for climate studies. Mon Weather Rev 124:148–166CrossRefGoogle Scholar
  13. Giorgi F, Marinucci MR (1996b) Improvements in the simulation of surface climatology over the European region with a nested modelling system. Geophys Res Lett 23:273–276CrossRefGoogle Scholar
  14. Giorgi F, Mearns LO (1999) Introduction to special section: regional climate modelling revisited. J Geophys Res 104:6335–6352CrossRefGoogle Scholar
  15. Giorgi F, Marinucci MR, Bates GT (1993a) Development of a second-generation regional climate model (RegCM2). Part I: boundary-layer and radiative transfer processes. Mon Weather Rev 121(10):2794–2813CrossRefGoogle Scholar
  16. Giorgi F, Marinucci MR, Bates GT, Canio GD (1993b) Development of a second-generation regional climate model (RegCM2). Part II: convective processes and assimilation of lateral boundary conditions. Mon Weather Rev 121(10):2814–2832CrossRefGoogle Scholar
  17. Giorgi F, Brodeur CS, Bates GT (1994) Regional climate change scenarios over the United States produced with a nested regional climate model. J Climate 7:375–399CrossRefGoogle Scholar
  18. Giorgi F, Mearns LO, Shields C, McDaniel L (1998) Regional nested model simulations of present day and 2 × CO2 climate over the Central Plains of the US. Clim Change 40:457–493CrossRefGoogle Scholar
  19. Grell GA, Dudhia J, Stauffer DR (1994) Description of the fifth generation Penn State/NCAR Mesoscale Model (MM5). Technical Note NCAR/TN—398+STR, p 121Google Scholar
  20. Hoerling MP, Hurrell JW, Eischeild J (2005) Detection and attribution of 20th century northern and southern African monsoon change. J Climate 19:3989–4008CrossRefGoogle Scholar
  21. Holtslag AAM, De Bruin EIF, Pan HL (1990) A high resolution air mass transformation model for short-range weather forecasting. Mon Weather Rev 118:1561–1575CrossRefGoogle Scholar
  22. Hudson DA, Jones R (2002a) Regional climate model simulations of present-day and future climates of southern Africa. Technical Note 39. Hadley Centre for Climate Prediction and Research, Met Off Bracknell, EnglandGoogle Scholar
  23. Hulme M, Doherty R, Ngara T, New M, Lister D (2001) African climate change: 1900–2100. Climate Res 17:145–168CrossRefGoogle Scholar
  24. IPCC (2001) Intergovernmental Panel on climate change, climate change: the scientific basis (Contribution of Working Group I to the 3rd Assessment Report of the IPCC). Cambridge University Press, CambridgeGoogle Scholar
  25. Janicot S (1997) Impact of warm ENSO events on atmospheric circulation and convection over the tropical Atlantic and West Africa. Ann Geophys 15:471–475CrossRefGoogle Scholar
  26. Janicot S, Moron V, Fontaine B (1996) Sahel drought and ENSO dynamics. Geophys Res Lett 23:515–518CrossRefGoogle Scholar
  27. Jenkins GS (1997) The 1988 and 1990 summer season simulations for West Africa using a regional climate model. J Climate 10:1255–1272CrossRefGoogle Scholar
  28. Jenkins GS, Gaye AT, Sylla B (2005) Late 20th century attribution of drying trends in the Sahel from the Regional Climate Model (RegCM3). Geophys Res Lett 32:L22705CrossRefGoogle Scholar
  29. Jones RG, Murphy JM, Noguer M (1995) Simulation of climate change over Europe using a nested regional climate model I: assessment of control climate, including sensitivity to location of lateral boundary conditions. Q J R Meteorol Soc 121:1413–1449Google Scholar
  30. Jones RG, Hassell D, Ward K (1999) First results from the Hadley Centre’s new regional climate model including effects of enhanced resolution. DETR report, March 1999. Hadley Centre for Climate Prediction and Research, Bracknell, London, UKGoogle Scholar
  31. Jungclaus JH, Botzet M, Haak H, Keenlyside N, Luo JJ, Latif M, Marotzke J, Mikolajewicz U, Roeckner E (2006) Ocean circulation and tropical variability in the coupled model ECHAM5/MPI-OM. J Climate 19:3952–3972CrossRefGoogle Scholar
  32. Kalnay E, Kanamitsu M, Kistler R, Collins W, Deaven D, Gandin L, Iredell M, Saha S, White G, Woollen J, Zhu Y, Leetmaa A, Reynolds R, Chelliah M, Ebisuzaki W, Higgins W, Janowiak J, Mo KC, Ropelewski C, Wang J, Jenne R, Joseph D (1996) The NCEP–NCAR 40-year reanalysis project. Bull Amer Soc 77:437–471CrossRefGoogle Scholar
  33. Kamga AF, Jenkins GS, Gaye AT, Garba A, Sarr A, Adedoyin A (2005) Evaluating the National Center for Atmospheric Research climate system model over West Africa: present-day and the 21st century A1 scenario. J Geophys Res 110:D03106 doi: 10.1029/2004JD004689 CrossRefGoogle Scholar
  34. Kiehl JT Hack JJ, Bonan GB, Boville BA, Briegleb BP, Williamson DL, Rasch PJ (1996) Description of the NCAR Community Climate Model (CCM3). Technical Note NCAR/TN—420+STR, p 152Google Scholar
  35. Leung LR, Qian Y, Bian X, Washington WM, Han J, Roads JO (2004) Mid-Century ensemble regional climate change scenarios for the western United States. Clim Change 62:75–113CrossRefGoogle Scholar
  36. Marsland SJ, Haak H, Jungclaus JH, Latif M, Röske F (2003) The Max-Planck Institute global ocean/sea-ice model with orthogonal curvilinear coordinates. Ocean Model 5:91–127CrossRefGoogle Scholar
  37. Mathon V, Laurent H (2001) Life cycle of Sahelian mesoscale convective cloud systems. Qt J R Meteorol Soc 127:377–406CrossRefGoogle Scholar
  38. McGregor JL, Walsh K (1994) Climate change simulations of Tasmanian precipitation using multiple nesting. J Geophys Res 99:20889–20905CrossRefGoogle Scholar
  39. McGregor JL, Katzfey JJ, Nguyen KC (1998) Fine resolution simulations of climate change for Southeast Asia. Final report for a Research Project commissioned by Southeast Asian Regional Committee for START (SARCS), Aspendale, Vic.. CSIRO Atmospheric Research VI:15–35Google Scholar
  40. Mearns LO, Giorgi F, McDaniel L, Shields C (1995a) Analysis of daily variability of precipitation in a nested regional climate model: comparison with observations and doubled CO2 results. Glob Planet Change 10:55–78CrossRefGoogle Scholar
  41. Mitchell TD, Carter TR, Jones PD, Hulme M, New M (2004) A comprehensive set of high-resolution grids of monthly climate for Europe and the globe: the observed record (1901–2000) and 16 scenarios (2001–2100). Tyndall Centre for Climate Change Research, Norwich, UK, Working Paper 55Google Scholar
  42. Nicholson SE, Some B, Kone B (2000) An analysis of recent rainfall conditions in West Africa, including the rainy seasons of the 1997 El Nino and the 1998 La Nina years. J Climate 13:2628–2640CrossRefGoogle Scholar
  43. Noguer M, Jones RG, Murphy JM (1998) Sources of systematic errors in the climatology of a nested regional climate model (RCM) over Europe. Clim Dyn 14:691–712CrossRefGoogle Scholar
  44. Paeth H, Born K, Podzun R, Jacob D (2005) Regional dynamical downscaling over West Africa: model evaluation and comparison of wet and dry years. Meteorol Z 14(3):349–367CrossRefGoogle Scholar
  45. Pal JS, Small EE, Eltahir EAB (2000) Simulation of regional-scale water and energy budgets: representation of subgrid cloud and precipitation processes within REGCM. J Geophys Res 105:29579–29594CrossRefGoogle Scholar
  46. Pal JS, Giorgi F, Bi X (2004) Consistency of recent European summer precipitation trends and extremes with future regional climate projections. Geophys Res Lett 31:L13202 doi: 10.1029/2004GL019836 CrossRefGoogle Scholar
  47. Pal JS, Giorgi F, Bi X, Elguindi N, Solomon F, Gao X, Francisco R, Zakey A, Winter J, Ashfaq M, Syed F, Bell JL, Diffanbaugh NS, Kamacharya J, Konare A, Martinez D, da Rocha RP, Sloan LC, Steiner A (2007) The ICTP RegCM3 and RegCNET: regional climate modeling for the developing world. Bull Am Meteorol Soc 88:1395–1409CrossRefGoogle Scholar
  48. Pan Z, Christensen JH, Arritt RW, Gutowski WJ Jr, Takle ES, Otieno F (2001) Evaluation of uncertainties in regional climate change simulations. J Geophys Res 106:17735–17752CrossRefGoogle Scholar
  49. Polcher J (1995) Sensitivity of tropical convection to land surface processes. J Atmos Sci 52(17):3143–3161CrossRefGoogle Scholar
  50. Roeckner E, Bäuml G, Bonaventura L, Brokopf R, Esch M, Giorgetta M, Hagemann S, Kirchner I, Kornblueh L, Manzini E, Rhodin A, Schlese U, Schulzweida U, Tompkins A (2003) The atmospheric general circulation model ECHAM5. Part I: model description. Report no. 349, Max-Planck-Institut für Meteorologie, Hamburg, Germany, p 127Google Scholar
  51. Roeckner E, Brokopf R, Esch M, Giorgetta M, Hagemann S, Kornblueh L, Schlese U, Schulzweida U, Manzini E (2004) The atmospheric general circulation model ECHAM5 Part II: Sensitivity of simulated climate to horizontal and vertical resolution. Report No. 354, Max-Planck-Institut für Meteorologie, Hamburg, GermanyGoogle Scholar
  52. Simmons AJ, Burridge DM (1981) An energy and angular-momentum conserving vertical finite difference scheme and hybrid vertical coordinates. Mon Weather Rev 109:758–766CrossRefGoogle Scholar
  53. Sun L, Semazzi FHM, Giorgi F, Ogallo L (1999b) Application of the NCAR regional climate model to eastern Africa: simulation of interannual variability of short rains. J Geophys Res 104:6549–6562CrossRefGoogle Scholar
  54. Thorncroft CD, Blackburn M (1999) Maintenance of the African Easterly Jet. Q J R Meteorol Soc 125:763–786Google Scholar
  55. Vizy E, Cook K (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 107(D3):4023 doi: 10.1029/2001JD000686 CrossRefGoogle Scholar
  56. Zeng X, Zhao M, Dickinson RE (1998) Intercomparison of bulk aerodynamic algorithms for the computation of sea surface fluxes using TOGA COARE and TAO data. J Climate 11:2628–2644CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • M. B. Sylla
    • 1
  • A. T. Gaye
    • 1
  • J. S. Pal
    • 2
  • G. S. Jenkins
    • 3
  • X. Q. Bi
    • 4
  1. 1.Laboratoire de Physique de l’Atmosphere et de l’Ocean—Simeon Fongang, Ecole Superieure PolytechniqueUniversity Cheikh Anta DiopDakarSenegal
  2. 2.Department of Civil Engineering and Environmental Science, Seaver College of Science and EngineeringLoyola Marymount UniversityLos AngelesUSA
  3. 3.Howard University Program in Atmospheric Sciences and Department of Physics and AstronomyWashingtonUSA
  4. 4.International Centre for Theoretical Physics, Earth System Physics SectionPhysics of Weather and Climate GroupTriesteItaly

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