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A sensitivity study on the role of the swamps of southern Sudan in the summer climate of North Africa using a regional climate model

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Abstract

We used the regional climate model RegCM3 to investigate the role of the swamps of southern Sudan in affecting the climate of the surrounding region. Towards this end, we first assessed the performance of a high resolution version of the model over northern Africa. RegCM3 shows a good skill in simulating the climatology of rainfall and temperature patterns as well as the related circulation features during the summer season, outperforming previous coarser resolution applications of the model over this region. Sensitivity experiments reveal that, relative to bare soil conditions, the swamps act to locally modify the surface energy budget primarily through an increase of surface latent heat flux. Existence of the swamps leads to lower ground temperature (up to 2 °C), a larger north–south temperature gradient, and increased local rainfall (up to 40 %). Of particular importance is the impact on rainfall in the surrounding regions. The swamps have almost no impact on the rainfall over the source region of the Nile in Ethiopia or in the Sahel region; however, they favor wetter conditions over central Sudan (up to 15 %) in comparison to the bare desert soil conditions.

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References

  • Adler RF, Susskind J, Huffman GJ, Bolvin D, Nelkin E, Chang A, Ferraro R, Gruber A, Xie PP, Janowiak J (2003) The version-2 global precipitation climatology project (GPCP) monthly precipitation analysis (1979–present). J Hydrometeorol 4:1147–1167

    Article  Google Scholar 

  • Anyah RO, Semazzi FHM (2007) Variability of East African rainfall based on multiyear RegCM3 simulations. Int J Climatol 27:357–371

    Google Scholar 

  • Awadalla SS (2011) Wetland model in an earth systems modeling framework for regional environmental policy Analysis. Massachusetts Institute of Technology

  • Butcher AD (1938) The Sadd hydraulics. Govt. Press, Cairo

    Google Scholar 

  • Chan SO, Eagleson PS (1980) Water balance studies of the Bahr El Ghazal Swamp. Dept. of Civil Engineering, Massachusetts Institute of Technology, Cambridge

    Google Scholar 

  • Chen TC, van Loon H (1987) Interannual variation of the tropical easterly jet. Monthly Weather Review, 115

  • Cook KH (1999) Generation of the African easterly jet and its role in determining West African precipitation. J Clim 12:1165–1184

    Article  Google Scholar 

  • 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 18:955–974

    Article  Google Scholar 

  • Dickinson RE, Henderson-Sellers A, Kennedy PJ, Wilson MF (1993) Biosphere–atmosphere transfer scheme (BATS) version 1e as coupled to the NCAR Community Climate Model. NCAR Tech. Note, NCAR/TN387+ STR

  • Diedhiou A, Janicot S, Viltard A, de Felice P, Laurent H (1999) Easterly wave regimes and associated convection over West Africa and tropical Atlantic: results from the NCEP/NCAR and ECMWF reanalyses. Clim Dyn 15:795–822

    Article  Google Scholar 

  • Druyan LM, Fulakeza M, Lonergan P (2008) The impact of vertical resolution on regional model simulation of the west African summer monsoon. Int J Climatol 28:1293–1314

    Article  Google Scholar 

  • Dumont HJ (2009) The Nile: origin, environments, limnology and human use. Springer, Dordrecht

    Google Scholar 

  • Eltahir EAB (1989) A feedback mechanism in annual rainfall, Central Sudan. J Hydrol 110:323–334

    Article  Google Scholar 

  • Flaounas E, Bastin S, Janicot S (2010) Regional climate modelling of the 2006 West African monsoon: sensitivity to convection and planetary boundary layer parameterisation using WRF. Climate Dynamics, 1–23

  • Fontaine B, Janicot S (1992) Wind-field coherence and its variations over West Africa. J Clim 5:512–524

    Article  Google Scholar 

  • Fritsch JM, Chappell CF (1980) Numerical prediction of convectively driven mesoscale pressure systems. Part I: convective parameterization. J Atmos Sci 37:1722–1733

    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:D05108

    Article  Google Scholar 

  • Gaudet SC, Eagleson PS (1984) Surface area variability of the Bahr el Ghazal swamp in the presence of perimeter canals. Massachusetts Institute of Technology, Cambridge

    Google Scholar 

  • Giorgi F, Bates GT (1989) The climatological skill of a regional model over complex terrain. Mon Weather Rev 117:2325

    Article  Google Scholar 

  • Giorgi F, Marinucci MR, Bates GT (1993) Development of a second-generation regional climate model (RegCM2). Part I: boundary-layer and radiative transfer processes. Mon Weather Rev 121:2794–2813

    Article  Google Scholar 

  • Green J, El-Moghraby AI (2009) Swamps of the upper White Nile. The Nile, 193-204.

  • Grell GA, Dudhia J, Stanffer DR (1994) A description of the fifth-generation Penn State/NCAR Mesoscale Model (MMS). NCAR Tech. Note, NCAR/TN-398+STR, 122 pp

  • Gu G, Adler RF, Huffman GJ, Curtis S (2004) African easterly waves and their association with precipitation. J Geophys Res 109:D04101

    Article  Google Scholar 

  • Holtslag AAM, de Bruijn EIF, Pan HL (1990) A high resolution air mass transformation model for short-range weather forecasting. Monthly Weather Review, 118

  • Hurst HE, Phillips P (1938) The Nile Basin, V, the hydrology of the Lake Plateau and Bahr el Jebel. Government Press, Cairo

    Google Scholar 

  • 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:L22705

    Article  Google Scholar 

  • Kiehl JT, Hack JJ, Bonan GB, Boville B (1996) Description of the NCAR Community Climate Model (CCM 3). NASA, Boulder

    Google Scholar 

  • Koteswaram P (1958) The Easterly Jet Stream in the tropics*. Tellus 10:43–57

    Article  Google Scholar 

  • Leroux S, Hall NMJ (2009) On the relationship between African easterly waves and the African easterly jet. J Atmos Sci 66:2303–2316

    Article  Google Scholar 

  • Liebmann B, Smith CA (1996) Description of a complete (interpolated) outgoing longwave radiation dataset. Bull Amer Meteor Soc 77:1275–1277

    Google Scholar 

  • Mekonnen A, Thorncroft CD, Aiyyer AR (2006) Analysis of convection and its association with African easterly waves. J Clim 19:5405–5421

    Article  Google Scholar 

  • 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). Journal of Climate.

  • Mohamed YA, Bastiaanssen WGM, Savenije HHG (2004) Spatial variability of evaporation and moisture storage in the swamps of the upper Nile studied by remote sensing techniques. J Hydrol 289:145–164

    Article  Google Scholar 

  • Mohamed YA, Van Den Hurk B, Savenije HHG, Bastiaanssen WGM (2005a) Hydroclimatology of the Nile: results from a regional climate model. Hydrol Earth Syst Sci Discuss 2:319–364

    Article  Google Scholar 

  • Mohamed YA, Van Den Hurk B, Savenije HHG, Bastiaanssen WGM (2005b) Impact of the Sudd wetland on the Nile hydroclimatology. Water Resour Res 41:W08420

    Article  Google Scholar 

  • Mohr KI, Thorncroft CD (2006) Intense convective systems in West Africa and their relationship to the African easterly jet. Q J R Meteorol Soc 132:163–176

    Article  Google Scholar 

  • Neue HU, Gaunt JL, Wang ZP, Becker-Heidmann P, Quijano C (1997) Carbon in tropical wetlands. Geoderma 79:163–185

    Article  Google Scholar 

  • Nicholson SE (2008) The intensity, location and structure of the tropical rainbelt over west Africa as factors in interannual variability. Int J Climatol 28:1775–1785

    Article  Google Scholar 

  • Nikulin G, Jones C, Samuelsson P, Giorgi F, Sylla MB, Asrar G, Baüchner M, Christensen OB, Déqué M, Fernandez J (2012) Precipitation climatology in an ensemble of CORDEX-Africa regional climate simulations. Journal of Climate. doi:10.1175/JCLI-D-11-00375.1

  • 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 14:349–368

    Article  Google Scholar 

  • Pal JS, Eltahir EAB, Small EE (2000) Simulation of regional-scale water and energy budgets—representation of subgrid cloud and precipitation processes within RegCM. J Geophys Res 105:567–594

    Article  Google Scholar 

  • Pal JS, Giorgi F, Bi X, Elguindi N, Solmon F, Rauscher SA, Gao X, Francisco R, Zakey A, Winter J (2007) Regional climate modeling for the developing world: the ICTP RegCM3 and RegCNET. Bull Am Meteorol Soc 88:1395–1409

    Article  Google Scholar 

  • Reynolds RW, Smith TM, Liu C, Chelton DB, Casey KS, Schlax MG (2007) Daily high-resolution-blended analyses for sea surface temperature

  • Ruti PM, Dell’aquila A (2010) The twentieth century African easterly waves in reanalysis systems and IPCC simulations, from intra-seasonal to inter-annual variability. Climate dynamics , 1–19.

  • Schuyt KD (2005) Economic consequences of wetland degradation for local populations in Africa. Ecol Econ 53:177–190

    Article  Google Scholar 

  • Shamseddin MAH, Hata T, Tada A, Bashir MA, Tanakamaru T (2006) Estimation of flooded area in the Bahr El-Jebel basin using remote sensing techniques. Hydrol Earth Syst Sci Discuss 3:1851–1877

    Article  Google Scholar 

  • Steiner AL, Pal JS, Rauscher SA, Bell JL, Diffenbaugh NS, Boone A, Sloan LC, Giorgi F (2009) Land surface coupling in regional climate simulations of the West African monsoon. Clim Dyn 33:869–892

    Article  Google Scholar 

  • Sun L, Semazzi FHM, Giorgi F, Ogallo L (1999) Application of the NCAR regional climate model to eastern Africa 1. Simulation of the short rains of 1988. J Geophys Res 104:6529–6548

    Google Scholar 

  • Sutcliffe, J. V., Parks, Y. P., International Association OF Hydrological, S., Iahs & Aish (1999) The hydrology of the Nile. International Association of Hydrological Sciences, Wallingford

    Google Scholar 

  • Sylla MB, Coppola E, Mariotti L, Giorgi F, Ruti PM, Dell’aquila A, Bi X (2010a) Multiyear simulation of the African climate using a regional climate model (RegCM3) with the high resolution ERA-interim reanalysis. Clim Dyn 35:231–247

    Article  Google Scholar 

  • Sylla MB, Dell'aquila A, Ruti PM, Giorgi F (2010b) Simulation of the intraseasonal and the interannual variability of rainfall over West Africa with RegCM3 during the monsoon period. Int J Climatol 30:1865–1883

    Google Scholar 

  • Sylla MB, Gaye AT, Jenkins GS, Pal JS, Giorgi F (2010c) Consistency of projected drought over the Sahel with changes in the monsoon circulation and extremes in a regional climate model projections. J Geophys Res 115:D16108

    Article  Google Scholar 

  • Sylla MB, Giorgi F, Ruti PM, Calmanti S, Dell’aquila A (2011) The impact of deep convection on the West African summer monsoon climate: a regional climate model sensitivity study. Q J R Meteorol Soc 137:1417–1430. doi:10.1002/qj.853

    Google Scholar 

  • Sylla MB, Giorgi F, Coppola E, Mariotti L (2012) Uncertainties in daily rainfall over Africa: assessment of gridded observation products and evaluation of a regional climate model simulation. Int J Climatol. doi:10.1002/joc.3551

  • Tate E, Sutcliffe J, Conway D, Farquharson F (2004) Water balance of Lake Victoria: update to 2000 and climate change modelling to 2100 / Bilan hydrologique du Lac Victoria: mise à jour jusqu’en 2000 et modélisation des impacts du changement climatique jusqu’en 2100. Hydrol Sci J 49:574

    Google Scholar 

  • Teferi E, Uhlenbrook S, Bewket W, Wenninger J, Simane B (2011) The use of remote sensing to quantify wetland loss in the Choke Mountain range, Upper Blue Nile basin, Ethiopia. Hydrol Earth Syst Sci 14:2415–2428

    Article  Google Scholar 

  • Thorncroft CD, Blackburn M (1999) Maintenance of the African easterly jet. Q J R Meteorol Soc 125:763–786

    Google Scholar 

  • Thorncroft CD, Hall NMJ, Kiladis GN (2008) Three-dimensional structure and dynamics of African easterly waves. Part III: genesis. J Atmos Sci 65:3596–3607

    Article  Google Scholar 

  • Turner RK, Van Den Bergh JCJM, Söderqvist T, Barendregt A, Van Der Straaten J, Maltby E, Van Ierland EC (2000) Ecological-economic analysis of wetlands: scientific integration for management and policy. Ecol Econ 35:7–23

    Article  Google Scholar 

  • Uppala S, Dee D, Kobayashi S, Berrisford P, Simmons A (2008) Towards a climate data assimilation system: status update of ERA-Interim. ECMWF Newsletter 115:12–18

    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 107:4023

    Article  Google Scholar 

  • Wu MLC, Reale O, Schubert SD, Suarez MJ, Koster RD, Pegion PJ (2009) African easterly jet: structure and maintenance. Journal of Climate , 4459–4480

  • 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 Clim 11:2628–2644

    Article  Google Scholar 

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Acknowledgments

This work has been supported by the Earth System Physics (ESP) in the International Centre for Theoretical Physics (ICTP), the STEP program, and the International Atomic Energy Agency (IAEA). The authors would like to acknowledge Dr. Gulilat Diro, Dr. Erika Coppola, and Dr. Laura Mariotti for their support in using the model and sharing their modeling calibration and experience. Finally, the authors would like to thank all the staff of the ESP and the RegCM team for their support.

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Authors and Affiliations

  1. Dinder Center for Environmental Research, Khartoum, Sudan

    Modathir A. H. Zaroug

  2. Earth System Physics, International Center for Theoretical Physics, Trieste, Italy

    Modathir A. H. Zaroug, M. B. Sylla & F. Giorgi

  3. Hydraulics Research Center, Ministry of Water Resources and Electricity, Wad Madani, Sudan

    Modathir A. H. Zaroug

  4. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA

    Elfatih A. B. Eltahir

  5. Isotope Hydrology Section, International Atomic Energy Agency, Vienna, Austria

    Pradeep K. Aggarwal

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  1. Modathir A. H. Zaroug
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Correspondence to Modathir A. H. Zaroug.

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Zaroug, M.A.H., Sylla, M.B., Giorgi, F. et al. A sensitivity study on the role of the swamps of southern Sudan in the summer climate of North Africa using a regional climate model. Theor Appl Climatol 113, 63–81 (2013). https://doi.org/10.1007/s00704-012-0751-6

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