SciELO - Scientific Electronic Library Online

vol.34 issue1 author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand



Related links

  • On index processCited by Google
  • On index processSimilars in Google


Water SA

On-line version ISSN 1816-7950
Print version ISSN 0378-4738

Water SA vol.34 n.1 Pretoria Jan. 2008


Application of satellite-derived rainfall estimates to extend water resource simulation modelling in South Africa



T Sawunyama; DA Hughes

Institute for Water Research, Rhodes University, 6140, South Africa





Spatially interpolated rainfall estimates from rain-gauges are widely used as input to hydrological models, but deriving accurate estimates at appropriate space and time scales remain a major problem. In South Africa there has been a gradual decrease in the number of active rain-gauges over time. Satellite-based estimates of spatial rainfall are becoming more readily available and offer a viable substitute. The paper presents the potential of using Climate Prediction Center African daily precipitation climatology (CPCAPC) satellite-based datasets (2001-2006) to drive a Pitman hydrological model which has been calibrated using gauge-based rainfall data (1920-1990). However, if two sources of rainfall data are to be used together, it is necessary to ensure that they are compatible in terms of their statistical properties. A non-linear frequency of exceedance transformation technique was used to correct the satellite data to be more consistent with historical spatial rainfall estimates. The technique generated simulation results for the 2001 to 2006 period that were greatly improved compared to the direct use of the untransformed satellite data. While there remain some further questions about the use of satellite-derived rainfall data in different parts of the country, they do seem to have the potential to contribute to extending water resource modelling into the future.

Keywords: satellite-based rainfall, hydrological model, water resources, South Africa


"Full text available in PDF"



ADLER RF, HUFMAN GH and KEEHN RP (1994) Global tropical rain estimates from microwave-adjusted, geosynchronous IR data. Remote Sens. Rev. 11 125-152.         [ Links ]

ANDRÉASSIAN V, PERRIN C, MICHEL C, USART-SANCHEZ-, I and LAVABRE-, J (2001) Impact of imperfect rainfall knowledge on the efficiency and the parameters of watershed models. J. Hydrol. 250 206-223.         [ Links ]

BARRERA DF, CEIRANO ED and ZUCARELLI GV (2007) Differences in area-averaged rainfall depth over a mid-size basin from two remote sensing methods of estimating precipitation. In: Proc. Predictions in Ungauged Basins: PUB Kick-Off. PUB Kick-off meeting held in Brasilia, 20-22 November 2002. IAHS Publ.309, IAHS Press, Wallingford, UK.         [ Links ]

BEVEN KJ and BINLEY AM (1992) The future of distributed models-model calibration and uncertainty prediction. Hydrol. Process. 6 (3) 279-298.         [ Links ]

GÖRGENS AHM (1983) Conceptual Modelling of Rainfall-Runoff Process in Semi-Arid Catchments. Report No. 1/83, Hydrological Research Unit, Rhodes University, Grahamstown, South Africa.         [ Links ]

GOURLEY JJ and VIEUX BE (2006) A method for identifying sources of model uncertainty in rainfall-runoff simulations. J. Hydrol. 327 (1-2) 68-80.         [ Links ]

GOVENDER M, CHETTY K and BULCOCK H (2007) A review of hyperspectral remote sensing and its application in vegetation and water resource studies. Water SA 33 (2) 145-152.         [ Links ]

GRIMES D and DIOP M (2003) Satellite-based rainfall estimation for river flow forecasting in Africa. Part 1. Rainfall estimates and hydrological forecasts. Hydrol. Sci. J. 48 (4) 567-584.         [ Links ]

HSU K, GUPTA HV, GAO X and SOROOSHIAN S (1999) Estimation of physical variables from multi-channel remotely sensed imagery using a neural network: Application to rainfall estimation. Water Resour. Res. 35 (5) 1605-1618.         [ Links ]

HUFFMAN GJ, ADLER RE, ARKIN PA, CHANG A, FERRARO R, GRUBER A, JANOWIAK JJ, JOYCE RJ, McNAB A, RUDOLF B, SCHNEIDER U and XIE P (1997) The Global Precipitation Climatology Project (GPCP) combined precipitation data set. Bull. Am. Met. Soc. 78 5-20.         [ Links ]

HUGHES DA (2004) Incorporating ground water recharge and discharge functions into an existing monthly rainfall-runoff model. Hydrol. Sci. J. 49 (2) 297-311.         [ Links ]

HUGHES DA (2006a) Comparison of satellite rainfall data with observations from gauging station networks. J. Hydrol. 256 234-235.         [ Links ]

HUGHES DA (2006b) An evaluation of potential use of satellite rainfall data for input to water resource estimation models in southern Africa. In: Proc. 5th Int. FRIEND Conf. on Climate Variability and Change-Hydrological Impacts. (Held in November, 2006 in Havana, Cuba.). IAHS Publ. No. 308 75-80. IAHS Press, Wallingford, UK.         [ Links ]

HUGHES DA and FORSYTH DA (2006) A generic database and spatial interface for the application of hydrological and water resource models. Comput. Geosci. 32 1389-1402.         [ Links ]

HUGHES DA and SMAKHTIN VY (1996) Daily flow time series patching or extension: a spatial interpolation approach based on flow duration curves. Hydrol. Sci. J. 41 (6) 851-871.         [ Links ]

KIDD C (2001) Satellite rainfall climatology: a review. Int. J. Climatol. 21 (9) 1041-1066.         [ Links ]

LABBERRY R, KNIVETON DR and TODD MC (2005) SAFARI 2000 Daily Rainfall Estimates, 0.1-Deg, Southern Africa, 1993-2001. Data set. Available on-line [] from Oak Ridge Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA.         [ Links ]

LAWS KB, JANOWIAK JE and HUFFMAN GJ (2004) Verification of Rainfall Estimates over Africa using RFE, NASA MPA-RT and CMORPH Paper P2.2. 18th Conf. on Hydrology. Ame. Met. Soc. 11-15 January 2004, held in Seattle, WA. 6 pp.         [ Links ]

LOVE TB, KUMAR V, XIE P and THIAW W (2004) A 20 year Daily Africa Precipitation Climatology using satellite and gauge data. 14th Conf. on Appl. Clim. Ame. Met. Soc. 11-15 January 2004, Seattle, WA.         [ Links ]

MIDGLEY DC, PITMAN WV and MIDDLETON BJ (1994) Surface Water Resources of South Africa 1990, Volumes I to VI. WRC Reports No. 298/1.1/94 to 298/6.2/94. Water Research Commission, Pretoria, South Africa.         [ Links ]

NASH JE and SUTCLIFFE JV (1970) River flow forecasting through conceptual models. Part I - a discussion of principles. J. Hydrol 10 282-290.         [ Links ]

SANDHAM LA, SEED AW and VAN RENSBURG PAJ (1998) The relationship between half-hourly rainfall occurrence and daily rainfall. Water SA 24 (2) 101-106.         [ Links ]

SCHÄFER NW (1991) Modelling the Areal Distribution of Daily Rainfall. Unpublished M.Sc. Eng. Thesis, Dept. of Agricultural Eng., University of Natal, Pietermaritzburg, South Africa.         [ Links ]

SEED AW and AUSTIN GL (1990) Sampling errors for raingauge-derived mean areal daily and monthly rainfall. J. Hydrol. 118 167-173.         [ Links ]

SOROOSHIAN S, HSU KL, GAO X, GUPTA HV, IMAM B and BRAITHWAITE D (2000) Evaluation of PERSIANN system satellite-based estimates of tropical rainfall. Bull. Am. Met. Soc. 81 (9) 2035-2046.         [ Links ]

THORNE V, COAKLEY P, GRIMES D and DUGDALE G (2001) Comparison of TAMSAT and CPC rainfall estimates with rainfall, for southern Africa. Int. J. Remote Sens. 22 (10) 1951-1974.         [ Links ]

TODD MC, BARRET EC, BEAUMONT MJ and BELLERYBY TJ (1999) Estimation of daily rainfall over the upper Nile River Basin using a continuously calibrated satellite infrared technique. J. Appl. Met. 6 201-210.         [ Links ]

TODD MC, KIDD C, KNIVETON D and BELLERYBY TJ (2001) A combined satellite and passive microwave technique for estimation of small-scale rainfall. J. Atmos. Ocean. Technol. 18 742-755.         [ Links ]

WILK J, KNIVETON D, ANDERSSON L, LAYBERRY R, TODD MC, HUGHES DA, RINGROSE S and VANDERPOST C (2006) Estimating rainfall and water balance over the Okavango River Basin for hydrological applications. J. Hydrol. 331 (1-2) 18-29.         [ Links ]

XIE P, YAROSH Y, LOVE T, JANOWIAK J and ARKIN P (2002) A real-time daily precipitation analysis over Africa as well as South Asia. 16th Conf. of Hydrol., Orlando, FL, Am. Met. Soc. Held on 12-17 January 2002.         [ Links ]

XU L, GAO X, SOROOSHIAN S, ARKIN P and IMAM B (1999) A microwave infrared threshold technique to improve the GOES precipitation index. J. Appl. Met. 38 569-579.         [ Links ]



+27 46 622-4014;
Fax: +27 46 622-9427

Received 16 October 2007
Accepted in revised form 14 November 2007.

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License