• Arkin, P. A. and P. Xie. 1994. The Global Precipitation Climatology Project: First algorithm intercomparison project. Bull. Amer. Meteor. Soc. 75:401419.

    • Search Google Scholar
    • Export Citation
  • Ba, M. B., R. Frouin, and S. E. Nicholson. 1995. Satellite-derived interannual variability of West African rainfall 1983–88. J. Appl. Meteor. 34:411431.

    • Search Google Scholar
    • Export Citation
  • Cook, K. H. 1997. Large-scale atmospheric dynamics and Sahelian precipitation. J. Climate 10:11371152.

  • Duvel, J. P. 1990. Convection over tropical Africa and the Atlantic Ocean during northern summer. Part II: Modulation by easterly waves. Mon. Wea. Rev. 118:18551868.

    • Search Google Scholar
    • Export Citation
  • Ferraro, R. R. 1997. Special Sensor Microwave Imager derived global rainfall estimates climatological applications. J. Geophys. Res. 102:1671516735.

    • Search Google Scholar
    • Export Citation
  • Griffiths, J. F. 1972. Climates of Africa. Vol. 10,. World Survey of Climatology, Elsevier, 604 pp.

  • Griffiths, J. F. and C. F. Hemming. 1964. A rainfall map of eastern Africa and southern Arabia. Memoirs, Vol. III, No. 10, East African Meteorological Department, 42 pp.

    • Search Google Scholar
    • Export Citation
  • Hollinger, J. 1991. DMSP SSM/I calibration/validation. Naval Research Laboratory Final Rep. Parts I and II, Washington, DC, 419 pp.

  • Huffman, G. J., R. F. Adler, B. Rudolf, U. Schneider, and P. R. Keehn. 1995. Global precipitation estimates based on a technique for combing satellite-based estimates, rain gauge analysis, and NWP model precipitation information. J. Climate 8:12841295.

    • Search Google Scholar
    • Export Citation
  • Huffman, G. J. Coauthors,. 1997. The Global Precipitation Climatology Project (GPCP) combined precipitation dataset. Bull. Amer. Meteor. Soc. 78:520.

    • Search Google Scholar
    • Export Citation
  • Janowiak, J. E. and P. A. Arkin. 1991. Rainfall variations in the Tropics during 1986–89, as estimated from observations of cloud-top temperature. J. Geophys. Res. 96:(Suppl.),. 33593373.

    • Search Google Scholar
    • Export Citation
  • Krajewski, W. F., G. J. Ciach, J. R. McCollum, and C. Bacotiu. 2000. Initial validation of the Global Precipitation Climatology Project monthly rainfall over the United States. J. Appl. Meteor. 39:10711086.

    • Search Google Scholar
    • Export Citation
  • Kummerow, C. Coauthors,. 2000. The status of the Tropical Rainfall Measuring Mission (TRMM) after two years in orbit. J. Appl. Meteor. 39:19651982.

    • Search Google Scholar
    • Export Citation
  • Laing, A. G. and J. M. Fritsch. 1993. Mesoscale convective complexes in Africa. Mon. Wea. Rev. 121:22542263.

  • Legates, D. R. and C. J. Willmott. 1990. Mean seasonal and spatial variability in gauge-corrected, global precipitation. Int. J. Climate 10:111127.

    • Search Google Scholar
    • Export Citation
  • Leroux, M. 1983. Le Climat de l'Afrique Tropicale. Vol. 2, Editions Champion, 24 pp. and 250 plates.

  • McCollum, J. R., A. Gruber, and M. B. Ba. 2000. Discrepancy between gauges and satellite estimates of rainfall in equatorial Africa. J. Appl. Meteor. 39:666679.

    • Search Google Scholar
    • Export Citation
  • Mohr, K. I. and E. J. Zipser. 1996. Mesoscale convective systems defined by their 85-GHz ice scattering signature: Size and intensity comparison over tropical oceans and continents. Mon. Wea. Rev. 124:24172437.

    • Search Google Scholar
    • Export Citation
  • Morrissey, M. L. and J. S. Greene. 1993. Comparison of two satellite-based rainfall algorithms using atoll rain gauge data. J. Appl. Meteor. 32:411425.

    • Search Google Scholar
    • Export Citation
  • Morrissey, M. L., M. A. Shafer, S. Postawko, and B. Gibson. 1995. Pacific raingauge data. Water Resour. Res. 31:21112113.

  • Nicholson, S. E. 1979. Revised rainfall series for the West African subtropics. Mon. Wea. Rev. 107:620623.

  • Nicholson, S. E. 1986. The spatial coherence of African rainfall anomalies—Interhemispheric teleconnections. J. Climate Appl. Meteor. 25:13651381.

    • Search Google Scholar
    • Export Citation
  • Nicholson, S. E. 2000. The availability of observational meteorological data over Africa. Proc. Int. Workshop on West African Monsoon Variability and Predictability, Dakar, Senegal, WMO, TMRP No. 63, WMO/TD-No. 1003, 7–10.

    • Search Google Scholar
    • Export Citation
  • Nicholson, S. E., J. Hoopingarner, and J. Kim. 1988. Atlas of African Rainfall and Its Interannual Variability. Florida State University, Department of Meteorology, 237 pp.

    • Search Google Scholar
    • Export Citation
  • Nicholson, S. E., M. B. Ba, and J. Kim. 1996. Rainfall in the Sahel during 1994. J. Climate 9:16731676.

  • Nicholson, S. E., B. Some, and B. Kone. 2000. A note on recent rainfall conditions in West Africa. including the rainy season of the 1997 ENSO year. J. Climate 13:26282640.

    • Search Google Scholar
    • Export Citation
  • Nicholson, S. E. Coauthors,. 2003. Validation of TRMM and other rainfall estimates with a high-density gauge dataset for West Africa. Part II: Validation of TRMM products. J. Appl. Meteor. 42:13551368.

    • Search Google Scholar
    • Export Citation
  • Rudolf, B. 1993. Management and analysis of precipitation data on a routine basis. Proc. Int. WMO/IAHS/ETH Symp. on Precipitation and Evaporation, Bratislava, Slovakia, Slovak Hydrometeorology Institute, 69–76.

    • Search Google Scholar
    • Export Citation
  • Rudolf, B., H. Hauschild, W. Rüth, and U. Schneider. 1994. Terrestrial precipitation analysis: Operational method and required density of point measurements. Global Precipitations and Climate Change, M. Dubois and F. Desalmand, Eds., Springer Verlag, 173–186.

    • Search Google Scholar
    • Export Citation
  • Sevruk, B. 1982. Methods of correction for systematic error in point precipitation measurement for operational use. WMO Operational Hydrology Rep. 21, WMO Rep. No. 589, 91 pp.

    • Search Google Scholar
    • Export Citation
  • Trewartha, G. 1970. The Earth's Problem Climates. The University of Wisconsin Press, 334 pp.

  • Xie, P. and P. A. Arkin. 1995. An intercomparison of gauge observations and satellite estimates of monthly precipitation. J. Appl. Meteor. 34:11431160.

    • Search Google Scholar
    • Export Citation
  • Xie, P. and P. A. Arkin. 1996. Analysis of global monthly precipitation using gauge observations, satellite estimates, and numerical model predictions. J. Climate 9:840858.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 433 134 4
PDF Downloads 232 88 3

Validation of TRMM and Other Rainfall Estimates with a High-Density Gauge Dataset for West Africa. Part I: Validation of GPCC Rainfall Product and Pre-TRMM Satellite and Blended Products

View More View Less
  • a Department of Meteorology, The Florida State University, Tallahassee, Florida
  • | b Centre Régional AGRHYMET, Niamey, Niger, and Service Météorologique Nationale, Ouagadougou, Burkina Faso
  • | c NOAA/NESDIS/ORA, Camp Springs, Maryland
  • | d NASA Goddard Space Flight Center, Greenbelt, Maryland
  • | e SODEXAM/Direction Météorologie Nationale, Abidjan, Ivory Coast
  • | f Direction Nationale de la Météorologie, Conakry, Guinea
  • | g Department of Water Resources, Banjul, Gambia
  • | h Direction de la Météorologie Nationale, Lomé, Togo
  • | i Direction Nationale de la Météorologie, Dakar, Senegal
  • | j Direction de la Météorologie Nationale, Cotonou, Benin
  • | k Meteorological Services Department, Legon-Accra, Ghana
  • | l Arizona Remote Sensing Center, Office of Arid Lands Studies, The University of Arizona, Tucson, Arizona
  • | m Direction Nationale de la Météorologie, Bamako, Mali
  • | n Service Climatologique, Direction de la Météorologie Nationale, Niamey, Niger
Restricted access

Abstract

Gauge data over North Africa are used to provide an assessment of satellite and blended rainfall products for 1988–94 and for 1998. A comparison is also made with the Global Precipitation Climatology Center (GPCC) gauge dataset. For the 1988–94 period, mean fields and latitudinal transects for the June–July–August season are presented, based on a 515-station gauge dataset, the GPCC gauge data, the Global Precipitation Climatology Project (GPCP) blended data, the infrared-based Geostationary Operational Environmental Satellite precipitation index (GPI), and the Special Sensor Microwave Imager (SSM/I) microwave estimates. Error calculations are also presented. The mean fields derived from the dense gauge network, the GPCC gauge-only analysis, and the GPCP are remarkably similar. The bias, with reference to the seasonal rainfall field based on the denser network, is about 3%–4% for either GPCC or GPCP. Agreement is relatively good, even in individual years. The rms error associated with these datasets is 12% for seasonal rainfall totals; thus, the error is largely random. In contrast, there are large systematic errors in the satellite-only analyses of GPI and SSM/I, with biases of 20% and 40% for the mean rain field as a whole and much larger biases in individual years. The rms errors are nearly 2 times as great. For 1998, a 920-station gauge dataset was available for a smaller section of West Africa. The comparison confirmed the superior performance of GPCP and demonstrated the lower level of performance of both GPCP and GPCC at the monthly scale as compared with the seasonal scale. Overall, the results of this study underscore the continued need for extensive gauge networks to describe adequately the large-scale precipitation field over Africa.

Deceased

Corresponding author address: Dr. Sharon Nicholson, Dept. of Meteorology, The Florida State University, Tallahassee, FL 32306. sen@met.fsu.edu

Abstract

Gauge data over North Africa are used to provide an assessment of satellite and blended rainfall products for 1988–94 and for 1998. A comparison is also made with the Global Precipitation Climatology Center (GPCC) gauge dataset. For the 1988–94 period, mean fields and latitudinal transects for the June–July–August season are presented, based on a 515-station gauge dataset, the GPCC gauge data, the Global Precipitation Climatology Project (GPCP) blended data, the infrared-based Geostationary Operational Environmental Satellite precipitation index (GPI), and the Special Sensor Microwave Imager (SSM/I) microwave estimates. Error calculations are also presented. The mean fields derived from the dense gauge network, the GPCC gauge-only analysis, and the GPCP are remarkably similar. The bias, with reference to the seasonal rainfall field based on the denser network, is about 3%–4% for either GPCC or GPCP. Agreement is relatively good, even in individual years. The rms error associated with these datasets is 12% for seasonal rainfall totals; thus, the error is largely random. In contrast, there are large systematic errors in the satellite-only analyses of GPI and SSM/I, with biases of 20% and 40% for the mean rain field as a whole and much larger biases in individual years. The rms errors are nearly 2 times as great. For 1998, a 920-station gauge dataset was available for a smaller section of West Africa. The comparison confirmed the superior performance of GPCP and demonstrated the lower level of performance of both GPCP and GPCC at the monthly scale as compared with the seasonal scale. Overall, the results of this study underscore the continued need for extensive gauge networks to describe adequately the large-scale precipitation field over Africa.

Deceased

Corresponding author address: Dr. Sharon Nicholson, Dept. of Meteorology, The Florida State University, Tallahassee, FL 32306. sen@met.fsu.edu

Save