Spatial Variability of Surface Rainfall as Observed from TRMM Field Campaign Data

Saswati Datta Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore, Maryland

Search for other papers by Saswati Datta in
Current site
Google Scholar
PubMed
Close
,
W. Linwood Jones School of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida

Search for other papers by W. Linwood Jones in
Current site
Google Scholar
PubMed
Close
,
Biswadev Roy Science Systems and Applications, Inc., Seabrook, and Mesoscale Processes Branch, NASA Goddard Space Flight Center, Greenbelt, Maryland

Search for other papers by Biswadev Roy in
Current site
Google Scholar
PubMed
Close
, and
Ali Tokay Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore, Maryland

Search for other papers by Ali Tokay in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

The spatial variability of surface rainfall over 5- and 30-day time periods is observed, and it is found that the spatial decorrelation length of precipitation is comparable to the size of a single surface gauge network. The observed variability is found to affect radar-derived precipitation estimation, particularly if it is based on calibration using rain gauges. The radar subgrid-scale variability is also observed using some redundant and finer-scale gauge networks deployed during the Tropical Rainfall Measuring Mission (TRMM) ground-validation field campaigns. Based upon statistical analysis and a point-based decision-making system, a best-suited spatial–temporal filtering technique is suggested and, when applied to match radar data with any other surface observation, is found to reduce bias.

Corresponding author address: Dr. Saswati Datta, Joint Center for Earth Systems Technology (JCET), University of Maryland, Baltimore County, ACIV Wing A, Rm 114, 1000 Hilltop Circle, Baltimore, MD 21250. sdatta@umbc.edu

Abstract

The spatial variability of surface rainfall over 5- and 30-day time periods is observed, and it is found that the spatial decorrelation length of precipitation is comparable to the size of a single surface gauge network. The observed variability is found to affect radar-derived precipitation estimation, particularly if it is based on calibration using rain gauges. The radar subgrid-scale variability is also observed using some redundant and finer-scale gauge networks deployed during the Tropical Rainfall Measuring Mission (TRMM) ground-validation field campaigns. Based upon statistical analysis and a point-based decision-making system, a best-suited spatial–temporal filtering technique is suggested and, when applied to match radar data with any other surface observation, is found to reduce bias.

Corresponding author address: Dr. Saswati Datta, Joint Center for Earth Systems Technology (JCET), University of Maryland, Baltimore County, ACIV Wing A, Rm 114, 1000 Hilltop Circle, Baltimore, MD 21250. sdatta@umbc.edu

Save
  • Atlas, D., D. Rosenfield, and A. R. Jameson. 1997. Evolution of radar rainfall measurements: Steps and mis-steps. Weather Radar Technology for Water Resources Management, B. Braga and O. Massambani, Eds., UNESCO, 1–60.

    • Search Google Scholar
    • Export Citation
  • Battan, L. J. 1973. Radar Observation of the Atmosphere. University of Chicago Press, 323 pp.

  • Brandes, E. A., G. Zhang, and J. Vivekanandan. 2002. Experiments in rainfall estimation with a polarimetric radar in a subtropical environment. J. Appl. Meteor. 41:674685.

    • Search Google Scholar
    • Export Citation
  • Datta, S., B. Roy, and B. S. Ferrier. 2000. Quantitative estimation of some possible errors associated with radar derived monthly rain maps and a scheme for spatial averaging of radar accumulation. Eos, Trans. Amer. Geophys. Union 81:S224.

    • Search Google Scholar
    • Export Citation
  • Efford, N. 2000. Digital Image Processing: A Practical Introduction Using Java. Addison-Wesley, 340 pp.

  • Habib, E. and W. F. Krajewski. 2002. Uncertainty analysis of the TRMM ground-validation radar-rainfall products: Application to the TEFLUN-B field campaign. J. Appl. Meteor. 41:558572.

    • Search Google Scholar
    • Export Citation
  • Jain, A. K. 1989. Fundamentals of Digital Image Processing. Prentice Hall, 350 pp.

  • Joss, J. and A. Waldvogel. 1990. Precipitation measurement and hydrology. Radar in Meteorology, D. Atlas, Ed., Amer. Meteor. Soc., 577–600.

    • 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
  • Le Bouar, E., J. Testud, and T. D. Keenan. 2001. Validation of the rain profiling algorithm “ZPHI” from the C-band polarimetric weather radar in Darwin. J. Atmos. Oceanic Technol. 18:18191837.

    • Search Google Scholar
    • Export Citation
  • Marks, D. A., M. S. Kulie, M. Robinson, B. S. Ferrier, and E. Amitai. 1999. Standardized reference rainfall products used in TRMM ground validation efforts. Preprints, 29th Int. Conf. of Radar Meteorology, Montreal, QC, Canada, Amer. Meteor. Soc., 744–747.

    • Search Google Scholar
    • Export Citation
  • Neff, E. L. 1977. How much rain does a rain gauge? J. Hydrol. 35:213220.

  • Odland, J. 1988. Spatial Autocorrelation. SAGE Publications, 87 pp.

  • Robinson, M., D. A. Marks, M. S. Kulie, and B. S. Ferrier. 1999. Seasonal characteristics of non-meteorological radar reflectivity returns in east central Florida and their impact on TRMM ground validation. Preprints, 29th Int. Conf. of Radar Meteorology, Montreal, QC, Canada, Amer. Meteor. Soc., 740–743.

    • Search Google Scholar
    • Export Citation
  • Roy, B., S. Datta, W. L. Jones, and T. Kasparis. 2000. On utilization of NEXRAD scan strategy information to infer discrepancies associated with radar and rain gauge surface volumetric rainfall accumulation. Eos, Trans. Amer. Geophys. Union 81:F162.

    • Search Google Scholar
    • Export Citation
  • Tokay, A., A. Kruger, and W. F. Krajewski. 2001. Comparison of drop size distribution measurements by impact and optical disdrometers. J. Appl. Meteor. 40:20832097.

    • Search Google Scholar
    • Export Citation
  • Zawadzki, I. I. 1975. On radar-raingauge comparison. J. Appl. Meteor. 14:14301436.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 147 31 2
PDF Downloads 44 17 0