Comparisons of Reflectivities from the TRMM Precipitation Radar and Ground-Based Radars

Jianxin Wang Science System and Applications, Inc., Lanham, and NASA Goddard Space Flight Center, Greenbelt, Maryland

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David B. Wolff Science System and Applications, Inc., Lanham, and NASA Goddard Space Flight Center, Greenbelt, Maryland

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Abstract

Given the decade-long and highly successful Tropical Rainfall Measuring Mission (TRMM), it is now possible to provide quantitative comparisons between ground-based radars (GRs) and the spaceborne TRMM precipitation radar (PR) with greater certainty over longer time scales in various tropical climatological regions. This study develops an automated methodology to match and compare simultaneous TRMM PR and GR reflectivities at four primary TRMM Ground Validation (GV) sites: Houston, Texas (HSTN); Melbourne, Florida (MELB); Kwajalein, Republic of the Marshall Islands (KWAJ); and Darwin, Australia (DARW). Data from each instrument are resampled into a three-dimensional Cartesian coordinate system. The horizontal displacement during the PR data resampling is corrected. Comparisons suggest that the PR suffers significant attenuation at lower levels, especially in convective rain. The attenuation correction performs quite well for convective rain but appears to slightly overcorrect in stratiform rain. The PR and GR observations at HSTN, MELB, and KWAJ agree to about ±1 dB on average with a few exceptions, whereas the GR at DARW requires +1 to −5 dB calibration corrections. One of the important findings of this study is that the GR calibration offset is dependent on the reflectivity magnitude. Hence, it is proposed that the calibration should be carried out by using a regression correction rather than by simply adding an offset value to all GR reflectivities.

This methodology is developed to assist TRMM GV efforts to improve the accuracy of tropical rain estimates, but can also be applied to the proposed Global Precipitation Measurement and other related activities over the globe.

Corresponding author address: Jianxin Wang, NASA Goddard Space Flight Center, Code 613.1, Greenbelt, MD 20771. Email: jianxin.wang@nasa.gov

Abstract

Given the decade-long and highly successful Tropical Rainfall Measuring Mission (TRMM), it is now possible to provide quantitative comparisons between ground-based radars (GRs) and the spaceborne TRMM precipitation radar (PR) with greater certainty over longer time scales in various tropical climatological regions. This study develops an automated methodology to match and compare simultaneous TRMM PR and GR reflectivities at four primary TRMM Ground Validation (GV) sites: Houston, Texas (HSTN); Melbourne, Florida (MELB); Kwajalein, Republic of the Marshall Islands (KWAJ); and Darwin, Australia (DARW). Data from each instrument are resampled into a three-dimensional Cartesian coordinate system. The horizontal displacement during the PR data resampling is corrected. Comparisons suggest that the PR suffers significant attenuation at lower levels, especially in convective rain. The attenuation correction performs quite well for convective rain but appears to slightly overcorrect in stratiform rain. The PR and GR observations at HSTN, MELB, and KWAJ agree to about ±1 dB on average with a few exceptions, whereas the GR at DARW requires +1 to −5 dB calibration corrections. One of the important findings of this study is that the GR calibration offset is dependent on the reflectivity magnitude. Hence, it is proposed that the calibration should be carried out by using a regression correction rather than by simply adding an offset value to all GR reflectivities.

This methodology is developed to assist TRMM GV efforts to improve the accuracy of tropical rain estimates, but can also be applied to the proposed Global Precipitation Measurement and other related activities over the globe.

Corresponding author address: Jianxin Wang, NASA Goddard Space Flight Center, Code 613.1, Greenbelt, MD 20771. Email: jianxin.wang@nasa.gov

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  • Anagnostou, E. N., Morales C. A. , and Dinku T. , 2001: The use of TRMM precipitation radar observations in determining ground radar calibration biases. J. Atmos. Oceanic Technol., 18 , 616628.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Awaka, J., Iguchi T. , Kumagai H. , and Okamoto K. , 1997: Rain type classification algorithm for TRMM precipitation radar. Proc. Int. Geoscience and Remote Sensing Symp., Suntec City, Singapore, IEEE, 1633–1635.

    • Search Google Scholar
    • Export Citation
  • Bolen, S. M., and Chandrasekar V. , 2000: Quantitative cross validation of space-based and ground-based radar observations. J. Appl. Meteor., 39 , 20712079.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Crum, T. D., Alberty R. L. , and Burgess D. W. , 1993: Recording, archiving, and using WSR-88D data. Bull. Amer. Meteor. Soc., 74 , 645653.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Durden, S. L., Im E. , Haddad Z. S. , and Li L. , 2003: Comparison of TRMM precipitation radar and airborne radar data. J. Appl. Meteor., 42 , 769774.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Heymsfield, G. M., Ghosh K. K. , and Chen L. C. , 1983: An interactive system for compositing digital radar and satellite data. J. Climate Appl. Meteor., 22 , 705713.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Heymsfield, G. M., Geerts B. , and Tian L. , 2000: TRMM precipitation radar reflectivity profiles as compared with high-resolution airborne and ground-based radar measurements. J. Appl. Meteor., 39 , 20802102.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hitschfeld, W., and Bordan J. , 1954: Errors inherent in the radar measurements of rainfall at attenuating wavelengths. J. Meteor., 11 , 5867.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Houze R. A. Jr., , Brodzik S. , Schumacher C. , and Yuter S. E. , 2004: Uncertainties in oceanic radar rain maps at Kwajalein and implications for satellite validation. J. Appl. Meteor., 43 , 11141132.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Iguchi, T., and Meneghini R. , 1994: Intercomparison of single-frequency methods for retrieving a vertical rain profile from airborne or spaceborne radar data. J. Atmos. Oceanic Technol., 11 , 15071516.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Iguchi, T., Kozu T. , Meneghini R. , Awaka J. , and Okamoto K. , 2000: Rain-profiling algorithm for the TRMM precipitation radar. J. Appl. Meteor., 39 , 20382052.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kawanishi, T., and Coauthors, 2000: TRMM precipitation radar. Adv. Space Res., 25 , 969972.

  • Kozu, T., and Iguchi T. , 1999: Nonuniform beamfilling correction for spaceborne radar rainfall measurement: Implications from TOGA COARE radar data analysis. J. Atmos. Oceanic Technol., 16 , 17221735.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kozu, T., and Coauthors, 2001: Development of precipitation radar on board the Tropical Rainfall Measuring Mission (TRMM) satellite. IEEE Trans. Geosci. Remote Sens., 39 , 102116.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liao, L., Meneghini R. , and Iguchi T. , 2001: Comparisons of rain rate and reflectivity factor derived from the TRMM precipitation radar and the WSR-88D over the Melbourne, Florida site. J. Atmos. Oceanic Technol., 18 , 19591974.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Marks, D. A., and Coauthors, 2000: Climatological processing and product development for the TRMM Ground Validation program. Phys. Chem. Earth, 25B , 871875.

    • Search Google Scholar
    • Export Citation
  • Marks, D. A., Wolff D. B. , Silberstein D. S. , Tokay A. , Pippitt J. L. , and Wang J. , 2009: Availability of high-quality TRMM ground validation data from Kwajalein, RMI: A practical application of the relative calibration adjustment technique. J. Atmos. Oceanic Technol., 26 , 413429.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mohr, C. G., and Vaughan R. L. , 1979: An economical procedure for Cartesian interpolation and display of reflectivity data in three-dimensional space. J. Appl. Meteor., 18 , 661670.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Robinson, M., and Coauthors, 2000: Evolving improvements to TRMM ground validation rainfall estimates. Phys. Chem. Earth, 25B , 971976.

    • Search Google Scholar
    • Export Citation
  • Rosenfeld, D., Wolff D. B. , and Amitai E. , 1994: The window probability matching method for rainfall measurements with radar. J. Appl. Meteor., 33 , 682693.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schumacher, C., and Houze R. A. Jr., 2000: Comparison of radar data from the TRMM satellite and Kwajalein oceanic validation site. J. Appl. Meteor., 39 , 21512164.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Silberstein, D. S., Wolff D. B. , Marks D. A. , Atlas D. , and Pippitt J. L. , 2008: Ground clutter as a monitor of radar stability at Kwajalein, RMI. J. Atmos. Oceanic Technol., 25 , 20372045.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Simpson, J., Kummerow C. , Tao W-K. , and Adler R. F. , 1996: On the Tropical Rainfall Measuring Mission (TRMM). Meteor. Atmos. Phys., 60 , 1936.

  • Steiner, M., Houze R. A. Jr., and Yuter S. E. , 1995: Climatological characterization of three-dimensional storm structure from operational radar and rain gauge data. J. Appl. Meteor., 34 , 19782007.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Takahashi, N., Kuroiwa H. , and Kawanishi T. , 2003: Four-year result of external calibration for Precipitation Radar (PR) of the Tropical Rainfall Measuring Mission (TRMM) satellite. IEEE Trans. Geosci. Remote Sens., 41 , 23982403.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wilks, D. S., 1995: An Introduction to Statistical Methods in the Atmospheric Sciences. Academic Press, 465 pp.

  • Wolff, D. B., Marks D. A. , Amitai E. , Silberstein D. S. , Fisher B. L. , Tokay A. , Wang J. , and Pippitt J. L. , 2005: Ground validation for the Tropical Rainfall Measuring Mission (TRMM). J. Atmos. Oceanic Technol., 22 , 365380.

    • Crossref
    • Search Google Scholar
    • Export Citation
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