Radar Rain-Rate Estimators and Their Variability due to Rainfall Type: An Assessment Based on Hydrometeorology Testbed Data from the Southeastern United States

Details

• Journal Title:
  Journal of Applied Meteorology and Climatology
• Personal Author:
  Matrosov, Sergey Y. ; Cifelli, Robert ; Neiman, Paul J. ; White, Allen B.
• NOAA Program & Office:
  OAR (Oceanic and Atmospheric Research) ; PSL (Physical Sciences Laboratory) ; CIRES (Cooperative Institute for Research in Environmental Sciences) ; CIRA (Cooperative Institute for Research in the Atmosphere)
• Description:
  S-band profiling (S-PROF) radar measurements from different southeastern U.S. Hydrometeorology Testbed sites indicated a frequent occurrence of rain that did not exhibit radar bright band (BB) and was observed outside the periods of deep-convective precipitation. This common nonbrightband (NBB) rain contributes similar to 15%-20% of total accumulation and is not considered as a separate rain type by current precipitation-segregation operational radar-based schemes, which separate rain into stratiform, convective, and, sometimes, tropical types. Collocated with S-PROF, disdrometer measurements showed that drop size distributions (DSDs) of NBB rain have much larger relative fractions of smaller drops when compared with those of BB and convective rains. Data from a year of combined DSD and rain-type observations were used to derive S-band-radar estimators of rain rate R, including those based on traditional reflectivity Z(e) and ones that also use differential reflectivity Z(DR) and specific differential phase K-DP. Differences among same-type estimators for mostly stratiform BB and deep-convective rain were relatively minor, but estimators derived for the common NBB rain type were distinct. Underestimations in NBB rain-rate retrievals derived using other rain-type estimators (e.g., those for BB or convective rain or default operational radar estimators) for the same values of radar variables can be on average about 40%, although the differential phase-based estimators are somewhat less susceptible to DSD details. No significant differences among the estimators for the same rain type derived using DSDs from different observational sites were present despite significant separation and differing terrain. Identifying areas of common NBB rain could be possible from Z(e) and Z(DR) measurements.
• Source:
  Journal of Applied Meteorology and Climatology, 55(6), 1345-1358.
• DOI:
  https://doi.org/10.1175/JAMC-D-15-0284.1
• Document Type:
  Journal Article
• Rights Information:
  Other
• Compliance:
  Submitted
• Download URL:
  https://repository.library.noaa.gov/view/noaa/14582/noaa_14582_DS1.pdf
• File Type:
  [PDF - 2.41 MB]
• Collection(s):
  Office of Oceanic and Atmospheric Research (OAR) ; NOAA Cooperative Institutes
• Main Document Checksum:
  urn:sha256:48e96cde84dbb10accf743d7007b9c60da97cb8e3194254bfb56dd9acc5f77b7