Skip to main content

Exploring the transient behavior of Z-R relationships: Implications for radar rainfall estimation

Publication ,  Journal Article
Prat, OP; Barros, AP
Published in: Journal of Applied Meteorology and Climatology
October 1, 2009

The objective of this study is to characterize the signature of dynamical microphysical processes on reflectivity-rainfall (Z-R) relationships used for radar rainfall estimation. For this purpose, a bin model with explicit microphysics was used to perform a sensitivity analysis of the shape parameters of the drop size distribution (DSD) as a function of time and rainfall regime. Simulations show that coalescence is the dominant microphysical process for low to moderate rain intensity regimes (R, 20 mm h21) and that the rain rate in this regime is strongly dependent on the spectral properties of the DSD (i.e., the shape). The time to equilibrium for light rainfall is at least twice as long as in the case of heavy rainfall (1 h for stratiform vis-à-vis 30 min for thunderstorms). For high-intensity rainfall (R. 20 mm h21), collision-breakup dynamics domi- nate the evolution of the raindrop spectra. The time-dependent Z-R relationships produced by the model converge to a universal Z-R relationship for heavy intensity rainfall (A 5 1257; b; 1) centered on the region of Z-R space defined by the ensemble of over 100 empirical Z-R relationships. Given the intrinsically transient nature of the DSD for light rainfall, it is proposed that the vertical raindrop spectra and cor- responding rain rates should be modeled explicitly by a microphysical model. A demonstration using a multicolumn simulation of a Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) over-pass over Darwin for a stratiform event during the Tropical Warm Pool-International Cloud Experiment (TWP-ICE) is presented. © 2009 American Meteorological Society.

Duke Scholars

Published In

Journal of Applied Meteorology and Climatology

DOI

ISSN

1558-8424

Publication Date

October 1, 2009

Volume

48

Issue

10

Start / End Page

2127 / 2143

Related Subject Headings

  • Meteorology & Atmospheric Sciences
  • 3702 Climate change science
  • 3701 Atmospheric sciences
  • 0701 Agriculture, Land and Farm Management
  • 0502 Environmental Science and Management
  • 0401 Atmospheric Sciences
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Prat, O. P., & Barros, A. P. (2009). Exploring the transient behavior of Z-R relationships: Implications for radar rainfall estimation. Journal of Applied Meteorology and Climatology, 48(10), 2127–2143. https://doi.org/10.1175/2009JAMC2165.1
Prat, O. P., and A. P. Barros. “Exploring the transient behavior of Z-R relationships: Implications for radar rainfall estimation.” Journal of Applied Meteorology and Climatology 48, no. 10 (October 1, 2009): 2127–43. https://doi.org/10.1175/2009JAMC2165.1.
Prat OP, Barros AP. Exploring the transient behavior of Z-R relationships: Implications for radar rainfall estimation. Journal of Applied Meteorology and Climatology. 2009 Oct 1;48(10):2127–43.
Prat, O. P., and A. P. Barros. “Exploring the transient behavior of Z-R relationships: Implications for radar rainfall estimation.” Journal of Applied Meteorology and Climatology, vol. 48, no. 10, Oct. 2009, pp. 2127–43. Scopus, doi:10.1175/2009JAMC2165.1.
Prat OP, Barros AP. Exploring the transient behavior of Z-R relationships: Implications for radar rainfall estimation. Journal of Applied Meteorology and Climatology. 2009 Oct 1;48(10):2127–2143.

Published In

Journal of Applied Meteorology and Climatology

DOI

ISSN

1558-8424

Publication Date

October 1, 2009

Volume

48

Issue

10

Start / End Page

2127 / 2143

Related Subject Headings

  • Meteorology & Atmospheric Sciences
  • 3702 Climate change science
  • 3701 Atmospheric sciences
  • 0701 Agriculture, Land and Farm Management
  • 0502 Environmental Science and Management
  • 0401 Atmospheric Sciences