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Uncertainties of GPM DPR Rain Estimates Caused by DSD Parameterizations.
- Source :
-
Journal of Applied Meteorology & Climatology . Nov2014, Vol. 53 Issue 11, p2524-2537. 14p. 1 Diagram, 8 Graphs. - Publication Year :
- 2014
-
Abstract
- A framework based on measured raindrop size distribution (DSD) data has been developed to assess uncertainties in DSD models employed in Ku- and Ka-band dual-wavelength radar retrievals. In this study, the rain rates and attenuation coefficients from DSD parameters derived by dual-wavelength algorithms are compared with those directly obtained from measured DSD spectra. The impact of the DSD gamma parameterizations on rain estimation from the Global Precipitation Measurement mission (GPM) Dual-Frequency Precipitation Radar (DPR) is examined for the cases of a fixed shape factor μ as well as for a constrained μ-that is, a μ-Λ relation (a relationship between the shape parameter and slope parameter Λ of the gamma DSD)-by using 11 Particle Size and Velocity (Parsivel) disdrometer measurements with a total number of about 50 000 one-minute spectra that were collected during the Iowa Flood Studies (IFloodS) experiment. It is found that the DPR-like dual-wavelength techniques provide fairly accurate estimates of rain rate and attenuation if a fixed- μ gamma DSD model is used, with the value of μ ranging from 3 to 6. Comparison of the results reveals that the retrieval errors from the μ-Λ relations are generally small, with biases of less than ±10%, and are comparable to the results from a fixed- μ gamma model with μ equal to 3 and 6. The DSD evaluation procedure is also applied to retrievals in which a lognormal DSD model is used. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 15588424
- Volume :
- 53
- Issue :
- 11
- Database :
- Academic Search Index
- Journal :
- Journal of Applied Meteorology & Climatology
- Publication Type :
- Academic Journal
- Accession number :
- 99345178
- Full Text :
- https://doi.org/10.1175/JAMC-D-14-0003.1