The Rain Profiling Algorithm Applied to Polarimetric Weather Radar

Testud, J.; Bouar, Erwan Le; Obligis, E.; Ali-Mehenni, Mustapha

doi:10.1175/1520-0426(2000)017<0332:trpaat>2.0.co;2

Cited by 375 publications

(345 citation statements)

References 22 publications

Supporting

Mentioning

323

Contrasting

Unclassified

Order By: Relevance

“…With a dual-polarization system, one can use the differential phase shift to calculate the attenuation due to rain. We applied the ZPHI method (Testud et al, 2000) to the entire dataset for which dualpolarization moments were available. The corrected Zh and , (e) bulk shear, and (f) mean rainfall rate (RR) and rainfall.…”

Section: Methodsmentioning

confidence: 99%

Overview: Precipitation characteristics and sensitivities to environmental conditions during GoAmazon2014/5 and ACRIDICON-CHUVA

et al. 2018

View full text Add to dashboard Cite

Abstract. This study provides an overview of precipitation processes and their sensitivities to environmental conditions in the Central Amazon Basin near Manaus during the GoAmazon2014/5 and ACRIDICON-CHUVA experiments. This study takes advantage of the numerous measurement platforms and instrument systems operating during both campaigns to sample cloud structure and environmental conditions during 2014 and 2015; the rainfall variability among seasons, aerosol loading, land surface type, and topography has been carefully characterized using these data. Differences between the wet and dry seasons were examined from a variety of perspectives. The rainfall rates distribution, total amount of rainfall, and raindrop size distribution (the massweighted mean diameter) were quantified over both seasons.The dry season generally exhibited higher rainfall rates than the wet season and included more intense rainfall periods. However, the cumulative rainfall during the wet season was 4 times greater than that during the total dry season rainfall, as shown in the total rainfall accumulation data. The typical size and life cycle of Amazon cloud clusters (observed by satellite) and rain cells (observed by radar) were examined, as were differences in these systems between the seasons. Moreover, monthly mean thermodynamic and dynamic variables were analysed using radiosondes to elucidate the differences in rainfall characteristics during the wet and dry seasons. The sensitivity of rainfall to atmospheric aerosol loading was discussed with regard to mass-weighted mean diameter and rain rate. This topic was evaluated only durPublished by Copernicus Publications on behalf of the European Geosciences Union. L. A. T. Machado et al.: Overview: Precipitation characteristics and sensitivities to environmental conditionsing the wet season due to the insignificant statistics of rainfall events for different aerosol loading ranges and the low frequency of precipitation events during the dry season. The impacts of aerosols on cloud droplet diameter varied based on droplet size. For the wet season, we observed no dependence between land surface type and rain rate. However, during the dry season, urban areas exhibited the largest rainfall rate tail distribution, and deforested regions exhibited the lowest mean rainfall rate. Airplane measurements were taken to characterize and contrast cloud microphysical properties and processes over forested and deforested regions. Vertical motion was not correlated with cloud droplet sizes, but cloud droplet concentration correlated linearly with vertical motion. Clouds over forested areas contained larger droplets than clouds over pastures at all altitudes. Finally, the connections between topography and rain rate were evaluated, with higher rainfall rates identified at higher elevations during the dry season.

show abstract

Section: Methodsmentioning

confidence: 99%

Overview: Precipitation characteristics and sensitivities to environmental conditions during GoAmazon2014/5 and ACRIDICON-CHUVA

et al. 2018

View full text Add to dashboard Cite

show abstract

“…It should be mentioned that the Hitschfeld and Bordan (1954) approach, which is sometimes used for retrieving the rainfall rate at modestly attenuating radar wavelengths (e.g., Testud et al 2000), is not suitable for highly attenuated K a -band radar measurements. One reason for that is that the exponent in a-Z e power-law relations at this band is very dependent on the details of the DSD (Matrosov 2005), while the constancy of this exponent is required by the Hitschfeld and Bordan approach.…”

Section: ͑5͒mentioning

confidence: 99%

Rainfall Profiling Using Atmospheric Radiation Measurement Program Vertically Pointing 8-mm Wavelength Radars

Matrosov

May

Shupe

2006

Journal of Atmospheric and Oceanic Technology

View full text Add to dashboard Cite

An attenuation-based method to retrieve vertical profiles of rainfall rate from vertically pointing K a -band radar measurements has been refined and adjusted for use with the U.S. Department of Energy's cloud radars deployed at multiple Atmospheric Radiation Program (ARM) test bed sites. This method takes advantage of the linear relationship between the rainfall rate and the attenuation coefficient, and can account for a priori information about the vertical profile of nonattenuated reflectivity. The retrieval method is applied to a wide variety of rainfall events observed at different ARM sites ranging from stratiform events with low-to-moderate rainfall rates (ϳ5 mm h Ϫ1 ) to heavy convective rains with rainfall rates approaching 100 mm h Ϫ1 . The K a -band attenuation-based retrieval results expressed in both instantaneous rainfall rates and in rainfall accumulations are compared to available surface data and measurements of a scanning C-band precipitation polarimetric radar located near the Darwin, Australia, ARM test bed site. The K a -band retrievals are found to be in good agreement with the C-band radar estimates, which are based both on conventional radar reflectivity approaches and on polarimetric differential phase shift measurements. Typically, the C-band-K a -band radar estimate differences are within the expected retrieval uncertainties. The magnitude of the K a -band rainfall-rate estimate error depends on the retrieval resolution, rain intensity, and uncertainties in the profiles of nonattenuated reflectivity. It is shown that reasonable retrieval accuracies (ϳ15%-40%) can be achieved for a large dynamic range of observed rainfall rates (4-100 mm h Ϫ1 ) and the effective vertical resolution of about 1 km. The potential enhancements of the K a -band attenuation-based method by including a priori information on vertical profiles of nonattenuated reflectivity and increasing the height range of the retrievals by using K a -band polarization measurements are also discussed. The addition of the precipitation products to the suite of ARM hydrometeor retrievals can enhance the overall characterization of the vertical atmospheric column.

show abstract

“…Rhyzkov et al (2005) used a combination of the different algorithms and Vulpiani et al (2009) used a neural network to retrieve the DSD parameters from polarimetric data. The ZPHI algorithm from Testud et al (2000) retrieves N w over a segment [r 0 ; r 1 ] by using the profiles of dp and (attenuated) Z h over [r 0 ; r 1 ]. Hogan (2007) developed a variational scheme which uses a forward model of Z dr and dp and iteratively retrieves the coefficient a in the Z -R relationship by minimizing the root mean square (RMS) error between the measured and the forward-modelled polarimetric variables.…”

Section: Selection Of the Qpe Algorithmsmentioning

confidence: 99%

Long‐term monitoring of French polarimetric radar data quality and evaluation of several polarimetric quantitative precipitation estimators in ideal conditions for operational implementation at C‐band

Ventura

Boumahmoud

Fradon

et al. 2012

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

This article presents the evaluation of several polarimetric quantitative precipitation estimation (Pol-QPE) algorithm candidates for operational implementation in the Météo-France polarimetric weather radars (nine C-band and one S-band out of a total of 24 radars in 2011). Since the performance of the algorithms depends on both the quality of the polarimetric variables and the applied polarimetric processing, the article first describes the current polarimetric processing chain and then provides a comprehensive analysis of the quality of the polarimetric variables.Three types of QPE algorithms have been studied at C-band in ideal conditions (short ranges, no partial beam blocking, no vertical profile of reflectivity effects): (i) algorithms based on simple Z-R relationships with and without attenuation correction using the differential phase dp , (ii) an algorithm based on reflectivity (Z h ) and differential reflectivity (Z dr ), and (iii) algorithms based on specific differential phase (K dp ).Evaluation against rain-gauges, performed hourly, confirms the superiority of polarimetric algorithms as repeatedly reported in the literature. It also shows that the benefits brought by algorithms based on power variables, Z h and Z dr , are critically dependent upon the capability to correctly calibrate them. Long-term monitoring shows that, with the current radar systems and operational calibration procedures, a stability of ±0.4 dB is achieved on Z dr . In that context, QPE algorithms based on K dp , which are considered to be immune to partial beam blocking, calibration, attenuation, etc., are preferred for operational use until improvements are made to the calibration of Z dr . To this end, a hybrid algorithm based on attenuationcorrected Z h for low rain rates and K dp for higher rain rates has been designed and tested Copyright c 2012 Royal Meteorological Society Key Words: polarimetry; polarimetric processing; radar calibration; radar-raingauge comparisons

show abstract

The Rain Profiling Algorithm Applied to Polarimetric Weather Radar

Cited by 375 publications

References 22 publications

Overview: Precipitation characteristics and sensitivities to environmental conditions during GoAmazon2014/5 and ACRIDICON-CHUVA

Overview: Precipitation characteristics and sensitivities to environmental conditions during GoAmazon2014/5 and ACRIDICON-CHUVA

Rainfall Profiling Using Atmospheric Radiation Measurement Program Vertically Pointing 8-mm Wavelength Radars

Long‐term monitoring of French polarimetric radar data quality and evaluation of several polarimetric quantitative precipitation estimators in ideal conditions for operational implementation at C‐band

Contact Info

Product

Resources

About