Identification of Vertical Profiles of Radar Reflectivity for Hydrological Applications Using an Inverse Method. Part I: Formulation

Andrieu, Hervé; Creutin, Jean‐Dominique

doi:10.1175/1520-0450(1995)034<0225:iovpor>2.0.co;2

Cited by 147 publications

(86 citation statements)

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“…He found the Gaussian approximation for more complicated beam patterns varies by less than 0.64 dB in comparison in most cases. Other investigators have also shown the Gaussian beam pattern is a good approximation for most meteorological applications (Donaldson 1964;Bogush 1989;Andrieu and Creutin 1995).…”

Section: Radar Beam Propagation Model Resultsmentioning

confidence: 95%

Radar Beam Occultation Studies Using GIS and DEM Technology: An Example Study of Guam

Kucera¹,

Krajewski²,

Young³

2004

J. Atmos. Oceanic Technol.

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Geographic information systems (GISs) combined with digital elevation models (DEMs) provide opportunities to evaluate weather radar beam blockage and other ground clutter phenomena. The authors explore this potential using topographic information and a simple beam propagation model for the complex terrain of Guam. To evaluate the effect of different DEM resolutions, they compare the simulated patterns of complete and partial beam blockage with probability of detection maps derived from a large database of level II radar reflectivity for the U.S. Air Force Weather Surveillance Radar-1988 Doppler (WSR-88D) on Guam. The main conclusion of the study is that the GIS approach provides useful insight into the actual pattern of blocked areas. The DEM resolution plays a role in resolving the blocked patterns. In general, higher DEM resolution provides better results although widely available lower-resolution DEMs can provide valuable information about beam-blocking effects.

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Section: Radar Beam Propagation Model Resultsmentioning

confidence: 95%

Radar Beam Occultation Studies Using GIS and DEM Technology: An Example Study of Guam

Kucera¹,

Krajewski²,

Young³

2004

J. Atmos. Oceanic Technol.

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“…An idealized vertical profile of reflectivity in convective-type rains has been suggested in a number of studies (e.g., Andrieu and Creutin 1995;Smyth and Illingworth 1997). These studies indicate that there is a general decrease of reflectivity with height AGL with an average gradient of b ϭ 2 dB km Ϫ1 or so such as…”

Section: Prospects For the Use Of Vertical Profiles Of Nonattenuated mentioning

confidence: 99%

“…The variability in the nonattenuated reflectivities is expected to be minimal in stratiform rain events, which are characterized by relatively modest rainfall rates (typically less than about 15 mm h Ϫ1 ), relatively strong radar bright bands, extensive spatial coverage, and long duration. Nonattenuated reflectivity profiles in stratiform rain are usually assumed to be constant (e.g., Andrieu and Creutin 1995). Assuming a typical 1-dB uncertainty in the nonattenuated K a -band reflectivity profiles for such events, the relative errors for the discussed method can be estimated as 40% for R ϭ 4 mm h Ϫ1 , 20% for R ϭ 10 mm h Ϫ1 , and 15% for R ϭ 15 mm h Ϫ1 (Matrosov 2005).…”

Section: Examples Of Retrievals Of Rainfall Rates At the Sgp Arm Cartmentioning

confidence: 99%

“…Neglecting vertical trends in VPNR in stratiform rain events is probably justified below the bright band. It is often done for the vertical extrapolation of scanning radar measurements when the lowest-elevation data are blocked or unavailable for some other reason (e.g., Andrieu and Creutin 1995;Smyth and Illingworth 1997). For convective rains, neglecting VPNR trends and variability is generally less justified, though as seen from Z ec profiles in Figs.…”

Section: Prospects For the Use Of Vertical Profiles Of Nonattenuated mentioning

confidence: 99%

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

Matrosov

May

Shupe

2006

Journal of Atmospheric and Oceanic Technology

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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.

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“…During the melting process in this layer, snowflakes and hail become coated with a film of water leading to the appearance of giant raindrops. The reflectivity in the bright band is generally 5-10 dB stronger than in the rain below or the snow directly above 17,[21][22][23][24] . The pseudoCAPPI reflectivity data at the altitudes below the freezing levels is therefore selected for further analysis to avoid the bright band effect that could cause radar rainfall overestimation.…”

Section: Radar Reflectivity Measurement Errorsmentioning

confidence: 97%

Climatological Z-R relationship for radar rainfall estimation in the upper Ping river basin

Mapiam¹,

Sriwongsitanon²

2008

ScienceAsia

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ABSTRACT:Weather radar can potentially provide high-resolution spatial and temporal rainfall estimates bringing more accuracy to flood estimations as well as having some other applications in areas with insufficient rainfall stations like Thailand. Weather radar cannot be used to measure the rainfall depth directly; so an empirical relationship between the reflectivity (Z) and rainfall rate (R), called the Z-R relationship (Z = AR b ), is generally used to assess the rainfall depth using radar. In this study, an optimization approach was used to find a suitable climatological Z-R relationship for the upper Ping river basin, Northern Thailand. The reflectivity data between June and October in 2003 and 2004 at the Omkoi radar station located in Chiangmai Province, together with the daily rainfall depths at fifty rainfall stations located in and around the basin during the same periods were used. A climatological Z-R relationship in the form Z = 74R 1.6 shows acceptable statistical indicators, making it suitable for radar rainfall prediction for the upper Ping river basin.

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Identification of Vertical Profiles of Radar Reflectivity for Hydrological Applications Using an Inverse Method. Part I: Formulation

Cited by 147 publications

References 0 publications

Radar Beam Occultation Studies Using GIS and DEM Technology: An Example Study of Guam

Radar Beam Occultation Studies Using GIS and DEM Technology: An Example Study of Guam

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

Climatological Z-R relationship for radar rainfall estimation in the upper Ping river basin

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