Dual-polarization challenges in weather radar requirements for multifunction phased array radar

2013 ◽  
Author(s):  
Caleb Fulton ◽  
Jeff Herd ◽  
Shaya Karimkashi ◽  
Guifu Zhang ◽  
Dusan Zrnic
Keyword(s):  
Phased Array ◽  
Weather Radar ◽  
Dual Polarization ◽  
Phased Array Radar

scholarly journals Rapid-Scan Radar Observations of an Oklahoma Tornadic Hailstorm Producing Giant Hail

2018 ◽  
Vol 33 (5) ◽  
pp. 1263-1282 ◽  
Author(s):  
Arthur Witt ◽  
Donald W. Burgess ◽  
Anton Seimon ◽  
John T. Allen ◽  
Jeffrey C. Snyder ◽  
...  
Keyword(s):  
Phased Array ◽  
Rotational Velocity ◽  
Weather Radar ◽  
Dual Polarization ◽  
Radar Observations ◽  
Rapid Scan ◽  
Phased Array Radar ◽  
X Band ◽  
Low Altitude ◽  
Rapid Scanning

Abstract Rapid-scan radar observations of a supercell that produced near-record size hail in Oklahoma are examined. Data from the National Weather Radar Testbed Phased Array Radar (PAR) in Norman, Oklahoma, are used to study the overall character and evolution of the storm. Data from the nearby polarimetric KOUN WSR-88D and rapid-scanning X-band polarimetric (RaXPol) mobile radar are used to study the evolution of low- to midaltitude dual-polarization parameters above two locations where giant hailstones up to 16 cm in diameter were observed. The PAR observation of the supercell’s maximum storm-top divergent outflow is similar to the strongest previously documented value. The storm’s mesocyclone rotational velocity at midaltitudes reached a maximum that is more than double the median value for similar observations from other storms producing giant hail. For the two storm-relative areas where giant hail was observed, noteworthy findings include 1) the giant hail occurred outside the main precipitation core, in areas with low-altitude reflectivities of 40–50 dBZ; 2) the giant hail was associated with dual-polarization signatures consistent with past observations of large hail at 10-cm wavelength, namely, low ZDR, low ρHV, and low KDP; 3) the giant hail fell along both the northeast and southwest edges of the primary updraft at ranges of 6–10 km from the updraft center; and 4) with the exception of one isolated report, the giant hail fell to the northeast and northwest of the large tornado and the parent mesocyclone.

Adaptive Range Oversampling to Achieve Faster Scanning on the National Weather Radar Testbed Phased-Array Radar

2011 ◽  
Vol 28 (12) ◽  
pp. 1581-1597 ◽  
Author(s):  
Christopher D. Curtis ◽  
Sebastián M. Torres
Keyword(s):  
Signal Processing ◽  
Phased Array ◽  
Matched Filter ◽  
Meteorological Data ◽  
Weather Radar ◽  
Meteorological Variable ◽  
Seamless Integration ◽  
Computational Burden ◽  
Phased Array Radar ◽  
Spatial Coverage

Abstract This paper describes a real-time implementation of adaptive range oversampling processing on the National Weather Radar Testbed phased-array radar. It is demonstrated that, compared to conventional matched-filter processing, range oversampling can be used to reduce scan update times by a factor of 2 while producing meteorological data with similar quality. Adaptive range oversampling uses moment-specific transformations to minimize the variance of meteorological variable estimates. An efficient algorithm is introduced that allows for seamless integration with other signal processing functions and reduces the computational burden. Through signal processing, a new dimension is added to the traditional trade-off triangle that includes the variance of estimates, spatial coverage, and update time. That is, by trading an increase in computational complexity, data with higher temporal resolution can be collected and the variance of estimates can be improved without affecting the spatial coverage.

High-Temporal-Resolution Capabilities of the National Weather Radar Testbed Phased-Array Radar

2011 ◽  
Vol 50 (3) ◽  
pp. 579-593 ◽  
Author(s):  
Pamela L. Heinselman ◽  
Sebastián M. Torres
Keyword(s):  
Temporal Resolution ◽  
Phased Array ◽  
Weather Radar ◽  
High Temporal Resolution ◽  
Data Archiving ◽  
Phased Array Radar ◽  
Control Interface ◽  
Trade Offs ◽  
Address Data ◽  
Processing Techniques

Abstract Since 2007 the advancement of the National Weather Radar Testbed Phased-Array Radar (NWRT PAR) hardware and software capabilities has been supporting the implementation of high-temporal-resolution (∼1 min) sampling. To achieve the increase in computational power and data archiving needs required for high-temporal-resolution sampling, the signal processor was upgraded to a scalable, Linux-based cluster with a distributed computing architecture. The development of electronic adaptive scanning, which can reduce update times by focusing data collection on significant weather, became possible through functionality added to the radar control interface and real-time controller. Signal processing techniques were implemented to address data quality issues, such as artifact removal and range-and-velocity ambiguity mitigation, absent from the NWRT PAR at its installation. The hardware and software advancements described above have made possible the development of conventional and electronic scanning capabilities that achieve high-temporal-resolution sampling. Those scanning capabilities are sector- and elevation-prioritized scanning, beam multiplexing, and electronic adaptive scanning. Each of these capabilities and related sampling trade-offs are explained and demonstrated through short case studies.

scholarly journals Multipatterns of the National Weather Radar Testbed Mitigate Clutter Received via Sidelobes

2011 ◽  
Vol 28 (3) ◽  
pp. 401-409 ◽  
Author(s):  
Guifu Zhang ◽  
Yinguang Li ◽  
Richard J. Doviak ◽  
Dave Priegnitz ◽  
John Carter ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Phased Array ◽  
Weather Radar ◽  
Main Lobe ◽  
Mean Power ◽  
Sample Mean ◽  
Ground Clutter ◽  
Phased Array Radar ◽  
Weather Observations

Abstract The phased-array radar (PAR) of the National Weather Radar Testbed (NWRT) has a unique hybrid (mechanical and electrical) azimuth scan capability, allowing weather observations with different antenna patterns. Observations show the standard deviation of the sample mean power of weather echoes received through the main lobe of a set of squinted beams is less than the clutter received via sidelobes. This then allows use of a multipattern technique to cancel sidelobe echoes from moving scatterers, echoes that cannot be filtered with a ground-clutter canceler. Although the multipattern technique was developed to cancel clutter received through sidelobes, results show clutter from objects moving within the beam can also be canceled.

scholarly journals Adaptive Range Oversampling Processing for Nontraditional Radar-Variable Estimators

2017 ◽  
Vol 34 (7) ◽  
pp. 1607-1623 ◽  
Author(s):  
Christopher D. Curtis ◽  
Sebastián M. Torres
Keyword(s):  
Analytical Solutions ◽  
Phased Array ◽  
Weather Radar ◽  
Radar Data ◽  
Original Version ◽  
Lookup Table ◽  
Dual Polarization ◽  
Spectrum Width ◽  
Simulation Results ◽  
The U.S

AbstractAdaptive range oversampling processing can be used either to reduce the variance of radar-variable estimates without increasing scan times or to reduce scan times without increasing the variance of estimates. For example, an implementation of adaptive pseudowhitening on the National Weather Radar Testbed Phased-Array Radar (NWRT PAR) led to a twofold reduction in scan times. Conversely, a proposed implementation of adaptive pseudowhitening the U.S. Next Generation Weather Radar (NEXRAD) network would reduce the variance of dual-polarization estimates while keeping current scan times. However, the original version of adaptive pseudowhitening is not compatible with radar-variable estimators for which an explicit variance expression is not readily available. One such nontraditional estimator is the hybrid spectrum-width estimator, which is currently used in the NEXRAD network. In this paper, an extension of adaptive pseudowhitening is proposed that utilizes lookup tables (rather than analytical solutions based on explicit variance expressions) to obtain range oversampling transformations. After describing this lookup table (LUT) adaptive pseudowhitening technique, its performance is compared to that of the original version of adaptive pseudowhitening using traditional radar-variable estimators. LUT adaptive pseudowhitening is then applied to the hybrid spectrum-width estimator, and simulation results are confirmed with a qualitative analysis of radar data.

Dual-polarization X-band phased array weather radar: Technology update

2014 ◽  
Author(s):  
Peter R. Drake ◽  
Jacqueline Bourgeois ◽  
Anthony P. Hopf ◽  
Francis Lok ◽  
David McLaughlin
Keyword(s):  
Phased Array ◽  
Weather Radar ◽  
Dual Polarization ◽  
X Band
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