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

scholarly journals Thunderstorm hail and lightning detection parameters based on dual-polarization Doppler weather radar data

2017 ◽  
Vol 24 (3) ◽  
pp. 521-530 ◽  
Author(s):  
Tanel Voormansik ◽  
Pekka J. Rossi ◽  
Dmitri Moisseev ◽  
Tarmo Tanilsoo ◽  
Piia Post
Keyword(s):  
Weather Radar ◽  
Radar Data ◽  
Doppler Weather Radar ◽  
Dual Polarization ◽  
Lightning Detection

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.

scholarly journals Rapid-Scan Super-Resolution Observations of a Cyclic Supercell with a Dual-Polarization WSR-88D

2010 ◽  
Vol 138 (10) ◽  
pp. 3762-3786 ◽  
Author(s):  
Matthew R. Kumjian ◽  
Alexander V. Ryzhkov ◽  
Valery M. Melnikov ◽  
Terry J. Schuur
Keyword(s):  
Phased Array ◽  
Super Resolution ◽  
Radar Data ◽  
Small Time ◽  
Limited Area ◽  
Dual Polarization ◽  
Scanning Strategy ◽  
Low Level ◽  
Rapid Scan ◽  
Phased Array Radar

Abstract In recent years, there has been widespread interest in collecting and analyzing rapid updates of radar data in severe convective storms. To this end, conventional single-polarization rapid-scan radars and phased array radar systems have been employed in numerous studies. However, rapid updates of dual-polarization radar data in storms are not widely available. For this study, a rapid scanning strategy is developed for the polarimetric prototype research Weather Surveillance Radar-1988 Doppler (WSR-88D) radar in Norman, Oklahoma (KOUN), which emulates the future capabilities of a polarimetric multifunction phased array radar (MPAR). With this strategy, data are collected over an 80° sector with 0.5° azimuthal spacing and 250-m radial resolution (“super resolution”), with 12 elevation angles. Thus, full volume scans over a limited area are collected every 71–73 s. The scanning strategy was employed on a cyclic nontornadic supercell storm in western Oklahoma on 1 June 2008. The evolution of the polarimetric signatures in the supercell is analyzed. The repetitive pattern of evolution of these polarimetric features is found to be directly tied to the cyclic occlusion process of the low-level mesocyclone. The cycle for each of the polarimetric signatures is presented and described in detail, complete with a microphysical interpretation. In doing so, for the first time the bulk microphysical properties of the storm on small time scales (inferred from polarimetric data) are analyzed. The documented evolution of the polarimetric signatures could be used operationally to aid in the detection and determination of various stages of the low-level mesocyclone occlusion.

Rapid Sampling of Severe Storms by the National Weather Radar Testbed Phased Array Radar

2008 ◽  
Vol 23 (5) ◽  
pp. 808-824 ◽  
Author(s):  
Pamela L. Heinselman ◽  
David L. Priegnitz ◽  
Kevin L. Manross ◽  
Travis M. Smith ◽  
Richard W. Adams
Keyword(s):  
Temporal Resolution ◽  
Phased Array ◽  
Weather Radar ◽  
Radar Data ◽  
Rapid Identification ◽  
High Temporal Resolution ◽  
Convective Storms ◽  
Rapid Sampling ◽  
Phased Array Radar ◽  
Frequent Sampling

Abstract A key advantage of the National Weather Radar Testbed Phased Array Radar (PAR) is the capability to adaptively scan storms at higher temporal resolution than is possible with the Weather Surveillance Radar-1988 Doppler (WSR-88D): 1 min or less versus 4.1 min, respectively. High temporal resolution volumetric radar data are a necessity for rapid identification and confirmation of weather phenomena that can develop within minutes. The purpose of this paper is to demonstrate the PAR’s ability to collect rapid-scan volumetric data that provide more detailed depictions of quickly evolving storm structures than the WSR-88D. Scientific advantages of higher temporal resolution PAR data are examined for three convective storms that occurred during the spring and summer of 2006, including a reintensifying supercell, a microburst, and a hailstorm. The analysis of the reintensifying supercell (58-s updates) illustrates the capability to diagnose the detailed evolution of developing and/or intensifying areas of 1) low-altitude divergence and rotation and 2) rotation through the depth of the storm. The fuller sampling of the microburst’s storm life cycle (34-s updates) depicts precursors to the strong surface outflow that are essentially indiscernible in the WSR-88D data. Furthermore, the 34-s scans provide a more precise sampling of peak outflow. The more frequent sampling of the hailstorm (26-s updates) illustrates the opportunity to analyze storm structures indicative of rapid intensification, the development of hail aloft, and the onset of the downdraft near the surface.

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