scholarly journals Advances in Chinese Dual-Polarization and Phased-Array Weather Radars: Observational Analysis of a Supercell in Southern China

2018 ◽  
Vol 35 (9) ◽  
pp. 1785-1806 ◽  
Author(s):  
Chong Wu ◽  
Liping Liu ◽  
Xi Liu ◽  
Guocui Li ◽  
Chao Chen
Keyword(s):  
Phased Array ◽  
Southern China ◽  
Dual Polarization ◽  
Observational Analysis ◽  
Weather Radars ◽  
Phased Array Radar ◽  
Storm Evolution ◽  
Microphysical Processes ◽  
Radar Calibration ◽  
Convective Cells

AbstractIn the summer of 2016, one phased-array radar and two polarimetric weather radars, representative of advancing radar technology in use in China, jointly collected data in the Foshan area to study severe convective storms in southern China. After an introduction to the technical characteristics and a verification of the radar calibration, the advantages of the abovementioned dual-polarization and phased-array radars are discussed in terms of an observational analysis of a supercell that occurred on 9 May 2016. The polarimetric signatures within the supercell are associated with specific microphysical processes that can reveal different stages of storm evolution. The hydrometeor classification algorithm is a more straightforward and useful method for nowcasting than conventional algorithms, which makes it favorable for further recommendation in China. During the mature and dissipating stages of this supercell, observations of the phased-array radar show detailed changes on short time scales that cannot be observed by parabolic-antenna radars. The initiation and mergers of new convective cells are found in the peak inflow region, and the formation and dissipation of the hook echo are associated with the relative intensities of inflow and outflow. The abovementioned results demonstrate that the phased-array radar and dual-polarization radars recently developed in China are powerful tools to better understand storm evolution for nowcasting and scientific studies.

scholarly journals A Low Cross-Polarization Configuration Method for Phased Array Radar Antenna

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 396 ◽  
Author(s):  
Yongzhen Li ◽  
Zhanling Wang ◽  
Chen Pang ◽  
Xuesong Wang
Keyword(s):  
Phased Array ◽  
Polarization State ◽  
Cross Polarization ◽  
Dual Polarization ◽  
Phased Array Radar ◽  
The Cross ◽  
Radar Antenna ◽  
Polarization Level ◽  
State Configuration ◽  
Key Parameter

The cross-polarization isolation (CPI) is a key parameter to assess the dual-polarization antenna because the cross-polarization closely affects the antenna application. A polarization state configuration (PSC) approach is proposed to configure the polarization state of the polarimetric phased array radar antenna. Unlike the traditional fixed polarization states such as the linear polarization (LP) and the circular polarization (CP), the PSC method modulates the polarization state of the radiated wave continuously. In addition, the optimal excitation magnitude and phase of the dual-polarization element is calculated, thereby maximizing the CPI. Most of the configured polarization state is the elliptical polarization (EP), and a lower cross-polarization level and higher CPI could be obtained. This method could expand the acceptable angle range when compared with the LP and CP waves. Numerical simulations and comparisons are conducted to manifest the validity of the proposed method.

scholarly journals The next generation airborne polarimetric Doppler weather radar

2014 ◽  
Vol 3 (2) ◽  
pp. 111-126 ◽  
Author(s):  
J. Vivekanandan ◽  
W.-C. Lee ◽  
E. Loew ◽  
J. L. Salazar ◽  
V. Grubišić ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Phased Array ◽  
Doppler Velocity ◽  
Airborne Radar ◽  
Dual Polarization ◽  
Polarization Measurements ◽  
Phased Array Radar ◽  
X Band ◽  
Temporal And Spatial ◽  
Airborne Phased Array Radar

Abstract. Results from airborne field deployments emphasized the need to obtain concurrently high temporal and spatial resolution measurements of 3-D winds and microphysics. A phased array radar on an airborne platform using dual-polarization antenna has the potential for retrieving high-resolution, collocated 3-D winds and microphysical measurements. Recently, ground-based phased array radar (PAR) has demonstrated the high time-resolution estimation of accurate Doppler velocity and reflectivity of precipitation and clouds when compared to mechanically scanning radar. PAR uses the electronic scanning (e-scan) to rapidly collect radar measurements. Since an airborne radar has a limited amount of time to collect measurements over a specified sample volume, the e-scan will significantly enhance temporal and spatial resolution of airborne radar observations. At present, airborne weather radars use mechanical scans, and they are not designed for collecting dual-polarization measurements to remotely estimate microphysics. This paper presents a possible configuration of a novel airborne phased array radar (APAR) to be installed on an aircraft for retrieving improved dynamical and microphysical scientific products. The proposed APAR would replace the aging, X-band Electra Doppler radar (ELDORA). The ELDORA X-band radar's penetration into precipitation is limited by attenuation. Since attenuation at C-band is lower than at X-band, the design specification of a C-band airborne phased array radar (APAR) and its measurement accuracies are presented. Preliminary design specifications suggest the proposed APAR will meet or exceed ELDORA's current sensitivity, spatial resolution and Doppler measurement accuracies of ELDORA and it will also acquire dual-polarization measurements.

scholarly journals SEA-POL Goes to Sea

2019 ◽  
Vol 100 (11) ◽  
pp. 2285-2301 ◽  
Author(s):  
Steven A. Rutledge ◽  
V. Chandrasekar ◽  
Brody Fuchs ◽  
Jim George ◽  
Francesc Junyent ◽  
...  
Keyword(s):  
Doppler Radar ◽  
The United States ◽  
Upper Ocean ◽  
State University ◽  
Dual Polarization ◽  
Regional Study ◽  
Ocean Turbulence ◽  
Colorado State University ◽  
Weather Radars ◽  
Microphysical Processes

AbstractA new, advanced radar has been developed at Colorado State University (CSU). The Sea-Going Polarimetric (SEA-POL) radar is a C-band, polarimetric Doppler radar specifically designed to deploy on research ships. SEA-POL is the first such weather radar developed in the United States. Ship-based weather radars have a long history, dating back to GATE in 1974. The GATE radars measured only reflectivity. After GATE, ship radars also provided Doppler measurements. SEA-POL represents the next advancement by adding dual-polarization technology, the ability to transmit and receive both horizontal and vertical polarizations. This configuration provides information about hydrometeor size, shape, and phase. As a result, superior rain-rate estimates are afforded by the dual-polarization technology, along with hydrometeor identification and overall improved data quality. SEA-POL made its first deployment as part of the Salinity Processes in the Upper Ocean Regional Study, second field phase (SPURS-2) fall 2017 cruise to the eastern tropical Pacific, sailing on the R/V Roger Revelle. SPURS-2 was a field project to investigate the fate of freshwater deposited on the ocean’s surface. Oceanographers are keenly interested in how fast these freshwater patches mix out by wind and upper-ocean turbulence, as the less dense rainfall sitting atop the salty ocean inhibits mixing through increased stability. To this end, during SPURS-2, SEA-POL produced rain maps identifying the location of freshwater lenses on the ocean’s surface thereby providing context for measurements of SST and salinity. Examples of SEA-POL polarization measurements are also discussed to assess microphysical processes within oceanic convection. Future ocean-based field campaigns will now benefit from SEA-POL’s advanced dual-polarization technology.

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.

Evolution of a Quasi-Linear Convective System Sampled by Phased Array Radar

2012 ◽  
Vol 140 (11) ◽  
pp. 3467-3486 ◽  
Author(s):  
Jennifer F. Newman ◽  
Pamela L. Heinselman
Keyword(s):  
Phased Array ◽  
Leading Edge ◽  
Early Morning ◽  
High Temporal Resolution ◽  
Convective System ◽  
Phased Array Radar ◽  
Bow Echo ◽  
Storm Evolution ◽  
Azimuthal Shear ◽  
Scanning Strategies

Abstract On 2 April 2010, a quasi-linear convective system (QLCS) moved eastward through Oklahoma during the early morning hours. Wind damage in Rush Springs, Oklahoma, approached (enhanced Fujita) EF1-scale intensity and was likely associated with a mesovortex along the leading edge of the QLCS. The evolution of the QLCS as it produced its first bow echo was captured by the National Weather Radar Testbed Phased Array Radar (NWRT PAR) in Norman, Oklahoma. The NWRT PAR is an S-band radar with an electronically steered beam, allowing for rapid volumetric updates (~1 min) and user-defined scanning strategies. The rapid temporal updates and dense vertical sampling of the PAR created a detailed depiction of the damaging wind mechanisms associated with the QLCS. Key features sampled by the PAR include microbursts, an intensifying midlevel jet, and rotation associated with the mesovortex. In this work, PAR data are analyzed and compared to data from nearby operational radars, highlighting the advantages of using high-temporal-resolution data to monitor storm evolution. The PAR sampled the events preceding the Rush Springs circulation in great detail. Based on PAR data, the midlevel jet in the QLCS strengthened as it approached Rush Springs, creating an area of strong midlevel convergence where it impinged on the system-relative front-to-rear flow. As this convergence extended to the lower levels of the storm, a preexisting azimuthal shear maximum increased in magnitude and vertical extent, and EF1-scale damage occurred in Rush Springs. The depiction of these events in the PAR data demonstrates the complex and rapidly changing nature of QLCSs.

scholarly journals The next generation airborne polarimetric Doppler weather radar

2014 ◽  
Vol 4 (1) ◽  
pp. 1-42 ◽  
Author(s):  
J. Vivekanandan ◽  
W.-C. Lee ◽  
E. Loew ◽  
J. L. Salazar ◽  
V. Grubišić ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Phased Array ◽  
Doppler Velocity ◽  
Airborne Radar ◽  
High Time Resolution ◽  
Dual Polarization ◽  
Phased Array Radar ◽  
X Band ◽  
Temporal And Spatial ◽  
Airborne Phased Array Radar

Abstract. Results from airborne field deployments emphasized the need to obtain concurrently high temporal and spatial resolution measurements of 3-D winds and microphysics. A phased array radar on an airborne platform using dual-polarization antenna has the potential for retrieving high resolution, collocated 3-D winds and microphysical measurements. Recently, ground-based phased array radar (PAR) demonstrated the high time resolution estimation of accurate Doppler velocity and reflectivity of precipitation and clouds when compared to mechanically scanning radar. PAR uses the electronic scanning (e-scan) to rapidly collect radar measurements. Since an airborne radar has a limited amount of time to collect measurements over a specified sample volume, the e-scan will significantly enhance temporal and spatial resolution of airborne radar observations. At present, airborne weather radars use mechanical scan, and they are not designed for collecting dual-polarization measurements to remotely estimate microphysics. This paper presents a possible configuration of a novel Airborne Phased Array Radar (APAR) to be installed on an aircraft for retrieving improved dynamical and microphysical scientific products. The proposed APAR would replace the aging, X-band Electra Doppler radar (ELDORA). The ELDORA X-band radar's penetration into precipitation is limited by attenuation. Since attenuation at C-band is lower than at X-band, the design specification of a C-band airborne phased array radar (APAR) and its measurement accuracies are presented.

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