A5029573738- Precipitation Measurement and Analysis
- Meteorological Phenomena and Simulations
- Soil Moisture and Remote Sensing
- Climate variability and models
- Antenna Design and Analysis
- Antenna Design and Optimization
- Radio Wave Propagation Studies
- Microwave Imaging and Scattering Analysis
- Microwave Engineering and Waveguides
- Atmospheric aerosols and clouds
- Radar Systems and Signal Processing
- Cryospheric studies and observations
- Geophysical Methods and Applications
- Radio Astronomy Observations and Technology
- Energy Harvesting in Wireless Networks
- Electromagnetic Scattering and Analysis
- Advanced Antenna and Metasurface Technologies
- Underwater Acoustics Research
- Tropical and Extratropical Cyclones Research
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Icing and De-icing Technologies
- Ocean Waves and Remote Sensing
- Random lasers and scattering media
- Advanced SAR Imaging Techniques
- Plant Molecular Biology Research
Radar (United States)
2013-2024
University of Oklahoma
2015-2024
Hubei University of Science and Technology
2024
Applied Radar (United States)
2023-2024
Southeast University
2022-2023
Jiujiang University
2021
Cooperative Institute for Mesoscale Meteorological Studies
2009-2019
Nanjing University
2016-2019
NOAA National Severe Storms Laboratory
2019
State Key Laboratory of Severe Weather
2019
A unique dataset consisting of high-resolution polarimetric radar measurements and dense rain gauge disdrometer observations collected in east-central Florida during the summer 1998 was examined. Comparison parameters computed from supported previous studies, which indicate that oscillating drops free atmosphere have more spherical apparent shapes mean than equilibrium shapes. Radar–disdrometer comparisons improved markedly when using an empirical axis ratio relation developed observational...
Abstract Winter-storm hydrometeor distributions along the Front Range in eastern Colorado are studied with a ground-based two-dimensional video disdrometer. The instrument provides shape, size, and terminal velocity information for particles that larger than about 0.4 mm. dataset is used to determine form of particle size (PSDs) search useful interrelationships among governing parameters assumed distribution forms environmental factors. Snowfalls dominated by almost spherical aggregates...
The three-parameter gamma distribution n(D) = N0Dµ exp(–ΛD) is often used to characterize a raindrop size (DSD). parameters µ and Λ correspond the shape slope of DSD. If are related one another, as recent disdrometer measurements suggest, DSD model simplified, which facilitates retrieval rain from remote measurements. It important determine whether µ–Λ relation arises errors in estimated moments, or natural processes, combination both statistical error physics. In this paper, propagation...
Abstract In this paper, data from three 2-dimensional video disdrometers (2DVDs) and an S-band polarimetric radar are used to characterize rain microphysics in Oklahoma. Sampling errors the 2DVD measurements quantified through side-by-side comparisons. attempt minimize sampling errors, a method of sorting averaging based on two parameters (SATP) is proposed. The shape–slope (μ–Λ) relation constrained gamma (C-G) model then refined for retrieval drop size distributions (DSDs) measurements. An...
Abstract A radar simulator for polarimetric variables, including reflectivities at horizontal and vertical polarizations, the differential reflectivity, specific phase, has been developed. This serves as a test bed developing testing forward observation operators of variables that are needed when directly assimilating these into storm-scale numerical weather prediction (NWP) models, using either variational or ensemble-based assimilation methods. The takes input results high-resolution NWP...
Raindrop size distribution (DSD) retrieval from remote radar measurements or in situ disdrometer is an important area of research. If the shape (μ) and slope (Λ) a three-parameter gamma n(D) = N0Dμ exp(−ΛD) are related to one another, as recent suggest, DSD model simplified two-parameter DSD, that is, constrained DSD. An empirical relation between μ Λ was derived using moments estimated video-disdrometer measurements. Here, effects truncation on were analyzed. It shown characteristic...
Abstract The characteristics of raindrop size distributions (DSDs) and vertical structures rainfall during the Asian summer monsoon season in East China are studied using measurements from a ground‐based two‐dimensional video disdrometer (2DVD) vertically pointing Micro Rain Radar (MRR). Based on intensity structure radar reflectivity, observed is classified into convective, stratiform, shallow precipitation types. Among them, has previously been ignored or treated as outliers due to...
Abstract A new general polarimetric radar simulator for nonhydrostatic numerical weather prediction (NWP) models has been developed based on rigorous scattering calculations using the T-matrix method reflectivity, differential specific phase, and copolar cross-correlation coefficient. continuous melting process accounts entire spectrum of varying density dielectric constants. This is able to simulate measurements at frequency bands can take as input prognostic variables high-resolution NWP...
Abstract The evolution of microphysical characteristics a rainband in Typhoon Matmo (2014) over eastern China, through its onset, developing, mature, and dissipating stages, is documented using observations from an S band polarimetric Doppler radar two‐dimensional video disdrometer (2DVD). drop size distributions observed by the 2DVD retrieved measurements indicate that convection generally contains smaller drops higher number concentrations than typical maritime type described Bringi et al....
Abstract The scientific community has expressed interest in the potential of phased array radars (PARs) to observe atmosphere with finer spatial and temporal scales. Although convergence occurred between meteorological engineering communities, need exists increase access PAR meteorologists. Here, we facilitate these interdisciplinary efforts field ground-based PARs for atmospheric studies. We cover high-level technical concepts terminology as applied studies atmosphere. A historical...
A method for estimating the governing parameters of gamma drop size distributions (DSDs) and associated rainfall rates from polarimetric radar measurements at S band is examined. The technique uses reflectivity horizontal polarization, differential reflectivity, an empirical constraining relationship between DSD shape factor slope parameter. Retrieved show good agreement with disdrometer observations. estimates are insensitive to climatological regime. Comparison fixed-form power-law...
Polarimetric radar measurements are used to retrieve properties of raindrop distributions. The procedure assumes that drops represented by a gamma distribution and retrieves the governing parameters from an empirical relation between shape slope reflectivity differential reflectivity. Retrieved physical characteristics drop size (DSD) were generally well matched with disdrometer observations. method is applied select storms demonstrate utility. Broad DSDs determined for core (high...
Abstract Disdrometer observations indicate that the raindrop size distribution (DSD) can be represented by a constrained-gamma (CG) model. The model is used to retrieve DSDs from polarization radar measurements of reflectivity and differential characterize rain microphysics physical processes such as evaporation, accretion, precipitation. CG parameterization simplified single parameter for application in single-moment numerical models. This applied Variational Doppler Radar Analysis System...
Abstract A data assimilation system based on the ensemble square-root Kalman filter (EnSRF) is extended to include additional capability of assimilating polarimetric radar variables. It used assess impact observations convective storm analysis in Observing System Simulation Experiment (OSSE) framework. The variables considered differential reflectivity ZDR, difference Zdp, and specific phase KDP. To simulate observational more realistically, a new error model introduced for characterizing...
Abstract X-band and shorter radar wavelengths are preferable for mobile systems because a narrow beam can be realized with moderately sized antenna. However, attenuation by precipitation becomes progressively more severe decreasing wavelength. As result, X band has become popular choice meteorological that balances these two considerations. Dual-polarization provides several methods which this (and differential attenuation) detected corrected, mitigating one of the primary disadvantages...
It is becoming widely accepted that radar polarimetry provides accurate and informative weather measurements, while phased-array technology can shorten data updating time. In this paper, a theory of phased array (PAR) developed to establish the relation between electric fields at antenna PAR in resolution volume filled with hydrometeors. shown polarimetric measurements an electronically steered beam cause measurement biases are comparable or even larger than intrinsic characteristics...
Abstract There have been debates and differences of opinion over the validity using drop size distribution (DSD) models to characterize precipitation microphysics retrieve DSD parameters from multiparameter radar measurements. In this paper, simulated observed rain DSDs are used evaluate moment estimators. Seven estimators for gamma evaluated in terms biases fractional errors five integral parameters: reflectivity (ZH), differential (ZDR), rainfall rate (R), mean volume diameter (Dm), total...
Abstract Examined is bias in differential reflectivity and its effect on estimates of rain rate due to coupling the vertically horizontally polarized fields through radiation patterns. To that end, a brief review effects quantitative rainfall measurements given. Suggestions for tolerable values this are made. Of utmost interest produced by radars simultaneously transmitting fields, as configuration has been chosen pending upgrades U.S. national network (Weather Surveillance Radar-1988...
Abstract This paper suggests a cylindrical configuration for agile beam polarimetric phased-array radar (PPAR) weather surveillance. The most often used array PAR is planar antenna. configuration, however, has significant deficiencies measurements, as well other limitations, such increases in beamwidth, decreases of sensitivity, and changes the polarization basis when scans off its broadside. (CPPAR) proposed to avoid these deficiencies. CPPAR principle potential performance are demonstrated...
The design and analysis of a dual-polarization frequency scanning array antenna, operating in band 2.7-3.0 GHz, for weather measurement applications are presented. Stacked patch elements coupled to feed lines through slots etched on the ground plane. A wall plated holes middle antenna column is designed improve isolation between two input ports. Both simulation measurements results confirm that very high polarization purity achieved.
Abstract As part of the third Tibetan Plateau Atmospheric Scientific Experiment field campaign, raindrop size distribution (DSD) measurements were taken with a laser optical disdrometer in Naqu, China, at 4,508 m above sea level (asl) during summer months 2013, 2014, and 2015. The characteristics DSDs for five different rain rates, two types (convective stratiform), daytime nighttime rains studied. shapes averaged similar width increased rainfall intensity. Little difference was found...
Abstract Accurate measurements of snow amounts by radar are very difficult to achieve. The inherent uncertainty in estimates that based on the reflectivity factor Z is caused variability particle size distributions and density as well large diversity among growth habits. In this study, a novel method for quantification joint use specific differential phase K DP introduced. An extensive dataset 2D-video-disdrometer central Oklahoma used derive polarimetric relations liquid-equivalent snowfall...
Abstract The evolution of the microphysical structures a subtropical squall line observed during Observation, Prediction and Analysis Severe Convection China (OPACC) field campaign in Eastern is documented this paper. data collected from C‐band, polarimetric Doppler radar (reflectivity Z , differential reflectivity DR specific phase K DP ) disdrometer are used to investigate variations characteristics within convective region formative, intensifying, mature stages line. noticeably different...
This paper presents a high-isolation, low crosspolarization dual-polarized patch antenna for multifunction phased array radar applications. Its hybrid feed design has been implemented, and the vertical horizontal polarizations are excited by balanced-probe slot-coupled feed, respectively. Simulations measurements have demonstrated an input isolation of 45 43 dB between ports, For further improvement in cross-polarization level, image method is also 2 × 2-element made up designed elements...