Intensity-level-selection-based wind retrieval from shipborne nautical X-band radar data

Currently, it is a hot research topic to retrieve the wave parameters by using X-band marine radar. However, the rainfall noise usually exists in the collected marine radar images, which seriously interferes with the extraction of the wave parameters. To reduce the influence of rainfall noise, the zero-pixel percentage (ZPP) method is widely used to detect rainfall in radar images, but the detection accuracy is limited, and the selection of the threshold needs to be further studied. Based on the ZPP method, the ratio of zero intensity to echo (RZE) method for rainfall detection is proposed in this paper. The detection threshold is determined by statistical analysis of a large amount of radar data. Additionally, it is proposed for the first time to retrieve the rainfall intensity level from X-band marine radar images. In addition, the concept of the occlusion area is proposed. The proposed area and the wave area are used as the rainfall detection area of the radar image, respectively, for experimental research. The data obtained from the Pingtan experimental base in Fujian Province are used to verify the effectiveness of the proposed method. The experimental results show that the detection accuracy of the proposed method is 11.7% higher than that of the ZPP method, and the accuracy of rainfall intensity level retrieval is 84%.

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The Multiple-Vortex Structure of the El Reno, Oklahoma, Tornado on 31 May 2013

Monthly Weather Review ◽

10.1175/mwr-d-18-0073.1 ◽

2018 ◽

Vol 146 (8) ◽

pp. 2483-2502 ◽

Cited By ~ 12

Author(s):

Howard B. Bluestein ◽

Kyle J. Thiem ◽

Jeffrey C. Snyder ◽

Jana B. Houser

Keyword(s):

Doppler Radar ◽

Radar Data ◽

Rapid Scan ◽

X Band ◽

Close Range ◽

Formation And Evolution ◽

Using Data ◽

Secondary Vortices ◽

The Right ◽

Gust Front

Abstract This study documents the formation and evolution of secondary vortices associated within a large, violent tornado in Oklahoma based on data from a close-range, mobile, polarimetric, rapid-scan, X-band Doppler radar. Secondary vortices were tracked relative to the parent circulation using data collected every 2 s. It was found that most long-lived vortices (those that could be tracked for ≥15 s) formed within the radius of maximum wind (RMW), mainly in the left-rear quadrant (with respect to parent tornado motion), passing around the center of the parent tornado and dissipating closer to the center in the right-forward and left-forward quadrants. Some secondary vortices persisted for at least 1 min. When a Burgers–Rott vortex is fit to the Doppler radar data, and the vortex is assumed to be axisymmetric, the secondary vortices propagated slowly against the mean azimuthal flow; if the vortex is not assumed to be axisymmetric as a result of a strong rear-flank gust front on one side of it, then the secondary vortices moved along approximately with the wind.

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Simulation of X-Band Rainfall Observations from S-Band Radar Data

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech1909.1 ◽

2006 ◽

Vol 23 (9) ◽

pp. 1195-1205 ◽

Cited By ~ 38

Author(s):

V. Chandrasekar ◽

S. Lim ◽

E. Gorgucci

Keyword(s):

Doppler Radar ◽

Theoretical Models ◽

Radar Data ◽

Shape Distribution ◽

Microphysical Properties ◽

Rain Medium ◽

Microphysical Parameters ◽

X Band ◽

State Water ◽

The Impact

Abstract To design X-band radar systems as well as evaluate algorithm development, it is useful to have simultaneous X-band observation with and without the impact of path attenuation. One way to develop that dataset is through theoretical models. This paper presents a methodology to generate realistic range profiles of radar variables at attenuating frequencies, such as X band, for rain medium. Fundamental microphysical properties of precipitation, namely, size and shape distribution information, are used to generate realistic profiles of X band starting with S-band observation. Conditioning the simulation from S band maintains the natural distribution of rainfall microphysical parameters. Data from the Colorado State University’s University of Chicago–Illinois State Water Survey (CHILL) radar and the National Center for Atmospheric Research S-band dual-polarization Doppler radar (S-POL) are used to simulate X-band radar variables. Three procedures to simulate the radar variables and sample applications are presented.

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Wave Energy Dissipation in a Shallow Coral Reef Lagoon Using Marine X‐Band Radar Data

Journal of Geophysical Research Oceans ◽

10.1029/2020jc017094 ◽

2021 ◽

Author(s):

W. Navarro ◽

A. Orfila ◽

A. Orejarena‐Rondón ◽

J.C. Velez ◽

S. Lonin

Keyword(s):

Coral Reef ◽

Energy Dissipation ◽

Wave Energy ◽

Radar Data ◽

Wave Energy Dissipation ◽

Reef Lagoon ◽

X Band ◽

Coral Reef Lagoon

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Rainfall Information System Based on Weather Radar for Debris Flow Disaster Mitigation

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.44.26976 ◽

2018 ◽

Vol 7 (4.44) ◽

pp. 165 ◽

Cited By ~ 1

Author(s):

Ratih Indri Hapsari ◽

Gerard Aponno ◽

Rosa Andrie Asmara ◽

Satoru Oishi

Keyword(s):

Information System ◽

Debris Flow ◽

Weather Radar ◽

Active Volcano ◽

Radar Data ◽

Disaster Mitigation ◽

Web Based ◽

X Band ◽

Secondary Hazards ◽

Debris Flow Disaster

Rainfall-triggered debris flow has caused multiple impacts to the environment. It. is regarded as the most severe secondary hazards of volcanic eruption. However, limited access to the active volcano slope restricts the ground rain measurement as well as the direct delivery of risk information. In this study, an integrated information system is proposed for volcanic-related disaster mitigation under the framework of X-Plore/X-band Polarimetric Radar for Prevention of Water Disaster. In the first part, the acquisition and processing of high-resolution X-band dual polarimetric weather/X-MP radar data in real-time scheme for demonstrating the disaster-prone region are described. The second part presents the design of rainfall resource database and extensive maps coverage of predicted hazard information in GIS web-based platform accessible both using internet and offline. The proposed platform would be useful for communicating the disaster risk prediction based on weather radar in operational setting.

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Precipitation analysis by X-band MP radar data using Google Earth

2013 IEEE International Geoscience and Remote Sensing Symposium - IGARSS ◽

10.1109/igarss.2013.6721220 ◽

2013 ◽

Cited By ~ 1

Author(s):

Masahiro Nishio ◽

Masatoshi Mori

Keyword(s):

Radar Data ◽

Google Earth ◽

X Band ◽

Precipitation Analysis

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Retrieval of three-dimensional wind fields from Doppler radar data using an efficient two-step approach

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-3-4459-2010 ◽

2010 ◽

Vol 3 (5) ◽

pp. 4459-4495 ◽

Cited By ~ 1

Author(s):

C. López Carrillo ◽

D. J. Raymond

Keyword(s):

Variational Approach ◽

Continuity Equation ◽

Doppler Radar ◽

Three Dimensional ◽

Relevant Information ◽

Radar Data ◽

Wind Fields ◽

Wind Retrieval ◽

Complex Sampling ◽

Doppler Radar Data

Abstract. In this work, we describe an efficient approach for wind retrieval from dual Doppler radar data. The approach produces a gridded field that not only satisfies the observations, but also satisfies the anelastic mass continuity equation. The method is based on the so-called three-dimensional variational approach to the retrieval of wind fields from radar data. The novelty consists in separating the task into steps that reduce the amount of data processed by the global minimization algorithm, while keeping the most relevant information from the radar observations. The method is flexible enough to incorporate observations from several radars, accommodate complex sampling geometries, and readily include dropsonde or sounding observations in the analysis. We demonstrate the usefulness of our method by analyzing a real case with data collected during the TPARC/TCS-08 field campaign.

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A Comparative Study of Rainfall Retrievals Based on Specific Differential Phase Shifts at X- and S-Band Radar Frequencies

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech1887.1 ◽

2006 ◽

Vol 23 (7) ◽

pp. 952-963 ◽

Cited By ~ 40

Author(s):

Sergey Y. Matrosov ◽

Robert Cifelli ◽

Patrick C. Kennedy ◽

Steven W. Nesbitt ◽

Steven A. Rutledge ◽

...

Keyword(s):

Comparative Study ◽

Radar Data ◽

Drop Diameter ◽

Horizontal Polarization ◽

Differential Phase Shift ◽

Phase Measurements ◽

Differential Phase ◽

X Band ◽

Raindrop Size ◽

Differential Reflectivity

Abstract A comparative study of the use of X- and S-band polarimetric radars for rainfall parameter retrievals is presented. The main advantage of X-band polarimetric measurements is the availability of reliable specific differential phase shift estimates, KDP, for lighter rainfalls when phase measurements at the S band are too noisy to produce usable KDP. Theoretical modeling with experimental raindrop size distributions indicates that due to some non-Rayleigh resonant effects, KDP values at a 3.2-cm wavelength (X band) are on average a factor of 3.7 greater than at 11 cm (S band), which is a somewhat larger difference than simple frequency scaling predicts. The non-Rayleigh effects also cause X-band horizontal polarization reflectivity, Zeh, and differential reflectivity, ZDR, to be larger than those at the S band. The differences between X- and S-band reflectivities can exceed measurement uncertainties for Zeh starting approximately at Zeh > 40 dBZ, and for ZDR when the mass-weighted drop diameter, Dm, exceeds about 2 mm. Simultaneous X- and S-band radar measurements of rainfall showed that consistent KDP estimates exceeding about 0.1° km−1 began to be possible at reflectivities greater than ∼26–30 dBZ while at the S band such estimates can generally be made if Zeh > ∼35–39 dBZ. Experimental radar data taken in light-to-moderate stratiform rainfalls with rain rates R in an interval from 2.5 to 15 mm h−1 showed availability of the KDP-based estimates of R for most of the data points at the X band while at the S band such estimates were available only for R greater than about 8–10 mm h−1. After correcting X-band differential reflectivity measurements for differential attenuation, ZDR measurements at both radar frequency bands were in good agreement with each other for Dm < 2 mm, which approximately corresponds to ZDR ≈ 1.6 dB. The ZDR-based retrievals of characteristic raindrop sizes also agreed well with in situ disdrometer measurements.

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Mobile Radar Observations of the Evolving Debris Field Compared with a Damage Survey of the Shawnee, Oklahoma, Tornado of 19 May 2013

Monthly Weather Review ◽

10.1175/mwr-d-19-0215.1 ◽

2020 ◽

Vol 148 (5) ◽

pp. 1779-1803 ◽

Cited By ~ 1

Author(s):

Roger M. Wakimoto ◽

Zachary Wienhoff ◽

Howard B. Bluestein ◽

David J. Bodine ◽

James M. Kurdzo

Keyword(s):

Cross Correlation ◽

Vertical Structure ◽

Leading Edge ◽

Radar Data ◽

Radar Reflectivity ◽

Vertical Profiles ◽

Damage Survey ◽

X Band ◽

First Time ◽

Rapid Scanning

Abstract A detailed damage survey is combined with high-resolution mobile, rapid-scanning X-band polarimetric radar data collected on the Shawnee, Oklahoma, tornado of 19 May 2013. The focus of this study is the radar data collected during a period when the tornado was producing damage rated EF3. Vertical profiles of mobile radar data, centered on the tornado, revealed that the radar reflectivity was approximately uniform with height and increased in magnitude as more debris was lofted. There was a large decrease in both the cross-correlation coefficient (ρhv) and differential radar reflectivity (ZDR) immediately after the tornado exited the damaged area rated EF3. Low ρhv and ZDR occurred near the surface where debris loading was the greatest. The 10th percentile of ρhv decreased markedly after large amounts of debris were lofted after the tornado leveled a number of structures. Subsequently, ρhv quickly recovered to higher values. This recovery suggests that the largest debris had been centrifuged or fallen out whereas light debris remained or continued to be lofted. Range–height profiles of the dual-Doppler analyses that were azimuthally averaged around the tornado revealed a zone of maximum radial convergence at a smaller radius relative to the leading edge of lofted debris. Low-level inflow into the tornado encountering a positive bias in the tornado-relative radial velocities could explain the existence of the zone. The vertical structure of the convergence zone was shown for the first time.

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