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1
Vivekanandan, J., W. C. Lee, E. Loew, J. L. Salazar, V. Grubišić, J. Moore, and P. Tsai. "The next generation airborne polarimetric Doppler weather radar." Geoscientific Instrumentation, Methods and Data Systems Discussions 4, no. 1 (January 20, 2014): 1–42. http://dx.doi.org/10.5194/gid-4-1-2014.
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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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Wu, Chong, Liping Liu, Xi Liu, Guocui Li, and Chao Chen. "Advances in Chinese Dual-Polarization and Phased-Array Weather Radars: Observational Analysis of a Supercell in Southern China." Journal of Atmospheric and Oceanic Technology 35, no. 9 (September 2018): 1785–806. http://dx.doi.org/10.1175/jtech-d-17-0078.1.
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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.
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Vivekanandan, J., W. C. Lee, E. Loew, J. L. Salazar, V. Grubišić, J. Moore, and P. Tsai. "The next generation airborne polarimetric Doppler weather radar." Geoscientific Instrumentation, Methods and Data Systems 3, no. 2 (July 21, 2014): 111–26. http://dx.doi.org/10.5194/gi-3-111-2014.
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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.
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Dong, Jian, Qingfu Liu, and Xuesong Wang. "New Polarization Basis for Polarimetric Phased Array Weather Radar: Theory and Polarimetric Variables Measurement." International Journal of Antennas and Propagation 2012 (2012): 1–15. http://dx.doi.org/10.1155/2012/193913.
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A novel scheme is developed for mitigating measurement biases in agile-beam polarimetric phased array weather radar. Based on the orthogonal Huygens source dual-polarized element model, a polarization measurement basis for planar polarimetric phased array radar (PPAR) is proposed. The proposed polarization basis is orthogonal to itself after a 90° rotation along the array’s broadside and can well measure the characteristics of dual-polarized element. With polarimetric measurements being undertaken in this polarization basis, the measurement biases caused by the unsymmetrical projections of dual-polarized element’s fields onto the local horizontal and vertical directions of radiated beam can be mitigated. Polarimetric variables for precipitation estimation and classification are derived from the scattering covariance matrix in horizontal and vertical polarization basis. In addition, the estimates of these parameters based on the time series data acquired with the new polarization basis are also investigated. Finally, autocorrelation methods for both the alternate transmission and simultaneous reception mode and the simultaneous transmission and simultaneous reception mode are developed.
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Salazar-Cerreño, Jorge L., V. Chandrasekar, Jorge M. Trabal, Paul Siquera, Rafael Medina, Eric Knapp, and David J. McLaughlin. "A Drop Size Distribution (DSD)-Based Model for Evaluating the Performance of Wet Radomes for Dual-Polarized Radars." Journal of Atmospheric and Oceanic Technology 31, no. 11 (November 2014): 2409–30. http://dx.doi.org/10.1175/jtech-d-13-00208.1.
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AbstractA novel analytical method is presented for evaluating the electrical performance of a radome for a dual-polarized phased-array antenna under rain conditions. Attenuation, reflections, and induced cross polarization are evaluated for different rainfall conditions and radome types. The authors present a model for estimating the drop size distribution on a radome surface based on skin surface material, area, inclination, and rainfall rate. Then, a multilayer radome model based on the transmission-line-equivalent circuit model is used to characterize the radome’s scattering parameters. Numerical results are compared with radar data obtained in the Next Generation Weather Radar (NEXRAD) and Collaborative Adaptive Sensing of the Atmosphere (CASA) systems, and good agreement is found.
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Bharadwaj, N., and V. Chandrasekar. "Phase Coding for Range Ambiguity Mitigation in Dual-Polarized Doppler Weather Radars." Journal of Atmospheric and Oceanic Technology 24, no. 8 (August 1, 2007): 1351–63. http://dx.doi.org/10.1175/jtech2061.1.
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Abstract This paper evaluates the retrieval of polarimetric variables when phase-coded waveforms are employed to suppress range overlaid echoes. A phase-coded waveform tags transmitted pulses with a phase code and then decodes the received signal to separate the overlaid echoes. Two methods suggested for separating overlaid echoes use random and systematic phase-coding techniques. In this paper, random phase and systematic phase-coded waveforms are evaluated for dual-polarized operation. The random phased-coded and systematic phase-coded waveforms are known to provide fairly good estimates of the Doppler spectral moments. This paper presents results at S band to quantify the performance of phase-coded waveform in retrieving polarimetric variables. It is shown that the polarimetric variables for both strong and weak trip echoes are estimated with acceptable accuracy.
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Kurdzo, James M., Boon Leng Cheong, Robert D. Palmer, Guifu Zhang, and John B. Meier. "A Pulse Compression Waveform for Improved-Sensitivity Weather Radar Observations." Journal of Atmospheric and Oceanic Technology 31, no. 12 (December 1, 2014): 2713–31. http://dx.doi.org/10.1175/jtech-d-13-00021.1.
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Abstract The progression of phased array weather observations, research, and planning over the past decade has led to significant advances in development efforts for future weather radar technologies. However, numerous challenges still remain for large-scale deployment. The eventual goal for phased array weather radar technology includes the use of active arrays, where each element would have its own transmit/receive module. This would lead to significant advantages; however, such a design must be capable of utilizing low-power, solid-state transmitters at each element in order to keep costs down. To provide acceptable sensitivity, as well as the range resolution needed for weather observations, pulse compression strategies are required. Pulse compression has been used for decades in military applications, but it has yet to be applied on a broad scale to weather radar, partly because of concerns regarding sensitivity loss caused by pulse windowing. A robust optimization technique for pulse compression waveforms with minimalistic windowing using a genetic algorithm is presented. A continuous nonlinear frequency-modulated waveform that takes into account transmitter distortion is shown, both in theory and in practical use scenarios. Measured pulses and weather observations from the Advanced Radar Research Center’s dual-polarized PX-1000 transportable radar, which utilizes dual 100-W solid-state transmitters, are presented. Both stratiform and convective scenarios, as well as dual-polarization observations, are shown, demonstrating significant improvement in sensitivity over previous pulse compression methods.
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Kikuchi, Hiroshi, Taku Suezawa, Tomoo Ushio, Nobuhiro Takahashi, Hiroshi Hanado, Katsuhiro Nakagawa, Masahiko Osada, et al. "Initial Observations for Precipitation Cores With X-Band Dual Polarized Phased Array Weather Radar." IEEE Transactions on Geoscience and Remote Sensing 58, no. 5 (May 2020): 3657–66. http://dx.doi.org/10.1109/tgrs.2019.2959628.
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Liou, Yu-Chieng, Howard B. Bluestein, Michael M. French, and Zachary B. Wienhoff. "Single-Doppler Velocity Retrieval of the Wind Field in a Tornadic Supercell Using Mobile, Phased-Array, Doppler Radar Data." Journal of Atmospheric and Oceanic Technology 35, no. 8 (August 2018): 1649–63. http://dx.doi.org/10.1175/jtech-d-18-0004.1.
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AbstractA three-dimensional data assimilation (3DVar) least squares–type single-Doppler velocity retrieval (SDVR) algorithm is utilized to retrieve the wind field of a tornadic supercell using data collected by a mobile, phased-array, Doppler radar [Mobile Weather Radar (MWR) 05XP] with very high temporal resolution (6 s). It is found that the cyclonic circulation in the hook-echo region can be successfully recovered by the SDVR algorithm. The quality of the SDVR analyses is evaluated by dual-Doppler syntheses using data collected by two mobile Doppler radars [Doppler on Wheels 6 and 7 (DOW6 and DOW7, respectively)]. A comparison between the SDVR analyses and dual-Doppler syntheses confirms the conclusion reached by an earlier theoretical analysis that because of the temporally discrete nature of the radar data, the wind speed retrieved by single-Doppler radar is always underestimated, and this underestimate occurs more significantly for the azimuthal (crossbeam) wind component than for the radial (along beam) component. However, the underestimate can be mitigated by increasing the radar data temporal resolution. When the radar data are collected at a sufficiently high rate, the azimuthal wind component may be overestimated. Even with data from a rapid scan, phased-array, Doppler radar, our study indicates that it is still necessary to calculate the SDVR in an optimal moving frame of reference. Finally, the SDVR algorithm’s robustness is demonstrated. Even with a temporal resolution (2 min) much lower than that of the phased-array radar, the cyclonic flow structure in the hook-echo region can still be retrieved through SDVR using data observed by DOW6 or DOW7, although a difference in the retrieved fields does exist. A further analysis indicates that this difference is caused by the location of the radars.
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Kumjian, Matthew R., Alexander V. Ryzhkov, Valery M. Melnikov, and Terry J. Schuur. "Rapid-Scan Super-Resolution Observations of a Cyclic Supercell with a Dual-Polarization WSR-88D." Monthly Weather Review 138, no. 10 (October 1, 2010): 3762–86. http://dx.doi.org/10.1175/2010mwr3322.1.
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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.
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Vollbracht, D. "Understanding and optimizing microstrip patch antenna cross polarization radiation on element level for demanding phased array antennas in weather radar applications." Advances in Radio Science 13 (November 3, 2015): 251–68. http://dx.doi.org/10.5194/ars-13-251-2015.
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Abstract. The antenna cross polarization suppression (CPS) is of significant importance for the accurate calculation of polarimetric weather radar moments. State-of-the-art reflector antennas fulfill these requirements, but phased array antennas are changing their CPS during the main beam shift, off-broadside direction. Since the cross polarization (x-pol) of the array pattern is affected by the x-pol element factor, the single antenna element should be designed for maximum CPS, not only at broadside, but also for the complete angular electronic scan (e-scan) range of the phased array antenna main beam positions. Different methods for reducing the x-pol radiation from microstrip patch antenna elements, available from literature sources, are discussed and summarized. The potential x-pol sources from probe fed microstrip patch antennas are investigated. Due to the lack of literature references, circular and square shaped X-Band radiators are compared in their x-pol performance and the microstrip patch antenna size variation was analyzed for improved x-pol pattern. Furthermore, the most promising technique for the reduction of x-pol radiation, namely "differential feeding with two RF signals 180° out of phase", is compared to single fed patch antennas and thoroughly investigated for phased array applications with simulation results from CST MICROWAVE STUDIO (CST MWS). A new explanation for the excellent port isolation of dual linear polarized and differential fed patch antennas is given graphically. The antenna radiation pattern from single fed and differential fed microstrip patch antennas are analyzed and the shapes of the x-pol patterns are discussed with the well-known cavity model. Moreover, two new visual based electromagnetic approaches for the explanation of the x-pol generation will be given: the field line approach and the surface current distribution approach provide new insight in understanding the generation of x-pol component in microstrip patch antenna radiation patterns.
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Valerio, Guido, Simona Mazzocchi, Alessandro Galli, Matteo Ciattaglia, and Marco Zucca. "New Configurations of Low-Cost Dual-Polarized Printed Antennas for UWB Arrays." International Journal of Antennas and Propagation 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/786791.
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A novel class of structures is proposed to realize ultra-wide-band radiating elements for large arrays, providing dual polarization, beam scanning, and compact and inexpensive realization based on suitable rhombic arrangements of dipoles printed on low-cost layered substrates. In a first implementation, four rhombic shapes, orthogonally placed on the same layer, provide two orthogonal polarizations. In a second implementation, the two polarizations are excited by two rhombic shapes printed on two different layers in a stacked-patch-like arrangement. This latter structure leads to a better lateral shielding of the single radiating element, in order to reduce mutual interactions among adjacent elements in array environment. The behavioral features of these antennas have been tested with various parametric analyses. Practical aspects have been addressed such as the choice of appropriate feeding and of commercially available dielectric layers. The resulting antennas are matched at the input ports in an extremely wide range of frequencies (5–25 GHz), covering various microwave applications, such as aircraft surveillance, weather polarimetric radars, and control and communications systems. Good radiating features, in terms of pattern shape and gain, are observed in a large band of frequencies. The basic scanning performance of large and small array configurations is finally investigated.
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Ivić, Igor R. "Statistical Evaluation of Time Multiplexing to Mitigate Differential Reflectivity Bias Due to Cross-Polar Coupling." Journal of Atmospheric and Oceanic Technology 33, no. 1 (January 2016): 127–47. http://dx.doi.org/10.1175/jtech-d-14-00224.1.
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AbstractOne of the main challenges to the use of phased array radar for weather observations is the implementation of dual polarization with acceptable levels of cross-polar fields induced by the antenna. For example, to achieve acceptable differential reflectivity (ZDR) bias (e.g., less than 0.1 dB) using simultaneous transmission and reception of H and V polarized waves, the isolation between coaxial cross-polar and copolar beams needs to be in excess of 50 dB. Because such isolation cannot be achieved at an affordable price by antenna hardware, additional methods are required to attain supplementary isolation of orthogonal channels. One such option is time multiplexing. Herein, this approach is evaluated from the statistical aspect, whereby the depolarization caused by the radar hardware is accounted for in this study. An evaluation is conducted using theoretical analysis as well as simulated and time series data from a weather radar. The main criteria for evaluation are the bias and standard deviation of differential reflectivity estimates. The results indicate that the implementation of the time-multiplexing method has the capability to significantly improve upon the radar intrinsic cross-polar isolation. However, it is demonstrated herein that the reflectivity gradients in range adversely affect the efficacy of the method and that the standard deviation of estimates can significantly increase as a result of the time-multiplexing application.
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Wurman, Joshua, David Dowell, Yvette Richardson, Paul Markowski, Erik Rasmussen, Donald Burgess, Louis Wicker, and Howard B. Bluestein. "The Second Verification of the Origins of Rotation in Tornadoes Experiment: VORTEX2." Bulletin of the American Meteorological Society 93, no. 8 (August 1, 2012): 1147–70. http://dx.doi.org/10.1175/bams-d-11-00010.1.
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The second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2), which had its field phases in May and June of 2009 and 2010, was designed to explore i) the physical processes of tornadogenesis, maintenance, and demise; ii) the relationships among tornadoes, tornadic storms, and the larger-scale environment; iii) numerical weather prediction and forecasting of supercell thunderstorms and tornadoes; and iv) the wind field near the ground in tornadoes. VORTEX2 is by far the largest and most ambitious observational and modeling study of tornadoes and tornadic storms ever undertaken. It employed 13 mobile mesonet–instrumented vehicles, 11 ground-based mobile radars (several of which had dual-polarization capability and two of which were phased-array rapid scan), a mobile Doppler lidar, four mobile balloon sounding systems, 42 deployable in situ observational weather stations, an unmanned aerial system, video and photogrammetric teams, damage survey teams, deployable disdrometers, and other experimental instrumentation as well as extensive modeling studies of tornadic storms. Participants were drawn from more than 15 universities and laboratories and at least five nations, with over 80 students participating in field activities. The VORTEX2 field phases spanned 2 yr in order to increase the probability of intercepting significant tornadoes, which are rare events. The field phase of VORTEX2 collected data in over three dozen tornadic and nontornadic supercell thunderstorms with unprecedented detail and diversity of measurements. Some preliminary data and analyses from the ongoing analysis phase of VORTEX2 are shown.
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Melnikov, Valery M., and Dušan S. Zrnić. "On the Alternate Transmission Mode for Polarimetric Phased Array Weather Radar." Journal of Atmospheric and Oceanic Technology 32, no. 2 (February 2015): 220–33. http://dx.doi.org/10.1175/jtech-d-13-00176.1.
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AbstractPulse-to-pulse switching of polarizations (alternate transmission mode) is considered for polarimetric phased array radar (PAR). It is argued that the performance of the radar in terms of data quality should match or exceed the achieved standards of the Weather Surveillance Radar-1988 Doppler (WSR-88D). It turns out that the most stringent demand on the radar concerns the surveillance scan at the lowest elevations wherein the polarimetric variables are free of overlaid echoes, while ground clutter is significantly reduced. The scan uses a long pulse repetition time that has repercussion on the standard errors of the polarimetric variables and hence the choice of polarimetric mode. Herein the dwell time of this scan serves as a benchmark for comparisons of the accuracy of estimates. Because weather PAR should provide useful information at low signal-to-noise ratios (SNR) as low as those measured by the WSR-88D, the statistics of polarimetric variables, known at high SNR, is extended to low SNRs. It follows that the alternate mode would not match the performance of the simultaneous mode in the surveillance scans on the WSR-88D. Quasi-simultaneous transmission and reception of horizontally polarized and vertically polarized waves is discussed as a cost-effective alternative.
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Perera, Sudantha, Yan Zhang, Dusan Zrnic, and Richard Doviak. "Electromagnetic Simulation and Alignment of Dual-Polarized Array Antennas in Multi-Mission Phased Array Radars." Aerospace 4, no. 1 (February 10, 2017): 7. http://dx.doi.org/10.3390/aerospace4010007.
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Yoshimi, Kazuhiro, Masakazu Wada, and Yukio Hiraoka. "Study on Water Level Prediction Using Observational Data from a Multi-Parameter Phased Array Weather Radar." Journal of Disaster Research 16, no. 3 (April 1, 2021): 410–14. http://dx.doi.org/10.20965/jdr.2021.p0410.
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A dual-polarization, phased array weather radar, also known as the multi-parameter phased array weather radar (MP-PAWR), was developed by the Japanese Cross-ministerial Strategic Innovation Promotion (SIP) Program. Since this weather radar has been made into an active phased array, three-dimensional observation of weather phenomena can be realized at high speed by means of electrical scanning in the elevation direction and mechanical scanning in the azimuth direction. This is expected to shed light on hydrological processes in river basins, such as those of urban rivers, and improve prediction accuracy. In this study, river water levels in urban areas were estimated from vertically integrated liquid (VIL) Nowcast water content results, a meteorological forecasting method based on the three-dimensional observation MP-PAWR data, using a synthesized rational formula. A runoff analysis for urban basins was carried out using the rainfall forecast results based on MP-PAWR observational data. Since it is known that this formula can be used to deliver a rapid response time for runoff phenomena in the basin, it is possible to fully exploit the features of the MP-PAWR. This study shows how MP-PAWR is used in a series of hydrological processes. In this paper, we report the results of a basic study on water level predictions based on MP-PAWR observational data and also present future prospects for the use of this technology.
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Ren, Yu-Jiun, and Yan Zhang. "Ultra-lightweight dual-polarized X-band array antenna for airborne weather radar applications." Microwave and Optical Technology Letters 51, no. 5 (March 13, 2009): 1324–26. http://dx.doi.org/10.1002/mop.24323.
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Vivekanandan, Jothiram, and Eric Loew. "Airborne polarimetric Doppler weather radar: trade-offs between various engineering specifications." Geoscientific Instrumentation, Methods and Data Systems 7, no. 1 (January 30, 2018): 21–37. http://dx.doi.org/10.5194/gi-7-21-2018.
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Abstract. NCAR EOL is investigating potential configurations for the next-generation airborne phased array radar (APAR) that is capable of retrieving dynamic and microphysical characteristics of clouds and precipitation. The APAR will operate at C band. The APAR will use the electronic scanning (e-scan) feature to acquire the optimal number of independent samples for recording research-quality measurements. Since the airborne radar has only a limited time for collecting measurements over a specified region (moving aircraft platform ∼ 100 m s−1), beam multiplexing will significantly enhance its ability to collect high-resolution, research-quality measurements. Beam multiplexing reduces errors in radar measurements while providing rapid updates of scan volumes. Beamwidth depends on the size of the antenna aperture. Beamwidth and directivity of elliptical, circular, and rectangular antenna apertures are compared and radar sensitivity is evaluated for various polarimetric configurations and transmit–receive (T/R) elements. In the case of polarimetric measurements, alternate transmit with alternate receive (single-channel receiver) and simultaneous reception (dual-channel receiver) is compared. From an overall architecture perspective, element-level digitization of T/R module versus digital sub-array is considered with regard to flexibility in adaptive beamforming, polarimetric performance, calibration, and data quality. Methodologies for calibration of the radar and removing bias in polarimetric measurements are outlined. The above-mentioned engineering options are evaluated for realizing an optimal APAR system suitable for measuring the high temporal and spatial resolutions of Doppler and polarimetric measurements of precipitation and clouds.
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Curtis, Christopher D., and Sebastián M. Torres. "Adaptive Range Oversampling Processing for Nontraditional Radar-Variable Estimators." Journal of Atmospheric and Oceanic Technology 34, no. 7 (July 2017): 1607–23. http://dx.doi.org/10.1175/jtech-d-16-0051.1.
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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.
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Melnikov, Valery, Dusan S. Zrnić, Mark E. Weber, Alexandre O. Fierro, and Donald R. MacGorman. "Electrified Cloud Areas Observed in the SHV and LDR Radar Modes." Journal of Atmospheric and Oceanic Technology 36, no. 1 (January 2019): 151–59. http://dx.doi.org/10.1175/jtech-d-18-0022.1.
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AbstractStrong in-cloud electric fields align ice particles that can be observed with polarization diversity radars. Radar data collected in the simultaneous transmission mode, wherein horizontally and vertically polarized waves are simultaneously transmitted and received (SHV), and in a mode whereby a single-polarization wave is transmitted and dual (orthogonal)-polarization waves are received simultaneously [linear depolarization (LDR) mode] are analyzed. The necessary time delay between the SHV and LDR modes for our radar was about 1–4 min. The data show that the areas of canted crystals from the LDR mode are larger than those from the SHV mode, thereby indicating that the LDR mode is more sensitive to canted ice cloud particles than the SHV mode. The data also demonstrate that the differential phase and correlation coefficient in the LDR mode are indicative of canted cloud crystals and that these variables often are more sensitive to canted crystals than the linear depolarization ratio studied earlier. Rapidly scanning radars such as those with a phased array antenna could operate sequentially in the SHV and LDR modes and thus better detect cloud volumes characterized by enhanced electric fields.
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刘, 艳. "Analysis of the Characteristics of X-Band Dual-Polarization and Phased-Array Weather Radar during a Hail Weather Process in Early Spring." Advances in Geosciences 11, no. 09 (2021): 1188–94. http://dx.doi.org/10.12677/ag.2021.119115.
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Ivić, Igor R. "An Approach to Simulate the Effects of Antenna Patterns on Polarimetric Variable Estimates." Journal of Atmospheric and Oceanic Technology 34, no. 9 (September 2017): 1907–34. http://dx.doi.org/10.1175/jtech-d-17-0015.1.
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AbstractOne of the main challenges of using phased array radar for weather observations is the implementation of dual polarization with acceptable errors of polarimetric variable estimates. This is because the differences between the copolar antenna patterns at the horizontal and vertical polarizations, as well as cross-polar fields, can introduce unacceptable measurement biases, as the main beam is electronically steered away from the principal planes. Because the sufficient cross-polar isolation is difficult to achieve by the phased array antenna hardware and because the copolar as well as cross-polar patterns inevitably vary with each beam position, it is crucial to properly evaluate errors of estimates due to radiation patterns. Herein, a method that combines the measured or simulated radiation patterns and simulated time series is introduced. The method is suited for phased array and parabolic antennas, and it allows for evaluation of radiation-pattern-induced polarimetric variable biases and standard deviations specific to the antenna used to produce the patterns. The method can be used either as an alternative to a well-established approach using analytical derivations or as a tool for cross validation of the bias computations. For standard deviation evaluation in the presence of antenna cross-polar fields, the analytical approach becomes overly complex, which inexorably leads to the introduction of numerous approximations to obtain the results. These approximations inevitably compromise the accuracy of such computations. The method proposed herein avoids such approximations and therefore provides a valuable tool for accurate assessment of polarimetric measurement precision.
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Wijayarathne, Dayal, Paulin Coulibaly, Sudesh Boodoo, and David Sills. "Evaluation of Radar-Gauge Merging Techniques to Be Used in Operational Flood Forecasting in Urban Watersheds." Water 12, no. 5 (May 23, 2020): 1494. http://dx.doi.org/10.3390/w12051494.
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Demand for radar Quantitative Precipitation Estimates (QPEs) as precipitation forcing to hydrological models in operational flood forecasting has increased in the recent past. It is practically impossible to get error-free QPEs due to the intrinsic limitations of weather radar as a precipitation measurement tool. Adjusting radar QPEs with gauge observations by combining their advantages while minimizing their weaknesses increases the accuracy and reliability of radar QPEs. This study deploys several techniques to merge two dual-polarized King City radar (WKR) C-band and two KBUF Next-Generation Radar (NEXRAD) S-band operational radar QPEs with rain gauge data for the Humber River (semi-urban) and Don River (urban) watersheds in Ontario, Canada. The relative performances are assessed against an independent gauge network by comparing hourly rainfall events. The Cumulative Distribution Function Matching (CDFM) method performed best, followed by Kriging with Radar-based Error correction (KRE). Although both WKR and NEXRAD radar QPEs improved significantly, NEXRAD Level III Digital Precipitation Array (DPA) provided the best results. All methods performed better for low- to medium-intensity precipitation but deteriorated with the increasing rainfall intensities. All methods outperformed radar only QPEs for all events, but the agreement is best in the summer.
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Trinidad Garcia, Elvis, Ruben Ortega, and Saad Tabet. "Rectangular Slot Array Antenna." Applied Computational Electromagnetics Society 35, no. 11 (February 3, 2021): 1302–3. http://dx.doi.org/10.47037/2020.aces.j.351120.
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Slot antenna elements are quite popular for use in flat-panel arrays, due to their compactness and relatively large bandwidth. According to Babinet’s Principle, slots and dipoles are duals in performance. Therefore, a vertically placed slot is horizontally polarized and a horizontally placed slot is vertically polarized. A rectangular slot array lends itself to a broad range of applications, e.g., tactical and weather radar. Such arrays can be gimbaled to point their beam in any azimuth and elevation angle of interest. In this effort, a slot antenna element is designed in WIPL-D Pro to operate over the 7.5 - 8.5 GHz frequency range. The element is designed to resonate at 8 GHz. The slot element is used to generate a 6x12 slot array normal to the xy-plane. Separate Taylor tapers (nbar = 5) are applied to the 6-row and 12-column elements to provide 25 dB and 30 dB sidelobe level (SLL) suppression, respectively. The input impedance and pattern performance for a single slot, as well as the slot array’s radiation performance show excellent broadband performance.
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Witt, Arthur, Donald W. Burgess, Anton Seimon, John T. Allen, Jeffrey C. Snyder, and Howard B. Bluestein. "Rapid-Scan Radar Observations of an Oklahoma Tornadic Hailstorm Producing Giant Hail." Weather and Forecasting 33, no. 5 (September 19, 2018): 1263–82. http://dx.doi.org/10.1175/waf-d-18-0003.1.
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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.
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Tadono, T., M. Ohki, and T. Abe. "SUMMARY OF NATURAL DISASTER RESPONSES BY THE ADVANCED LAND OBSERVING SATELLITE-2 (ALOS-2)." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W7 (March 1, 2019): 69–72. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w7-69-2019.
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<p><strong>Abstract.</strong> The Advanced Land Observing Satellite-2 (ALOS-2) was launched on May 24, 2014, and it is operating very well in space more than 4.5 years. The designed mission life is five years as nominal operational phase and the target is over seven years since launch the satellite. The mission objectives of ALOS-2 are 1) disaster monitoring, 2) national land and infrastructure information, 3) cultivated area monitoring, and 4) global forest monitoring. To achieve the objectives, ALOS-2 carries on the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2), which is an active microwave radar using the 1.2 GHz frequency band and observes in day and night times even in bad weather conditions as successor PALSAR instrument onboard ALOS satellite operated from 2006 to 2011. PALSAR-2 instrument has several enhanced features from PALSAR e.g. finer spatial resolution, spotlight observing mode, dual-polarisation ScanSAR. This paper summarises an introduction of typical data analysis results for monitoring natural disasters by ALOS-2 during the operational phase. As the response natural disasters, more than 400 times of the emergency observations have been conducted to identify damages caused by volcanic activities, earthquakes, flooding etc. happened in Japan and the World.</p>
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Pedraza, Carlos, Nicola Clerici, Cristian Forero, América Melo, Diego Navarrete, Diego Lizcano, Andrés Zuluaga, Juliana Delgado, and Gustavo Galindo. "Zero Deforestation Agreement Assessment at Farm Level in Colombia Using ALOS PALSAR." Remote Sensing 10, no. 9 (September 13, 2018): 1464. http://dx.doi.org/10.3390/rs10091464.
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Due to the fast deforestation rates in the tropics, multiple international efforts have been launched to reduce deforestation and develop consistent methodologies to assess forest extension and change. Since 2010 Colombia implemented the Mainstream Sustainable Cattle Ranching project with the participation of small farmers in a payment for environmental services (PES) scheme where zero deforestation agreements are signed. To assess the fulfillment of such agreements at farm level, ALOS-1 and ALOS-2 PALSAR fine beam dual imagery for years 2010 and 2016 was processed with ad-hoc routines to estimate stable forest, deforestation, and stable nonforest extension for 2615 participant farms in five heterogeneous regions of Colombia. Landsat VNIR imagery was integrated in the processing chain to reduce classification uncertainties due to radar limitations. Farms associated with Meta Foothills regions showed zero deforestation during the period analyzed (2010–2016), while other regions showed low deforestation rates with the exception of the Cesar River Valley (75 ha). Results, suggests that topography and dry weather conditions have an effect on radar-based mapping accuracy, i.e., deforestation and forest classes showed lower user accuracy values on mountainous and dry regions revealing overestimations in these environments. Nevertheless, overall ALOS Phased Array L-band SAR (PALSAR) data provided overall accurate, relevant, and consistent information for forest change analysis for local zero deforestation agreements assessment. Improvements to preprocessing routines and integration of high dense radar time series should be further investigated to reduce classification errors from complex topography conditions.
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Payne, Clark D., Terry J. Schuur, Donald R. MacGorman, Michael I. Biggerstaff, Kristin M. Kuhlman, and W. David Rust. "Polarimetric and Electrical Characteristics of a Lightning Ring in a Supercell Storm." Monthly Weather Review 138, no. 6 (June 1, 2010): 2405–25. http://dx.doi.org/10.1175/2009mwr3210.1.
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Abstract On 30 May 2004, a supercell storm was sampled by a suite of instrumentation that had been deployed as part of the Thunderstorm Electrification and Lightning Experiment (TELEX). The instrumentation included the Oklahoma Lightning Mapping Array (OK-LMA), the National Severe Storms Laboratory S-band Weather Surveillance Radar-1988 Doppler (WSR-88D) polarimetric radar at Norman, Oklahoma, and two mobile C-band, Shared Mobile Atmospheric Research and Teaching Radars (SMART-R). Combined, datasets collected by these instruments provided a unique opportunity to investigate the possible relationships among the supercell’s kinematic, microphysical, and electrical characteristics. This study focuses on the evolution of a ring of lightning activity that formed near the main updraft at approximately 0012 UTC, matured near 0039 UTC, and collapsed near 0050 UTC. During this time period, an F2-intensity tornado occurred near the lightning-ring region. Lightning density contours computed over 1-km layers are overlaid on polarimetric and dual-Doppler data to assess the low- and midlevel kinematic and microphysical characteristics within the lightning-ring region. Results indicate that the lightning ring begins in the middle and upper levels of the precipitation-cascade region, which is characterized by inferred graupel. The second time period shows that the lightning source densities take on a horizontal u-shaped pattern that is collocated with midlevel differential reflectivity and correlation coefficient rings and with the strong cyclonic vertical vorticity noted in the dual-Doppler data. The final time period shows dissipation of the u-shaped pattern and the polarimetric signatures as well as an increase in the lightning activity at the lower levels associated with the development of the rear-flank downdraft (RFD) and the envelopment of the vertical vorticity maximum by the RFD.
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Tai, Sai-Choi, Edwin Wing-Lui Ginn, and Chiu-Ying Lam. "Dual-Doppler Observations of Severe Tropical Storm Maggie 1999." Weather and Forecasting 20, no. 1 (February 1, 2005): 112–23. http://dx.doi.org/10.1175/waf-828.1.
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Abstract Severe Tropical Storm Maggie crossed Hong Kong, China, in June 1999. The dual-Doppler winds of Maggie captured by the Hong Kong Observatory's (HKO) S-band Doppler weather radar array were studied. The tracks of Maggie's vorticity centers at 1–3-km levels were analyzed and compared with that at the surface as determined from the wind observations of automatic weather stations. The results indicated that the storm had a vertical tilt toward the west to northwest during the transit over Hong Kong. The tracks also deviated significantly from the deep-layer environmental steering flow. The southward movement and vertical tilt could be partly attributed to the easterly vertical shear in the ambient flow. But the terrain of Hong Kong could have also played a significant role in the lowest 1 km of the atmosphere. The tendency of the storm track to avoid mountains was well illustrated and may serve as a useful forecasting guidance indicator for tropical areas with significant terrain. Experimental runs of a nonhydrostatic model at 5-km resolution were able to simulate the broad west-southwestward movement of Maggie and the vertical tilt of the circulation near the center of the tropical cyclone as revealed by the dual-Doppler observations.
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Friedrich, Katja, Robinson Wallace, Bernard Meier, Nezette Rydell, Wiebke Deierling, Evan Kalina, Brian Motta, Paul Schlatter, Thomas Schlatter, and Nolan Doesken. "CHAT: The Colorado Hail Accumulation from Thunderstorms Project." Bulletin of the American Meteorological Society 100, no. 3 (March 2019): 459–71. http://dx.doi.org/10.1175/bams-d-16-0277.1.
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AbstractIn recent years, hail accumulations from thunderstorms have occurred frequently enough to catch the attention of the National Weather Service, the general public, and news agencies. Despite the extreme nature of these thunderstorms, no mechanism is currently in place to obtain adequate reports, measurements, or forecasts of accumulated hail depth. To better identify and forecast hail accumulations, the Colorado Hail Accumulation from Thunderstorms (CHAT) project was initiated in 2016 with the goals of collecting improved and more frequent hail depth reports on the ground as well as studying characteristics of storms that produce hail accumulations in Colorado. A desired outcome of this research is to identify predictors for hail-producing thunderstorms typically occurring along the Colorado Front Range that might be used as operational nowcast products in the future. During the 2016 convective season, we asked amateur meteorologists to send general information, photos, and videos on hail depth using social media. They submitted over 58 reports in Colorado with information on location, time, depth, and areal coverage of hail accumulations. We have analyzed dual-polarization radar and lightning mapping array data from 32 thunderstorms in Colorado, which produced between 0.5 and 50 cm of hail accumulation on the ground, to identify characteristics unique to storms with hail accumulations. This preliminary analysis shows how enhanced in-cloud hail presence and surface accumulation can be tracked throughout the lifetime of a thunderstorm using dual-polarization radar and lightning data, and how hail accumulation events are associated with large in-cloud ice water content, long hailfall duration, or a combination of these.
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Hu, Jiaxi, Daniel Rosenfeld, Alexander Ryzhkov, and Pengfei Zhang. "Synergetic Use of the WSR-88D Radars, GOES-R Satellites, and Lightning Networks to Study Microphysical Characteristics of Hurricanes." Journal of Applied Meteorology and Climatology 59, no. 6 (June 2020): 1051–68. http://dx.doi.org/10.1175/jamc-d-19-0122.1.
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AbstractThis study analyzes the microphysics and precipitation pattern of Hurricanes Harvey (2017) and Florence (2018) in both the eyewall and outer rainband regions. From the retrievals by a satellite red–green–blue scheme, the outer rainbands show a strong convective structure while the inner eyewall has less convective vigor (i.e., weaker upper-level reflectivities and electrification), which may be related to stronger vertical wind shear that hinders fast vertical motions. The WSR-88D column-vertical profiles further confirm that the outer rainband clouds have strong vertical motion and large ice-phase hydrometeor formation aloft, which correlates well with 3D Lightning Mapping Array source counts in height and time. From the results from this study, it is determined that the inner eyewall region is dominated by warm rain, whereas the external rainband region contains intense mixed-phase precipitation. External rainbands are defined here as those that reside outside of the main hurricane circulation, associated with surface tropical storm wind speeds. The synergy of satellite and radar dual-polarization parameters is instrumental in distinguishing between the key microphysical features of intense convective rainbands and the warm-rain-dominated eyewall regions within the hurricanes. Substantial amounts of ice aloft and intense updrafts in the external rainbands are indicative of heavy surface precipitation, which can have important implications for severe weather warnings and quantitative precipitation forecasts. The novel part of this study is to combine ground-based radar measurement with satellite observations to study hurricane microphysical structure from surface to cloud top so as to fill in the gaps between the two observational techniques.
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Grover, A., S. Kumar, and A. Kumar. "SHIP DETECTION USING SENTINEL-1 SAR DATA." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-5 (November 15, 2018): 317–24. http://dx.doi.org/10.5194/isprs-annals-iv-5-317-2018.
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<p><strong>Abstract.</strong> The Earth’s surface is covered with 72% water. This fact alone emphasizes the importance of proper monitoring and regulation of maritime activities. This monitoring can be useful in an array of applications including illegal transitions, rescue operations, territory regulation among many other applications. In order to achieve the task of “Maritime Surveillance” or simply the marine object detection, we need a structured approach combined with a set of algorithms. The objective of this paper is to study an emerging open source tool- Search for Unidentified Maritime Objects (SUMO) developed for the detection of ships which work regardless of weather conditions and coverage limits. Based on the Synthetic Aperture Radar (SAR) data, this paper aims to process the satellite-borne data provided by the Sentinel-1 satellite. Proposed by the Joint Research Centre, SUMO is a pixel-based algorithm which follows a structured approach in order to identify marine objects and remove false alarms. It is observed that many of the false alarms are caused due to the presence of land. These are reduced by using the buffered coastlines referred to as land masks. A local threshold is calculated using the background clutter for the generation of false alarm rate and the pixels above this threshold are identified and clustered to form targets. A reliability value is computed for the elimination of azimuth ambiguities. Also, various attributes of the detected targets are calculated in order to give an accurate description of ships and its characteristics. With the SAR data being freely available due to the open data policy of the EU’s Copernicus program, it has never been more viable to employ new methods for marine object detection and this paper explores this possibility by analyzing the results obtained. Specifically, the employed data consists of Sentinel-1 fine dual-pol acquisitions over the coastal regions of India.</p>
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Asai, Keitaro, Hiroshi Kikuchi, Tomoo Ushio, and Yasuhide Hobara. "Validation of X-band multi-parameter phased array weather radar by comparing data from Doppler weather radar with a parabolic dish antenna." Journal of Atmospheric and Oceanic Technology, July 6, 2021. http://dx.doi.org/10.1175/jtech-d-20-0213.1.
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AbstractThe multi-parameter phased array weather radar (MP-PAWR) was the first dual-polarized phased array weather radar to be commissioned in Japan (2017). When conducting a volume scan, the MP-PAWR respectively uses electronic and mechanical scanning in the elevation and azimuth angles to achieve rapid scanning and high-density observations. Although the effectiveness of the MP-PAWR has been demonstrated in case studies, its observation accuracy is yet to be quantitatively analyzed. Therefore, this study compared data of MP-PAWR with that of an operational dual-polarized weather radar with a parabolic-type antenna (X-MP radar) using 2,347,097 data samples obtained over 14 h. The results showed that the observation accuracy of the MP-PAWR was approximately the same as that of the X-MP radar at low elevations. The correlations of observational parameters (radar reflectivity factor, differential resistivity, specific differential phase, and Doppler velocity) between the MP-PAWR and X-MP radar ranged from 0.77–0.99 when MP-PAWR data were recorded within 15 s of the X-MP radar observations. The correlation between the observational parameters of the two radars decreased as the observation time difference between the X-MP radar and MP-PAWR increased. In particular, the correlation coefficients between the specific differential phase and the differential reflectivity were considerably lower than the single-polarization parameter at observation time difference of 240–300 s. By providing high-frequency and high-density dual-polarization observations, the MP-PAWR can contribute to rainfall prediction in Japan and reduce the damage caused by localized, rapidly developing cumulonimbus clouds.
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Wurman, Joshua, Karen Kosiba, Brian Pereira, Paul Robinson, Andrew Frambach, Alycia Gilliland, Trevor White, et al. "The FARM (Flexible Array of Radars and Mesonets)." Bulletin of the American Meteorological Society, April 20, 2021, 1–88. http://dx.doi.org/10.1175/bams-d-20-0285.1.
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AbstractThe Flexible Array of Radars and Mesonets (FARM) Facility is an extensive mobile/quickly-deployable (MQD) multiple-Doppler radar and in-situ instrumentation network.The FARM includes four radars: two 3-cm dual-polarization, dual-frequency (DPDF), Doppler On Wheels DOW6/DOW7, the Rapid-Scan DOW (RSDOW), and a quickly-deployable (QD) DPDF 5-cm COW C-band On Wheels (COW).The FARM includes 3 mobile mesonet (MM) vehicles with 3.5-m masts, an array of rugged QD weather stations (PODNET), QD weather stations deployed on infrastructure such as light/power poles (POLENET), four disdrometers, six MQD upper air sounding systems and a Mobile Operations and Repair Center (MORC).The FARM serves a wide variety of research/educational uses. Components have deployed to >30 projects during 1995-2020 in the USA, Europe, and South America, obtaining pioneering observations of a myriad of small spatial and temporal scale phenomena including tornadoes, hurricanes, lake-effect snow storms, aircraft-affecting turbulence, convection initiation, microbursts, intense precipitation, boundary-layer structures and evolution, airborne hazardous substances, coastal storms, wildfires and wildfire suppression efforts, weather modification effects, and mountain/alpine winds and precipitation. The radars and other FARM systems support innovative educational efforts, deploying >40 times to universities/colleges, providing hands-on access to cutting-edge instrumentation for their students.The FARM provides integrated multiple radar, mesonet, sounding, and related capabilities enabling diverse and robust coordinated sampling of three-dimensional vector winds, precipitation, and thermodynamics increasingly central to a wide range of mesoscale research.Planned innovations include S-band On Wheels NETwork (SOWNET) and Bistatic Adaptable Radar Network (BARN), offering more qualitative improvements to the field project observational paradigm, providing broad, flexible, and inexpensive 10-cm radar coverage and vector windfield measurements.