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Short-range forecasts (nowcasts) of rainfall facilitate providing early warning of severe rainfall and flooding, which is particularly important in densely populated urban areas. Nowcasts are conventionally obtained by the extrapolation of radar echoes from a constant altitude plan position indicator (CAPPI) or lowest-angle plan position indicator (PPI). Lacking a model for growth or decay, this approach has a limited ability to forecast the summertime convective storms. In a previous attempt to address this shortcoming, called RadVil, the predicted surface rain rate is obtained from mass balance equations of vertically integrated liquid (VIL) retrieved from volumetric reflectivity measurements. Predicting the growth and decay has also been attempted by using an autoregressive (AR) model, which led to the development of spectral prognosis (S-PROG). A novel combination of these two methodologies, called ANVIL, is proposed. In this approach, the growth and decay of VIL are modeled by an autoregressive integrated (ARI) process. It is shown that the predictability of growth and decay is scale-dependent. Thus, the key idea of ANVIL is to decompose the VIL into multiple spatial scales and apply a separate ARI model to each scale. The operational feasibility of ANVIL is evaluated using the Next-Generation Radar (NEXRAD)/WSR-88D radar that covers the Dallas–Fort Worth metropolitan area. The evaluation is done using ten convective events in 2018 and 2019. Using several verification metrics, it is shown that ANVIL has up to 25% improved skill compared to conventional nowcasting techniques. The improvement is consistent for a wide range of spatial scales (1–11 km) and rain rate thresholds (5–20 mmh−1).

The planning and realization of wind energy projects requires an as accurate and precise wind resource estimation as possible. Standard procedures combine shorter on-site measurements with the application of numerical models. The uncertainties of the numerical data generated from these models are, particularly in complex onshore terrain, not just rather high but typically not well quantified. In this article we propose a methodology for using a single scanning Doppler wind lidar device to calibrate the output data of a numerical flow model and with this not just quantify but potentially also reduce the uncertainties of the final wind resource estimate. The scanning lidar is configured to perform Plan Position Indicator (PPI) scans and the numerical flow data are projected onto this geometry. Deviations of the derived from the recorded line-of-sight wind speeds are used to identify deficiencies of the model and as starting point for an improvement and tuning. The developed methodology is demonstrated based on a study for a site in moderately complex terrain in central Germany and using two rather different types of numerical flow models. The findings suggest that the use of the methodology and the introduced scanning wind lidar technology offers a promising opportunity to control the uncertainty of the applied flow models, which can otherwise only be estimated very roughly.

This paper generalizes a previous formulation of signal separation problem for dynamic wind turbine clutter mitigation at weather radar systems. In this modified formulation, we use nonconvex regularizers together with multichannel overlapping group shrinkage (MOGS) to penalize weather signals and adopt multidimensional processing. We show the restored weather signals in plan position indicator (PPI) format and, to demonstrate the improvement, compare them with the ones produced by the previous method in reflectivity, spectral width, and Doppler velocity estimates of weather data. The improvement results from a better characterization of the sparsities of the weather radar returns. During the course of experiments, we observe that the proposed method successfully mitigates the wind turbine clutter and dramatically increases the signal-to-clutter ratio, even for different weather and wind turbine signatures. In addition, when the wind turbine clutter is weak in the mixture, our algorithm manages to attenuate the ground clutters and produces clutter-free weather signals favorable for further processing.

The increasing need of renewable energy fosters the expansion of wind turbine sites for power production throughout Europe with manifold effects, both on the positive and negative side. The latter concerns, among others, radar observations in the proximity of wind turbine (WT) sites. With the aim of better understanding the effects of large, moving scatterers like wind turbines on radar returns, MeteoSwiss performed two dedicated measurement campaigns with a mobile X-band Doppler polarimetric weather radar (METEOR 50DX) in the northeastern part of Switzerland in March 2019 and March 2020. Based on the usage of an X-band radar system, the performed campaigns are up to now unique. The main goal was to quantify the effects of wind turbines on the observed radar moments, to retrieve the radar cross-section (RCS) of the turbines themselves and to investigate the conditions leading to the occurrence of the largest RCS. Dedicated scan strategies, consisting of PPI (plan position indicator), RHI (range–height indicator) and fixed-pointing modes, were defined and used for observing a wind park consisting of three large wind turbines. During both campaigns, measurements were taken in 24/7 operation. The highest measured maxima of horizontal reflectivity (ZH) and RCS reached 78.5 dBZ and 44.1 dBsm, respectively. A wind turbine orientation (yawing) stratified statistical analysis shows no clear correlation with the received maximum returns. However, the median values and 99th percentiles of ZH show different enhancements for specific relative orientations. Some of them remain still for Doppler-filtered data, supporting the importance of the moving parts of the wind turbine for the radar returns. Further, we show, based on investigating correlations and an OLS (ordinary least square) model analysis, that the fast-changing rotor blade angle (pitch) is a key parameter, which strongly contributes to the variability in the observed returns.

The accuracy required for a correct interpretation of differential reflectivity (ZDR) is typically estimated to be between 0.1 and 0.2 dB. This is achieved through calibration, defined as the identification of the constant or time-varying offset to be subtracted from the measurements in order to isolate the meteorological signals. We propose two innovative steps: the automated selection of sufficiently homogeneous sections of Plan Position Indicator (PPI) scans at 90∘ elevation, performed in both rain and snow, and the ordinary kriging interpolation of the median ZDR value of the chosen radar volumes. This technique has been successfully applied to five field campaigns in various climatic regions. The availability of overlapping scans from two nearby radars allowed us to evaluate the calibration approach, and demonstrated the benefits of defining a time-varying offset. Even though the method has been designed to work with both solid and liquid precipitation, it particularly benefits radar systems with limited access to rain measurements due to the deployment in mountainous or polar regions or to issues affecting the lowest range gates.

Indonesian Weather Radar Polarimetric (I-WARP) is a pulse doppler X-band dual-polarized weather radar, located in Institut Teknologi Bandung, Indonesia. Since the radar is still in its refinement stage, the measured raw data show inconsistency in some parts of the data stream. The inconsistency is in terms of the amplitude of the received echoes which in some frames, exhibit very high values although the object distance is assumed to be far away from the radar. Therefore, it is assumed that in each frame, the location of the maximum amplitude determines the start of the frame. After adjusting the initial location of each frame, the plan position indicator (PPI) reflectivity plot shows a more realistic result.

This paper presents an approach to manage metadata (target class labels) for the recorded primary Doppler radar data. This information is necessary for further research and development of target classification algorithms. For this purpose, a labelling methodology and an application radar data analysis and target labelling was developed. The application includes radar records file processing, Doppler filtering, tag creation, data visualizationand tag database. For the better context of analysed data, an interface to Geographic Information Software (GIS) program is included as well. GIS program allows overlaying radar Plan Position Indicator (PPI) data with map data, airplane transponder tracks, drone flight path log and other support data. Finally, the application notes and observations are presented.

The increasing need of renewable energy fosters the expansion of wind turbine sites for power production throughout Europe with manifold effects, both on the positive and negative side. The latter concerns, among others, radar observations in the proximity of wind turbine (WT) sites. With the aim of better understanding the effects of large, moving scatterers like wind turbines on radar returns, MeteoSwiss performed two dedicated measurement campaigns with a mobile X-band Doppler polarimetric weather radar (METEOR 50DX) in the north-eastern part of Switzerland in March 2019 and March 2020. Based on the usage of a X-band radar system, the performed campaigns are up to now unique. The main goal was to quantify the effects of wind turbines on the observed radar moments, to retrieve the radar cross section (RCS) of the turbine themselves, and to investigate the conditions leading to the occurrence of the largest RCS. Dedicated scan strategies, consisting of PPI (Plan Position Indicator), RHI (Range-height Indicator) and fixed-pointing modes, were defined and used for observing a wind park consisting of three large wind turbines. During both campaigns, measurements were taken in 24/7 operation. The highest measured maxima of horizontal reflectivity (ZH) and RCS reached 78.5 dBZ respectively 44.1 dBsm. A wind turbine orientation (yawing) stratified statistical analysis shows no clear correlation with the received maximum returns. However, the median values and 99th percentiles of ZH and RCS show different enhancements for specific relative orientations. Further, we show, based on investigating correlations and an OLS (ordinary least square) model analyses, that the fast changing rotor blade angle (pitch) is a key parameter, which strongly contributes to the variability of the observed returns.

Decreasing gate closure times on the electricity stock exchange market and the rising share of renewables in today's energy system cause an increasing demand for very short-term power forecasts. While the potential of dual-Doppler radar data for that purpose was recently shown, the utilisation of single-Doppler lidar measurements needs to be explored further to make remote sensing-based very short-term forecasts more feasible for offshore sites. The aim of this work was to develop a lidar-based forecasting methodology, which addresses a lidar's comparatively low scanning speed. We developed a lidar-based forecast methodology using horizontal plan position indicator (PPI) lidar scans. It comprises a filtering methodology to recover data at far ranges, a wind field reconstruction, a time synchronisation to account for time shifts within the lidar scans and a wind speed extrapolation to hub height. Applying the methodology to seven free-flow turbines in the offshore wind farm Global Tech I revealed the model's ability to outperform the benchmark persistence during unstable stratification, in terms of deterministic as well as probabilistic scores. The performance during stable and neutral situations was significantly lower, which we attribute mainly to errors in the extrapolation of wind speed to hub height.

A wind measurement campaign using a single scanning light detection and ranging (LiDAR) device was conducted at the Hazaki Oceanographical Research Station (HORS) on the Hazaki coast of Japan to evaluate the performance of the device for coastal wind measurements. The scanning LiDAR was deployed on the landward end of the HORS pier. We compared the wind speed and direction data recorded by the scanning LiDAR to the observations obtained from a vertical profiling LiDAR installed at the opposite end of the pier, 400 m from the scanning LiDAR. The best practice for offshore wind measurements using a single scanning LiDAR was evaluated by comparing results from a total of nine experiments using several different scanning settings. A two-parameter velocity volume processing (VVP) method was employed to retrieve the horizontal wind speed and direction from the radial wind speed. Our experiment showed that, at the current offshore site with a negligibly small vertical wind speed component, the accuracy of the scanning LiDAR wind speeds and directions was sensitive to the azimuth angle setting, but not to the elevation angle setting. In addition to the validations for the 10-minute mean wind speeds and directions, the application of LiDARs for the measurement of the turbulence intensity (TI) was also discussed by comparing the results with observations obtained from a sonic anemometer, mounted at the seaward end of the HORS pier, 400 m from the scanning LiDAR. The standard deviation obtained from the scanning LiDAR measurement showed a greater fluctuation than that obtained from the sonic anemometer measurement. However, the difference between the scanning LiDAR and sonic measurements appeared to be within an acceptable range for the wind turbine design. We discuss the variations in data availability and accuracy based on an analysis of the carrier-to-noise ratio (CNR) distribution and the goodness of fit for curve fitting via the VVP method.

Real-time monitoring of volcanic tephra fallout rate is an important factor to predict ash plume dispersion and to mitigate risk to air traffic. Ground-based weather radar has been one of the fundamental instruments to detect the plume and derive eruptive source parameters, such as the tephra fallout rate. The current work presents the use of two small and compact X-band Multi-Parameter (X-MP) radars for a new tephra fallout rate model development and the technical aspects of the system in Sinabung and Merapi Volcanoes. The new model estimates the tephra fallout rate using two radar parameters: the specific differential phase shift parameter and the reflectivity intensity factor. Total cumulated mass estimated from the radar-based tephra fallout rate model from the radar is compared with the plume height model and an empirical radar-based model. A volcanic eruptive index (VEI)-2 of Sinabung generated a plume exceeding 15 km, resulting in a maximum tephra fallout rate of 0.58 kg m−2 h−1 and a total tephra mass of 51 × 106 kg. The VEI 1 of Sinabung caused a plume height of 2.5 km, resulting in a maximum tephra fallout rate of 0.3 kg m−2 h−1 and a total cumulated tephra of 9 × 106 kg. In the last case, a VEI 1 eruption of Mt. Merapi produces a 6 km plume, resulting in a maximum tephra fallout rate of 0.28 kg m−2 h−1 and a total cumulated tephra of 35 × 106 kg. The sector range height indicator scan-mode strategy in the VEI 2 eruption of Mt. Sinabung ran at six degrees azimuth angles capturing only a partial volume of the plume. Thus, the total mass was only 22% of the result from the empirical plume height model, even though the plume height was assumed to be equally the same with the maximum height scanned of radar at 7 km. In contrast, the volumetric scan by a plan position indicator strategy gave a total cumulated tephra mass, that matches better to the result of the empirical plume height model at 65–92%. Based on these results and the ability of the X-MP radar to capture the volcanic plume at the same reported onset time, we can confirm the importance of an X-MP radar for real-time tephra fallout monitoring during an eruption.

Data assimilation is one of method to improve initial atmospheric conditions data in numerical weather prediction. The assimilation of weather radar data that has quite extensive and tight data is considered to be able to improve the quality of weather prediction and analysis. This study aims to investigate the effect of assimilation of Doppler weather radar data in Weather Research Forecasting (WRF) numerical model for the prediction of heavy rain events in the Jabodetabek area with dates representing four seasons respectively on 20 February 2017, 3 April 2017, 13 June 2017, and 9 November 2017. For this purpose, the reflectivity (Z) and radial velocity (V) data from Plan Position Indicator (PPI) product and reflectivity (Z) data from Constant Altitude PPI (CAPPI) product were assimilated using WRFDA (WRF Data Assimilation) numerical model with 3DVar (The Three Dimensional Variational) system. The output of radar data assimilation and without assimilation of the numerical model of WRF is verified by spatial with GSMaP data and by point with precipitation observation data. In general, WRF radar assimilation provides a better simulation of spatial and point rain events compared to the WRF model without assimilation which is improvements of rain prediction from WRF radar data assimilation would be more visible in areas close to radar sources and not echo-blocked from fixed objects, and more visible during the rainy season

Observation of optical properties of atmospheric aerosols, especially their behavior near the surface level, is indispensable for better understanding of atmospheric environmental conditions. Concurrent observations of ground-based instruments and satellite-borne sensors are useful for attaining improved accuracy in the observation of relatively wide area. In the present paper, aerosol parameters in the lower troposphere are monitored using a plan position indicator (PPI) lidar, ground-sampling instruments (a nephelometer, an aethalometer, and optical particle counters), as well as a sunphotometer. The purpose of these observations is to retrieve the aerosol extinction coefficient (AEC) and aerosol optical thickness (AOT) simultaneously at the overpass time of Landsat-8 satellite. The PPI lidar, operated at 349 nm, provides nearly horizontal distribution of AEC in the lower part of the atmospheric boundary layer. For solving the lidar equation, the boundary condition and lidar ratio are determined from the data of ground sampling instruments. The value of AOT, on the other hand, is derived from sunphotometer, and used to analyze the visible band imagery of Landsat-8 satellite. The radiative transfer calculation is conducted using the MODTRAN code with the original aerosol type that has been determined from the ground sampling data coupled with the Mie scattering calculation. Reasonable agreement is found between the spatial distribution of AEC from the PPI lidar and that of AOT from the blue band (band 2) of Landsat-8. The influence of AOT on the values of apparent surface reflectance is also discussed.

The authors have developed a device for imitation of the signal-interference environment for radars, equipped with the plan-position indicator (PPI) «Picket», which does not require a PC for operation. Thanks to the use of the original method of forming marks from targets, it was possible to significantly reduce the amount of memory, required to store information about the scenario that reliably imitates the operation of the radar in real conditions. The device provides simultaneous operation of twelve indicators of a circular survey and is intended for equipping training centers for the training of air control operators.

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, Accepted: 2017-03-07, 資料番号: PA1720013000

Characterisation of atmospheric turbulence is a central step prior to the construction of long-span bridges. The present paper investigates the potential of a long-range scanning pulsed coherent lidar to measure the wind field at the inlet of a fjord. The wind velocity data acquired by the lidar is compared to the data recorded by sonic anemometers installed on the bridge. The focus is on the ability of the lidar to capture single and two-point statistics of turbulence in complex terrains. Satisfying results are obtained with the Line-of-Sight scanning mode, which provides the best sampling frequency (1 Hz). The low temporal resolution and the low signal-to-noise ratio for the Range Height Indicator and the Plan Position Indicator scanning modes are important limiting factors in the pilot study performed. Better results may be achieved for a lidar measurement set-up which is adapted specifically for investigating coherence.

We proposed the Fast Fourier Transform (FFT) to represent the sparsity of weather radar signals based on Compressive Sampling (CS). Since the real weather radar signal that we used in this research was produced by Frequency Modulated Continuous Wave (FMCW) radar, the frequency beat signal is proportional to the delay of the targets. FFT then used to get the coefficient of frequency beat signal that could show the range information. Evidently, FFT produced the large number of sparse frequency beat signal, so we can perform CS to reduce the large volume of the weather radar data. We sampled the sparse of range information using random measurement and then reconstructed using Orthogonal Matching Pursuit (OMP) algorithm. We construct a Plan Position Indicator (PPI) from compressed beat signals and compare with the uncompressed ones. The reconstruction results at various compression rates show that the proposed method has works properly.

This paper describes the initial results of trials with a noise radar demonstrator which has a noise-limited sensitivity and antenna configuration similar to a small conventional marine radar. The ability to obtain a plan position indicator (PPI) display, such as is needed for navigation is shown. The importance of being able to control the dynamic range is highlighted. In this respect, the trials have demonstrated the effectiveness of BLASA tailored waveforms in order to improve the useful dynamic range of the radar. The importance of being able to handle the effects of interference due to pulse radars operating in the same band is also illustrated.

A prototype high-resolution (1 km, 5 min) multiradar 3D gridded reflectivity product, including a suite of derived 2D vertical column products, has been developed for the Single European Skies Air Traffic Management Research program. As part of this, a new method for mapping radar data to grid points is being used, based on the concept of a binary space partitioning (BSP) tree that treats radar data as a set of points in a 3D point cloud. This allows the resulting analysis to be based on a complete picture of the nearby data from overlapping radars and can easily adapt to irregular grid configurations. This method is used with a Barnes successive corrections technique to retrieve finescale features while avoiding problems of undersmoothing in data-sparse regions. This has been tested using 3D domains enclosing the terminal maneuvering areas surrounding Paris, France, and London, United Kingdom, and using reflectivity plan position indicator scan data from the French and U.K. operational networks, encoded using the standard European Operational Programme for the Exchange of Weather Radar Information (OPERA) Data Information Model format. Quantitative intercomparisons between the new method, in various configurations; a high-resolution version of an existing method, in operational use at Météo-France; and a method that was developed by the National Oceanic and Atmospheric Administration for use with the Weather Surveillance Radar-1998 Doppler radar network, have been done using simulated radar scans derived from 3D synthetic radar reflectivity fields in stratiform and convective regimes.

An application of machine intelligence technique for the identification of micro-Doppler features from an airborne pulsed-Doppler radar sensor is developed. The key challenges for surveillance mode are the dynamic nature of the wind farm clutters, short-CPI length, and lack of prior information on the specific wind turbine (WT) in the site. The micro-Doppler spectrum segments based on short CPIs are used as the fundamental feature vectors for detection and classification. Both supervised and unsupervised approaches, including artificial neural network and random forest, are applied to airborne plan position indicator scan outputs. A simulator for airborne pulsed-Doppler radar operation over wind farm is used with realistic WT scattering signatures, platform motion impacts as well as the terrain clutter impacts. Based on the clutter identification result, the feasibility of detecting small moving targets in the presence of WT clutter is discussed.

This paper describes the steps of developing a Plan Position Indicator (PPI) radar display to be used on military ships. The PPI radar display system is a display of radar data in a polar coordinate representation. The PPI radar display is one of the most critical parts of the radar system, which provides information of the detection results of radar signal reflection objects. This PPI radar display system is built from a sea surveillance PPI radar display system that we developed previously. The added function is the integration of ship navigation sensor data by adjusting the communication protocol of the ship navigation sensor in the form of RS 422 to RS 232. Also, data extraction of sensors available in NMEA format is needed. ADAM 6052 and 6017 are required for RF system measurement interfaces and gain level setting in the radar transmitter. This system is also equipped with object tracking function, Guard Zone, and alarm. The method of calculating the location of pixels and azimuths, as well as the threshold in this study produces a good object reflection data plotting so that the PPI display application can be applied on the actual military ship.

The influence of aerosols to the atmosphere has been discussed in the context of the Earth radiation budget and global climate change. Therefore, precise monitoring of aerosol parameters is important for better understanding of their real characteristics and impacts on the environment. In this study, we report on a novel method of concurrent measurements of aerosol near the surface level by means of slant-path (SP) and plan position indicator (PPI) lidars. The SP lidar utilizes a diode-laser-pumped Nd:YAG laser operating at 532 nm, while the PPI is based on a Nd:YLF laser at 349 nm. The PPI system including the laser transmitter and telescope section is rotated over 360° for covering all the horizontal directions with the maximum observation range up to around 3 km. At the same time, the SP lidar is employed for monitoring the near surface region that cannot be covered by vertical observation lidars. Furthermore, the backscattered signals recorded by both PPI and SP lidars are analyzed using the Fernald method to retrieve aerosol extinction coefficient by employing lidar ratios for 349 and 532 nm. These values of lidar ratio are estimated by adjusting and fitting parameters in the Mie scattering calculation (mode radius, variance, and both real and imaginary parts of refractive index) to real data from ground-based sampling instruments, namely, the scattering coefficient, absorption coefficient, and size distribution observed with an integrating nephelometer, an aethalometer, and an optical particle counter, respectively. Real-time values of the extinction coefficient inside the atmospheric boundary-layer are derived as the summation of scattering and absorption coefficients. The results are then compared with those from a vertical lidar, operated by the National Institute of Environmental Studies (NIES) on the campus of Chiba University. We discuss the observed features of aerosol characteristics that vary both temporally and spatially.

In this paper, design and development of air surveillance radar software using QT creator application is presented. The software manufacture was performed in two stages, where the first stage is to design a flowchart and the second stage is to create the program using codes. Radar software must be integrated with hardware to display the results of the target detection. All detection results will be shown on the plan position indicator (PPI) display. From the detection results, all flying objects that can reflect radar signals will be shown in the display, i.e., airplanes, clouds, birds, mountains, tall buildings, as long as they are still in the radar detection range. The radar software has been tested with very significant good results. To only see moving objects such as high-speed aircrafts, moving target indicator (MTI) feature is enabled. The radar software was shown to be able to track objects and to create guard zones feature as an observation area.

Scanning Doppler lidars are the best tools for acquiring 3D velocity fields of full scale wind turbine wakes, whether the objective is a better understanding of some features of the wake or the validation of wake models. Since these lidars are based on the Doppler effect, a single scanning lidar normally relies on certain assumptions when estimating some components of the wind velocity vector. Furthermore, in order to reconstruct volumetric information, one needs to aggregate data, perform statistics on it and, most likely, interpolate to a convenient coordinate system, all of which introduce uncertainty in the measurements. This study simulates the performance of a virtual lidar performing stacked step-and-stare plan position indicator (PPI) scans on large-eddy simulation (LES) data, reconstructs the wake in terms of the average and the standard deviation of the longitudinal velocity component, and quantifies the errors. The variables included in the study are as follows: the location of the lidar (ground-based and nacelle-mounted), different atmospheric conditions, and varying scan speeds, which in turn determine the angular resolution of the measurements. Testing different angular resolutions allows one to find an optimum that balances the different error sources and minimizes the total error. An optimum angular resolution of 3 ∘ has been found to provide the best results. The errors found when reconstructing the average velocity are low (less than 2% of the freestream velocity at hub height), which indicates the possibility of high quality field measurements with an optimal angular resolution. The errors made when calculating the standard deviation are similar in magnitude, although higher in relative terms than for the mean, thus leading to a poorer quality estimation of the standard deviation. This holds true for the different inflow cases studied and for both ground-based and nacelle-mounted lidars.

Simulations of a squall line system which occurred on 12 August 2004 near Munich, Germany are performed using a fine grid version of the Weather Research and Forecasting (WRF) model with five different microphysical schemes. Synthetic dual polarization observations are created from the model output and compared with detailed observations gathered by the DLR polarimetric radar POLDIRAD located near Munich. Synthetic polarimetric radar scans are derived from the model forecasts employing the polarimetric radar forward operator SynPolRad. Evaluations of the microphysical parameterization schemes are carried out comparing Plan Position Indicator (PPI) and Range Height Indicator (RHI) scans of reflectivity and the spatial distribution of hydrometeor types. The hydrometeor types are derived applying a hydrometeor classification scheme to the observed and simulated polarimetric radar quantities. Furthermore, the Ebert-McBride contiguous rain area method of verification is tested in a variety of ways on the reflectivity output from the simulations. It is found that all five schemes overestimate reflectivity in the domain, particularly in the stratiform region of the convective system. All four schemes including graupel as a hydrometeor type produce too much of it. Differences are seen among the schemes in their depiction of reflectivity in the convective line and their representation of radar bright bands.

Weather radar data volumes are commonly processed to obtain various 2-D Cartesian products based on the transfer from polar to Cartesian representations through a certain interpolation method. In this research, an algorithm of the spatial interpolation of polar reflectivity data with respect to QI (quality index) data is applied to find the Cartesian reflectivity as PPI (plan position indicator) product and generate a corresponding QI field. On this basis, quality-based versions of standard algorithms for the generation of the following products have been developed: ETOP (echo top), MAX (maximum of reflectivity), and VIL (vertically integrated liquid water). Moreover, as an example of a higher-level product, a CONVECTION (detection of convection) has been defined as a specific combination of the above-listed standard products. A corresponding QI field is determined for each generated product, taking into account the quality of the pixels from which a given product was determined and how large a fraction of the investigated heights was scanned. Examples of such quality-based products are presented in the paper.

In this paper, we propose a reconfigurable Monopulse tracking system. The system proposes dual-pulse PRI scheme to reduce blind range while increasing the maximum range of the radar. The system can track multiple targets in Track-While-Scan (TWS) mode with angular accuracy of 0.1 degree. The system is implemented on a board containing two kintex-7 FPGAs and two TI DSPs (6713 & 6678). One FPGA acquires data and performs down sampling. The other FPGA performs Digital Down Conversion (DDC), Pulse Compression (PC), Moving Target Indication (MTI) and Moving Target Detection (MTD). The 6713 DSP then applies Constant False Alarm Rate (CFAR), plot cohesion and amplitude comparison angle measurement algorithms to MTD processed data for targets detection and angular error calculation. Customized software is developed in Visual C (VC) for the system which performs data association, tracking, online parameters' configuration and display processing results. The system is tested in real-time using an Off-The-Shelf Radar Echo Simulator. The Echo Simulator generates sum & azimuth difference IF signals, which are processed by the proposed system and target tracks are displayed on the Plan Position Indicator (PPI).

The local environment during the joint Atmospheric Radiation Measurement Program (ARM) Madden–Julian oscillation (MJO) Investigation Experiment (AMIE)–Cooperative Indian Ocean Experiment on Intraseasonal Variability in Year 2011 (CINDY2011)–Dynamics of the MJO (DYNAMO) field experiments caused frequent occurrences of sidelobe artifacts in the NCAR S-Pol radar dataset. Although generally low in radar reflectivity factor value (less than 5 dBZ), this contamination still proved problematic for Bragg scattering layer (BSL) analysis, generating numerous false BSL edge detections. In this paper, a statistical filtering technique is developed that effectively removes these false BSL edge detections, utilizing a new version of BSL analysis based on range–height indicator (RHI) data instead of plan position indicator data.

Typical methods used to acquire wind profiles from Doppler radar measurements rely on plan position indicator (PPI) scans being performed at multiple elevation angles to utilize the velocity–azimuth display technique or to construct dual-Doppler synthesis. These techniques, as well as those employed by wind profilers, often produce wind profiles that lack the spatial or temporal resolution to resolve finescale features. If two radars perform range–height indicator (RHI) scans (constant azimuth, multiple elevations) along azimuths separated by approximately 90°, then the intersection of the coordinated RHI planes represents a vertical set of points where dual-Doppler wind syntheses are possible and wind speed and direction profiles can be retrieved. This method also allows for the generation of high-resolution wind time histories that can be compared to anemometer time histories. This study focuses on the use of the coordinated RHI scanning strategy by two high-resolution mobile Doppler radars in close proximity to a 200-m instrumented tower. In one of the first high-resolution, long-duration comparisons of dual-Doppler wind synthesis with in situ anemometry, the mean and turbulence states of the wind measured by each platform were compared in varying atmospheric conditions. Examination of mean wind speed and direction profiles in both clear-air (nonprecipitating) and precipitating environments revealed excellent agreement above approximately 50 m. Below this level, dual-Doppler wind speeds were still good but slightly overestimated as compared to the anemometer-measured wind speeds in heavy precipitation. Bulk turbulence parameters were also slightly underestimated by the dual-Doppler syntheses.

The use of radar technology as a defense equipment in the maritime territory has been widely applied in almost all regions of Indonesia. FMCW radar displays the raw data streamed from the DSP device. It is often observed that the data plotting results formed in an incomplete echo image because of the non-continuous pixels between the pixel data with the surrounding. This is caused by the execution time of the plotting process could not accommodate the changes of subsequent data. There are two ways to overcome these problems, by upgrading hardware capabilities, and perform image processing that stored in the buffer before it is displayed on the screen. This paper describes the design of morphological dilation which is applied in the plan position indicator (PPI) radar to improve the quality of radar image so that it can improve the quality of the extraction object in the research that has been done to reduce the loss of the object when the object tracking process takes place.

This paper describes the implementation of an improved clutter suppression method for the multiple pulse repetition time (PRT) technique based on simulated radar data. The suppression method is constructed using maximum likelihood methodology in time domain and is called parametric time domain method (PTDM). The procedure relies on the assumption that precipitation and clutter signal spectra follow a Gaussian functional form. The multiple interleaved pulse repetition frequencies (PRFs) that are used in this work are set to four PRFs (952, 833, 667, and 513 Hz). Based on radar simulation, it is shown that the new method can provide accurate retrieval of Doppler velocity even in the case of strong clutter contamination. The obtained velocity is nearly unbiased for all the range of Nyquist velocity interval. Also, the performance of the method is illustrated on simulated radar data for plan position indicator (PPI) scan. Compared with staggered 2-PRT transmission schemes with PTDM, the proposed method presents better estimation accuracy under certain clutter situations.

Observation of rainfall accumulation, distribution and wind direction spatially and temporally is very essential for meteorologists and hydrologists in the Upper Blue Nile basin and different locations of Ethiopia. The Bahir Dar (BAH) Cband weather radar used to estimate the intensity, amount and distribution of precipitation with a high resolution temporally and spatially. It is dual polarization with horizontal and vertical reflectivity; six variables are used to determine the hydrometer and non-hydrometer types, shape and sizes of targets up to range of 250 km and 450 km at constant altitude plan position indicator (CAPPI) and plan position indicator (PPI) products. From our first observation, we used different types of products to observe rainfall intensity, distribution, wind direction and warnings across Upper Blue Nile. For RainN on 01 July 2016 the rainfall distribution over twenty four hours (24 Hr) UTC at Bahir Dar, parts of lake Tana, most northern parts, western parts of Gondar town, and south western parts of lake Tana a resolution of 809 m/Pixel with frequency of 600 Hz the maximum rainfall accumulation 91.6 mm was achieved. By using CAPPI product with vertical height of 1 km on 26 June 2016 the maximum reflectivity 53.5 dBZ is observed.

In this research, the design and manufacture of radar display software using Plan Position Indicator (PPI) format for air surveillance radar application are presented. The PPI display shows interpretations of echo detections of radar signal reflected from the flying objects/targets. The detection results will be displayed on a circular 360ᵒ area, where the radar position is at the center. System configuration is done via interface from the display, by adjusting the level of transmit signal, by setting the gain for threshold, and by enabling moving target indicator (MTI) mode. The MTI mode only displays moving objects and no non-moving objects are shown such as mountains and buildings. Based on the results of this research, the PPI display shows the targets on the display according to its position, some desired targets can also be tracked, information on target, GPS location, target ID, required parameters, and some settings. The radar display fulfills all the required capabilities for air surveillance radar.

Radar imaging system is strongly influenced by other supporting systems. There is a motor system that provides angular information to the display system, and Digital Signal Processing (DSP) system that provides the main information for radar imaging. The new approach, we substitute a DC servo motor with a DC stepper motor as radar antenna rotator in our navigation radar system development. Different from the use of servo motors that can provide angle movements smoothly, the new motor system provides angle information of 0.56 degrees in every step, results in empty pixel gaps in every 0.56 degrees in radar Plan Position Indicator (PPI) image. The width of the empty pixel gaps becomes wider when the cell array of raw data is increasing regarding the image plotting process. In this paper, we proposed a new morphological dilation method to the radar raw data based on binary template matching to accommodate the various width of empty pixel gaps before the radar raw data are plotted into the radar PPI image. By this method, the morphological dilation will only be applied to the raw data that meet the same criteria as the binary template. Otherwise, the raw data will be left as they are. The result shows that there is 150.52% pixel data addition in the empty pixel gaps from the original image, and 48.44% increase of the morphological dilation without binary template matching method.

Interferometric radar is a rather popular equipment able to remotely perform dynamic testing of large structures (towers, bridges, buildings …) by detecting the relative displacement in the line of sight between the radar and geometric discontinuities in the engineering structure under test. This technique has been demonstrated effective when the radar is positioned at ground on a stable position. Unfortunately there are practical cases for which a suitable stable position is not available. This is the case of the towers of San Gimignano (Italy) that are embedded in the narrow streets of the old town. A solution to monitor the towers is to install the radar on the top of a tower, which is located in a central position of the town. The tower is not a stable arrangement for the radar and in this paper the authors propose and test the use of an accelerometer fixed to the radar head for detecting and removing its own movement.

This paper presents signal processing of position plan indicator (PPI) display for weather radar. The radar uses technique of frequency-modulated continuous-wave (FMC) to monitor the precipitation events in atmosphere and climate investigation. The use of FMCW technique is chosen in order to reduce the power at transmitter. For time efficiency, real-time domain processing conducted using Matlab® is implemented to process the received signal. Meanwhile, the PPI display is employed in the system due to its ability to map the area covered by the radar beam.

The design and realization of radar antenna direction chart is important in the simulation of radar system. The good design of radar antenna direction chart can improve the rate and reality of radar system simulation. Firstly this paper introduces the traditional antenna direction chart which has two bugs which are normalization and pitch angle. Because of these bugs, this paper introduces antenna direction chart function which is improved and added. This paper simulates the direction chart function. The simulation indicates that through the improved antenna direction, chart is better in pitching and direction and also approaches real radar antenna direction chart. Keywords-radar; antenna; simulate; direction chart