policy statement of the American Meteorological Society on weather radar

1981 ◽  
Vol 62 (5) ◽  
pp. 678-679
Keyword(s):  
Doppler Radar ◽  
Weather Radar ◽  
Digital Processing ◽  
Radar System ◽  
Policy Statement ◽  
Weather Radars ◽  
American Meteorological Society ◽  
Radar Systems ◽  
Technological Advances ◽  
Radar Measurements

Recent technological advances have greatly enhanced the value of weather radar for storm detection, warning, and study. The use of digital computing equipment in association with weather radars now provides techniques for collecting, monitoring, archiving, and presenting the radar measurements in a variety of useful ways and at rates that can keep pace with the acquisition of the data. Developments in Doppler radar technology allow the measurement of air motions (such as tornado vortices) and other features of storm structures. The AMS commends the U.S. Government for its initiative in planning for an advanced weather radar system. The AMS urges governments to place a high priority on the design, procurement, and deployment of the new weather radar systems that incorporate both Doppler and digital processing capabilities.

scholarly journals Statistical and neural classifiers in estimating rain rate from weather radar measurements

2007 ◽  
Vol 10 ◽  
pp. 111-115
Author(s):  
C. I. Christodoulou ◽  
S. C. Michaelides
Keyword(s):  
Electromagnetic Radiation ◽  
Rain Rate ◽  
Weather Radar ◽  
Radar Data ◽  
Rain Gauge ◽  
Meteorological Conditions ◽  
Swiss Alps ◽  
Rain Gauges ◽  
Weather Radars ◽  
Radar Measurements

Abstract. Weather radars are used to measure the electromagnetic radiation backscattered by cloud raindrops. Clouds that backscatter more electromagnetic radiation consist of larger droplets of rain and therefore they produce more rain. The idea is to estimate rain rate by using weather radar as an alternative to rain-gauges measuring rainfall on the ground. In an experiment during two days in June and August 1997 over the Italian-Swiss Alps, data from weather radar and surrounding rain-gauges were collected at the same time. The statistical KNN and the neural SOM classifiers were implemented for the classification task using the radar data as input and the rain-gauge measurements as output. The proposed system managed to identify matching pattern waveforms and the rainfall rate on the ground was estimated based on the radar reflectivities with a satisfactory error rate, outperforming the traditional Z/R relationship. It is anticipated that more data, representing a variety of possible meteorological conditions, will lead to improved results. The results in this work show that an estimation of rain rate based on weather radar measurements treated with statistical and neural classifiers is possible.

scholarly journals Ice Hydrometeor Shape Estimations Using Polarimetric Operational and Research Radar Measurements

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 97 ◽  
Author(s):  
Sergey Y. Matrosov
Keyword(s):  
Depolarization Ratio ◽  
Model Uncertainties ◽  
Shape Information ◽  
Ice Cloud ◽  
Cloud Radar ◽  
Weather Radars ◽  
Aspect Ratios ◽  
Radar Systems ◽  
Radar Measurements ◽  
Differential Reflectivity

A polarimetric radar method to estimate mean shapes of ice hydrometeors was applied to several snowfall and ice cloud events observed by operational and research weather radars. The hydrometeor shape information is described in terms of their aspect ratios, r, which represent the ratio of particle minor and major dimensions. The method is based on the relations between depolarization ratio (DR) estimates and aspect ratios. DR values, which are a proxy for circular depolarization ratio, were reconstructed from radar variables of reflectivity factor, Ze, differential reflectivity, ZDR, and copolar correlation coefficient ρhv, which are available from radar systems operating in either simultaneous or alternate transmutation of horizontally and vertically polarized signals. DR-r relations were developed for retrieving aspect ratios and their sensitivity to different assumptions and model uncertainties were discussed. To account for changing particle bulk density, which is a major contributor to the retrieval uncertainty, an approach is suggested to tune the DR-r relations using reflectivity-based estimates of characteristic hydrometeor size. The analyzed events include moderate snowfall observed by an operational S-band weather radar and a precipitating ice cloud observed by a scanning Ka-band cloud radar at an Arctic location. Uncertainties of the retrievals are discussed.

Cue Utilization, Perceptions, and Experience in the Interpretation of Weather Radar Returns

2018 ◽  
Vol 62 (1) ◽  
pp. 721-725
Author(s):  
Mark W. Wiggins ◽  
Monique Crane ◽  
Thomas Loveday
Keyword(s):  
System Design ◽  
Weather Radar ◽  
Radar System ◽  
Pilot Training ◽  
Online Assessment ◽  
Operational Experience ◽  
Cue Utilization ◽  
Flight Experience ◽  
Radar Systems

This study was designed to examine the role of cue utilization, perceptions, and measures of operational experience in the interpretation of a scenario involving the interpretation of weather radar returns. A total of 47 qualified pilots completed EXPERTise 2.0, an online assessment of cue utilization in the context of weather radar systems. They also completed a scenario involving the interpretation of weather radar returns which required an assessment as to whether they could continue the flight safely in the absence of a change in track or altitude. Consistent with research in other domains, the results revealed a relationship between performance and cue utilization. No relationships were evident on the basis of flight experience nor the inclination to use or trust weather radar systems. The results provide the basis for a tool that might be employed to assess pilots’ cue utilization, thereby enabling more targeted approaches to pilot training and weather radar system design.

scholarly journals Polarisation basis transformation of weather radar measurements in the power domain

2009 ◽  
Vol 7 ◽  
pp. 279-284
Author(s):  
T. Otto ◽  
J. Lu ◽  
M. Chandra
Keyword(s):  
Transfer Functions ◽  
Weather Radar ◽  
Radar Data ◽  
Radar Remote Sensing ◽  
Weather Radars ◽  
Huge Data ◽  
Power Domain ◽  
Radar Measurements ◽  
Polarimetric Weather Radar ◽  
Power Measurements

Abstract. Polarisation diversity in radar remote sensing proved to be very successful in a variety of applications. Hydrometeors as raindrops or ice crystals are anisotropic radar targets giving rise to the use of polarisation diversity in weather radars. One advanced polarimetric weather radar is DLR's POLDIRAD in Oberpfaffenhofen. The huge data archive of this radar consists mainly of power measurements at diverse polarisation bases. This study investigates the possibility to apply the polarisation basis transformation directly on power measurements. As a result, empirical transfer functions for the change of the polarisation basis of radar reflectivities are derived. To check their validity they are applied to appropriate polarimetric radar data from the POLDIRAD.

scholarly journals Wind turbine impact on operational weather radar I/Q data: characterisation and filtering

2017 ◽  
Vol 10 (5) ◽  
pp. 1739-1753 ◽  
Author(s):  
Lars Norin
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Negative Impact ◽  
Weather Radar ◽  
Rapid Expansion ◽  
Weather Radars ◽  
Radar Systems ◽  
Increasing Demand ◽  
Yaw Angle ◽  
The Impact

Abstract. For the past 2 decades wind turbines have been growing in number all over the world as a response to the increasing demand for renewable energy. However, the rapid expansion of wind turbines presents a problem for many radar systems, including weather radars. Wind turbines in the line of sight of a weather radar can have a negative impact on the radar's measurements. As weather radars are important instruments for meteorological offices, finding a way for wind turbines and weather radars to co-exist would be of great societal value.Doppler weather radars base their measurements on in-phase and quadrature phase (I/Q) data. In this work a month's worth of recordings of high-resolution I/Q data from an operational Swedish C-band weather radar are presented. The impact of point targets, such as masts and wind turbines, on the I/Q data is analysed and characterised. It is shown that the impact of point targets on single radar pulses, when normalised by amplitude, is manifested as a distinct and highly repeatable signature. The shape of this signature is found to be independent of the size, shape and yaw angle of the wind turbine. It is further demonstrated how the robustness of the point target signature can be used to identify and filter out the impact of wind turbines in the radar's signal processor.

scholarly journals A sun-tracking method to improve the pointing accuracy of weather radar

2012 ◽  
Vol 5 (3) ◽  
pp. 547-555 ◽  
Author(s):  
X. Muth ◽  
M. Schneebeli ◽  
A. Berne
Keyword(s):  
Weather Radar ◽  
Radar Data ◽  
Swiss Alps ◽  
The Sun ◽  
Sources Of Information ◽  
Weather Radars ◽  
Radar Systems ◽  
Pointing Accuracy ◽  
Instrumental Bias ◽  
Land Cover Maps

Abstract. Accurate positioning of data collected by a weather radar is of primary importance for their appropriate georeferencing, which in turn makes it possible to combine those with additional sources of information (topography, land cover maps, meteorological simulations from numerical weather models to list a few). This issue is especially acute for mobile radar systems, for which accurate and stable leveling might be difficult to ensure. The sun is a source of microwave radiation, which can be detected by weather radars and used for accurate positioning of radar data. This paper presents a technique based on the similarity between theodolites and radar systems as well as on the sun echoes to quantify and hence correct the instrumental errors which can affect the pointing accuracy of radar antenna. The proposed method is applied to data collected in the Swiss Alps using a mobile X-band radar system. The obtained instrumental bias values are evaluated by comparing the locations of the ground echoes predicted using these bias estimates with the observed ground echo locations. The very good agreement between the two confirms the accuracy of the proposed method.

scholarly journals Dual-polarization C-band weather radar algorithms for rain rate estimation and hydrometeor classification in an alpine region

2009 ◽  
Vol 20 ◽  
pp. 3-8 ◽  
Author(s):  
H. Paulitsch ◽  
F. Teschl ◽  
W. L. Randeu
Keyword(s):  
Rain Rate ◽  
Polarization Plane ◽  
Weather Radar ◽  
Dual Polarization ◽  
Rate Estimation ◽  
Weather Radars ◽  
Radar Systems ◽  
First Results ◽  
Correlation Information ◽  
Rain Events

Abstract. Dual polarization is becoming the standard for new weather radar systems. In contrast to conventional weather radars, where the reflectivity is measured in one polarization plane only, a dual polarization radar provides transmission in either horizontal, vertical, or both polarizations while receiving both the horizontal and vertical channels simultaneously. Since hydrometeors are often far from being spherical, the backscatter and propagation are different for horizontal and vertical polarization. Comparing the reflected horizontal and vertical power returns and their ratio and correlation, information on size, shape, and material density of cloud and precipitation particles can be obtained. The use of polarimetric radar variables can therefore increase the accuracy of the rain rate estimation compared to standard Z-R relationships of non-polarimetric radars. It is also possible to derive the type of precipitation from dual polarization parameters, although this is not an easy task, since there is no clear discrimination between the different values. Fuzzy logic approaches have been shown to work well with overlapping conditions and imprecisely defined class output. In this paper the implementation of different polarization algorithms for the new Austrian weather radar on Mt. Valluga is described, and first results from operational use are presented. This study also presents first observations of rain events in August 2007 during the test run of the radar. Further, the designated rain rate estimation and hydrometeor classification algorithms are explained.

scholarly journals A Simple Method for Attenuation Correction in Local X-Band Radar Measurements Using C-Band Radar Data

2016 ◽  
Vol 33 (11) ◽  
pp. 2315-2329 ◽  
Author(s):  
Katharina Lengfeld ◽  
Marco Clemens ◽  
Claire Merker ◽  
Hans Münster ◽  
Felix Ament
Keyword(s):  
Attenuation Correction ◽  
Radar Data ◽  
Simple Method ◽  
Band Frequency ◽  
Advantages And Disadvantages ◽  
Weather Radars ◽  
Radar Systems ◽  
Radar Networks ◽  
X Band ◽  
Radar Measurements

AbstractThis paper presents a novel, simple method to correct reflectivity measurements of weather radars that operate in attenuation-influenced frequency bands using observations from less attenuated radar systems. In recent years radar systems operating in the X-band frequency range have been developed to provide precipitation fields for areas of special interest in high temporal (≤1 min) and spatial (≤250 m) resolution in complement to nationwide radar networks. However, X-band radars are highly influenced by attenuation. C- and S-band radars typically have coarser resolution (250 m–1 km and 5 min) but are less affected by attenuation.Correcting for attenuation effects in simple (non-Doppler) single-polarized X-band radars remains challenging and is often dependent on restriction parameters, for example, those derived from mountain returns. Therefore, these algorithms are applicable only in limited areas. The method proposed here uses measurements from C-band radars and hence can be applied in all regions covered by nationwide C- (or S-) band radar networks. First, a single scan of X-band radar measurements is used exemplary to identify advantages and disadvantages of the novel algorithm compared to a standard single radar algorithm. The performance of the correction algorithms in different types of precipitation is examined in nine case studies. The proposed method provides very promising results for each type of precipitation. Additionally, it is evaluated in a 5-month comparison with Micro Rain Radar (MRR) observations. The bias between uncorrected X-band radar and MRR data is nearly eliminated by the attenuation correction algorithm, and the RMSE is reduced by 20% while the correlation of ~0.9 between both systems remains nearly constant.

scholarly journals Wind turbine impact on operational weather radar I/Q data: characterisation and filtering

2017 ◽  
Author(s):  
Lars Norin
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Negative Impact ◽  
Weather Radar ◽  
Rapid Expansion ◽  
Weather Radars ◽  
Radar Systems ◽  
Increasing Demand ◽  
Yaw Angle ◽  
The Impact

Abstract. For the past two decades wind turbines have been growing in number all over the world as a response to the increasing demand for renewable energy. However, the rapid expansion of wind turbines presents a problem for many radar systems, including weather radars. Wind turbines in line-of-sight of a weather radar can have a negative impact on the radar's measurements. As weather radars are important instruments for meteorological offices, finding a way for wind turbines and weather radars to co-exist would be of great societal value. Doppler weather radars base their measurements on in-phase and quadrature phase (I/Q) data. In this work a month worth of recordings of high resolution I/Q data from an operational Swedish C-band weather radar are presented. The impact of point targets, such as masts and wind turbines, on the I/Q data is analysed and characterised. It is shown that the impact of point targets on single radar pulses is manifested as a distinct and highly repeatable signature. The shape of this signature is found to be independent of the size, shape, and yaw angle of the wind turbine. It is further demonstrated how the robustness of the point target signature can be used to identify and filter out the impact of wind turbines in the radar's signal processor.

Concept and realization of a low-cost multi-target simulator for CW and FMCW radar system calibration and testing

2018 ◽  
Vol 10 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Werner Scheiblhofer ◽  
Reinhard Feger ◽  
Andreas Haderer ◽  
Andreas Stelzer
Keyword(s):  
Continuous Wave ◽  
Doppler Radar ◽  
Dynamic Range ◽  
Low Cost ◽  
Intermediate Frequency ◽  
Radar System ◽  
Fmcw Radar ◽  
Radar Systems ◽  
Single Target ◽  
Wave Radar

AbstractWe present the realization of an frequency-modulated continuous-wave radar target simulator, based on a modulated-reflector radar system. The simulator, designed for the 24 GHz frequency band, uses low-cost modulated-reflector nodes and is capable to simultaneously generate multiple targets in a real-time environment. The realization is based on a modular approach and thus provides a high scalability of the whole system. It is demonstrated that the concept is able to simulate multiple artificial targets, located at user-selectable ranges and even velocities, utilized within a completely static setup. The characterization of the developed hardware shows that the proposed concept allows to dynamically and precisely adjust the radar cross-section of each single target within a dynamic range of 50 dB. Additionally, the provided range-proportional target frequency bandwidth makes the system perfectly suitable for fast and reliable intermediate frequency-chain calibration of multi-channel radar systems. Within this paper we demonstrate the application of the concept for a linear sweeped frequency-modulated continuous-wave radar. The presented approach is applicable to any microwave-based measurement system using frequency differences between transmit- and receive signals for range- and velocity evaluation, such as (non-)linear sweeped as well as pure Doppler radar systems.

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