A standalone application to monitor the stability of a low cost maintenance free X-band mini weather radar, using ground clutter echoes

An operational, single-polarized X-band weather radar monitors precipitation within a 20 km scan radius around Hamburg&#8217;s city center for almost eight years. This weather radar operates at an elevation angle (~3.5&#176;) with a high temporal (30 s), range (60 m), and sampling (1&#176;) resolution refining observations of the German nationwide C-band radars. Studies on short time periods (several months and case studies) proofs the performance of this low-cost local area weather radar. The synergy of observations of the X-band radar, vertically pointing micro rain radars, and rain gauges yields a reliable eight-year precipitation climatology with 100 m resolution. The two guiding questions of this presentation are: Is the variability of this precipitation climatology representative and not contaminated by measurement errors? Which sub-hourly precipitation characteristics can we infer from this precipitation climatology?Several sources of radar-based errors were adjusted gradually affecting the precipitation estimate, e.g. the radar calibration, alignment, attenuation, noise, non-meteorologial echoes. Additionally, statistical relations (k-Z and Z-R relation) increase the uncertainty of the precipitation estimate. However, the deployment of additional vertically pointing micro rain radars yields drop size distributions at relevant heights, which increases the data quality effectively and assesses the statistics of the long-term precipitation observations. The resulting climatology allows studies on the spatial and temporal scale of urban precipitation. We outline the performance of the climatology, present first results on sub-hourly precipitation characteristics and discuss open issues and limitations.This multi-year urban precipitation analysis is groundwork for further hydrological research in an urban area within the project Sustainable Adaption Scenarios for Urban Areas &#8211; Water from Four Sides of the Cluster of Excellence Climate Climatic Change, and Society (CliCCS). Future urban precipitation studies will be improved by the extension of networked observations with a second X-band weather radar site and additional micro rain radars in Hamburg measuring since the beginning of 2021.

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Hail storm hazard in urban areas: identification and probability of occurrence by using a single-polarization X-band weather radar

10.5194/hess-2016-177 ◽

2016 ◽

Cited By ~ 4

Author(s):

Vincenzo Capozzi ◽

Errico Picciotti ◽

Vincenzo Mazzarella ◽

Giorgio Budillon ◽

Frank Silvio Marzano

Keyword(s):

Urban Areas ◽

Low Cost ◽

Weather Radar ◽

Ground Truth ◽

Liquid Density ◽

Data Set ◽

Area Of Interest ◽

X Band ◽

Radar Measurements ◽

Single Polarization

Abstract. This work exploits the potentiality of hail warning, based on single-polarization X-band weather radar measurements and tested on a large and well-documented data set of thunderstorm events in southern Italy near Naples. Even though X-band radars may suffer of two-way path attenuation especially at long ranges, due to their relatively low cost their use is rapidly increasing for short-range applications such as urban environments. To identify hail through radar measurements, two different methodologies have been selected and adapted to X-band data within the study area: one uses the Waldvogel (WAL) approach, whereas the other one uses the Vertically-Integrated Liquid Density (VIL-Density) product. The study aims at developing a Probability-of-Hail (POH) index in order to support hail risk management at urban scales. In order to find the optimal threshold values to discriminate between hail and severe rain, an extensive intercomparison between outcomes of the two methodologies and ground truth observations of hail has been performed, using a 2 x 2 contingency table and statistical scores. The results show that both methods are accurate for hail detection in the area of interest, although VIL-Density product is less satisfactory than WAL method in terms of false alarm ratio. The relationship between the output of these two methodologies and POH has been derived through a heuristic approach, using a third-order polynomial fitting curve. As an example, the POH indexes have been applied for the thunderstorm event occurred on 21 July 2014, proving to be reliable for hail core detection.

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Performance of high-resolution X-band weather radar networks – the PATTERN example

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-7-8233-2014 ◽

2014 ◽

Vol 7 (8) ◽

pp. 8233-8270

Author(s):

K. Lengfeld ◽

M. Clemens ◽

H. Münster ◽

F. Ament

Keyword(s):

High Resolution ◽

Spatial Resolution ◽

Low Cost ◽

Weather Radar ◽

Local Area ◽

Small Scale ◽

Rain Event ◽

Range Resolution ◽

Radar Networks ◽

X Band

Abstract. This publication intends to proof that a network of low-cost local area weather radars (LAWR) is a reliable and scientifically valuable complement to nationwide radar networks. A network of four LAWRs has been installed in northern Germany within the framework of the project Precipitation and Attenuation Estimates from a High-Resolution Weather Radar Network (PATTERN) observing precipitation with temporal resolution of 30 s, azimuthal resolution of 1° and spatial resolution of 60 m. The network covers an area of 60 km × 80 km. In this paper algorithms used to obtain undisturbed precipitation fields from raw reflectivity data are described and their performance is analysed. In order to correct for background noise in reflectivity measurements operationally, noise level estimates from the measured reflectivity field is combined with noise levels from the last 10 time steps. For detection of non-meteorological echoes two different kinds of clutter filters are applied: single radar algorithms and network based algorithms that take advantage of the unique features of high temporal and spatial resolution of the network. Overall the network based clutter filter works best with a detection rate of up to 70%, followed by the classic TDBZ filter using the texture of the logarithmic reflectivity field. A comparison of a reflectivity field from the PATTERN network with the product from a C-band radar operated by the German Meteorological Service indicates high spatial accordance of both systems in geographical position of the rain event as well as reflectivity maxima. A longterm study derives good accordance of X-band radar of the network with C-band radar. But especially at the border of precipitation events the standard deviation within a range gate of the C-band radar with range resolution of 1 km is up to 3 dBZ. Therefore, a network of high-resolution low-cost LAWRs can give valuable information on the small scale structure of rain events in areas of special interest, e.g. urban regions, in addition the nationwide radar networks.

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Low-Cost CMOS Active Array Solution for Highly Dense X-Band Weather Radar Network

IEEE Transactions on Antennas and Propagation ◽

10.1109/tap.2019.2947135 ◽

2020 ◽

Vol 68 (7) ◽

pp. 5421-5430

Author(s):

Javier A. Ortiz ◽

Jorge L. Salazar-Cerreno ◽

Jose D. Diaz ◽

Rodrigo M. Lebron ◽

Nafati A. Aboserwal ◽

...

Keyword(s):

Low Cost ◽

Weather Radar ◽

Radar Network ◽

X Band

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Performance of high-resolution X-band radar for rainfall measurement in The Netherlands

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-6-6035-2009 ◽

2009 ◽

Vol 6 (5) ◽

pp. 6035-6085 ◽

Cited By ~ 8

Author(s):

C. Z. van de Beek ◽

H. Leijnse ◽

J. N. M. Stricker ◽

R. Uijlenhoet ◽

H. W. J. Russchenberg

Keyword(s):

High Resolution ◽

The Netherlands ◽

Weather Radar ◽

Rain Gauge ◽

Signal Loss ◽

Rainfall Events ◽

Ground Clutter ◽

X Band ◽

Urban Catchments ◽

Radar Calibration

Abstract. This study presents an analysis of 195 rainfall events gathered with the X-band weather radar SOLIDAR and a tipping bucket rain gauge network near Delft, The Netherlands, between May 1993 and April 1994. The high spatial (120 m) and temporal (16 s) resolution of the radar combined with the extent of the database make this study a climatological analysis of the potential for high-resolution rainfall measurement with non-polarimetric X-band radar over completely flat terrain. An appropriate radar reflectivity – rain rate relation is derived from measurements of raindrop size distributions and compared with radar – rain gauge data. The radar calibration is assessed using a long-term comparison of rain gauge measurements with corresponding radar reflectivities as well as by analyzing the evolution of the stability of ground clutter areas over time. Three different methods for ground clutter correction as well as the effectiveness of forward and backward attenuation correction algorithms have been studied. Five individual rainfall events are discussed in detail to illustrate the strengths and weaknesses of high-resolution X-band radar and the effectiveness of the presented correction methods. X-band radar is found to be able to measure the space-time variation of rainfall at high resolution, far greater than can be achieved by rain gauge networks or a typical operational C-band weather radar. On the other hand, SOLIDAR can suffer from receiver saturation, wet radome attenuation as well as signal loss along the path. During very strong convective situations the signal can even be lost completely. In combination with several rain gauges for quality control, high resolution X-band radar is considered to be suitable for rainfall monitoring over relatively small (urban) catchments. These results offer great prospects for the new high resolution polarimetric doppler X-band radar IDRA.

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An integrated approach to monitor the calibration stability of operational dual-polarization radars

10.5194/amt-2016-36 ◽

2016 ◽

Author(s):

Mattia Vaccarono ◽

Renzo Bechini ◽

Venkatachalam Chandrasekar ◽

Roberto Cremonini ◽

Claudio Cassardo

Keyword(s):

Weather Prediction ◽

Weather Radar ◽

Integrated Approach ◽

The Sun ◽

Dual Polarization ◽

Ground Clutter ◽

Hardware Failures ◽

Radar Calibration ◽

The Stability ◽

Self Consistency

Abstract. The stability of the weather radar calibration is a mandatory aspect for quantitative applications, such as rainfall estimation, short-term weather prediction and initialization of numerical atmospheric and hydrological models. Over the years, calibration monitoring techniques based on external sources have been developed, specifically the calibration using the Sun, and the calibration based on ground clutter returns. In this paper, these two techniques are integrated and complemented with a self-consistency procedure and an intercalibration technique. The aim of the integrated approach is to implement a robust method for online monitoring, able to detect significant changes in the radar calibration. The physical consistency of polarimetric radar observables is exploited using the self-consistency approach, based on the expected correspondence between the dual-polarization power and phase measurements in rain. This technique allows to provide a reference absolute value for the radar calibration, from which eventual deviations may be detected using the other procedures. In particular, the ground clutter calibration is implemented on both polarization channels (horizontal and vertical) and for each radar scan, allowing to monitor the polarimetric variables and promptly recognize hardware failures. The Sun calibration allows to monitor the calibration and sensitivity of the radar receiver, in addition to the antenna pointing accuracy. It is also applied using observations collected during the standard operational scans, but requires longer integration times (several days) in order to accumulate a sufficient amount of data. Finally, an intercalibration technique is developed and performed to compare co-located measurements collected in rain by two radars on overlapping regions. The integrated approach is performed on the C-band weather radar network in northwestern Italy, during July–October 2014. The set of methods considered is shown to provide a robust online tool to monitor the stability of the radar calibration. The attainable accuracy for the calibration of the radar reflectivity is about 1 dB, which is considered adequate for most quantitative applications.

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An integrated approach to monitoring the calibration stability of operational dual-polarization radars

Atmospheric Measurement Techniques ◽

10.5194/amt-9-5367-2016 ◽

2016 ◽

Vol 9 (11) ◽

pp. 5367-5383 ◽

Cited By ~ 4

Author(s):

Mattia Vaccarono ◽

Renzo Bechini ◽

Chandra V. Chandrasekar ◽

Roberto Cremonini ◽

Claudio Cassardo

Keyword(s):

Weather Prediction ◽

Weather Radar ◽

Integrated Approach ◽

The Sun ◽

Dual Polarization ◽

Ground Clutter ◽

Hardware Failures ◽

Radar Calibration ◽

The Stability ◽

Self Consistency

Abstract. The stability of weather radar calibration is a mandatory aspect for quantitative applications, such as rainfall estimation, short-term weather prediction and initialization of numerical atmospheric and hydrological models. Over the years, calibration monitoring techniques based on external sources have been developed, specifically calibration using the Sun and calibration based on ground clutter returns. In this paper, these two techniques are integrated and complemented with a self-consistency procedure and an intercalibration technique. The aim of the integrated approach is to implement a robust method for online monitoring, able to detect significant changes in the radar calibration. The physical consistency of polarimetric radar observables is exploited using the self-consistency approach, based on the expected correspondence between dual-polarization power and phase measurements in rain. This technique allows a reference absolute value to be provided for the radar calibration, from which eventual deviations may be detected using the other procedures. In particular, the ground clutter calibration is implemented on both polarization channels (horizontal and vertical) for each radar scan, allowing the polarimetric variables to be monitored and hardware failures to promptly be recognized. The Sun calibration allows monitoring the calibration and sensitivity of the radar receiver, in addition to the antenna pointing accuracy. It is applied using observations collected during the standard operational scans but requires long integration times (several days) in order to accumulate a sufficient amount of useful data. Finally, an intercalibration technique is developed and performed to compare colocated measurements collected in rain by two radars in overlapping regions. The integrated approach is performed on the C-band weather radar network in northwestern Italy, during July–October 2014. The set of methods considered appears suitable to establish an online tool to monitor the stability of the radar calibration with an accuracy of about 2 dB. This is considered adequate to automatically detect any unexpected change in the radar system requiring further data analysis or on-site measurements.

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