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

2016 ◽  
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.

scholarly journals Multi-year 100-metre-scale urban precipitation study based on X-band radar observations

2021 ◽  
Author(s):  
Finn Burgemeister ◽  
Marco Clemens ◽  
Felix Ament
Keyword(s):  
Urban Areas ◽  
Measurement Errors ◽  
Low Cost ◽  
Elevation Angle ◽  
Weather Radar ◽  
Local Area ◽  
Hourly Precipitation ◽  
Precipitation Climatology ◽  
X Band ◽  
Precipitation Characteristics

<p>An operational, single-polarized X-band weather radar <span>monitors precipitation within a 20 km scan radius around</span> Hamburg’s city center for almost eight years. This weather radar operates at an elevation angle (~3.5°) with a high temporal (30 s), range (60 m), and sampling (1°) resolution refining observations of the German nationwide C-band radars. <span>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. </span><span>The two guiding questions of this presentation are: </span><span>Is the variability of this precipitation climatology representative </span><span>and not contaminated by measurement errors</span><span>? </span><span>Which </span><span>sub-hourly precipitation characteristics </span><span>can we infer</span><span> from th</span><span>is</span><span> precipitation climatology?</span></p><p><span>S</span>everal sources of radar-based errors <span>were</span> <span>adjusted gradually</span> affecting th<span>e</span> <span>precipitation</span> estimate, <span>e.g.</span> the radar calibration, alignment, attenuation, noise, non-meteorologial echoes<span>. Additionally, statistical relations (</span><span><em>k</em></span><span>-</span><span><em>Z</em></span><span> and </span><span><em>Z</em></span><span>-</span><span><em>R</em></span><span> 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 assess</span><span>es</span><span> 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.</span></p><p>This multi-year urban precipitation analysis is groundwork for further hydrological research in an urban area within the project <em>Sustainable Adaption Scenarios for Urban Areas – Water from Four Sides</em> of the Cluster of Excellence <em>Climate Climatic Change, and Society</em> (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.</p>

scholarly journals Mosaicking Weather Radar Retrievals from an Operational Heterogeneous Network at C and X Band for Precipitation Monitoring in Italian Central Apennines

2022 ◽  
Vol 14 (2) ◽  
pp. 248
Author(s):  
Stefano Barbieri ◽  
Saverio Di Fabio ◽  
Raffaele Lidori ◽  
Francesco L. Rossi ◽  
Frank S. Marzano ◽  
...  
Keyword(s):  
Atmospheric Precipitation ◽  
Weather Radar ◽  
Geographic Area ◽  
Single Frequency ◽  
Estimation Accuracy ◽  
Central Apennines ◽  
Data Set ◽  
Area Of Interest ◽  
Spatial Coverage ◽  
Network Pattern

Meteorological radar networks are suited to remotely provide atmospheric precipitation retrieval over a wide geographic area for severe weather monitoring and near-real-time nowcasting. However, blockage due to buildings, hills, and mountains can hamper the potential of an operational weather radar system. The Abruzzo region in central Italy’s Apennines, whose hydro-geological risks are further enhanced by its complex orography, is monitored by a heterogeneous system of three microwave radars at the C and X bands with different features. This work shows a systematic intercomparison of operational radar mosaicking methods, based on bi-dimensional rainfall products and dealing with both C and X bands as well as single- and dual-polarization systems. The considered mosaicking methods can take into account spatial radar-gauge adjustment as well as different spatial combination approaches. A data set of 16 precipitation events during the years 2018–2020 in the central Apennines is collected (with a total number of 32,750 samples) to show the potentials and limitations of the considered operational mosaicking approaches, using a geospatially-interpolated dense network of regional rain gauges as a benchmark. Results show that the radar-network pattern mosaicking, based on the anisotropic radar-gauge adjustment and spatial averaging of composite data, is better than the conventional maximum-value merging approach. The overall analysis confirms that heterogeneous weather radar mosaicking can overcome the issues of single-frequency fixed radars in mountainous areas, guaranteeing a better spatial coverage and a more uniform rainfall estimation accuracy over the area of interest.

Towards a multi-year urban precipitation climatology at 100 m scale using X-band radar observations

2021 ◽  
Author(s):  
Finn Burgemeister ◽  
Marco Clemens ◽  
Felix Ament
Keyword(s):  
Urban Area ◽  
Elevation Angle ◽  
Weather Radar ◽  
Rain Event ◽  
Data Set ◽  
Radar Observations ◽  
Precipitation Climatology ◽  
X Band ◽  
Time Periods ◽  
Radar Calibration

<p>An operational, single-polarized X-band weather radar provides measurements in Hamburg’s city center for almost eight years. This weather radar operates at an elevation angle (~3.5°) with a high temporal (30 s), range (60 m), and sampling (1°) resolution resulting<span> in a</span> high information density within <span>the</span> 20 km <span>scan radius</span>. <span>Studies on short time periods (several months) proofs the performance of this low-cost local area weather radar. </span><span>For example, a</span><span> case study on a tornado in a rain event demonstrates its refined resolution </span><span>compared to</span><span> the German nationwide C-band radars. </span><span>Now, we aim for a eight-year precipitation climatology with 100 m resolution. This data set will enable reliable studies on urban extreme precipitation. This presentation will describe h</span><span>ow we </span><span>can</span><span> infer a precipitation estimate based on multi-</span><span>year</span><span> weather radar observations in the urban area of Hamburg.</span></p><p>The single-polarization and <span>small</span> <span>wavelength</span> <span>comes along with</span> high resolution <span>but at the same time</span> high uncertainties. We address several sources of errors affecting th<span>e</span> radar-based <span>precipitation</span> estimate, like the radar calibration, alignment, attenuation, noise, non-meteorologial echoes, <span>and </span><span><em>Z</em></span><span>-</span><span><em>R</em></span><span> relation. The deployment of additional vertically pointing micro rain radars yields drop size distributions at relevant heights reducing errors effectively concerning the radar calibration and required statistical relations (</span><span><em>k</em></span><span>-</span><span><em>Z</em></span><span> and </span><span><em>Z</em></span><span>-</span><span><em>R</em></span><span> relation). We outline the performance of the correction methods for long time periods and discuss open issues and limitations.</span></p><p><span>With this high-quality and -resolution weather radar product, refined studies on the spatial and temporal scale of </span><span>urban </span><span>precipitation will be possible. </span><span>This data set will be used for</span><span> further hydrological research in an urban area </span><span>within the project <em>Sustainable Adaption Scenarios for Urban Areas – Water from Four Sides</em> of the</span><span> Cluster of Excellence <em>Climate Climatic Change, and Society</em> (CliCCS).</span></p>

Hail detection in Naples urban area using single-polarization X-band weather radar: Preliminary results

2015 ◽  
Author(s):  
Vincenzo Capozzi ◽  
Vincenzo Mazzarella ◽  
Marzia Moccia ◽  
Giorgio Budillon ◽  
Errico Picciotti ◽  
...  
Keyword(s):  
Urban Area ◽  
Weather Radar ◽  
Preliminary Results ◽  
X Band ◽  
Single Polarization ◽  
Naples Urban Area

Exploring single polarization X-band weather radar potentials for local meteorological and hydrological applications

2015 ◽  
Vol 531 ◽  
pp. 508-522 ◽  
Author(s):  
Francesco Lo Conti ◽  
Antonio Francipane ◽  
Dario Pumo ◽  
Leonardo V. Noto
Keyword(s):  
Weather Radar ◽  
X Band ◽  
Single Polarization ◽  
Hydrological Applications

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

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.

scholarly journals Group Line Energy in Phase-Resolved Ocean Surface Wave Orbital Velocity Reconstructions from X-band Doppler Radar Measurements of the Sea Surface

2019 ◽  
Vol 11 (1) ◽  
pp. 71 ◽  
Author(s):  
Andrew J. Kammerer ◽  
Erin E. Hackett
Keyword(s):  
Dispersion Curve ◽  
Ground Truth ◽  
Orbital Velocity ◽  
Line Energy ◽  
First Order ◽  
Dispersion Relationship ◽  
X Band ◽  
Radar Measurements ◽  
Wave Orbital Velocity ◽  
Order Dispersion

The wavenumber-frequency spectra of many radar measurements of the sea surface contain a linear feature at frequencies lower than the first order dispersion relationship commonly referred to as the “group line”. Plant and Farquharson, showed numerically that the group line is at least partially caused by wave interference-induced breaking of steep short gravity waves. This paper uses two wave retrieval techniques, proper orthogonal decomposition (POD) and FFT-based dispersion curve filtering, to examine two X-band radar datasets, and compare wave orbital velocity reconstructions to ground truth wave buoy measurements within the field of view of the radar. POD allows group line energy to be retained in the reconstruction, while dispersion curve filtering removes all energy not associated with the first order dispersion relationship. Results show that when group line energy is higher or comparable to dispersion curve energy, the inclusion of this group line energy in phase-resolved orbital velocity reconstructions increases the accuracy of the reconstruction. This increased accuracy is demonstrated by higher correlations between POD reconstructed time series with buoy ground truth measurements than dispersion curve filtered reconstructions. When energy lying on the dispersion relationship is much higher than the group line energy, the FFT and POD reconstruction methods perform comparably.

scholarly journals A Multi-Platform Hydrometeorological Analysis of the Flash Flood Event of 15 November 2017 in Attica, Greece

2018 ◽  
Vol 11 (1) ◽  
pp. 45 ◽  
Author(s):  
George Varlas ◽  
Marios N. Anagnostou ◽  
Christos Spyrou ◽  
Anastasios Papadopoulos ◽  
John Kalogiros ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Water Level ◽  
Urban Areas ◽  
Flash Flood ◽  
Weather Prediction ◽  
Weather Radar ◽  
Flood Event ◽  
Wave System ◽  
Dual Polarization ◽  
X Band

Urban areas often experience high precipitation rates and heights associated with flash flood events. Atmospheric and hydrological models in combination with remote-sensing and surface observations are used to analyze these phenomena. This study aims to conduct a hydrometeorological analysis of a flash flood event that took place in the sub-urban area of Mandra, western Attica, Greece, using remote-sensing observations and the Chemical Hydrological Atmospheric Ocean Wave System (CHAOS) modeling system that includes the Advanced Weather Research Forecasting (WRF-ARW) model and the hydrological model (WRF-Hydro). The flash flood was caused by a severe storm during the morning of 15 November 2017 around Mandra area resulting in extensive damages and 24 fatalities. The X-band dual-polarization (XPOL) weather radar of the National Observatory of Athens (NOA) observed precipitation rates reaching 140 mm/h in the core of the storm. CHAOS simulation unveils the persistent orographic convergence of humid southeasterly airflow over Pateras mountain as the dominant parameter for the evolution of the storm. WRF-Hydro simulated the flood using three different precipitation estimations as forcing data, obtained from the CHAOS simulation (CHAOS-hydro), the XPOL weather radar (XPOL-hydro) and the Global Precipitation Measurement (GMP)/Integrated Multi-satellitE Retrievals for GPM (IMERG) satellite dataset (GPM/IMERG-hydro). The findings indicate that GPM/IMERG-hydro underestimated the flood magnitude. On the other hand, XPOL-hydro simulation resulted to discharge about 115 m3/s and water level exceeding 3 m in Soures and Agia Aikaterini streams, which finally inundated. CHAOS-hydro estimated approximately the half water level and even lower discharge compared to XPOL-hydro simulation. Comparing site-detailed post-surveys of flood extent, XPOL-hydro is characterized by overestimation while CHAOS-hydro and GPM/IMERG-hydro present underestimation. However, CHAOS-hydro shows enough skill to simulate the flooded areas despite the forecast inaccuracies of numerical weather prediction. Overall, the simulation results demonstrate the potential benefit of using high-resolution observations from a X-band dual-polarization radar as an additional forcing component in model precipitation simulations.

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