Insights into wind turbine reflectivity and RCS and their variability using X-Band weather radar observations by Martin Leiner et al.

Abstract. 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.

Download Full-text

Insights into wind turbine reflectivity and radar cross-section (RCS) and their variability using X-band weather radar observations

Atmospheric Measurement Techniques ◽

10.5194/amt-14-3541-2021 ◽

2021 ◽

Vol 14 (5) ◽

pp. 3541-3560

Author(s):

Martin Lainer ◽

Jordi Figueras i Ventura ◽

Zaira Schauwecker ◽

Marco Gabella ◽

Montserrat F.-Bolaños ◽

...

Keyword(s):

Wind Turbine ◽

Cross Section ◽

Wind Turbines ◽

Weather Radar ◽

Radar Cross Section ◽

Least Square ◽

Clear Correlation ◽

Radar Observations ◽

X Band ◽

Polarimetric Weather Radar

Abstract. 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.

Download Full-text

Radar Applications in Northern Scotland (RAiNS)

Journal of Hydrometeorology ◽

10.1175/jhm-d-19-0184.1 ◽

2020 ◽

Author(s):

Ryan R Neely ◽

Louise Parry ◽

David Dufton ◽

Lindsay Bennett ◽

Chris Collier

Keyword(s):

High Resolution ◽

Weather Radar ◽

Polarimetric Radar ◽

Summer Period ◽

Radar Observations ◽

X Band ◽

Precipitation Estimates ◽

Radar Applications ◽

Quantitative Precipitation Estimates ◽

Hydrological Applications

AbstractThe Radar Applications in Northern Scotland (RAiNS) experiment took place from February to August 2016 near Inverness, Scotland. The campaign was motivated by the need to provide enhanced weather radar observations for hydrological applications for the Inverness region. Here we describe the campaign in detail and observations over the summer period of the campaign that show the improvements that high-resolution polarimetric radar observations may have on quantitative precipitation estimates in this region compared to concurrently generated operational radar quantitative precipitation estimates (QPE). We further provide suggestions of methods for generating QPE using dual-polarisation X-band radars in similar regions.

Download Full-text

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

10.5194/egusphere-egu21-1411 ◽

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

An operational, single-polarized X-band weather radar provides measurements in 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 resulting in a high information density within the 20 km scan radius. Studies on short time periods (several months) proofs the performance of this low-cost local area weather radar. For example, a case study on a tornado in a rain event demonstrates its refined resolution compared to the German nationwide C-band radars. 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 how we can infer a precipitation estimate based on multi-year weather radar observations in the urban area of Hamburg.The single-polarization and small wavelength comes along with high resolution but at the same time high uncertainties. We address several sources of errors affecting the radar-based precipitation estimate, like the radar calibration, alignment, attenuation, noise, non-meteorologial echoes, and Z-R 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 (k-Z and Z-R relation). We outline the performance of the correction methods for long time periods and discuss open issues and limitations.With this high-quality and -resolution weather radar product, refined studies on the spatial and temporal scale of urban precipitation will be possible. This data set will be used 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).

Download Full-text

High‐resolution polarimetric X‐band weather radar observations at the C abauw E xperimental S ite for A tmospheric R esearch

Geoscience Data Journal ◽

10.1002/gdj3.5 ◽

2013 ◽

Vol 1 (1) ◽

pp. 7-12 ◽

Cited By ~ 3

Author(s):

Tobias Otto ◽

Herman W. J. Russchenberg

Keyword(s):

High Resolution ◽

Weather Radar ◽

Radar Observations ◽

X Band

Download Full-text

Coupling X-band dual-polarized mini-radars and hydro-meteorological forecast models: the HYDRORAD project

Natural Hazards and Earth System Science ◽

10.5194/nhess-13-1229-2013 ◽

2013 ◽

Vol 13 (5) ◽

pp. 1229-1241 ◽

Cited By ~ 9

Author(s):

E. Picciotti ◽

F. S. Marzano ◽

E. N. Anagnostou ◽

J. Kalogiros ◽

Y. Fessas ◽

...

Keyword(s):

Decision Support ◽

High Frequency ◽

Weather Radar ◽

Decision Support Tool ◽

Dual Polarization ◽

Radar Observations ◽

Support Tool ◽

Radar Network ◽

X Band ◽

Modelling System

Abstract. Hydro-meteorological hazards like convective outbreaks leading to torrential rain and floods are among the most critical environmental issues world-wide. In that context weather radar observations have proven to be very useful in providing information on the spatial distribution of rainfall that can support early warning of floods. However, quantitative precipitation estimation by radar is subjected to many limitations and uncertainties. The use of dual-polarization at high frequency (i.e. X-band) has proven particularly useful for mitigating some of the limitation of operational systems, by exploiting the benefit of easiness to transport and deploy and the high spatial and temporal resolution achievable at small antenna sizes. New developments on X-band dual-polarization technology in recent years have received the interest of scientific and operational communities in these systems. New enterprises are focusing on the advancement of cost-efficient mini-radar network technology, based on high-frequency (mainly X-band) and low-power weather radar systems for weather monitoring and hydro-meteorological forecasting. Within the above context, the main objective of the HYDRORAD project was the development of an innovative \\mbox{integrated} decision support tool for weather monitoring and hydro-meteorological applications. The integrated system tool is based on a polarimetric X-band mini-radar network which is the core of the decision support tool, a novel radar products generator and a hydro-meteorological forecast modelling system that ingests mini-radar rainfall products to forecast precipitation and floods. The radar products generator includes algorithms for attenuation correction, hydrometeor classification, a vertical profile reflectivity correction, a new polarimetric rainfall estimators developed for mini-radar observations, and short-term nowcasting of convective cells. The hydro-meteorological modelling system includes the Mesoscale Model 5 (MM5) and the Army Corps of Engineers Hydrologic Engineering Center hydrologic and hydraulic modelling chain. The characteristics of this tool make it ideal to support flood monitoring and forecasting within urban environment and small-scale basins. Preliminary results, carried out during a field campaign in Moldova, showed that the mini-radar based hydro-meteorological forecasting system can constitute a suitable solution for local flood warning and civil flood protection applications.

Download Full-text

X-Band Polarimetric Weather Radar Observations of a Hailstorm

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-12-00243.1 ◽

2013 ◽

Vol 30 (9) ◽

pp. 2143-2151 ◽

Cited By ~ 12

Author(s):

Jordi Figueras i Ventura ◽

Françoise Honoré ◽

Pierre Tabary

Keyword(s):

Weather Radar ◽

Radar Data ◽

Polarimetric Radar ◽

Complementary Information ◽

Radar Observations ◽

National Network ◽

X Band ◽

Polarimetric Weather Radar

Abstract This paper presents an analysis of a hail event that occurred 27 May 2012 over Brignoles, located in southeastern France. The event was observed by an X-band polarimetric radar located in Mont Maurel, 75 km northeast of the hailstorm. Lightning data from the French national network (owned and operated by Météorage) are also used in the study. The analysis highlights that the lightning and radar data provide complementary information that may allow a better microphysical interpretation of the hailstorm and potentially increase the probability of its detection.

Download Full-text

Two weather radar time series of the altitude of the volcanic plume during the May 2011 eruption of Grímsvötn, Iceland

Earth System Science Data Discussions ◽

10.5194/essdd-5-281-2012 ◽

2012 ◽

Vol 5 (1) ◽

pp. 281-299 ◽

Cited By ~ 5

Author(s):

G. N. Petersen ◽

H. Bjornsson ◽

P. Arason ◽

S. von Löwis

Keyword(s):

Time Series ◽

Rise Time ◽

Weather Radar ◽

Volcanic Plume ◽

Radar Observations ◽

International Airport ◽

Initial Rise ◽

X Band ◽

Eruption Plume ◽

Good Agreement

Abstract. The eruption of Grímsvötn volcano in Iceland in 2011 lasted for a week, 21–28 May. The eruption was explosive and peaked during the first hours, with the eruption plume reaching 20–25 km altitude. The height of the plume was monitored every 5 min with a C-band weather radar located at Keflavík International Airport and a mobile X-band radar, 257 km and 75 km distance from the volcano, respectively. In addition, photographs taken during the first half-hour of the eruption give information regarding the initial rise. Time series of the plume-top altitude were constructed from the radar observations. This paper presents the two independent radar time series. The series have been cross validated and there is a good agreement between the time series. The echo top radar series of the altitude of the volcanic plume are publicly available from the Pangaea Data Publisher (http://doi.pangaea.de/10.1594/PANGAEA.778390).

Download Full-text

Rapid-Scan Radar Observations of an Oklahoma Tornadic Hailstorm Producing Giant Hail

Weather and Forecasting ◽

10.1175/waf-d-18-0003.1 ◽

2018 ◽

Vol 33 (5) ◽

pp. 1263-1282 ◽

Cited By ~ 8

Author(s):

Arthur Witt ◽

Donald W. Burgess ◽

Anton Seimon ◽

John T. Allen ◽

Jeffrey C. Snyder ◽

...

Keyword(s):

Phased Array ◽

Rotational Velocity ◽

Weather Radar ◽

Dual Polarization ◽

Radar Observations ◽

Rapid Scan ◽

Phased Array Radar ◽

X Band ◽

Low Altitude ◽

Rapid Scanning

Abstract Rapid-scan radar observations of a supercell that produced near-record size hail in Oklahoma are examined. Data from the National Weather Radar Testbed Phased Array Radar (PAR) in Norman, Oklahoma, are used to study the overall character and evolution of the storm. Data from the nearby polarimetric KOUN WSR-88D and rapid-scanning X-band polarimetric (RaXPol) mobile radar are used to study the evolution of low- to midaltitude dual-polarization parameters above two locations where giant hailstones up to 16 cm in diameter were observed. The PAR observation of the supercell’s maximum storm-top divergent outflow is similar to the strongest previously documented value. The storm’s mesocyclone rotational velocity at midaltitudes reached a maximum that is more than double the median value for similar observations from other storms producing giant hail. For the two storm-relative areas where giant hail was observed, noteworthy findings include 1) the giant hail occurred outside the main precipitation core, in areas with low-altitude reflectivities of 40–50 dBZ; 2) the giant hail was associated with dual-polarization signatures consistent with past observations of large hail at 10-cm wavelength, namely, low ZDR, low ρHV, and low KDP; 3) the giant hail fell along both the northeast and southwest edges of the primary updraft at ranges of 6–10 km from the updraft center; and 4) with the exception of one isolated report, the giant hail fell to the northeast and northwest of the large tornado and the parent mesocyclone.

Download Full-text

Two weather radar time series of the altitude of the volcanic plume during the May 2011 eruption of Grímsvötn, Iceland

Earth System Science Data ◽

10.5194/essd-4-121-2012 ◽

2012 ◽

Vol 4 (1) ◽

pp. 121-127 ◽

Cited By ~ 28

Author(s):

G. N. Petersen ◽

H. Bjornsson ◽

P. Arason ◽

S. von Löwis

Keyword(s):

Time Series ◽

Rise Time ◽

Weather Radar ◽

Volcanic Plume ◽

Radar Observations ◽

International Airport ◽

Initial Rise ◽

X Band ◽

Eruption Plume ◽

Good Agreement

Abstract. The eruption of Grímsvötn volcano in Iceland in 2011 lasted for a week, 21–28 May. The eruption was explosive and peaked during the first hours, with the eruption plume reaching 20–25 km altitude. The height of the plume was monitored every 5 min with a C-band weather radar located at Keflavík International Airport and a mobile X-band radar, 257 km and 75 km distance from the volcano respectively. In addition, photographs taken during the first half-hour of the eruption give information regarding the initial rise. Time series of the plume-top altitude were constructed from the radar observations. This paper presents the two independent radar time series. The series have been cross validated and there is a good agreement between them. The echo top radar series of the altitude of the volcanic plume are publicly available from the Pangaea Data Publisher (doi:10.1594/PANGAEA.778390).

Download Full-text