scholarly journals Assessment of virtual towers performed with scanning wind lidars and Ka-band radars during the XPIA experiment

2016 ◽  
Author(s):  
Mithu Debnath ◽  
G. Valerio Iungo ◽  
W. Alan Brewer ◽  
Aditya Choukulkar ◽  
Ruben Delgado ◽  
...  
Keyword(s):  
Sonic Anemometer ◽  
Great Accuracy ◽  
Horizontal Wind ◽  
Wind Profiler ◽  
Horizontal Wind Speed ◽  
Ka Band ◽  
Radar Measurements ◽  
Remote Sensing Techniques ◽  
Sonic Anemometer Data ◽  
Scanning Strategies

Abstract. During the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign, which was carried out at the Boulder Atmospheric Observatory (BAO) in spring 2015, multiple-Doppler scanning strategies were performed with scanning wind lidars and Ka-band radars. Specifically, step-stare measurements were performed simultaneously with three scanning Doppler lidars, while two scanning Ka-band radars performed simultaneous range height indicator (RHI) scans. The XPIA experiment provided the unique opportunity to compare directly virtual tower measurements performed simultaneously with Ka-band radars and Doppler wind lidars. Furthermore, multiple-Doppler measurements were assessed against sonic anemometer data acquired from the met-tower present at the BAO site and a lidar wind profiler. This survey shows that despite the different technologies, measurement volumes and sampling periods used for the lidar and radar measurements, a great accuracy is achieved for both remote sensing techniques for probing horizontal wind speed and wind direction with the virtual tower scanning technique.

scholarly journals Assessment of virtual towers performed with scanning wind lidars and Ka-band radars during the XPIA experiment

2017 ◽  
Vol 10 (3) ◽  
pp. 1215-1227 ◽  
Author(s):  
Mithu Debnath ◽  
Giacomo Valerio Iungo ◽  
W. Alan Brewer ◽  
Aditya Choukulkar ◽  
Ruben Delgado ◽  
...  
Keyword(s):  
Good Accuracy ◽  
Sonic Anemometer ◽  
Horizontal Wind ◽  
Horizontal Wind Speed ◽  
Ka Band ◽  
Meteorological Tower ◽  
Radar Measurements ◽  
Remote Sensing Techniques ◽  
Sonic Anemometer Data ◽  
Scanning Strategies

Abstract. During the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign, which was carried out at the Boulder Atmospheric Observatory (BAO) in spring 2015, multiple-Doppler scanning strategies were carried out with scanning wind lidars and Ka-band radars. Specifically, step–stare measurements were collected simultaneously with three scanning Doppler lidars, while two scanning Ka-band radars carried out simultaneous range height indicator (RHI) scans. The XPIA experiment provided the unique opportunity to compare directly virtual-tower measurements performed simultaneously with Ka-band radars and Doppler wind lidars. Furthermore, multiple-Doppler measurements were assessed against sonic anemometer data acquired from the meteorological tower (met-tower) present at the BAO site and a lidar wind profiler. This survey shows that – despite the different technologies, measurement volumes and sampling periods used for the lidar and radar measurements – a very good accuracy is achieved for both remote-sensing techniques for probing horizontal wind speed and wind direction with the virtual-tower scanning technique.

scholarly journals Field intercomparison of prevailing sonic anemometers

2018 ◽  
Vol 11 (1) ◽  
pp. 249-263 ◽  
Author(s):  
Matthias Mauder ◽  
Matthias J. Zeeman
Keyword(s):  
Wind Speed ◽  
Sonic Anemometer ◽  
Three Dimensional ◽  
Buoyancy Flux ◽  
Horizontal Wind ◽  
Horizontal Wind Speed ◽  
Sonic Anemometers ◽  
Adjacent Structures ◽  
Mean Wind Speed ◽  
Field Intercomparison

Abstract. Three-dimensional sonic anemometers are the core component of eddy covariance systems, which are widely used for micrometeorological and ecological research. In order to characterize the measurement uncertainty of these instruments we present and analyse the results from a field intercomparison experiment of six commonly used sonic anemometer models from four major manufacturers. These models include Campbell CSAT3, Gill HS-50 and R3, METEK uSonic-3 Omni, R. M. Young 81000 and 81000RE. The experiment was conducted over a meadow at the TERENO/ICOS site DE-Fen in southern Germany over a period of 16 days in June of 2016 as part of the ScaleX campaign. The measurement height was 3 m for all sensors, which were separated by 9 m from each other, each on its own tripod, in order to limit contamination of the turbulence measurements by adjacent structures as much as possible. Moreover, the high-frequency data from all instruments were treated with the same post-processing algorithm. In this study, we compare the results for various turbulence statistics, which include mean horizontal wind speed, standard deviations of vertical wind velocity and sonic temperature, friction velocity, and the buoyancy flux. Quantitative measures of uncertainty, such as bias and comparability, are derived from these results. We find that biases are generally very small for all sensors and all computed variables, except for the sonic temperature measurements of the two Gill sonic anemometers (HS and R3), confirming a known transducer-temperature dependence of the sonic temperature measurement. The best overall agreement between the different instruments was found for the mean wind speed and the buoyancy flux.

scholarly journals Wind Measurements from Arc Scans with Doppler Wind Lidar

2015 ◽  
Vol 32 (11) ◽  
pp. 2024-2040 ◽  
Author(s):  
H. Wang ◽  
R. J. Barthelmie ◽  
A. Clifton ◽  
S. C. Pryor
Keyword(s):  
Wind Speed ◽  
Sonic Anemometer ◽  
Elevation Angle ◽  
Horizontal Wind ◽  
Horizontal Wind Speed ◽  
Energy Applications ◽  
Mean Wind Speed ◽  
Wind Measurements ◽  
Wind Lidar ◽  
Doppler Wind Lidar

AbstractDefining optimal scanning geometries for scanning lidars for wind energy applications remains an active field of research. This paper evaluates uncertainties associated with arc scan geometries and presents recommendations regarding optimal configurations in the atmospheric boundary layer. The analysis is based on arc scan data from a Doppler wind lidar with one elevation angle and seven azimuth angles spanning 30° and focuses on an estimation of 10-min mean wind speed and direction. When flow is horizontally uniform, this approach can provide accurate wind measurements required for wind resource assessments in part because of its high resampling rate. Retrieved wind velocities at a single range gate exhibit good correlation to data from a sonic anemometer on a nearby meteorological tower, and vertical profiles of horizontal wind speed, though derived from range gates located on a conical surface, match those measured by mast-mounted cup anemometers. Uncertainties in the retrieved wind velocity are related to high turbulent wind fluctuation and an inhomogeneous horizontal wind field. The radial velocity variance is found to be a robust measure of the uncertainty of the retrieved wind speed because of its relationship to turbulence properties. It is further shown that the standard error of wind speed estimates can be minimized by increasing the azimuthal range beyond 30° and using five to seven azimuth angles.

Application of Wind Profiler Radar in Guided Missile Range Experiment

2015 ◽  
Vol 713-715 ◽  
pp. 668-671
Author(s):  
Qing Yang ◽  
Ya Ke Wu ◽  
Zhao Yang
Keyword(s):  
Meteorological Data ◽  
Measurement Range ◽  
Horizontal Wind ◽  
Wind Profiler ◽  
Horizontal Wind Speed ◽  
Application Range ◽  
Testing Environment ◽  
Test Application ◽  
Wind Profiler Radar ◽  
Range Test

The high altitude meteorological data is the basic parameters for weapon system trajectory calculation, firing ballistic correction, and ballistic standardization. Measurement range weapon testing is essential to evaluate the final results, so it is accurate or not will directly influence the test. This paper outlines the wind profiler radar in guided missile range experiment and the necessity of working mechanism, and gives the testing environment of radar range test application and erection of wind profiles and parameter setting, finally derived horizontal wind speed measurement precision, theoretical radial velocity measurement accuracy, as well as the theoretical horizontal wind. Making the range test of wind profiler radar measured data can fit the fast and the theoretical solution of data, in order to test application range stroke profile radar has a more comprehensive understanding, and application of more mature and rational.

scholarly journals Using sonic anemometer temperature to measure sensible heat flux in strong winds

2012 ◽  
Vol 5 (1) ◽  
pp. 447-469 ◽  
Author(s):  
S. P. Burns ◽  
T. W. Horst ◽  
P. D. Blanken ◽  
R. K. Monson
Keyword(s):  
Heat Flux ◽  
Sonic Anemometer ◽  
Sensible Heat Flux ◽  
Heat Fluxes ◽  
Horizontal Wind ◽  
Subalpine Forest ◽  
Sensible Heat ◽  
Scientific Model ◽  
Horizontal Wind Speed ◽  
Sonic Anemometers

Abstract. The sensible heat flux (H) is a significant component of the surface energy balance (SEB). Sonic anemometers simultaneously measure the turbulent fluctuations of vertical wind (w') and sonic temperature (Ts'), and are commonly used to measure H. Our study examines 30-min heat fluxes measured with a Campbell Scientific model CSAT3 sonic anemometer above a subalpine forest. We compare H calculated with Ts to H calculated with a co-located thermocouple and find that for horizontal wind speed (U) less than 8 m s−1 the agreement is ≈±30 W m−2. However, for U >≈ 8 m s−1, the CSAT3 H becomes larger than H calculated with the thermocouple, reaching a maximum difference of ≈250 W m−2 at U ≈ 18 m s−1. H calculated with the thermocouple results in a SEB that is relatively independent of U at high wind speeds. In contrast, the SEB calculated with H from the CSAT3 varies considerably with U, particularly at night. Cospectral analysis of w'Ts' suggest that spurious correlation is a problem during high winds which leads to a positive (additive) increase in H calculated with the CSAT3. At night, when H is typically negative, this CSAT3 error results in a measured H that falsely approaches zero or even becomes positive. Within a broader context, the usefulness of side-by-side instrument comparisons are discussed.

scholarly journals Using sonic anemometer temperature to measure sensible heat flux in strong winds

2012 ◽  
Vol 5 (9) ◽  
pp. 2095-2111 ◽  
Author(s):  
S. P. Burns ◽  
T. W. Horst ◽  
L. Jacobsen ◽  
P. D. Blanken ◽  
R. K. Monson
Keyword(s):  
Heat Flux ◽  
Sonic Anemometer ◽  
Sensible Heat Flux ◽  
Heat Fluxes ◽  
Horizontal Wind ◽  
Subalpine Forest ◽  
Sensible Heat ◽  
Horizontal Wind Speed ◽  
Sonic Anemometers ◽  
Significant Underestimation

Abstract. Sonic anemometers simultaneously measure the turbulent fluctuations of vertical wind (w') and sonic temperature (Ts'), and are commonly used to measure sensible heat flux (H). Our study examines 30-min heat fluxes measured with a Campbell Scientific CSAT3 sonic anemometer above a subalpine forest. We compared H calculated with Ts to H calculated with a co-located thermocouple and found that, for horizontal wind speed (U) less than 8 m s−1, the agreement was around ±30 W m−2. However, for U ≈ 8 m s−1, the CSAT H had a generally positive deviation from H calculated with the thermocouple, reaching a maximum difference of ≈250 W m−2 at U ≈ 18 m s−1. With version 4 of the CSAT firmware, we found significant underestimation of the speed of sound and thus Ts in high winds (due to a delayed detection of the sonic pulse), which resulted in the large CSAT heat flux errors. Although this Ts error is qualitatively similar to the well-known fundamental correction for the crosswind component, it is quantitatively different and directly related to the firmware estimation of the pulse arrival time. For a CSAT running version 3 of the firmware, there does not appear to be a significant underestimation of Ts; however, a Ts error similar to that of version 4 may occur if the CSAT is sufficiently out of calibration. An empirical correction to the CSAT heat flux that is consistent with our conceptual understanding of the Ts error is presented. Within a broader context, the surface energy balance is used to evaluate the heat flux measurements, and the usefulness of side-by-side instrument comparisons is discussed.

scholarly journals Can Lidars compete with sonic anemometers? - Comparison of wind measurements from different Doppler Lidar scan strategies to sonic anemometer data

2021 ◽  
Author(s):  
Kevin Wolz ◽  
Frank Beyrich ◽  
Julian Steinheuer ◽  
Carola Detring ◽  
Ronny Leinweber ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Spatial Data ◽  
Technological Development ◽  
Weather Prediction ◽  
Sonic Anemometer ◽  
Horizontal Wind ◽  
Doppler Lidar ◽  
Sonic Anemometers ◽  
Wind Measurements ◽  
Sonic Anemometer Data

<p>The technological development of ground-based active remote sensing instruments has reached a point where they have the possibility to drastically increase the temporal and spatial data density compared to conventional instruments, which would allow for a better process understanding and is expected to enhance the forecasting skills of numerical weather prediction systems and reduce its uncertainties. To test the measurement uncertainty and feasibility of Doppler Lidar systems we participated in the FESST@MOL 2020 field campaign, organized by the German Meteorological Service (DWD) in Lindenberg, Germany. During this campaign, eight Doppler Lidars were operated at the boundary layer field site (GM) Falkenberg. We evaluated different scanning strategies for the determination of the wind profile in the Atmospheric Boundary Layer (ABL) using multiple different triple Lidar virtual tower (VT) scan patterns including range height indicator (RHI) and step/stare scan modes. We compared these Lidar-based wind measurements with the data from a sonic anemometer on a 99 m tall instrumented tower also located in Falkenberg over a period of four months. The lidar and the sonic anemometer data were processed to 10- and 30- minute averages and compared to each other. The VT measurements underestimated the mean horizontal wind compared to the sonic anemometer by around 0.2 m s<sup>‑1</sup>. Besides that, we compared the VT data with those from a single fourth nearby Doppler Lidar which was running in a velocity-azimuth display (VAD) mode. The calculated mean horizontal wind values between the two different modes showed a good comparability but differed stronger with increasing height.</p>

scholarly journals Field intercomparison of prevailing sonic anemometers

2017 ◽  
Author(s):  
Matthias Mauder ◽  
Matthias J. Zeeman
Keyword(s):  
Wind Speed ◽  
Sonic Anemometer ◽  
Three Dimensional ◽  
Buoyancy Flux ◽  
Horizontal Wind ◽  
Horizontal Wind Speed ◽  
Sonic Anemometers ◽  
Adjacent Structures ◽  
Mean Wind Speed ◽  
Field Intercomparison

Abstract. Three-dimensional sonic anemometers are the core component of eddy-covariance systems, which are widely used for micrometeorological and ecological research. In order to characterize the measurement uncertainty of these instruments we present and analyse the results from a field intercomparison experiment of six commonly used sonic anemometer models from four major manufacturers. These models include Campbell CSAT3, Gill HS-50 and R3, METEK uSonic-3 Omni, R.M. Young 81000 and 81000RE. The experiment was conducted over a meadow at the TERENO/ICOS site De-Fen in southern Germany over a period of 16 days in June of 2016 as part of the ScaleX campaign. The measurement height was 3 m for all sensors, which were separated by 9 m from each other, each on its own tripod, in order to limit contamination of the turbulence measurements by adjacent structures as much as possible. Moreover, the high-frequency data from all instruments were treated with the same post-processing algorithm. In this study, we compare the results for various turbulence statistics, which include mean horizontal wind speed, standard deviations of vertical wind velocity and sonic temperature, friction velocity and the buoyancy flux. Quantitative measures of uncertainty, such as bias and comparability, are derived from these results. We find that biases are generally very small for all sensors and all computed variables, except for the sonic temperature measurements of the two Gill sonic anemometers (HS and R3), confirming a known transducer-temperature dependence of the sonic temperature measurement. The best overall agreement between the different instruments was found for the mean wind speed and the buoyancy flux.

Snow Grain Size Estimates from Airborne Ka-Band Radar Measurements

2020 ◽  
Author(s):  
J. Li ◽  
B. Camps-Raga ◽  
F. Rodriguez-Morales ◽  
D. Gomez-Garcia ◽  
J. Paden ◽  
...  
Keyword(s):  
Grain Size ◽  
Ka Band ◽  
Radar Measurements ◽  
Size Estimates

scholarly journals Wind shear over the Nice Côte d'Azur airport: case studies

2013 ◽  
Vol 13 (9) ◽  
pp. 2223-2238 ◽  
Author(s):  
A. Boilley ◽  
J.-F. Mahfouf
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Numerical Simulations ◽  
Wind Shear ◽  
Horizontal Wind ◽  
Wind Profiler ◽  
Measurement Campaign ◽  
Wind Lidar ◽  
Real Time Applications ◽  
Wind Shears

Abstract. The Nice Côte d'Azur international airport is subject to horizontal low-level wind shears. Detecting and predicting these hazards is a major concern for aircraft security. A measurement campaign took place over the Nice airport in 2009 including 4 anemometers, 1 wind lidar and 1 wind profiler. Two wind shear events were observed during this measurement campaign. Numerical simulations were carried out with Meso-NH in a configuration compatible with near-real time applications to determine the ability of the numerical model to predict these events and to study the meteorological situations generating an horizontal wind shear. A comparison between numerical simulation and the observation dataset is conducted in this paper.

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