Scopes and Challenges of Dual-Doppler Lidar Wind Measurements—An Error Analysis

Stawiarski, Christina; Träumner, K.; Knigge, Christoph; Calhoun, Ronald

doi:10.1175/jtech-d-12-00244.1

Cited by 75 publications

(108 citation statements)

References 29 publications

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“…Scanner movements can be performed with different speeds for both axes at the same time. A specially designed control system for the two lidar systems (Stawiarski et al 2013) allows highly synchronized scan patterns as well as real time adaptation of scan parameters to atmospheric conditions e.g., the current wind speed.…”

Section: Field Studymentioning

confidence: 99%

“…This secured a minimization of the time sampling error (Stawiarski et al 2013). Wind-speed profiles were obtained from a full PPI scan that was performed by both lidars at the beginning of each hour using a velocity-azimuth display (VAD) algorithm (Browning and Wexler 1968).…”

Section: Field Studymentioning

confidence: 99%

“…where χ is the angle measured fromr 1 tor 2 and 2 r v is the uncorrelated noise for both lidars (Stawiarski et al 2013). To avoid propagation errors that are too large, an upper limit of sin −2 ( χ) = 4 was chosen, which implies that only intersection angles between 30 • and 150 • were considered.…”

Section: Data Handlingmentioning

confidence: 99%

See 2 more Smart Citations

Turbulent Structures and Coherence in the Atmospheric Surface Layer

Träumner

Damian

Stawiarski

et al. 2014

Boundary-Layer Meteorol

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Organized structures in turbulent flow fields are a well-known and still fascinating phenomenon. Although these so-called coherent structures are obvious from visual inspection, quantitative assessment is a challenge and many aspects e.g., formation mechanisms and contribution to turbulent fluxes, are discussed controversially. During the "High Definition Clouds and Precipitation for Advancing Climate Prediction" Observational Prototype Experiment (HOPE) from April to May 2013, an advanced dual Doppler lidar technique was used to image the horizontal wind field near the surface for approximately 300 h. A visual inspection method, as well as a two-dimensional integral length scale analysis, were performed to characterize the observations qualitatively and quantitatively. During situations with forcing due to shear, the wind fields showed characteristic patterns in the form of clearly bordered, elongated areas of enhanced or reduced wind speed, which can be associated with near-surface streaks. During calm situations with strong buoyancy forcing, open cell patterns in the horizontal divergence field were observed. The measurement technique used enables the calculation of integral length scales of both horizontal wind components in the streamwise and cross-stream directions. The individual length scales varied considerably during the observation period but were on average shorter during situations with z/L < 0 compared to strongly stable situations. During unstable situations, which were dominated by wind fields with structures, the streamwise length scales increased with increasing wind speed, whereas the cross-stream length scales decreased. Consequently, the anisotropy increased from 1 for calm situations to values of 2-3 for wind speeds of 8-10 m s −1 . During neutral to stable situations, the eddies were on average quite isotropic in the horizontal plane.

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Section: Field Studymentioning

confidence: 99%

Section: Field Studymentioning

confidence: 99%

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Turbulent Structures and Coherence in the Atmospheric Surface Layer

Träumner

Damian

Stawiarski

et al. 2014

Boundary-Layer Meteorol

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“…The 2-D and 3-D wind measurements from Doppler lidars are useful in various fields of study such as boundary layer meteorology (Fernando et al, 2015;Vanderwende et al, 2015), air quality (Barlow et al, 2011;Collier et al, 2005), wind energy research (Banta et al, 2015;Käsler et al, 2010;Mikkelsen, 2014;Newsom et al, 2015) and others. The simplest techniques to derive a profile of wind speed and direction using a single-Doppler lidar are the velocity azimuth display (VAD) technique (Browning and Wexler, 1968) and the Doppler beam swinging (DBS) technique (Strauch et al, 1984). These techniques assume horizontal homogeneity of the wind in the measurement volume to estimate the profile of wind speed and direction.…”

Section: Introductionmentioning

confidence: 99%

“…For example, measurement uncertainties in wind measurements made using the DBS technique in complex terrain were investigated by Bingöl et al (2009) while Lundquist et al (2015) studied the uncertainties in wind measurements using the DBS technique in presence of complex flow by simulating lidar measurements within a wind turbine wake using a wind field created with large-eddy simulation. Wind-field measurements made using the virtual tower technique have been validated (Damian et al, 2014;Gunter et al, 2015) to show high skill in measuring 2-D wind fields and Stawiarski et al (2013) did a detailed error analysis of dual Doppler co-planar PPI technique. Uncertainties in 3-D wind-field retrievals using triple-Doppler lidar techniques have also been investigated.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of single and multiple Doppler lidar techniques to measure complex flow during the XPIA field campaign

et al. 2017

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Abstract. Accurate three-dimensional information of wind flow fields can be an important tool in not only visualizing complex flow but also understanding the underlying physical processes and improving flow modeling. However, a thorough analysis of the measurement uncertainties is required to properly interpret results. The XPIA (eXperimental Planetary boundary layer Instrumentation Assessment) field campaign conducted at the Boulder Atmospheric Observatory (BAO) in Erie, CO, from 2 March to 31 May 2015 brought together a large suite of in situ and remote sensing measurement platforms to evaluate complex flow measurement strategies.In this paper, measurement uncertainties for different single and multi-Doppler strategies using simple scan geometries (conical, vertical plane and staring) are investigated. The tradeoffs (such as time-space resolution vs. spatial coverage) among the different measurement techniques are evaluated using co-located measurements made near the BAO tower. Sensitivity of the single-/multi-Doppler measurement uncertainties to averaging period are investigated using the sonic anemometers installed on the BAO tower as the standard reference. Finally, the radiometer measurements are used to partition the measurement periods as a function of atmospheric stability to determine their effect on measurement uncertainty.It was found that with an increase in spatial coverage and measurement complexity, the uncertainty in the wind measurement also increased. For multi-Doppler techniques, the increase in uncertainty for temporally uncoordinated measurements is possibly due to requiring additional assumptions of stationarity along with horizontal homogeneity and less representative line-of-sight velocity statistics. It was also found that wind speed measurement uncertainty was lower during stable conditions compared to unstable conditions.

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Foehn–cold pool interactions in the Inn Valley during PIANO IOP2

Haid

Gohm

Umek

et al. 2020

Quart J Royal Meteoro Soc

169

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A case-study is presented of a south foehn emanating from the Wipp Valley, Austria, which encountered a cold-air pool (CAP) in the Inn Valley near the city of Innsbruck. The analysis is based on data collected during the second Intensive Observation Period of the Penetration and Interruption of Alpine Foehn (PIANO) field experiment. Foehn was initiated on 3 November 2017 by an eastward moving trough and terminated in the afternoon of 5 November 2017 by a cold front passage. On two occasions, reversed foehn flow deflected at the mountain ridge north of Innsbruck penetrated to the bottom of the Inn Valley. The first breakthrough occurred in the afternoon of 4 November 2017. It was transient and locally limited to the northwest of the city. The second (final) breakthrough occurred in the morning of 5 November 2017 and was recorded by all surface stations in the vicinity of Innsbruck. It started with a foehn air intrusion to the northeast of Innsbruck and continued with the westward propagation of the foehn-CAP boundary along the valley. Subsequently observed northerly winds above the city were caused by an atmospheric rotor. A few hours later and prior to the cold front passage, the CAP pushed back and lifted the foehn air from the ground. During both nights, shear flow instabilities formed at the foehn-CAP interface, which resulted in turbulent heating of the CAP and cooling of the foehn. However, this turbulent heating/cooling was partly compensated by other mechanisms. Especially in the presence of strong spatial CAP heterogeneity during the second night, heating in the CAP was most likely overcompensated by negative horizontal temperature advection. K E Y W O R D S cold-air pool, foehn, heat budget, multiple Doppler wind lidars, shear flow instabilties, turbulent erosion This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Scopes and Challenges of Dual-Doppler Lidar Wind Measurements—An Error Analysis

Cited by 75 publications

References 29 publications

Turbulent Structures and Coherence in the Atmospheric Surface Layer

Turbulent Structures and Coherence in the Atmospheric Surface Layer

Evaluation of single and multiple Doppler lidar techniques to measure complex flow during the XPIA field campaign

Foehn–cold pool interactions in the Inn Valley during PIANO IOP2

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