A comparison of ground-based Doppler lidar and airborne in situ wind observations above complex terrain

2003 ◽  
Vol 129 (588) ◽  
pp. 693-713 ◽  
Author(s):  
Dale R. Durran ◽  
Tomislav Maric ◽  
Robert M. Banta ◽  
Lisa S. Darby ◽  
R. Michael Hardesty
Keyword(s):  
Complex Terrain ◽  
Doppler Lidar

Untersuchungen zur Ableitung von Windböen aus Doppler-Lidar-Messungen

2021 ◽  
Author(s):  
Carola Detring ◽  
Eileen Päschke ◽  
Julian Steinheuer ◽  
Ronny Leinweber ◽  
Markus Kayser ◽  
...  
Keyword(s):  
Field Experiment ◽  
Temporal Variability ◽  
Surface Wind ◽  
Doppler Lidar ◽  
Signal To Noise ◽  
Observation Volume ◽  
Wind Gusts ◽  
Die Profile ◽  
Spatio Temporal

<p>Mit Hilfe von Doppler-Lidar-Systemen, lassen sich die Profile von Windgeschwindigkeit und -richtung in der Atmosphärischen Grenzschicht (AGS) auf der Basis klassischer Messstrategien wie einem VAD-24 Scan (Velocity Azimuth Display mit 24 Strahlrichtungen) zuverlässig bestimmen (Päschke et al., 2015). Für praktische Anwendungen von großem Interesse sind jedoch neben dem mittleren Windprofil auch kurzzeitige Fluktuationen des Windes, wie sie zum Beispiel in Verbindung mit Windböen auftreten. Untersuchungen zu Windböen waren ein wesentlicher Aspekt der Messkampagne FESSTVaL (Field Experiment on Sub-Mesoscale Spatio-Temporal Variability in Lindenberg, www.fesstval.de).</p><p>Eine Studie von Suomi et al. (2017) hat gezeigt, dass eine Ableitung von Windböen aus Doppler Lidar Messungen prinzipiell möglich ist. Allerdings wird mit üblichen Messstrategien die hierfür erforderliche hohe zeitliche Auflösung in der Ermittlung des Windvektors nicht erreicht, so dass mit Skalierungsansätzen unter Verwendung von in-situ Windmessungen eine Korrektur der aus den Lidar-Daten abgeleiteten Böenwerte erfolgen muss.</p><p>Im Rahmen der vorliegenden Arbeit wurde eine alternative Messstrategie für Doppler-Lidar-Systeme vom Typ „Streamline“ (Halo Photonics) entwickelt und über mehrere Monate in den Jahren 2020/21 auf dem Grenzschichtmessfeld Falkenberg des DWD erprobt. Die Böenableitung basiert auf einem sog. Continous Scan Mode (CSM); dabei werden die während einer vollständigen Rotation des Lidar-Scan-Kopfes kontinuierlich durchgeführten Messungen 10-11 Strahlrichtungen zugeordnet und die Radialwindgeschwindigkeiten wiederum mit dem VAD-Verfahren ermittelt. Die Dauer eines Scans beträgt etwa 3.4s, damit kann eine Zeitauflösung erreicht werden, die der heute weit verbreiteten Definition einer Windbö entspricht (3s gleitendes Mittel; WMO (2018)).</p><p>Diese neue Konfiguration bringt Herausforderungen an die Datenverarbeitung mit sich. Im CSM muss mit vergleichsweise wenigen Lidar-Pulsen pro Messstrahl gearbeitet werden, so dass klassische Ansätze der Datenfilterung (Signal-to-Noise Schwellwert, Consensus Filterung) nicht verwendet werden können. Es wird ein alternatives Verfahren für die Prozessierung der Lidar-Rohdaten vorgeschlagen. Die Ergebnisse der Ableitung sowohl des mittleren Windvektors als auch der jeweiligen maximalen Windbö in einem 10-Minuten-Mittelungsintervall werden mit Sonic-Messungen in 90m Höhe verglichen. </p><p>Im Rahmen des FESSTVaL Experimentes wurde diese neue Messkonfiguration an drei Standorten, die ein annähernd gleichseitiges Dreieck mit einer Kantenlänge von etwa 5 km bildeten, genutzt. Es werden Fallbeispiele aus der FESSTVaL Kampagne für die Variabilität im Auftreten von Windböen gezeigt.</p><p><strong>Referenzen</strong></p><p>Päschke, E., Leinweber, R., and Lehmann, V. (2015): An assessment of the performance of a 1.5 μm Doppler lidar for operational vertical wind profiling based on a 1-year trial, Atmos. Meas. Tech., 8, 2251–2266, https://doi.org/10.5194/amt-8-2251-2015</p><p>Suomi, I., Gryning, S.‐E., O'Connor, E.J. and Vihma, T. (2017): Methodology for obtaining wind gusts using Doppler lidar. Q.J.R. Meteorol. Soc., 143: 2061-2072. https://doi.org/10.1002/qj.3059</p><p>World Meteorological Organization (WMO) (2018): Measurement of surface wind. In Guide to Meteorological Instruments and Methods of Observation, Volume I -Measurement of Meteorological Variables, No.8: 196–213, URL: https://library.wmo.int/doc_num.php?explnum_id=10616 (accessed November 2021)</p>

scholarly journals High-Resolution Observations of Transport and Exchange Processes in Mountainous Terrain

Atmosphere ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 457 ◽  
Author(s):  
Stefan Emeis ◽  
Norbert Kalthoff ◽  
Bianca Adler ◽  
Eric Pardyjak ◽  
Alexandre Paci ◽  
...  
Keyword(s):  
Complex Terrain ◽  
Mountainous Terrain ◽  
Full Spectrum ◽  
Spatiotemporal Information ◽  
Exchange Processes ◽  
Atmospheric Dynamic ◽  
In Situ Observations ◽  
Measurement Strategies ◽  
Mesoscale Processes

Mountainous areas require appropriate measurement strategies to cover the full spectrum of details concerning the energy exchange at the Earth’s surface and to capture the spatiotemporal distribution of atmospheric dynamic and thermodynamic fields over them. This includes the range from turbulence to mesoscale processes and its interaction. The surface energy balance needs appropriate measurement strategies as well. In this paper, we present an overview of important experiments performed over mountainous terrain and summarize the available techniques for flow and energy measurements in complex terrain. The description includes ground-based and airborne in situ observations as well as ground-based and airborne remote sensing (passive and active) observations. Emphasis is placed on systems which retrieve spatiotemporal information on mesoscale and smaller scales, fitting mountainous terrain research needs. Finally, we conclude with a short list summarizing challenges and gaps one faces when dealing with measurements over complex terrain.

scholarly journals Short-term variation in atmospheric constituents associated with local front passage observed by a 3-D coherent Doppler lidar and in-situ aerosol/gas measurements

2019 ◽  
Vol 3 ◽  
pp. 100043
Author(s):  
Hisahiro Takashima ◽  
Keiichiro Hara ◽  
Chiharu Nishita-Hara ◽  
Yasushi Fujiyoshi ◽  
Koichi Shiraishi ◽  
...  
Keyword(s):  
Doppler Lidar ◽  
Short Term ◽  
Coherent Doppler Lidar ◽  
Term Variation ◽  
Gas Measurements

scholarly journals A Method for Estimating the Turbulent Kinetic Energy Dissipation Rate from a Vertically Pointing Doppler Lidar, and Independent Evaluation from Balloon-Borne In Situ Measurements

2010 ◽  
Vol 27 (10) ◽  
pp. 1652-1664 ◽  
Author(s):  
Ewan J. O’Connor ◽  
Anthony J. Illingworth ◽  
Ian M. Brooks ◽  
Christopher D. Westbrook ◽  
Robin J. Hogan ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Convective Boundary Layer ◽  
Sonic Anemometer ◽  
Horizontal Wind ◽  
Inertial Subrange ◽  
Doppler Velocity ◽  
Doppler Lidar ◽  
Convective Boundary ◽  
Dissipation Rates

Abstract A method of estimating dissipation rates from a vertically pointing Doppler lidar with high temporal and spatial resolution has been evaluated by comparison with independent measurements derived from a balloon-borne sonic anemometer. This method utilizes the variance of the mean Doppler velocity from a number of sequential samples and requires an estimate of the horizontal wind speed. The noise contribution to the variance can be estimated from the observed signal-to-noise ratio and removed where appropriate. The relative size of the noise variance to the observed variance provides a measure of the confidence in the retrieval. Comparison with in situ dissipation rates derived from the balloon-borne sonic anemometer reveal that this particular Doppler lidar is capable of retrieving dissipation rates over a range of at least three orders of magnitude. This method is most suitable for retrieval of dissipation rates within the convective well-mixed boundary layer where the scales of motion that the Doppler lidar probes remain well within the inertial subrange. Caution must be applied when estimating dissipation rates in more quiescent conditions. For the particular Doppler lidar described here, the selection of suitably short integration times will permit this method to be applicable in such situations but at the expense of accuracy in the Doppler velocity estimates. The two case studies presented here suggest that, with profiles every 4 s, reliable estimates of ε can be derived to within at least an order of magnitude throughout almost all of the lowest 2 km and, in the convective boundary layer, to within 50%. Increasing the integration time for individual profiles to 30 s can improve the accuracy substantially but potentially confines retrievals to within the convective boundary layer. Therefore, optimization of certain instrument parameters may be required for specific implementations.

Validierung von Doppler Wind LiDARen des Deutschen Wetterdienstes (DWD) mit unbemannten kleinen Forschungsflugzeugen (UAS

2021 ◽  
Author(s):  
Jakob Boventer ◽  
Ines Weber ◽  
Martin Schön ◽  
Kjell zum Berge ◽  
Andreas Platis ◽  
...  
Keyword(s):  
Doppler Lidar

<p>Die Leistung und Verfügbarkeit von Lidar Systemen bei verschiedenen atmosphärischen Bedingungen ist unabdingbares Mittel zur Beobachtung der Atmosphärischen Grenzschicht. Um diese sicherzustellen werden Messungen benötigt die es ermöglichen die Lidar Messungen  zu validieren.</p> <p>Zu diesem Zwecke wurden im Rahmen der FESSTVaL Feldmess-Kampagne  im Sommer 2021 fluggestützte meteorologische Messdaten in der atmosphärischen Grenzschicht über dem Messfeld Falkenberg des Deutschen Wetterdienstes erfasst.</p> <p>Der Schwerpunkt lag dabei auf der Validierung von Doppler-Lidar Messungen der Windgeschwindigkeit, Windrichtung und der turbulenten kinetischen Energie im Höhenbereich von 90 m bis 600 m über Grund. Die Validierungsdaten wurden mit dem unbemannten Luftfahrtsystem (UAS) vom Typ MASC-3 (Multipurpose Airborne SensorCarrier, Typ 3) aufgenommen. Das UAS MASC-3 wird für meteorologische in-situ Messungen turbulenter Größen (Wind, Temperatur, Feuchte) sowie von Aerosol-Partikeln in der unteren Atmosphäre genutzt.[1]</p> <p>Mithilfe der UAS-Messungen wird die Qualität, die räumliche Auflösung und die Signifikanz der Lidar-Daten in verschiedenen Messkonfigurationen und unter unterschiedlichen atmosphärischen Bedingungen, wie z.B. thermische Schichtung, Wasserdampfgehalt, Konzentration und Größenverteilung der Aerosol-Partikel, bewertet.</p> <p>Geeignete Scanning-Strategien für die Lidar-Systeme können so bestimmt, charakterisiert und der Messfehler sowie die Repräsentativität und Verfügbarkeit der Lidar Wind- und Turbulenzdaten quantifiziert werden. Das Ergebnis der Bewertung wird dazu beitragen die anfänglich erwähnte Leistung und Verfügbarkeit von Lidar genauer zu beurteilen und um Fernerkundungsinstrumente besser in ein operationales Messnetzwerk integrieren zu können.</p> <p>[1] A. Rautenberg et al., MDPI Sensors doi:10.3390/s19102292 (2019)</p>

scholarly journals Detection of Complex Terrain-Induced Wind Shear by Doppler Lidar at Beijing Capital International Airport

2020 ◽  
Vol 237 ◽  
pp. 06004
Author(s):  
Xiaoying Liu ◽  
Songhua Wu ◽  
Hongwei Zhang ◽  
Jianjun Zhang ◽  
Zhiqiang He ◽  
...  
Keyword(s):  
Wind Field ◽  
Complex Terrain ◽  
Wind Shear ◽  
Field Structure ◽  
Shielding Effect ◽  
Doppler Lidar ◽  
Wake Effect ◽  
International Airport ◽  
Glide Path ◽  
Coherent Doppler Lidar

In November 2018, the lidar-based wind shear synchronous experiment was performed at Beijing Capital International Airport (BCIA). In this experiment, aiming at the measurement of the terrain-induced wind shear and the wind field around the runway, the glide path scanning mode, and the RHI strategy were conducted alternately. Radial velocity retrieved from the glide path scanning can obviously present the wakes caused by complex terrain (e.g., hills, tall trees, residential and terminal buildings). The Pulse Coherent Doppler Lidar (PCDL) warned the terrain-induced wind shear, which was verified by the pilot report. The wind field structure around the runway under the wake effect and the building shielding effect is also analyzed.

scholarly journals Three-Dimensional Wind Retrieval: Application of MUSCAT to Dual-Doppler Lidar

2009 ◽  
Vol 26 (3) ◽  
pp. 635-646 ◽  
Author(s):  
Susanne Drechsel ◽  
Georg J. Mayr ◽  
Michel Chong ◽  
Martin Weissmann ◽  
Andreas Dörnbrack ◽  
...  
Keyword(s):  
Complex Terrain ◽  
Doppler Radar ◽  
Three Dimensional ◽  
Doppler Lidar ◽  
Wind Fields ◽  
Owens Valley ◽  
Horizontal Structure ◽  
Wind Retrieval ◽  
Weather Radars ◽  
Spatial Coverage

Abstract During the field campaign of the Terrain-induced Rotor Experiment (T-REX) in the spring of 2006, Doppler lidar measurements were taken in the complex terrain of the Californian Owens Valley for six weeks. While fast three-dimensional (3D) wind analysis from measured radial wind components is well established for dual weather radars, only the feasibility was shown for dual-Doppler lidars. A computationally inexpensive, variational analysis method developed for multiple-Doppler radar measurements over complex terrain was applied. The general flow pattern of the 19 derived 3D wind fields is slightly smoothed in time and space because of lidar scan duration and analysis algorithm. The comparison of extracted wind profiles to profiles from radiosondes and wind profiler reveals differences of wind speed and direction of less than 1.1 m s−1 and 3°, on average, with standard deviations not exceeding 2.7 m s−1 and 27°, respectively. Standard velocity–azimuth display (VAD) retrieval method provided higher vertical resolution than the dual-Doppler retrieval, but no horizontal structure of the flow field. The authors suggest a simple way to obtain a good first guess for a dual-lidar scan strategy geared toward 3D wind retrieval that minimizes scan duration and maximizes spatial coverage.

Validation for ESA’s Aeolus Mission using the in-situ instruments at Canadian Arctic and reanalysis data

2020 ◽  
Author(s):  
Chih-Chun Chou ◽  
Paul Kushner ◽  
Zen Mariani ◽  
Peter Rodriguez ◽  
Christopher Fletcher
Keyword(s):  
Climate Change ◽  
Rayleigh Scattering ◽  
Line Of Sight ◽  
Horizontal Line ◽  
Vertical Resolution ◽  
Doppler Lidar ◽  
Depolarization Ratio ◽  
Ka Band ◽  
Wind Profiles

<p>ESA’s Aeolus mission, launched in August 2018, is designed to capture tropospheric wind profiles on a global scale in near-real time. The Aeolus lidar system, Atmospheric LAser Doppler INstrument (ALADIN), uses two modes of lidar-driven active scattering, Mie and Rayleigh scattering channels, to retrieve horizontal line-of-sight (HLOS) winds under both clear and cloudy conditions. ESA Aeolus aims to improve numerical weather and climate prediction, and to advance understanding of atmospheric circulation and weather systems.</p><p>This presentation will describe the Canadian validation activities for ESA Aeolus level-2B product, coordinated by the University of Toronto’s Department of Physics and Environment and Climate Change Canada (ECCC). The main focus is the evaluation of Aeolus overpasses using the fifth major global reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ECMWF ERA5), and in-situ measurements at Environment and Climate Change Canada’s (ECCC) Iqaluit and Whitehorse supersites where several wind sensing instruments are co-located. It will compare the Aeolus HLOS winds with the profiles of wind vector from regular radiosonde launches, line-of-sight winds from Doppler Lidar and Ka-Band Radar. The accuracy of the Aeolus measurements is analyzed based on the type of scattering and natural variability of the wind on different levels.</p><p>The radiosonde measures the profiles of temperature, relative humidity, pressure, and winds twice a day with a vertical resolution of 15 m up to 30 km. On the other hand, the Mie scattered 1.5 micron Doppler Lidar retrieves LOS winds at every 3 m as well as aerosol backscatter and depolarization ratio every 5 minutes up to 3 km. Lastly, for every 10 minutes, the dual-polarization Doppler Ka-Band Radar measures the LOS wind speed and direction, cloud and fog backscatter, and depolarization ratio up to a range of 25 km with a vertical resolution of 10 m.</p><p>The wind profiles were directly compared to the profiles derived from other instruments or reanalysis. The vertical structure of the Aeolus winds, for example the wind shear, will also be compared and discussed. The validation results showed that Aeolus is providing some promising initial products and that the ERA5 reanalysis is the most consistent dataset with the Aeolus wind measurements from level-2B product.</p>

scholarly journals Advancing Precipitation Estimation and Streamflow Simulations in Complex Terrain with X-Band Dual-Polarization Radar Observations

2018 ◽  
Vol 10 (8) ◽  
pp. 1258 ◽  
Author(s):  
Marios Anagnostou ◽  
Efthymios Nikolopoulos ◽  
John Kalogiros ◽  
Emmanouil Anagnostou ◽  
Francesco Marra ◽  
...  
Keyword(s):  
Complex Terrain ◽  
Rain Gauge ◽  
Storm Events ◽  
Error Statistics ◽  
Radar Rainfall ◽  
Radar Observations ◽  
X Band ◽  
Precipitation Estimation ◽  
Rainfall Estimates

In mountain basins, the use of long-range operational weather radars is often associated with poor quantitative precipitation estimation due to a number of challenges posed by the complexity of terrain. As a result, the applicability of radar-based precipitation estimates for hydrological studies is often limited over areas that are in close proximity to the radar. This study evaluates the advantages of using X-band polarimetric (XPOL) radar as a means to fill the coverage gaps and improve complex terrain precipitation estimation and associated hydrological applications based on a field experiment conducted in an area of Northeast Italian Alps characterized by large elevation differences. The corresponding rainfall estimates from two operational C-band weather radar observations are compared to the XPOL rainfall estimates for a near-range (10–35 km) mountainous basin (64 km2). In situ rainfall observations from a dense rain gauge network and two disdrometers (a 2D-video and a Parsivel) are used for ground validation of the radar-rainfall estimates. Ten storm events over a period of two years are used to explore the differences between the locally deployed XPOL vs. longer-range operational radar-rainfall error statistics. Hourly aggregate rainfall estimates by XPOL, corrected for rain-path attenuation and vertical reflectivity profile, exhibited correlations between 0.70 and 0.99 against reference rainfall data and 21% mean relative error for rainfall rates above 0.2 mm h−1. The corresponding metrics from the operational radar-network rainfall products gave a strong underestimation (50–70%) and lower correlations (0.48–0.81). For the two highest flow-peak events, a hydrological model (Kinematic Local Excess Model) was forced with the different radar-rainfall estimations and in situ rain gauge precipitation data at hourly resolution, exhibiting close agreement between the XPOL and gauge-based driven runoff simulations, while the simulations obtained by the operational radar rainfall products resulted in a greatly underestimated runoff response.

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