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Journal articles on the topic 'SODAR'

Author: Grafiati

Published: 4 June 2021

Last updated: 22 February 2023

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1

Anandan, V. K., M. Shravan Kumar, and I. Srinivasa Rao. "First Results of Experimental Tests of the Newly Developed NARL Phased-Array Doppler Sodar." Journal of Atmospheric and Oceanic Technology 25, no. 10 (October 1, 2008): 1778–84. http://dx.doi.org/10.1175/2008jtecha1050.1.

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Abstract A multifrequency phased-array Doppler sodar system has been installed recently at the National Atmospheric Research Laboratory (NARL) for the continuous observation of the lower atmosphere from near ground to the atmospheric boundary layer (ABL). The NARL sodar, developed in technical collaboration with the Society for Applied Microwave Electronics Engineering and Research (SAMEER), was built using piezoceramic tweeters, which are capable of generating 100-W acoustic power. In favorable atmospheric conditions, the sodar gives wind profiles up to 1 km. The performance evaluation is one of the most important aspects for quality assurance of sodar operations. This paper presents the first results of experimental observations of the NARL sodar system and its scientific validation. The NARL sodar has been validated using the simultaneous observation of another sodar system (Scintec model MFAS64). Various physical parameters of the atmosphere are derived using the results obtained from both of the systems. Comparison of simultaneous measurements by both of the sodars, located about 100 m apart, shows good agreement on wind speed, wind direction, and vertical wind variance. The correlation coefficient of more than 0.80 in wind speed and direction between the sodars shows the usefulness of the system for observing the atmosphere and deriving physical parameters below the ABL.

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2

Bradley, Stuart, and Sabine von Hünerbein. "Beam Geometry Calibration of Sodars without Use of a Mast." Journal of Atmospheric and Oceanic Technology 30, no. 9 (September 1, 2013): 2161–67. http://dx.doi.org/10.1175/jtech-d-12-00112.1.

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Abstract A new method for calibration of sodar wind speed measurements is described. The method makes no assumptions whatsoever about the sodar operation and its hardware and software, other than the assumption that only one beam is transmitted at a time. Regardless of the complexity of the actual beam shape, the effective beam zenith angle is accurately estimated: this is the angle that must be used in estimations of velocity components. In a very simple experiment, the effective beam zenith angle has been found to within around 0.2°, which is as good as is required in the most stringent sodar calibration procedures. It has been found, even for such a short data run, that the estimated beam angle is very close to that calculated from the sodar array geometry. The main limitation is the requirement for horizontally homogeneous flow, since the regression methods use both a tilted beam and a vertical beam. Note that this is also a fundamental limiting assumption in the normal operation of ground-based wind lidars and sodars.

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3

Piringer, Martin. "Ausgewählte Ergebnisse eines Sodar-Vergleichsexperiments." Meteorologische Zeitschrift 3, no. 3 (July 11, 1994): 132–37. http://dx.doi.org/10.1127/metz/3/1994/132.

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4

Kendrick, Paul, and Sabine von Hünerbein. "Fixed Echo Rejection in Sodar Using Noncoherent Matched Filter Detection and Gaussian Mixture Model–Based Postprocessing." Journal of Atmospheric and Oceanic Technology 36, no. 1 (January 2019): 3–16. http://dx.doi.org/10.1175/jtech-d-18-0095.1.

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AbstractDoppler sodar is a technology used for acoustic-based remote sensing of the lower planetary boundary layer. Sodars are often used to measure wind profiles; however, they suffer from problems caused by noise (both acoustic and electrical) and echoes from fixed objects, which can bias radial velocity estimates. An experimental bistatic sodar was developed with 64 independent channels. The device enables flexible beamforming; beams can be tilted at the same angle irrelevant of frequency, a limitation in most commercial devices. This paper presents an alternative sodar signal-processing algorithm for wind profiling using a multifrequency stepped-chirp pulse. A noncoherent matched filter was used to analyze returned signals. The noncoherent matched filter combines radial velocity estimates from multiple frequencies into a single optimization. To identify and separate sources of backscatter, noise, and fixed echoes, a stochastic pattern-recognition technique, Gaussian mixture modeling, was used to postprocess the noncoherent matched filter data. This method allowed the identification and separation of different stochastic processes. After identification, noise and fixed echo components were removed and a clean wind profile was produced. This technique was compared with traditional spectrum-based radial velocity estimation methods, and an improvement in the rejection of fixed echo components was demonstrated; this is one of the major limitations of sodar performance when located in complex terrain and urban environments.

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5

Anderson, Philip S., Russell S. Ladkin, and Ian A. Renfrew. "An Autonomous Doppler Sodar Wind Profiling System." Journal of Atmospheric and Oceanic Technology 22, no. 9 (September 1, 2005): 1309–25. http://dx.doi.org/10.1175/jtech1779.1.

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Abstract An autonomous Doppler sodar wind profiling system has been designed, built, tested, and then deployed for 2 years at a remote site in Coats Land, Antarctica. The system is designed around a commercially available phased-array sodar (a Scintec flat-array sodar, FAS64) and powered from five modular power system units. Each power unit comprises two batteries, two photovoltaic solar panels, and two vertical axis wind generators, plus charging control and isolation circuitry. The sodar’s main processing unit is located at the antenna, but is controlled from a manned research station 50 km distant, in real time, by a line-of-sight UHF radio link. Data from an integral automatic weather station (AWS) are also transmitted over the radio link, allowing meteorologically informed decisions on whether or not to operate the Doppler sodar. Over the 2-yr experiment dozens of sounding episodes, lasting from a few hours to a few days, were obtained. Successful soundings were obtained in temperatures down to −33°C, and wind speeds up to 12 m s−1. In general, the wind data quality was good, but the range was disappointing, probably as a result of the strongly stable atmospheric conditions that were experienced. The wind profiling system that is described has been used to obtain the first remote wintertime observations of katabatic winds over the Antarctic continent.

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6

Bradley, Stuart, Erich Mursch-Radlgruber, and Sabine von Hünerbein. "Sodar Measurements of Wing Vortex Strength and Position." Journal of Atmospheric and Oceanic Technology 24, no. 2 (February 1, 2007): 141–55. http://dx.doi.org/10.1175/jtech1966.1.

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Abstract A method is developed for robust real-time visualization of aircraft vortex spatial and temporal development based on measurement data from a line array of sodars. The method relies on using a potential-flow vortex model, with spatial averaging according to the along-beam and transverse spatial resolution of the sodar. The model comprises the wing vortex pair, together with two image vortices below ground such that there is no flow through the ground surface. An analytic solution for the temporal–spatial evolution of this four-vortex system is obtained as an aid to establishing relevant scales and performance criteria for any sodar. Field results from an array of four sodars are used on an individual profile basis (every 2 s of real time) to fit the model parameters of vortex circulation, position, and spacing. This method gives vortex trajectories and strength as a function of real time without dependence on assumptions regarding interactions with the atmosphere. Estimates of parameter uncertainties are also produced in real time, and it is found that estimates of position and spacing can be obtained to around ±4 m and of vortex circulation to ±50 m2 s−1. Recommendations are given for optimizing sodars for vortex measurements using practical technology.

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7

Bradley, Stuart. "Aspects of the Correlation between Sodar and Mast Instrument Winds." Journal of Atmospheric and Oceanic Technology 30, no. 10 (October 1, 2013): 2241–47. http://dx.doi.org/10.1175/jtech-d-12-00256.1.

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Abstract On a uniform terrain site, differences between a sodar and a mast-mounted cup anemometer will arise because of turbulent fluctuations and wind components being measured in different spaces, and because of the inherent difference between scalar and vector averaging. This paper develops theories for turbulence-related random fluctuations resulting from finite sampling rates and sampling from spatially distributed volumes. Coefficients of determination (R2) are predicted comparable to those obtained in practice. It is shown that more than two-thirds of the reduction in R2 arises from differences in the winds measured by mast instruments and by sodars, rather than by sodar errors: both instruments are measuring accurately, but just not in the same place or at the same time. The result is that sodars being used operationally should be able to measure winds to a root-mean-square accuracy of around 2%.

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8

Reitebuch, Oliver, and Stefan Emeis. "SODAR Messungen zur Atmosphärenforschung und Umweltüberwachung." Meteorologische Zeitschrift 7, no. 1 (February 18, 1998): 11–14. http://dx.doi.org/10.1127/metz/7/1998/11.

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9

Alzahrani, Abdullah A. H., Eltayeb M. Alhassan, Mahmoud A. Attia, and Mohammad A. Albanghali. "Enhancing Dental Carving Skills of Preclinical Dental Hygiene Students Using Online Dental Anatomy Resources." Open Dentistry Journal 13, no. 1 (December 31, 2019): 499–504. http://dx.doi.org/10.2174/1874210601913010499.

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Background: A key role of dental carving is enhancing manual proficiency and dexterity of dental hygiene students. Yet, utilizing Supplementary Online Dental Anatomy Resources (SODAR) as a supportive teaching approach has demonstrated the ability to improve carving skills. Objective: This study aims to examine the effectiveness of SODAR training in improving the quality of dental carving skills and knowledge among preclinical Saudi male students in Saudi Arabia. Methods: A basic double-blinded randomized controlled trial of 30 preclinical Saudi dental male students was conducted between January and April 2019. Participants were classified into an experimental group that received SODAR training (n = 15) and a control group comprising students who did not receive SODAR training (n = 15). The t-test and Fisher’s exact test were performed to assess differences in theoretical knowledge between the two groups. While Cohen’s d test, t-test, and Pearson correlation were conducted to evaluate differences in students’ dental carvings. Results: Students with SODAR training performed better on practical carving sessions than those without intervention (P-value < 0.001). However, SODAR intervention had no significant effect on the theoretical knowledge evaluations in both the groups. Conclusion: SODAR training demonstrated its ability to support students learning in practical carving sessions; however, no effect on theoretical knowledge was observed. Future research should focus on factors that impact carving teaching strategies, including the quality and depth of online learning content, students’ perceptions of online learning, and experiences of teachers who run the online resources.

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10

Rao, I. Srinivasa, V. K. Anandan, and M. Shravan Kumar. "Multifrequency Decoding of a Phased Array Doppler Sodar." Journal of Atmospheric and Oceanic Technology 26, no. 4 (April 1, 2009): 759–68. http://dx.doi.org/10.1175/2008jtecha1166.1.

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Abstract Doppler sodar is being used for studying the lower part of atmospheric boundary layer (ABL) and wind profiling. To obtain maximum altitude coverage multifrequency transmission has been used along with more transmitted power. In this article, the implementation of multifrequency transmission of a Doppler sodar and its decoding to extract the atmospheric parameters are presented. This article also shows the advantage of profiling using multifrequency sodar operation. The range of frequency used for transmission is between 1700 and 2100 Hz. The decoded Doppler spectra have shown significant improvement in signal-to-noise ratio (SNR) as well as higher altitude coverage compared to single-frequency transmission and reception. Wind profiles obtained from sodar have been compared with data obtained from high-resolution GPS sonde balloons, which were launched from a place close to the sodar system. The authors observed that 30% more wind data height coverage in when transmission is in multifrequency mode; the consistency in wind estimate is also improved compared to the single-frequency transmission.

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11

Wainwright, Charlotte E., Phillip M. Stepanian, Phillip B. Chilson, Robert D. Palmer, Evgeni Fedorovich, and Jeremy A. Gibbs. "A Time Series Sodar Simulator Based on Large-Eddy Simulation." Journal of Atmospheric and Oceanic Technology 31, no. 4 (April 1, 2014): 876–89. http://dx.doi.org/10.1175/jtech-d-13-00161.1.

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Abstract A sodar simulator capable of producing time series data emulating sodar signals has been developed and tested. The atmospheric fields used to populate the sodar simulator are taken from output of a large-eddy simulation code. The characteristics of the sodar (number and zenith angle of beams, beamwidth, transmit frequency, range resolution, etc.) are defined by the user to allow emulation of existing systems. The range of the reflected acoustic signal is calculated based upon a temperature-dependent speed of sound. Realistic acoustic background noise is simulated using filtered white noise. The raw acoustic time series data are processed using a Fourier transform to yield acoustic Doppler spectra, from which the radial velocities are calculated. The design of the simulator allows for the testing of and comparisons between various signal-processing techniques and averaging periods. An example case of feeding the sodar simulator with large-eddy simulation data representative of a developing convective boundary layer is presented and discussed.

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12

Bradley, Stuart, Sabine von Hünerbein, and Torben Mikkelsen. "A Bistatic Sodar for Precision Wind Profiling in Complex Terrain." Journal of Atmospheric and Oceanic Technology 29, no. 8 (August 1, 2012): 1052–61. http://dx.doi.org/10.1175/jtech-d-11-00035.1.

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Abstract A new ground-based wind profiling technology—a scanned bistatic sodar—is described. The motivation for this design is to obtain a “mastlike” wind vector profile in a single atmospheric column extending from the ground to heights of more than 200 m. The need for this columnar profiling arises from difficulties experienced by all existing lidars and sodars in the presence of nonhorizontally uniform wind fields, such as found generically in complex terrain. Other advantages are described, including improved signal strength from turbulent velocity fluctuations, improved data availability in neutral atmospheric temperature profiles, improved rejection of rain echoes, and improved rejection of echoes from fixed (nonatmospheric) objects. Initial brief field tests indicate that the scattered intensity profile agrees with theoretical expectations, and bistatic sodar winds are consistent with winds from standard mast-mounted instruments.

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13

Behrens, Paul, Stuart Bradley, and Travis Wiens. "A Multisodar Approach to Wind Profiling." Journal of Atmospheric and Oceanic Technology 27, no. 7 (July 1, 2010): 1165–74. http://dx.doi.org/10.1175/2010jtecha1345.1.

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Abstract This paper presents the development of a multisodar mode from a five-beam sodar whereby a wind speed vector is found for sets of three acoustic beams. If the vertical beam is used, this mode enables the profiling of four wind speed measurements around the sodar. These multisodars can be used to investigate the spatial and temporal nature of winds in both flat and complex terrain. The spatial, temporal, and signal-to-noise qualities of the sodar signal in this mode are analyzed, and a metric for understanding the inhomogeneity of the atmosphere through cross-correlating opposing multisodars is developed. A driving factor for this work is developing the use of such sodar systems in complex terrain, where experimental measurements are traditionally difficult and expensive.

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14

Asadov, Kh G., and V. M. Garaev. "Dual-frequency sodar measurements." Measurement Techniques 54, no. 3 (June 2011): 351–55. http://dx.doi.org/10.1007/s11018-011-9731-y.

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15

Gera, B. S., D. R. Pahwa, Neeraj Saxena, Gurbir Singh, and Rakesh Aggarwal. "Sodar in Dispersion Modeling." Journal of Applied Meteorology 35, no. 10 (October 1996): 1632–36. http://dx.doi.org/10.1175/1520-0450(1996)035<1632:sidm>2.0.co;2.

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16

Singal, S. P. "Design of Sodar Transducers." IETE Technical Review 9, no. 2 (March 1992): 157–60. http://dx.doi.org/10.1080/02564602.1992.11438855.

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17

Kallistratova, Margarita A., Rostislav D. Kouznetsov, Valerii F. Kramar, and Dmitrii D. Kuznetsov. "Profiles of Wind Speed Variances within Nocturnal Low-Level Jets Observed with a Sodar." Journal of Atmospheric and Oceanic Technology 30, no. 9 (September 1, 2013): 1970–77. http://dx.doi.org/10.1175/jtech-d-12-00265.1.

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Abstract Continuous sodar measurements of wind profiles have been carried out at the Zvenigorod Scientific Station of the Obukhov Institute of Atmospheric Physics since 2008. The station is located in a slightly inhomogeneous rural area about 45 km west of Moscow, Russia. The data were used to determine the parameters of wind and turbulence within low-level jets in the stable atmospheric boundary layer (ABL). Along with the mean velocity profiles, the profiles of variances of wind speed components from the sodar and the profiles of temperature from a microwave radiometer have been used to quantify turbulence and thermal stratification. Data from two sonic anemometers were used to get the near-surface parameters. The typical standard deviation of the vertical wind component σw within the low-level jet is about 5% of the maximum wind speed in the jet. No noticeable vertical variation of σw across the jets was detected in several earlier sodar campaigns, and it was not found in the present study. An increase in horizontal variances was detected in zones of substantial wind shear, which agrees with earlier published lidar data. Quasi-periodic structures in the sodar return signal, which appear in sodar echograms as braid-shaped patterns, were found to emerge preferably when a substantial increase of wind shear occurs at the top of the stable ABL. The braid patterns in the sodar echograms were not accompanied by any noticeable increase of observed σw, which disagrees with earlier data and indicates that such patterns may originate from various phenomena.

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18

Argentini, S., G. Mastrantonio, and A. Viola. "Estimation of turbulent heat fluxes and exchange coefficients for heat at Dumont d'Urville, East Antarctica." Antarctic Science 11, no. 1 (March 1999): 93–99. http://dx.doi.org/10.1017/s0954102099000127.

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Simultaneous acoustic Doppler sodar and tethersonde measurements were used to study some of the characteristics of the unstable boundary layer at Dumont d'Urville, Adélie Land, East Antarctica during the summer 1993–94. A description of the convective boundary layer and its behaviour in connection with the wind regime is given along with the frequency distribution of free convection episodes. The surface heat flux has been evaluated using the vertical velocity variance derived from sodar measurements. The turbulent exchange coefficients, estimated by coupling sodar and tethered balloon measurements, are in strong agreement with those present in literature for the Antarctic regions.

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19

Kouznetsov, Rostislav D. "The multi-frequency sodar with high temporal resolution." Meteorologische Zeitschrift 18, no. 2 (May 13, 2009): 169–73. http://dx.doi.org/10.1127/0941-2948/2009/0373.

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20

Lokoshchenko, Mikhail A., Eugenia A. Yavlyaeva, and Hans-Jürgen Kirtzel. "Sodar data about wind profiles in Moscow city." Meteorologische Zeitschrift 18, no. 3 (June 1, 2009): 321–30. http://dx.doi.org/10.1127/0941-2948/2009/0383.

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21

González-Rocha, Javier, Stephan F. J. De Wekker, Shane D. Ross, and Craig A. Woolsey. "Wind Profiling in the Lower Atmosphere from Wind-Induced Perturbations to Multirotor UAS." Sensors 20, no. 5 (February 29, 2020): 1341. http://dx.doi.org/10.3390/s20051341.

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We present a model-based approach to estimate the vertical profile of horizontal wind velocity components using motion perturbations of a multirotor unmanned aircraft system (UAS) in both hovering and steady ascending flight. The state estimation framework employed for wind estimation was adapted to a set of closed-loop rigid body models identified for an off-the-shelf quadrotor. The quadrotor models used for wind estimation were characterized for hovering and steady ascending flight conditions ranging between 0 and 2 m/s. The closed-loop models were obtained using system identification algorithms to determine model structures and estimate model parameters. The wind measurement method was validated experimentally above the Virginia Tech Kentland Experimental Aircraft Systems Laboratory by comparing quadrotor and independent sensor measurements from a sonic anemometer and two SoDAR instruments. Comparison results demonstrated quadrotor wind estimation in close agreement with the independent wind velocity measurements. However, horizontal wind velocity profiles were difficult to validate using time-synchronized SoDAR measurements. Analysis of the noise intensity and signal-to-noise ratio of the SoDARs proved that close-proximity quadrotor operations can corrupt wind measurement from SoDARs, which has not previously been reported.

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22

Chabbey, Adrien, Stuart Bradley, and Fernando Porté-Agel. "Scale Model Evaluation and Optimization of Sodar Acoustic Baffles." Journal of Atmospheric and Oceanic Technology 32, no. 3 (March 2015): 507–17. http://dx.doi.org/10.1175/jtech-d-13-00253.1.

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AbstractA 21:1 scaled sodar, operating at 40 kHz, has been built and tested in the laboratory. Sodars, which use sound scattered by turbulence to profile the lowest few hundred meters of the atmosphere, need good acoustic shielding to diminish annoyance and to reduce unwanted reflections from nearby objects. Design of the acoustic shielding is generally inhibited by the difficulty of testing on full-scale systems and uncertainty as to accuracy of models. In contrast, the scale model approach described allows for “bench testing” of many designs under controlled conditions, and efficient comparison with models. Measured beam patterns from the scale model were compared with those from a numerical model based on the Kirchhoff integral theorem. Satisfactory agreement has allowed using the numerical model to optimize the acoustic shield design, both for the gross acoustic baffle geometry and for the geometry of rim modulations known as thnadners. Optimization was performed in the specific case of a scaled model of a commercial phased array sodar.

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23

Busse, Jessica, and Kevin Knupp. "Observed Characteristics of the Afternoon–Evening Boundary Layer Transition Based on Sodar and Surface Data." Journal of Applied Meteorology and Climatology 51, no. 3 (March 2012): 571–82. http://dx.doi.org/10.1175/2011jamc2607.1.

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AbstractThe early-evening boundary layer transition has been defined in the past using a variety of criteria, the most popular of which is the onset of a negative surface heat flux. According to this definition, the transition is an almost-instantaneous event that occurs when the positive daytime heat flux switches to the negative nighttime heat flux. This definition is simplistic, however, because the stable boundary layer does not form instantaneously over a deep layer. Other factors are involved, and many changes occur aloft during the transition period that this definition does not account for—for example, a more gradual reduction in turbulence and an increase in wind speed. The combined use of sodar data, as well as 915-MHz wind profiler, surface temperature, dewpoint, and wind data, provides a more-comprehensive definition of the early-evening boundary layer transition. Sodar backscatter is sensitive to temperature fluctuations, and therefore as the heat flux decreases, the sodar return power exhibits changes from a time-varying convective structure to a more-stratified and steady structure. A relative minimum in intensity and height of the sodar backscatter is one indication that the transition is occurring. As the boundary layer evolves from the unstable convective afternoon conditions to the more stable nocturnal conditions, the finescale temporal variations in many parameters, including temperature, the 10–2-m temperature difference, dewpoint, and wind speed, decrease. There is often a distinct steplike shape in the temperature/wind decrease or dewpoint increase within 30 min of the sodar minimum. In this paper, an analysis of sodar and surface data is presented for low-wind cases to demonstrate the efficacy of this combined sensor technique, and to illustrate the average physical characteristics of the transition period for 21 cases during the summer months (June–August) and 9 cases during the autumn months (November–December) in Huntsville, Alabama.

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24

Oleynikov, V. N., V. M. Kartashov, S. A. Sheiko, O. V. Zubkov, and E. I. Oleynikova. "Determining the location of small unmanned aerial vehicles by acoustic radiation." Radiotekhnika, no. 210 (September 28, 2022): 113–27. http://dx.doi.org/10.30837/rt.2022.3.210.09.

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The features of the acoustic method for determining the location of the UAV using microphone arrays are considered: classical methods, super-resolution methods and the method of the difference in the arrival time of acoustic oscillations. A description of a sodar with a minimum number of microphones is given. The factors influencing the magnitude of the error in determining the coordinates of the UAV are analyzed. Estimates of the instrumental location error and errors caused by the Doppler effect were obtained by simulation modeling for a given configuration of the sodar microphone array. Using the considered sodar, the coordinates of a moving UAV were measured in open areas. Processing of field measurement results shows that the absolute values of errors in determining the coordinates of the UAV obtained using sodar at a distance of up to 100 m in 95% of cases do not exceed 3 m and in determining the height of no more than 1 m. Measurements of the azimuth and elevation angle are quite accurate at the same time high resolution.

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25

Reid, S. "Hilltop Wind Profiles Using Sodar." Boundary-Layer Meteorology 108, no. 2 (August 2003): 305–14. http://dx.doi.org/10.1023/a:1024183616829.

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26

KAMDA, Yasunari, Takao MAEDA, Junsuke MURATA, Nobuyuki HAYASAKI, Makoto IIDA, and Tetsuya KOGAKI. "J056021 Turbulence in SODAR measurements." Proceedings of Mechanical Engineering Congress, Japan 2013 (2013): _J056021–1—_J056021–5. http://dx.doi.org/10.1299/jsmemecj.2013._j056021-1.

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27

Ito, Yoshiki, Yasuhiro Kobori, Mitsuaki Horiguchi, Masato Takehisa, and Yasushi Mitsuta. "Development of Wind Profiling Sodar." Journal of Atmospheric and Oceanic Technology 6, no. 5 (October 1989): 779–84. http://dx.doi.org/10.1175/1520-0426(1989)006<0779:dowps>2.0.co;2.

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28

Chatterjee, N., P. Pal, and J. Das. "Boundary extraction of sodar images." Signal Processing 62, no. 2 (October 1997): 229–35. http://dx.doi.org/10.1016/s0165-1684(97)00127-8.

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29

Gera, B. S., and S. P. Singal. "Sodar in air pollution meteorology." Atmospheric Environment. Part A. General Topics 24, no. 8 (January 1990): 2003–9. http://dx.doi.org/10.1016/0960-1686(90)90234-e.

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30

Behrens, P., S. Bradley, and S. Von Hunerbein. "A scanning bi-static SODAR." IOP Conference Series: Earth and Environmental Science 1 (May 1, 2008): 012010. http://dx.doi.org/10.1088/1755-1315/1/1/012010.

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31

Pinkel, R., and J. A. Smith. "Repeat-Sequence Coding for Improved Precision of Doppler Sonar and Sodar." Journal of Atmospheric and Oceanic Technology 9, no. 2 (April 1992): 149–63. http://dx.doi.org/10.1175/1520-0426(1992)009<0149:rscfip>2.0.co;2.

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32

Warmbier, Günter, Frank Albers, and Klaus Hanswillemenke. "Wind energy related measurements with a commercial SODAR system." Meteorologische Zeitschrift 16, no. 4 (August 30, 2007): 425–28. http://dx.doi.org/10.1127/0941-2948/2007/0222.

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33

Bradley, Stuart, and Alexander Strehz. "Corrections to sodar Doppler winds due to wind drift." Meteorologische Zeitschrift 24, no. 6 (November 5, 2015): 605–14. http://dx.doi.org/10.1127/metz/2014/0627.

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34

Luiz Silva, W., F. L. Albuquerque Neto, G. B. França, and M. R. Matschinske. "Conceptual model for runway change procedure in Guarulhos International Airport based on SODAR data." Aeronautical Journal 120, no. 1227 (May 2016): 725–34. http://dx.doi.org/10.1017/aer.2016.33.

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ABSTRACTIn this work, we qualify and quantify the advantages of using SODAR (sonic detection and ranging) from current scenarios of Aeronautical Meteorology, with the goal of establishing a conceptual model for runway change procedures at Guarulhos International Airport (São Paulo, Brazil). The methods consist of analysing data from the Department of Airspace Control (DECEA) and Brazilian Airport Infrastructure (Infraero) about the reports of runway changes in Guarulhos in addition to SODAR data from September 2011 and December 2013. It is noted that in 234 analysed cases of runway change, there were significant periods of weak-intensity wind on the surface as well as the anticipated modification wind direction at altitude detected by sonic detection and ranging (SODAR), indicating future changes in levels closer to the surface. By examining the intersection of both scenarios, it is possible to observe that there is enough time for the air traffic controller to anticipate the needed runway change while minimising the impact on the aircraft flow, and this period has an average duration of 1 hour and 24 minutes. This confirms that the preliminary analysis of the information provided by SODAR can help predict alterations in wind direction, requiring redirection and bringing advantages in economic and security terms.

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Kouznetsov, Rostislav, Priit Tisler, Timo Palo, and Timo Vihma. "Evidence of Very Shallow Summertime Katabatic Flows in Dronning Maud Land, Antarctica." Journal of Applied Meteorology and Climatology 52, no. 1 (January 2013): 164–68. http://dx.doi.org/10.1175/jamc-d-12-0218.1.

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AbstractThe three-axis “Latan-3” Doppler sodar was operated near the Finnish Antarctic station Aboa in Dronning Maud Land (73.04°S, 13.40°W) in the austral summer of 2010/11. The measuring site is located at a practically flat, slightly sloped (about 1%) surface of the glacier. The sodar was operated in multiple-frequency parallel mode with 20–800-m sounding range, 20-m vertical resolution, and 10-s temporal resolution. To reveal the wind and temperature profiles below the sounding range as well as turbulent fluxes at 2 and 10 m, the data from a 10-m meteorological mast were used. During the measurements, the atmospheric boundary layer was within the sounding range of the sodar most of the time. Despite a large variety of observed sodar echo patterns and wind speed profiles, several cases of clear steady katabatic flows were observed. Practically all of them were easterly, whereas the uphill direction is southern. The thickness of the katabatic flow varied from a few tens to several hundreds of meters; the wind speed maximum could be as low as 5 m. Thin katabatic flows had lower wind speed and much stronger temperature gradients (up to 1 K m−1) but had smaller surface heat flux than did the thicker ones.

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Peters, G., and H. J. Kirtzel. "Complementary wind sensing techniques: sodar and RASS." Annales Geophysicae 12, no. 6 (May 31, 1994): 506–17. http://dx.doi.org/10.1007/s00585-994-0506-5.

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Abstract. Radioacoustic sounding (RASS), normally used for temperature profiling, can also be applied for wind measurements. The RASS detects echoes of radar waves, which have been scattered at acoustic waves, and derives the sound velocity from the frequency shift. From the difference of sound velocities measured under different beam directions windprofiles can be determined. Ground clutter does not principally interfere with RASS echoes due to their big frequency shift. Therefore, RASS can supplement radar wind profilers at lower levels where clear-air echoes may be not detectable due to ground clutter. The upper measuring altitude of RASS is limited to a few thousand radar wavelengths by the sound absorption and by the drift of the focal spot of the RASS echo. A further alternative for low-level wind measurements is the Doppler sodar. It is less sensitive to ground clutter than radar, but the measuring height is also limited by sound absorption. It requires no frequency allocation and may therefore be the only choice at some locations. In Germany, Doppler sodars have been operating successfully on a routine basis for more than 10 years at several sites for environmental monitoring purposes.

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Lyulyukin, Vasily, Rostislav Kouznetsov, and Margarita Kallistratova. "The Composite Shape and Structure of Braid Patterns in Kelvin–Helmholtz Billows Observed with a Sodar." Journal of Atmospheric and Oceanic Technology 30, no. 12 (December 1, 2013): 2704–11. http://dx.doi.org/10.1175/jtech-d-12-00255.1.

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Abstract The structure and dynamic characteristics of the Kelvin–Helmholtz billows (KHB), observed with a sodar in the stable atmospheric boundary layer, are studied by means of composite analysis, which consists in the averaging of samples selected according to certain criteria. Using a specific kind of this method allowed the authors to obtain the fine structure of the perturbation velocity fields from the sodar data. The events of most pronounced KHB were visually selected from echograms of continuous sodar measurements in the Moscow region over 2008–10. The composite patterns of KHB have been constructed for a few cases of clear inclined–stripes echogram patterns to derive a typical finescale structure of billows and a spatial distribution of wind speed and shear within them. The interconnection between echo intensity and wind shear variations within such patterns is shown. The typical distributions of velocity perturbation within various forms of billows are found.

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Buzdugan, Livius, Denisa Urlea, Paul Bugeac, and Sabina Stefan. "Remote sensing of low visibility over otopeni airport." EPJ Web of Conferences 176 (2018): 11001. http://dx.doi.org/10.1051/epjconf/201817611001.

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The paper is focused on the study of atmospheric conditions determining low vertical visibility over Henri Coanda airport. A network of ceilometers and a Sodar were used to detect fog and low level cloud layers. In our study, vertical visibility from ceilometers and acoustic reflectivity from Sodar for November 2016 were used to estimate fog depth and top of fog layers, respectively. The correlation between fog and low cloud occurrence and the wind direction and speed is also investigated.

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ITO, Yoshiki, Tsuyoshi NAGANUMA, Ryou KODAMA, Tatsuo HANAFUSA, Junji SATO, Takahisa KOBAYASHI, Kiyohide TAKEUCHI, and Tominori SUZUKI. "Wind measurements using a Doppler sodar." Wind Engineers, JAWE 1996, no. 67 (1996): 33–38. http://dx.doi.org/10.5359/jawe.1996.67_33.

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Deb, Narayan Chandra, Kumar S. Ray, and Hirday N. Dutta. "SODAR Pattern Classification by Graph Matching." IEEE Geoscience and Remote Sensing Letters 8, no. 3 (May 2011): 483–87. http://dx.doi.org/10.1109/lgrs.2010.2088105.

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GAYNOR, J. E. "Accuracy of sodar wind variance measurements." International Journal of Remote Sensing 15, no. 2 (January 1994): 313–24. http://dx.doi.org/10.1080/01431169408954075.

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Jordan, J. R., B. D. Templeman, S. W. Abbott, and R. J. Lataitis. "Wavelet Filtering of Sodar Reflectivity Signals." Meteorology and Atmospheric Physics 71, no. 1-2 (December 7, 1999): 25–34. http://dx.doi.org/10.1007/s007030050040.

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Kataoka, Tsuyoshi, Masato Takehisa, Yoshiki Ito, and Yasushi Mitsuta. "A low Level Jet Observed by a Doppler Sodar during the International Sodar Intercomparison Experiment (ISIE)." Journal of the Meteorological Society of Japan. Ser. II 69, no. 2 (1991): 171–77. http://dx.doi.org/10.2151/jmsj1965.69.2_171.

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Heinemann, Günther, Clemens Drüe, and Alexander Makshtas. "A Three-Year Climatology of the Wind Field Structure at Cape Baranova (Severnaya Zemlya, Siberia) from SODAR Observations and High-Resolution Regional Climate Model Simulations during YOPP." Atmosphere 13, no. 6 (June 12, 2022): 957. http://dx.doi.org/10.3390/atmos13060957.

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Measurements of the atmospheric boundary layer (ABL) structure were performed for three years (October 2017–August 2020) at the Russian observatory “Ice Base Cape Baranova” (79.280° N, 101.620° E) using SODAR (Sound Detection And Ranging). These measurements were part of the YOPP (Year of Polar Prediction) project “Boundary layer measurements in the high Arctic” (CATS_BL) within the scope of a joint German–Russian project. In addition to SODAR-derived vertical profiles of wind speed and direction, a suite of complementary measurements at the observatory was available. ABL measurements were used for verification of the regional climate model COSMO-CLM (CCLM) with a 5 km resolution for 2017–2020. The CCLM was run with nesting in ERA5 data in a forecast mode for the measurement period. SODAR measurements were mostly limited to wind speeds <12 m/s since the signal was often lost for higher winds. The SODAR data showed a topographical channeling effect for the wind field in the lowest 100 m and some low-level jets (LLJs). The verification of the CCLM with near-surface data of the observatory showed good agreement for the wind and a negative bias for the 2 m temperature. The comparison with SODAR data showed a positive bias for the wind speed of about 1 m/s below 100 m, which increased to 1.5 m/s for higher levels. In contrast to the SODAR data, the CCLM data showed the frequent presence of LLJs associated with the topographic channeling in Shokalsky Strait. Although SODAR wind profiles are limited in range and have a lot of gaps, they represent a valuable data set for model verification. However, a full picture of the ABL structure and the climatology of channeling events could be obtained only with the model data. The climatological evaluation showed that the wind field at Cape Baranova was not only influenced by direct topographic channeling under conditions of southerly winds through the Shokalsky Strait but also by channeling through a mountain gap for westerly winds. LLJs were detected in 37% of all profiles and most LLJs were associated with channeling, particularly LLJs with a jet speed ≥ 15 m/s (which were 29% of all LLJs). The analysis of the simulated 10 m wind field showed that the 99%-tile of the wind speed reached 18 m/s and clearly showed a dipole structure of channeled wind at both exits of Shokalsky Strait. The climatology of channeling events showed that this dipole structure was caused by the frequent occurrence of channeling at both exits. Channeling events lasting at least 12 h occurred on about 62 days per year at both exits of Shokalsky Strait.

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Bandyopadhyay, L. K., Prabhat Kumar, B. S. Gera, Neeraj Saxena, S. K. Sinha, and H. D. Pandey. "Sodar studies of some atmospheric boundary layer parameters during a solar eclipse." International Journal of Remote Sensing 22, no. 17 (January 2001): 3611–17. http://dx.doi.org/10.1080/01431160152609353.

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Bradley, Stuart, Janet Barlow, John Lally, and Christoforos Halois. "A sodar for profiling in a spatially inhomogeneous urban environment." Meteorologische Zeitschrift 24, no. 6 (November 5, 2015): 615–24. http://dx.doi.org/10.1127/metz/2015/0657.

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CARDOSO, L. F. N., W. F. MENEZES, and R. M. SILVA. "Insertion of SODAR Data into WRF Using Cressman Objective Analysis." Anuário do Instituto de Geociências - UFRJ 42, no. 2 (August 9, 2019): 274–81. http://dx.doi.org/10.11137/2019_2_274_281.

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48

Kramar, Valery F., Evgeniya Baykova, Margarita Kallistratova, Rostislav Kouznetsov, and Sergei Kulichkov. "Ground-Based Remote Sensing of the ABL Structure in Moscow and Its Use to Estimate Pollutant Surface Emission Rates." Journal of Applied Meteorology and Climatology 53, no. 5 (May 2014): 1272–81. http://dx.doi.org/10.1175/jamc-d-13-010.1.

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AbstractCurrently used methods to estimate surface pollutant emissions require a set of specific air-sampling surveys. Data from a network of ground-based sodars and a network of air-quality stations in Moscow, Russia, are used to estimate the emission rates of carbon monoxide (CO) and nitric oxide (NO). The sodar network, consisting of three “LATAN-3” Doppler sodars and three “MTP-5” microwave temperature profilers, is used to measure the vertical profiles of vertical and horizontal wind velocity, wind direction, and temperature, which are used to determine the average mixing-layer height. The network of ground-based air-quality stations, consisting of 17 automated stations distributed uniformly across Moscow, continuously measured the CO and NO concentrations. This study focuses on an anticyclonic episode of high surface pressure over Moscow during 30 July–1 August 2012. After sunrise, the solar-induced convection effectively moderated the pollutant levels in the lowest 100–200 m. After sunset, convective mixing stopped and the wind weakened, which allowed CO and NO to reach hazardous levels. With an assumption of an average mixing-layer height of 150 m, the resulting estimate of surface emission of CO is ~6 μg m−2 s−1, whereas that for NO is ~0.6 μg m−2 s−1.

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49

Santos, Luiz André R. dos, and Gilberto Fisch. "Intercomparação entre quatro métodos de estimativa da altura da camada limite convectiva durante o experimento RaCCI - LBA (2002) em Rondônia - Amazônia." Revista Brasileira de Meteorologia 22, no. 3 (December 2007): 322–28. http://dx.doi.org/10.1590/s0102-77862007000300005.

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Este trabalho tem como objetivo fazer uma comparação entre quatro diferentes métodos de estimativa da altura da Camada Limite Convectiva (CLC), utilizando dados obtidos pelo equipamento SODAR e por radiossondas, durante a campanha DRY - to - WET do experimento RaCCI - LBA (2002) em Rondônia. Os quatro métodos de estimativa utilizados foram os seguintes: o das Parcelas; do Número de Richardson; dos Perfis; e um método de medição direta através do SODAR. Os resultados mostraram que o Método das Parcelas superestimou as alturas da CLC (em 15% para às 08:00 HL e 14:00 HL e 30% nos demais horários), em quase todos os casos analisados, obtendo índices baixos do coeficiente de determinação (r²), quando comparado com os outros métodos. O Método do Número de Richardon e o Método dos Perfis apresentaram alturas muito semelhantes, com diferenças médias de menos de 50 m, alcançando um valor de r² igual a 0,97, durante o período de início da estação chuvosa. As medidas realizadas com o SODAR não se mostraram adequadas nas primeiras horas da manhã, indicando que o equipamento mediu a Camada Limite Residual (do dia anterior) e não a Camada Limite Convectiva rasa, em fase de desenvolvimento.

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Santos e Silva, Cláudio Moisés, and Roberto Fernando da Fonseca Lyra. "Comparação do perfil de vento medido por Radiossondas e por um SODAR durante o experimento DRYTOWET-AMC/LBA." Revista Brasileira de Meteorologia 24, no. 3 (September 2009): 356–63. http://dx.doi.org/10.1590/s0102-77862009000300009.

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Foram comparados perfis do vento horizontal medidos por radiossondagens e por um equipamento SODAR durante experimento DRYTOWET-AMC/LBA. em 2002, no Estado de Rondônia. As análises foram feitas para três camadas, a saber: da superfície até 500 m, de 500 m até 1000 m e de 1000 m até 1500 m. Na primeira camada os campos apresentaram boa concordância, porém, a correlação entre as medidas diminuiu de forma significativa nas outras duas camadas. Os resultados sugerem que os dados do SODAR poderiam ser mais bem aproveitados se na instalação do instrumento fosse dada prioridade a uma camada menos profunda (até 500 m) e com uma resolução vertical maior.

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