Article
Environmental Sciences
Alfredo Pena, Jakob Mann, Nikolas Angelou, Arnhild Jacobsen
Summary: Estimates of atmospheric turbulence by floating lidars are affected by the buoy motions, which impact the standard deviation of horizontal velocity. Correcting the measurements based on simulations helps reduce the bias in turbulence estimation.
Article
Environmental Sciences
Patrick Vrancken, Jonas Herbst
Summary: We report the development of a novel direct-detection Doppler wind lidar based on fringe imaging technology, which meets the strong requirements of an aeronautic feed-forward control application. The effectiveness of detailed simulation and demonstrator development is validated by field measurements, and the lidar also satisfies the requirements of wind speed measurement, making it suitable for the analysis and optimization of the GLA control scheme.
Article
Oceanography
Laur Ferris, Donglai Gong, Carol Anne Clayson, Sophia Merrifield, Emily L. Shroyer, Madison Smith, Louis St Laurent
Summary: The ocean surface boundary layer plays a crucial role in energy transfer, and the estimation of turbulence using boundary layer scalings (BLS) has limitations. By utilizing data from autonomous sampling platforms, this study reveals significant discrepancies between measured turbulence and standard shear-convective BLS in different depths and conditions.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Article
Environmental Sciences
Hengheng Zhang, Frank Wagner, Harald Saathoff, Heike Vogel, Gholamali Hoshyaripour, Vanessa Bachmann, Jochen Foerstner, Thomas Leisner
Summary: The evolution and properties of a Saharan dust plume near Karlsruhe, Germany were studied using scanning LiDAR, a vertically pointing LiDAR, a sun photometer, and the transport model ICON-ART. The study discussed the advantages of scanning aerosol LiDAR and validated a method to determine LiDAR ratios independently. The measurements showed good agreement with previous studies and the transport model accurately predicted the plume's arrival time and structure. The work will be useful for future studies characterizing aerosol particles with scanning LiDARs.
Article
Environmental Sciences
Lu Jie, Zhi Jin, Jinping Wang, Letian Zhang, Xiaojun Tan
Summary: This paper presents a versatile and velocity-aware LiDAR-based odometry and mapping (VLOM) system, which uses a spherical projection-based feature extraction method to process raw point clouds from various LiDARs and improve feature representation. Bundle adjustment is adopted to jointly estimate poses and velocities, improving velocity estimation accuracy and compensating for point cloud distortions. Experimental results demonstrate the superiority of VLOM in terms of accuracy and robustness.
Article
Remote Sensing
Alexander Shelekhov, Alexey Afanasiev, Evgeniya Shelekhova, Alexey Kobzev, Alexey Tel'minov, Alexander Molchunov, Olga Poplevina
Summary: This study experimentally investigates the capabilities of hovering UAVs to sense atmospheric turbulence with high spatial resolution at low altitudes. Vertical profiles of turbulence were measured at the Basic Experimental Observatory in Tomsk, Russia, using three quadcopters hovering at different altitudes. The analysis includes the behavior of wind velocity components and the discrepancy between UAV and anemometer data. Spectral and correlation analysis of the measurements were carried out to determine the longitudinal and lateral scales of turbulence.
Article
Environmental Sciences
Razvan Pirloaga, Mariana Adam, Bogdan Antonescu, Simona Andrei, Sabina Stefan
Summary: For the first time in Romania, Doppler wind lidar measurements were used to analyze wind and turbulence statistics at a peri-urban site in Magurele, southwest of Bucharest. Vertical and scanning measurements from December 2019 to November 2021 were processed, and statistics were performed based on seasonal and diurnal cycles. The results showed variations in diurnal wind speed and direction, with lower speed during the day and higher at night. The ERA5 reanalysis exhibited similar patterns to the Doppler wind lidar measurements, albeit slightly underestimated in terms of wind speed.
Article
Meteorology & Atmospheric Sciences
Ian N. N. Williams, Shaoyue Qiu
Summary: Doppler lidar vertical velocity retrievals were analyzed to study the scale and structure of mixed-layer turbulence over a 7-year period in the US Southern Great Plains. The study found significant variations in spectral density in the energy-production subrange and mesoscale regimes. The results showed that surface forcing and updraft size had significant effects on turbulence scale, with increasing buoyancy flux leading to narrower updrafts and cellular structures.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Environmental Sciences
Marcos Paulo Araujo da Silva, Andreu Salcedo-Bosch, Francesc Rocadenbosch, Alfredo Pena
Summary: We reexamine two recent methodologies, the 2D method and Hybrid-Wind (HW), based on Monin-Obukhov Similarity Theory (MOST), which aim to estimate Obukhov length, friction velocity, and kinematic heat flux within the surface layer using wind-speed profile measurements. Both methods are compared using synthetic and observational data. A procedure to generate synthetic noise-corrupted wind profiles is also presented. The 2D algorithm outperforms the HW method in estimating the three parameters, making it a prominent method for surface-layer parameter estimation.
Article
Mechanics
Lingxin Zhang, Kai Peng, Xueming Shao, Jian Deng
Summary: This study numerically investigates the dynamics of gas bubbles rising freely under buoyancy at low Reynolds numbers, focusing on clustering morphology and velocity fluctuations' probability density functions. The research reveals that the probability density functions for bubble velocity fluctuations exhibit distinct behavior at high gas fractions compared to high Reynolds number experiments, indicating that strong bubble-bubble interactions trigger turbulent flow efficiently.
Article
Meteorology & Atmospheric Sciences
Richard Wilson, Clara Pitois, Aurelien Podglajen, Albert Hertzog, Milena Corcos, Riwal Plougonven
Summary: This article discusses the detection of small-scale turbulence using meteorological measurements from superpressure balloons. Information about turbulence occurrence can be derived from well-resolved measurements of pressure, temperature, and position. The study overcomes the challenge of quantifying turbulence from a measurement set not designed for it. Results show that turbulence occurs for about 5% of the observation time, with significant longitudinal inhomogeneities.
ATMOSPHERIC MEASUREMENT TECHNIQUES
(2023)
Article
Environmental Sciences
Xingxu Zhou, Chao Zhang, Yunying Li, Zhiwei Zhang
Summary: This paper explores and compares the gust characteristics at two sites, Xining in the eastern Tibetan Plateau and Qingdao on the coast in China, using Doppler lidar data. The results show that the gusts in Xining are more intense and occur at a higher height compared to Qingdao. Turbulence intensity is responsible for the differences in gust, suggesting high turbulence in the eastern part of the Tibetan Plateau. These findings provide observational evidence for studying the impact of wind gusts on complex terrains such as the Tibetan Plateau.
Article
Chemistry, Analytical
Marius Dulau, Florin Oniga
Summary: This paper presents an obstacle detection approach using facet-based representation, with three main steps for obstacle recognition. The proposed method shows similar or better results for some obstacle categories with lower computational complexity in evaluation.
Article
Multidisciplinary Sciences
Fanglin Bao, Xueji Wang, Shree Hari Sureshbabu, Gautam Sreekumar, Liping Yang, Vaneet Aggarwal, Vishnu N. N. Boddeti, Zubin Jacob
Summary: Machine perception uses advanced sensors to collect information for situational awareness. State-of-the-art machine perception faces difficulties with increasing number of intelligent agents. Exploiting omnipresent heat signal could be a new frontier for scalable perception. The proposed heat-assisted detection and ranging (HADAR) overcomes the challenge of ghosting and shows promising results compared to AI-enhanced thermal sensing.
Article
Engineering, Civil
Mohammad Nafisifard, Jasna B. Jakobsen, Jonas T. Snaebjornsson, Mikael Sjoholm, Jakob Mann
Summary: Remote wind sensing technologies using Doppler lidars have been used to measure the wind flow upstream and the disturbed flow around a bridge. A measurement campaign was conducted using three synchronized lidars at the Lysefjord bridge in Norway. The lidar measurements were validated by comparing them with sonic anemometer data recorded at different locations near the bridge deck. The results show that the lidars successfully captured 3D turbulence characteristics around the bridge and provided valuable information on the bridge aerodynamics.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2023)
