scholarly journals Vertical Characteristics of Winter Ozone Distribution within the Boundary Layer in Shanghai Based on Hexacopter Unmanned Aerial Vehicle Platform

2019 ◽  
Vol 11 (24) ◽  
pp. 7026 ◽  
Author(s):  
Qian Chen ◽  
Dongsheng Wang ◽  
Xiaobing Li ◽  
Bai Li ◽  
Ruifeng Song ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Unmanned Aerial Vehicle ◽  
Field Experiments ◽  
Surface Ozone ◽  
Air Pollutant ◽  
Ozone Level ◽  
Systematic Classification ◽  
Ozone Distribution ◽  
Aerial Vehicle ◽  
Vertical Ozone

Ozone is an important secondary air pollutant and plays different significant roles in regulating the formation of secondary organic aerosols. However, the characteristics of winter vertical ozone distributions have rarely been studied. In the winter of 2017, field experiments were performed in Shanghai, China using hexacopter unmanned aerial vehicle (UAV) platforms. The vertical profiles of ozone were obtained from 0–1200 m above the ground level. Results show that the UAV observations were reliable to capture the vertical variations of ozone. Vertical ozone profiles in the winter are classified into four categories: (1) well-mixed profile, (2) altitudinal increasing profile, (3) stratification profile, and (4) spike profile. Results show that although the average surface ozone level was relatively low, strong ozone variability and high ozone concentrations occurred at the upper air. The maximum observed ozone concentration was 220 ppb. In addition, using meteorological profiles and backward trajectories, we found that the ozone elevation aloft can be attributed to the downward transport of air flow from higher altitudes. Furthermore, ozone accumulation in the winter could be influenced by the horizontal transport of air masses for the northern part of China. This study successfully used hexacopter UAV platforms to perform vertical observations within the boundary layer. This provides systematic classification of winter ozone distribution within the boundary layer.

scholarly journals Using Improved Edge Detection Method to Detect Mining-Induced Ground Fissures Identified by Unmanned Aerial Vehicle Remote Sensing

2021 ◽  
Vol 13 (18) ◽  
pp. 3652
Author(s):  
Duo Xu ◽  
Yixin Zhao ◽  
Yaodong Jiang ◽  
Cun Zhang ◽  
Bo Sun ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Edge Detection ◽  
Unmanned Aerial Vehicle ◽  
Field Experiments ◽  
High Efficiency ◽  
Detection Method ◽  
Laplacian Operator ◽  
Ground Fissures ◽  
Aerial Vehicle ◽  
Edge Detection Method

Information on the ground fissures induced by coal mining is important to the safety of coal mine production and the management of environment in the mining area. In order to identify these fissures timely and accurately, a new method was proposed in the present paper, which is based on an unmanned aerial vehicle (UAV) equipped with a visible light camera and an infrared camera. According to such equipment, edge detection technology was used to detect mining-induced ground fissures. Field experiments show high efficiency of the UAV in monitoring the mining-induced ground fissures. Furthermore, a reasonable time period between 3:00 a.m. and 5:00 a.m. under the studied conditions helps UAV infrared remote sensing identify fissures preferably. The Roberts operator, Sobel operator, Prewitt operator, Canny operator and Laplacian operator were tested to detect the fissures in the visible image, infrared image and fused image. An improved edge detection method was proposed which based on the Laplacian of Gaussian, Canny and mathematical morphology operators. The peak signal-to-noise rate, effective edge rate, Pratt’s figure of merit and F-measure indicated that the proposed method was superior to the other methods. In addition, the fissures in infrared images at different times can be accurately detected by the proposed method except at 7:00 a.m., 1:00 p.m. and 3:00 p.m.

scholarly journals Development of an unmanned aerial vehicle to study atmospheric boundary-layer turbulent structure

2021 ◽  
Vol 1925 (1) ◽  
pp. 012068
Author(s):  
D G Chechin ◽  
A Yu Artamonov ◽  
N Ye Bodunkov ◽  
M Yu Kalyagin ◽  
A M Shevchenko ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Unmanned Aerial Vehicle ◽  
Turbulent Structure ◽  
Aerial Vehicle

scholarly journals A hierarchical vision-based localization of rotor unmanned aerial vehicles for autonomous landing

2018 ◽  
Vol 14 (9) ◽  
pp. 155014771880065 ◽  
Author(s):  
Haiwen Yuan ◽  
Changshi Xiao ◽  
Supu Xiu ◽  
Wenqiang Zhan ◽  
Zhenyi Ye ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Unmanned Aerial Vehicle ◽  
Feature Detection ◽  
Field Experiments ◽  
Measurement Range ◽  
Autonomous Landing ◽  
Detection Range ◽  
Aerial Vehicles ◽  
Aerial Vehicle ◽  
Vision Based Localization

The vision-based localization of rotor unmanned aerial vehicles for autonomous landing is challenging because of the limited detection range. In this article, to extend the vision detection and measurement range, a hierarchical vision-based localization method is proposed for unmanned aerial vehicle autonomous landing. In such a hierarchical framework, the landing is defined into three phases: “Approaching,”“Adjustment,” and “Touchdown,” in which visual artificial features at different scales can be detected from the designed object pattern for unmanned aerial vehicle pose recovery. The corresponding feature detection and pose estimation algorithms are also presented. In the end, typical simulation and field experiments have been carried out to illustrate the proposed method. The results show that our hierarchical vision-based localization has the ability to a consecutive unmanned aerial vehicle localization in a wider working range from far to near, which is significant for autonomous landing.

scholarly journals Development of an Unmanned Aerial Vehicle for the Measurement of Turbulence in the Atmospheric Boundary Layer

Atmosphere ◽  
2017 ◽  
Vol 8 (10) ◽  
pp. 195 ◽  
Author(s):  
Brandon Witte ◽  
Robert Singler ◽  
Sean Bailey
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Atmospheric Boundary Layer ◽  
Unmanned Aerial Vehicle ◽  
Sensor Data ◽  
Velocity Sensor ◽  
Aerial Vehicle ◽  
Probe Velocity ◽  
Convective State ◽  
Using Data

This paper describes the components and usage of an unmanned aerial vehicle developed for measuring turbulence in the atmospheric boundary layer. A method of computing the time-dependent wind speed from a moving velocity sensor data is provided. The physical system built to implement this method using a five-hole probe velocity sensor is described along with the approach used to combine data from the different on-board sensors to allow for extraction of the wind speed as a function of time and position. The approach is demonstrated using data from three flights of two unmanned aerial vehicles (UAVs) measuring the lower atmospheric boundary layer during transition from a stable to convective state. Several quantities are presented and show the potential for extracting a range of atmospheric boundary layer statistics.

scholarly journals A Lightweight Observation System for Atmospheric Carbon Dioxide Concentration Using a Small Unmanned Aerial Vehicle

2006 ◽  
Vol 23 (5) ◽  
pp. 700-710 ◽  
Author(s):  
T. Watai ◽  
T. Machida ◽  
N. Ishizaki ◽  
G. Inoue
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Unmanned Aerial Vehicle ◽  
Atmospheric Carbon Dioxide ◽  
Carbon Dioxide Concentration ◽  
Ground Surface ◽  
Atmospheric Co2 ◽  
Observation System ◽  
Aerial Vehicle ◽  
A Site

Abstract To make the investigation of the temporal and spatial variations of atmospheric CO2 in and above the planetary boundary layer more flexible and economical, a lightweight observation system using a small unmanned aerial vehicle has been developed whose flight path is preset using GPS. The total weight of the CO2 measurement device carried inside the vehicle is about 3.5 kg. The device is equipped with both flow and pressure controllers and can be used to measure atmospheric CO2 from the ground surface to a maximum altitude of about 3000 m. The response time of the instrument is about 20 s, with a precision of about ±0.26 ppm. The observation system is easy to handle and can be easily and quickly deployed at a site to make frequent measurements in and above the boundary layer. Compared to the deployment of a piloted aircraft the system shows distinctive advantages, in addition to being more affordable. To test the system, preliminary measurements over a boreal forest area in Japan in the summer of 2000 have been conducted. The results indicate that the unmanned aerial vehicle measurement system provides an affordable platform that can be used to obtain quantitative understanding of the temporal and vertical variations of atmospheric CO2 in and above the planetary boundary layer.

scholarly journals The running kinematics of free-roaming giraffes, measured using a low cost unmanned aerial vehicle (UAV)

2018 ◽  
Author(s):  
Christopher K Basu ◽  
Francois Deacon ◽  
John R Hutchinson ◽  
Alan M Wilson
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Field Experiments ◽  
Low Cost ◽  
The Body ◽  
Video Frame ◽  
Surface Model ◽  
Central Field ◽  
Gold Standard Method ◽  
Biomechanical Models ◽  
Aerial Vehicle

The study of animal locomotion can be logistically challenging, especially in the case of large or unhandleable animals in uncontrolled environments. Recent technological advances have permitted the use of Global Positioning System and inertial sensors in locomotion studies, but these methods require manual access to each study subject. Here we demonstrate the utility of a low cost unmanned aerial vehicle (UAV) in measuring two-dimensional running kinematics from free-roaming giraffes (Giraffa camelopardalis giraffa) in the Free State Province, South Africa. We collected 120 Hz video of running giraffes, and calibrated each video frame using metatarsal length as a constant object of scale. We tested a number of methods to measure metatarsal length. The method with the least variation used close range photography and a trigonometric equation to spatially calibrate the still image, and derive metatarsal length. In the absence of this option, a spatially calibrated surface model of the study terrain was used to estimate topographical dimensions in video footage of interest. Data for the terrain models were collected using the same equipment, during the same study period. We subsequently validated the accuracy of the UAV method by comparing similar speed measurements of a running human subject, with a gold standard method. We recommend that future users maximise the camera focal distance, and keep the subject in the central field of view. The studied giraffes used a grounded rotary gallop with a speed range of 3.4 to 6.9 ms-1 (never cantering, trotting or pacing), and lower duty factors when compared with other cursorial quadrupeds. As this pattern might result in adverse increases in peak vertical limb forces with speed, it was notable to find that contralateral limbs became more in-phase with speed. Considering the latter pattern and the modest maximal speed of giraffes, we speculate that tissue safety factors are maintained within tolerable bounds this way. Furthermore, the angular kinematics of the neck were frequently isolated from the pitching of the body during running; this may be a result of the large mass of the head and neck. Further field experiments and biomechanical models are needed to robustly test these speculations.

scholarly journals Measurement of turbulent water vapor fluxes using a lightweight unmanned aerial vehicle system

2011 ◽  
Vol 4 (4) ◽  
pp. 5529-5568 ◽  
Author(s):  
R. M. Thomas ◽  
K. Lehmann ◽  
H. Nguyen ◽  
D. L. Jackson ◽  
D. Wolfe ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Unmanned Aerial Vehicle ◽  
System Development ◽  
Spatial Scales ◽  
Ground Level ◽  
Heat Fluxes ◽  
Data Logging ◽  
Pass Filter ◽  
Aerial Vehicle

Abstract. We present here the first application of a lightweight unmanned aerial vehicle (UAV) system designed to measure turbulent properties and vertical latent heat fluxes (λE). Such measurements are crucial to improve our understanding of linkages between surface moisture supply and boundary layer clouds and phenomena such as atmospheric rivers. The application of UAVs allows for measurements on spatial scales complimentary to satellite, aircraft, and tower derived fluxes. Key system components are: a turbulent gust probe; a fast response water vapor sensor; an inertial navigation system (INS) coupled to global positioning system (GPS); and a 100 Hz data logging system. We present measurements made in the continental boundary layer at the National Aeronautics and Space Administration (NASA) Dryden Research Flight Facility located in the Mojave Desert. Two flights consisting of several horizontal straight flux run legs up to ten kilometers in length and between 330 and 930 m above ground level (m a.g.l.) are compared to measurement from a surface tower. Surface measured λE ranged from −53 W m−2 to 41 W m−2, and the application of a Butterworth High Pass Filter (HPF) to the datasets improved agreement to within ± 12 W m−2 for 86 % of flux runs, by removing improperly sampled low frequency flux contributions. This result, along with power and co-spectral comparisons and consideration of the differing spatial scales indicates the system is able to resolve vertical fluxes for the measurement conditions encountered. Challenges remain, and the outcome of these measurements will be used to inform future sampling strategies and further system development.

The Complex Terrain Measurement and Modeling Project of Land–Atmosphere Energy Exchanges (COMPLEX) Experiment

2020 ◽  
Author(s):  
Laura Herrera ◽  
Carlos Hoyos ◽  
Julián Urán
Keyword(s):  
Boundary Layer ◽  
Air Quality ◽  
Complex Terrain ◽  
Field Experiments ◽  
Air Pollutant ◽  
Turbulent Heat ◽  
Modeling Framework ◽  
Orographic Rainfall ◽  
Energy Exchanges

<p>The heterogeneity of the urban features, in addition to the inherent challenges added by highly complex terrain, has not allowed the scientific community to reach a complete understanding of the Atmospheric Boundary Layer (ABL) dynamics regarding the land-atmosphere interactions. The intricacies are higher when trying to simulate the observed interactions and their implications for air quality in a numerical modeling framework.</p><p> </p><p>Over the last two decades, the ABL research community has dedicated several research efforts to study turbulent exchanges and ABL processes over complex terrain, and the implications of the particular features of these sites have on turbulence characteristics. A better knowledge of the ABL structure and dynamics is fundamental to understand processes such as air pollutant dispersion and disposal in the atmosphere, development and evolution of deep convection, and urban effects on meteorology. One of the aspects hindering our understanding is the lack of pertinent information from urbanized mountainous regions representative of the entire globe, useful to assess the different hypotheses and conceptual models of the Mountain Boundary Layer (MBL) dynamics. Most of the short- and long-term ABL field experiments in mountainous terrains have taken place over the high-latitude regions such as the Alps and the Rockies, and few over in the tropical Andes, where the Cordillera plays an essential role in controlling orographic rainfall intensification and the ventilation in inter-Andean valleys, resulting in knowledge gap regarding momentum, and latent and sensible heat flux exchanges over low-latitude, urban, complex terrain regions. In addition to a top-down approach, it is essential to follow a bottom-up strategy to study in detail the turbulent heat, mass, and momentum transfer in the Andean region.</p><p>The COMPLEX Experiment (COmplex terrain Measurement and modeling Project of Land-atmosphere Energy eXchanges) is a new effort focused on the long-term energy balance measurement campaign settled in the Aburrá Valley, a narrow highly complex mountainous-urban terrain located in the Colombian Andes. The primary purpose of this campaign is to identify the more relevant phenomenological features and processes responsible for ABL spatio-temporal variability, and land-atmosphere interactions in inter-Andean valleys. The long-term observational set-up includes eight sites equipped with turbulent flux sensors and net radiometers, in a cross-section of the valley, a microwave radiometer, a boundary layer radar, a scintillometer, and radiosonde intense observation periods (IOPs). We present the status of the COMPLEX experiment equipment deployment and preliminary results on the relationship of the transition between the stable boundary layer and the convective boundary layer and air quality in the region, and an exploration of the diurnal cycle of the different turbulent terms of the energy budget as a function of time and hill location.</p>

scholarly journals Estimation of Sensible Heat Flux and Atmospheric Boundary Layer Height Using an Unmanned Aerial Vehicle

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 363 ◽  
Author(s):  
Min-Seong Kim ◽  
Byung Hyuk Kwon
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Wind Speed ◽  
Atmospheric Boundary Layer ◽  
Unmanned Aerial Vehicle ◽  
Sensible Heat Flux ◽  
Eddy Correlation ◽  
Sensible Heat ◽  
Aerial Vehicle ◽  
Transfer Method

In this work, sensible heat flux estimated using a bulk transfer method was validated with a three-dimensional ultrasonic anemometer or surface layer scintillometer at various sites. Results indicate that it remains challenging to obtain temperature and wind speed at an appropriate reference height. To overcome this, alternative observations using an unmanned aerial vehicle (UAV) were considered. UAV-based wind speed and sensible heat flux were indirectly estimated and atmospheric boundary layer (ABL) height was then derived using the sensible heat flux data. UAV-observed air temperature was measured by attaching a temperature sensor 40 cm above the rotary-wing of the UAV, and UAV-based wind speed was estimated using attitude data (pitch, roll, and yaw angles) recorded using the UAV’s inertial measurement unit. UAV-based wind speed was close to the automatic weather system-observed wind speed, within an error range of approximately 10%. UAV-based sensible heat flux estimated from the bulk transfer method corresponded with sensible heat flux determined using the eddy correlation method, within an error of approximately 20%. A linear relationship was observed between the normalized UAV-based sensible heat flux and radiosonde-based normalized ABL height.

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