scholarly journals On the Use of Rotary-Wing Aircraft to Sample Near-Surface Thermodynamic Fields: Results from Recent Field Campaigns

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 10 ◽  
Author(s):  
Temple Lee ◽  
Michael Buban ◽  
Edward Dumas ◽  
C. Baker
Keyword(s):  
Weather Prediction ◽  
Chemical Properties ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Spatiotemporal Variability ◽  
Near Surface ◽  
Field Campaigns ◽  
High Level ◽  
Rotary Wing

Rotary-wing small unmanned aircraft systems (sUAS) are increasingly being used for sampling thermodynamic and chemical properties of the Earth’s atmospheric boundary layer (ABL) because of their ability to measure at high spatial and temporal resolutions. Therefore, they have the potential to be used for long-term quasi-continuous monitoring of the ABL, which is critical for improving ABL parameterizations and improving numerical weather prediction (NWP) models through data assimilation. Before rotary-wing aircraft can be used for these purposes, however, their performance and the sensors used therein must be adequately characterized. In the present study, we describe recent calibration and validation procedures for thermodynamic sensors used on two rotary-wing aircraft: A DJI S-1000 and MD4-1000. These evaluations indicated a high level of confidence in the on-board measurements. We then used these measurements to characterize the spatiotemporal variability of near-surface (up to 300-m AGL) temperature and moisture fields as a component of two recent field campaigns: The Verification of the Origins of Rotation in Tornadoes Experiment in the Southeast U.S. (VORTEX-SE) in Alabama, and the Land Atmosphere Feedback Experiment (LAFE) in northern Oklahoma.

scholarly journals Wind plants can impact long-term local atmospheric conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicola Bodini ◽  
Julie K. Lundquist ◽  
Patrick Moriarty
Keyword(s):  
Wind Speed ◽  
Urban Areas ◽  
Weather Prediction ◽  
Atmospheric Conditions ◽  
Near Surface ◽  
Direct Observations ◽  
Stable Conditions ◽  
Weather And Climate ◽  
Central United States

AbstractLong-term weather and climate observatories can be affected by the changing environments in their vicinity, such as the growth of urban areas or changing vegetation. Wind plants can also impact local atmospheric conditions through their wakes, characterized by reduced wind speed and increased turbulence. We explore the extent to which the wind plants near an atmospheric measurement site in the central United States have affected their long-term measurements. Both direct observations and mesoscale numerical weather prediction simulations demonstrate how the wind plants induce a wind deficit aloft, especially in stable conditions, and a wind speed acceleration near the surface, which extend $$\sim 30$$ ∼ 30  km downwind of the wind plant. Turbulence kinetic energy is significantly enhanced within the wind plant wake in stable conditions, with near-surface observations seeing an increase of more than 30% a few kilometers downwind of the plants.

scholarly journals Human Factors Contributions to the Development of Standards for Displays of Unmanned Aircraft Systems in Support of Detect-and-Avoid

2020 ◽  
Vol 62 (4) ◽  
pp. 505-515 ◽  
Author(s):  
Kim-Phuong L. Vu ◽  
Robert Conrad Rorie ◽  
Lisa Fern ◽  
Robert Jay Shively
Keyword(s):  
Human Factors ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Evidence Based ◽  
National Airspace System ◽  
Human In The Loop ◽  
Aircraft Systems ◽  
Human Systems Integration ◽  
High Level ◽  
Evidence Based Guidelines

Objective The aim is to provide a high-level synthesis of human factors research that contributed to the development of detect-and-avoid display requirements for unmanned aircraft systems (UAS). Background The integration of UAS into the U.S. National Airspace System is a priority under the Federal Aviation Administration’s Modernization and Reform Act. For UAS to have routine access to the National Airspace System, UAS must have detect-and-avoid capabilities. One human factors challenge is to determine how to display information effectively to remote pilots for performing detect-and-avoid tasks. Method A high-level review of research informing the display requirements for UAS detect-and-avoid is provided. In addition, description of the contributions of human factors researchers in the writing of the requirements is highlighted. Results Findings from human-in-the-loop simulations are used to illustrate how evidence-based guidelines and requirements were established for the display of information to assist pilots in performing detect-and-avoid. Implications for human factors are discussed. Conclusion Human factors researchers and engineers made many contributions to generate the data used to justify the detect-and-avoid display requirements. Human factors researchers must continue to be involved in the development of standards to ensure that requirements are evidence-based and take into account human operator performance and human factors principles and guidelines. Application The research presented in this paper is relevant to the design of UAS, the writing of standards and requirements, and the work in human–systems integration.

Long-term rice rotation, tillage, and fertility effects on near-surface chemical properties in a silt-loam soil

2014 ◽  
Vol 100 (1) ◽  
pp. 77-94 ◽  
Author(s):  
Jill M. Motschenbacher ◽  
Kristofor R. Brye ◽  
Merle M. Anders ◽  
Edward E. Gbur
Keyword(s):  
Chemical Properties ◽  
Silt Loam ◽  
Surface Chemical ◽  
Near Surface ◽  
Silt Loam Soil ◽  
Loam Soil

Spatiotemporal Variability of Snow Depth in Subarctic Environment Using Unmanned Aircraft Systems (UAS)

2020 ◽  
Author(s):  
Anssi Rauhala ◽  
Leo-Juhani Meriö ◽  
Pertti Ala-aho ◽  
Pasi Korpelainen ◽  
Anton Kuzmin ◽  
...  
Keyword(s):  
Land Cover ◽  
Snow Depth ◽  
Snow Accumulation ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Spatiotemporal Variability ◽  
Light Conditions ◽  
Land Cover Types ◽  
Depth Maps ◽  
Aircraft Systems

<p>Seasonal snow accumulation and melt dominates the hydrology in high latitude areas, providing water storages for both ecological and human needs. However, until recent years there has been a lack of cost-efficient way to measure the spatiotemporal variability of the snow depth and cover in high resolution. Unmanned aircraft systems (UAS) can offer spatial resolutions up to few centimeters, depending on the weather and light conditions, camera quality and drone specification. We used multiple different quadcopters and a fixed wing UAS to determine and analyze the spatiotemporal variability of snow depth and cover in three test plots with different land-cover types (forested slope, open peatland, and peatland-forest) in subarctic northern Finland, where weather and light conditions are challenging. Five measurement campaigns were conducted during winter 2018/2019 and a snow-free bare ground survey after snowmelt. Snow depth maps were constructed using Structure from Motion (SfM) photogrammetry technique and by differentiating the acquired models from snow-covered and snow-free surveys. Due to poor sub-canopy penetration with UAS-SfM method, tree masks were utilized to remove canopy effects prior to analysis. The snow depth maps produced with different UAS were compared to in situ snow course and an automatic ultrasonic measurement data. We highlight the difficulties of working in subarctic winter conditions and discuss the accuracy of UAS-derived snow depth maps. We show that the UAS-derived snow depth measurements agree well with manual snow survey measurements and UAS are suitable method for extending the spatial snow data coverage, whereas a continuous point snow depth measurement is unable to accurately present sub-catchment scale snow depth variability. Furthermore, the spatiotemporal variability of snow accumulation and melt between and within different land cover types is presented.</p>

scholarly journals The Impact of Sensor Response and Airspeed on the Representation of the Convective Boundary Layer and Airmass Boundaries by Small Unmanned Aircraft Systems

2018 ◽  
Vol 35 (8) ◽  
pp. 1687-1699 ◽  
Author(s):  
Adam L. Houston ◽  
Jason M. Keeler
Keyword(s):  
Boundary Layer ◽  
Convective Boundary Layer ◽  
Sensor Response ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Lapse Rate ◽  
Convective Boundary ◽  
Aircraft Systems ◽  
The Impact ◽  
Rotary Wing

AbstractThe objective of the research presented is to assess the impact of sensor response and aircraft airspeed on the accuracy of in situ observations collected by small unmanned aircraft systems profiling the convective boundary layer or transecting airmass boundaries. Estimates are made using simulated aircraft flown within large-eddy simulations. Both instantaneous errors (differences between observed temperature, which include the effects of sensor response and airspeed, and actual temperature) and errors in representation (differences between serial observations and representative snapshots of the atmospheric state) are considered. Synthetic data are retrieved assuming a well-aspirated first-order sensor mounted on rotary-wing aircraft operated as profilers in a simulated CBL and fixed-wing aircraft operated through transects across a simulated airmass boundary. Instantaneous errors are found to scale directly with sensor response time and airspeed for both CBL and airmass boundary experiments. Maximum errors tend to be larger for airmass boundary transects compared to the CBL profiles. Instantaneous errors for rotary-wing aircraft profiles in the CBL simulated for this work are attributable to the background lapse rate and not to turbulent temperature perturbations. For airmass boundary flights, representation accuracy is found to degrade with decreasing airspeed. This signal is most pronounced for flights that encounter the density current wake. When representation errors also include instantaneous errors resulting from sensor response, instantaneous errors are found to be dominant for flights that remain below the turbulent wake. However, for flights that encounter the wake, sensor response times generally need to exceed ~5 s before instantaneous errors become larger than errors in representation.

scholarly journals Environmental and Sensor Integration Influences on Temperature Measurements by Rotary-Wing Unmanned Aircraft Systems

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1470 ◽  
Author(s):  
Brian Greene ◽  
Antonio Segales ◽  
Tyler Bell ◽  
Elizabeth Pillar-Little ◽  
Phillip Chilson
Keyword(s):  
Unmanned Aircraft ◽  
The Body ◽  
Unmanned Aircraft Systems ◽  
Sensor Integration ◽  
Heat Sources ◽  
Aircraft Systems ◽  
Ducted Fan ◽  
Rotary Wing

Obtaining thermodynamic measurements using rotary-wing unmanned aircraft systems (rwUAS) requires several considerations for mitigating biases from the aircraft and its environment. In this study, we focus on how the method of temperature sensor integration can impact the quality of its measurements. To minimize non-environmental heat sources and prevent any contamination coming from the rwUAS body, two configurations with different sensor placements are proposed for comparison. The first configuration consists of a custom quadcopter with temperature and humidity sensors placed below the propellers for aspiration. The second configuration incorporates the same quadcopter design with sensors instead shielded inside of an L-duct and aspirated by a ducted fan. Additionally, an autopilot algorithm was developed for these platforms to face them into the wind during flight for kinematic wind estimations. This study will utilize in situ rwUAS observations validated against tower-mounted reference instruments to examine how measurements are influenced both by the different configurations as well as the ambient environment. Results indicate that both methods of integration are valid but the below-propeller configuration is more susceptible to errors from solar radiation and heat from the body of the rwUAS.

scholarly journals MODELLING STEEP SURFACES BY VARIOUS CONFIGURATIONS OF NADIR AND OBLIQUE PHOTOGRAMMETRY

2016 ◽  
Vol III-1 ◽  
pp. 175-182 ◽  
Author(s):  
V. Casella ◽  
M. Franzini
Keyword(s):  
Point Cloud ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Control Points ◽  
Careful Monitoring ◽  
Aircraft Systems ◽  
Aerial Photogrammetry ◽  
Check Points ◽  
Reconstructed Surface ◽  
High Level

Among the parts of the territory requiring periodical and careful monitoring, many have steep surfaces: quarries, river basins, land-slides, dangerous mountainsides. Aerial photogrammetry based on lightweight unmanned aircraft systems (UAS) is rapidly becoming the tool of election to survey limited areas of land with a high level of detail. Aerial photogrammetry is traditionally based on vertical images and only recently the use of significantly inclined imagery has been considered. Oblique photogrammetry presents peculiar aspects and offers improved capabilities for steep surface reconstruction. Full comprehension of oblique photogrammetry still requires research efforts and the evaluation of diverse case studies. In the present paper, the focus is on the photogrammetric UAS-based survey of a part of a large sandpit. Various flight configurations are considered: ordinary linear strips, radial strips (as the scarp considered has a semi-circular shape) and curved ones; moreover, nadir looking and oblique image blocks were acquired. Around 300 control points were measured with a topographic total station. The various datasets considered are evaluated in terms of density of the extracted point cloud and in terms of the distance between the reconstructed surface and a number of check points.

Nd-Sr Isotope and REE Evidence for the Long-Term Stability of HLW Glass Products and Trace Metal Migration in a Salt Repository: Corroding Basaltic Dykes in Evaporites as Natural Analogues

1997 ◽  
Vol 506 ◽  
Author(s):  
M. Steinmann ◽  
P. Stille ◽  
K. Mengel ◽  
M. Siemann ◽  
W. Bernotat
Keyword(s):  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Sr Isotope ◽  
Long Term Stability ◽  
Natural Analogues ◽  
Metal Migration ◽  
High Level ◽  
Physical And Chemical ◽  
And Chemical Properties

Basaltic dykes in salt rocks can be used in two different ways as natural analogues for high level radioactive waste (HLW) in a salt repository: In the first approach the basalts serve as analogues for the corrosion behavior of HiLW glass products during millions of years because of many similarities in their physical and chemical properties.

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