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The present study shows the development of computational algorithms to represent aircraft instruments such as the attitude indicator or the turn-and-slip indicator; moreover, the algorithms represent a magnetic compass and other instruments that function according to other physical theories. These instruments work by using the gyroscope and magnetic principles and help the pilot in navigation. These are considered to be the basic instruments required to provide location-related and positional information about the actual aircraft attitude. The algorithms developed in this study are capable of working in concordance with other instruments and the physical conditions established. The programming language used was C++ and the algorithms were compiled in independent files and subroutines for computational efficiency, eliminating unnecessary code. The display options were successfully tested. Additionally, an analysis that evaluated the error and approached flight simulation as a function of step time (Δt) is also described. [ABSTRACT FROM AUTHOR]

This paper studies how firms adapt to demand shocks when facing capacity constraints. I show that increases in government purchases raise total factor productivity in quantity units at the production line level. Productivity gains are concentrated in plants facing tighter capacity constraints, a phenomenon I call "learning by necessity." Evidence is based on newly digitized archival data on US World War II aircraft production. Shifts in demand across aircraft with different strategic roles provide an instrument for aircraft demand. I show that plants adapted to surging demand by improving production methods, outsourcing, and combating absenteeism, primarily when facing tighter capacity constraints. (JEL D22, D24, E62, L93, N12, N42, N62) [ABSTRACT FROM AUTHOR]

Using smartphones, we aimed to clarify the characteristics of anticipatory postural adjustments (APA) in older adults and examine the relationship between cognitive and balance functions. The study participants were 10 young and 13 older adults. An accelerometer built into a smartphone was attached to the lower back (L5) of the participant, and acceleration in the mediolateral direction was measured using a one-leg stance (OLS). As APA features, we analyzed the time to the peak value in the stance direction (peak latency [PL]) and the amount of displacement to the peak value in the stance direction (peak magnitude [PM]). Additionally, the measured PL was divided by PM for each group to obtain the APA ratio (APAr). We investigated the relationship between the APAr and Mini-BESTest subitems. Older adults showed delayed PL and decreased PM levels (p < 0.01). While in the Mini-BESTest sub-items, deductions were most common in the order of dual-task and single-leg standing, and most participants with low APAr scores were degraded in APA of sub-items. The correlation was observed between APAr and both TUG and dual-task cost (DTC) (r= −0.56, r= −0.67). According to the receiver operating characteristic curve, the APAr value was 1.71 in the older age group. Older adults showed delayed PL and decreased PM, and APAr was associated with cognitive and locomotor functions. By evaluating the APAr at the initiation of movement, it may be possible to distinguish the APA of the older adluts from the possible to the impossible of OLS movement. • Anticipatory postural adjustments (APA) were compared in older and young adults. • PL and PM of lumbar acceleration in one-leg stance were used for evaluation of APA. • Older adults show delayed peak latency(PL) and decreased peak magnitude(PM). • The characteristic values of APA is associated with cognitive and balance functions. • APA evaluation is useful as an index reflecting cognitive motor-processing function. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Modular organization in brain regions often performs specific biological functions and is largely based on anatomically and/or functionally related brain areas. The current study aimed to explore changes in whole-brain modular organization affected by flight training. METHODS: The study included 25 male flight cadets and 24 male controls. The first assessment was performed in 2019, when the subjects were university freshmen. The second assessment was completed in 2022. High spatial resolution structural imaging (T1) and resting-state functional MRI data were collected. Then, 90 cerebral regions were organized into 6 brain modules. The intensity of intra- and intermodular communication was calculated. RESULTS: Mixed-effect regression model analysis identified significantly increased interconnections between the parietal and occipital modules in the cadet group, but significantly decreased interconnections in the control group. This change was largely attributed to flight training. DISCUSSION: Pilots need to control the aircraft (e.g., attitude, heading, etc.) using the stick and pedal in response to the current state of the aircraft displayed by the instrument panel; as such, flying requires a large amount of hand-eye coordination. Day-to-day flight training appeared to intensify the connection between the parietal and occipital modules among cadets. [ABSTRACT FROM AUTHOR]

Evaluating integrated flight monitoring devices in general aviation plays a crucial role in overseeing aircraft operation. This article analyses the effectiveness of the MVP 50 engine monitoring system based on data from Aero AT 3 aircraft. The study focuses on assessing the utility of these devices in ensuring flight safety and maintaining aircraft efficiency within aviation organizations. The results confirm that integrated flight monitoring devices play a significant role in overseeing aircraft operation, detecting potential issues and facilitating appropriate corrective actions. [ABSTRACT FROM AUTHOR]

The BiLateral Operational Storm‐Scale Observation and Modeling (BLOSSOM) project was initiated to establish a long‐term supersite to improve understanding of cloud physical states and processes as well as to support satellite and climate model programs over the Wallops Flight Facility site via a bilateral approach of storm‐scale observations and process modeling. This study highlights a noble systematic validation framework of the BLOSSOM ensemble cloud‐process simulations through mixed‐phase, light‐rain, and deep‐convective precipitation cases. The framework consists of creating a domain‐shifted ensemble of large‐scale forcing data sets, and configuring and performing cloud‐process simulations with three different bulk microphysics schemes. Validation uses NASA S‐band dual‐POLarimetric radar observations in the form of statistical composites and skill scores via a polarimetric radar simulator and newly developed CfRad Data tool (CfRAD). While the simulations capture the overall structures of the reflectivity composites, polarimetric signals are still poorly simulated, mainly due to a lack of representation of ice microphysics diversity in shapes, orientation distributions, and their complex mixtures. Despite the limitation, this new ensemble‐based validation framework demonstrates that (a) no particular forcing or microphysics scheme outperforms the rest and (b) the skill scores of coarse‐ and fine‐resolution ensemble simulations with different domain‐shifted forcing and microphysics schemes are highly correlated with each other with no clear improvement. On the other hand, this suggests that coarse‐resolution ensemble simulations are relevant for selecting the best meteorological forcing and microphysics scheme before conducting computationally demanding large eddy simulations in support of aircraft and satellite instrument development as well as cloud‐precipitation‐convection parameterizations. Plain Language Summary: Cloud‐process simulations are state‐of‐art numerical simulations to represent realistic cloud and convection development through numerous microphysical processes. These simulations are largely affected by thermodynamic fields. This work generates slightly modified thermodynamic fields to create many different states of cloud process simulations, which are systematically validated by the weather radar available in NASA Wallops Flight Facility. Key Points: Systematic validation of ensemble cloud‐process simulations is established over the NASA Wallops Flight FacilitiesNASA polarimetric radar and simulators reveal strength and weakness of cloud‐process simulationsCoarse‐resolution cloud‐process simulations are sufficient to select best forcing and microphysics options [ABSTRACT FROM AUTHOR]

Forecasting volcanic ash atmospheric pathways is of utmost importance for aviation. Volcanic ash can interfere with aircraft navigational instruments and can damage engine parts. Early warning systems, activated after volcanic eruptions can alleviate the impacts on aviation by providing forecasts of the volcanic ash plume dispersion. The quality of these short-term forecasts is subject to the accuracy of the meteorological wind fields used for the initialization of regional models. Here, we use wind profiling data from the first high spectral resolution lidar in space, Aeolus, to examine the impact of measured wind fields on regional NWP and subsequent volcanic ash dispersion forecasts, focusing on the case of Etna's eruption on March 2021. The results from this case study demonstrate a significant improvement of the volcanic ash simulation when using Aeolus-assimilated meteorological fields, with differences in wind speed reaching up to 8 m/s when compared to the control run. When comparing the volcanic ash forecast profiles with downwind surface-based aerosol lidar observations, the modeled field is consistent with the measurements only when Aeolus winds are assimilated. This result clearly demonstrates the potential of Aeolus and highlights the necessity of future wind profiling satellite missions for improving volcanic ash forecasting and hence aviation safety. [ABSTRACT FROM AUTHOR]

Effective exploration technology is urgently needed to carry out the strategic action of mineral exploration breakthrough in China. Aerogeophysics is an important and efficient mineral exploration method, which has played an important role in the world mineral exploration history. Since the 21st century, aero geophysical technology has made great progress in China, such as self-developed high-sensitivity instruments, higher resolution and more types of seamless data collection methods, finer data processing and more accurate interpretation methods, greater detection depth, and wider application fields. In particular, new exploration technologies such as multi-parameter aeromagnetic, airborne time-domain electromagnetic, and airborne gravity, have developed rapidly. Examples of mineral exploration show that aerogeophysics can play an important direct or indirect role in different stages of strategic mineral exploration, especially in the exploration of iron, copper, nickel, uranium, sylvite and other scarce minerals. However, for the new requirements of difficult access and deep earth prospecting, aero geophysical mineral exploration faces some difficulties, such as weak useful geophysical signals, large interference from shallow parts, uncertainty of detection results and difficult construction of geological and geophysical prospecting models. Moreover, the self-developed aeronautical geophysical instruments are not sufficiently practical and used enough. In addition, the development of UAV survey technology is slow, and higher resolution technologies such as aeromagnetic gradient tensor, aero gravity gradient tensor and airborne electromagnetic technology are developing slowly. Advanced and practical high-precision airborne geophysical data acquisition and data processing technologies need to be improved, and the integration of aero geophysical and other methods is not deep enough. The functions of different methods and stages of aero geophysical prospecting were preliminarily summarized, as well as the effectiveness of detecting different mineral species and types, and the idea of aero geophysical technology supporting strategic mineral exploration was proposed. Guided by advanced metallogenic system theory, the effective technologies or technology combinations were studied to solve the problems of mineral exploration deployment and accurate positioning of concealed mineral bodies or geological bodies. Making breakthroughs were focused on in the practicability of domestic instruments and software platforms, developing instruments with higher sensitivity, developing efficient low-altitude high-resolution aero geophysical integration exploration methods, effective information enhancement and weak signal extraction technologies, and intelligent multi-source joint inversion and geophysical geological modeling methods. At the same time, the air-ground-borehole geophysical exploration technology was looked forward to the application prospect of aviation geophysical strategic minerals exploration, and the development trend of aero geophysical exploration technology and the technical methods that need to be developed in the future were discussed. [ABSTRACT FROM AUTHOR]

To improve the accuracy of the Ultra-Wide Band (UWB) based quadrotor aircraft localization, a Finite Impulse Response (FIR) filter aided with an integration of the predictive model and Extreme Learning Machine (ELM) is proposed in this work. The FIR filter estimates the quad-rotor aircraft 's position by fusing the positions measured with the UWB and Inertial Navigation System respectively. When the UWB dada are unavailable, both the ELM and the predictive model are used to provide the measurements, replacing those unavailable UWB data, for the FIR filter. The ELM estimates the measurement via the mapping between the one step prediction of state vector and the measurement built when the UWB data are available. For the predictive model, we mathematically describe the missing UWB data. Then, both the measurements estimated with the ELM and predictive model are employed to estimate the observations via Mahalanobis distance. The test results show that the FIR filter aided by the predictive model/ELM integrated can reduce the Cumulative Distribution Function and position Root Mean Square Error effectively when the UWB is unavailable. Compared with the ELM assisted FIR filter, the proposed FIR filter can reduce the localization error by about 48.59 %, meanwhile, the integrated method is close to the method with a better solution. [ABSTRACT FROM AUTHOR]

Ti-6Al-4V is known for its lightweight, high tensile strength, exceptional corrosion resistance, and low thermal coefficient of expansion due to which it finds its application in precision surgical instruments and aeronautical and marine engine parts. In this study, Ti-6Al-4V has been machined using wire EDM machine with two different wire materials. The wire thickness of 0.25 mm heat-treated brass and zinc-coated brass tool and super cool oil as dielectric fluid were utilized for the machining process. Taguchi L9 orthogonal array was used. Ton (Pulse ON time), Toff (Pulse OFF time), wire feed, and Ip (Current) were the input parameters, and the response parameters such as surface roughness (Ra), material removal rate (MRR), tool wear rate (TWR), and recast layer thickness were optimized by TOPSIS optimization. From the results, higher tool wear rate was observed in brass tool. The titanium percentage after machining was found to be 55.05% for zinc-coated brass wire, whereas it was 51.58% for brass wire. Better productivity and surface integrity were observed in zinc-coated brass tool compared to heat-treated brass. MRR increased to 54.93%, surface roughness decreased to 2.40%, recast layer thickness increased to 3.44%, and tool wear rate was increased to 47.96%. [ABSTRACT FROM AUTHOR]

INTRODUCTION: This case report describes two instrument-rated commercial pilots' loss of aircraft control and subsequent accident with 7 resulting fatalities due to spatial disorientation. BACKGROUND: Vestibular illusions during flight operations lacking adequate visual horizon are a sensory response from a normal functioning vestibular system. Accident(s) due to spatial disorientation and resulting loss of aircraft control still account for 5-10% of aviation accidents and are associated with a 90% or higher fatality rate. Despite artificial cockpit horizon reference and instrument training pilots still succumb to spatial disorientation in both general and commercial aviation. CASE PRESENTATION: On May 29th 2021, at 1053:06 CST a Cessna Citation departed Smyrna, Tennessee destined for Palm Beach International Airport on an IFR flight plan with two pilots and 5 passengers. The aircraft entered instrument meteorological conditions shortly after take-off and during maneuvering flight executed a series of abnormal flight control inputs resulting in controlled flight into terrain at 1055:05. A review of radar track data revealed the aircraft executed a series of heading changes along with several climbs and descents before it entered a steep descending turn and impacted the ground with a vertical descent speed in excess 30,000 feet-per-minute. Both pilots' were instrument and type-rated in the Cessna CE-501 and held commercial pilot certificates. Weather reporting at the time of the accident included winds out of the North at 10 knots and a cloud ceiling of 1,300 ft AGL. The final NTSB determined the probable cause of the accident to be loss of aircraft control due to spatial disorientation during aircraft climb. DISCUSSION: While non-instrument rated pilots operating VFR into IMC is a well described and recurrent cause for spatial disorientation accidents, instrument rated experienced pilots are not immune to loss of aircraft control due to spatial disorientation. Piloting an aircraft is dependent upon the combination of valid sensory information combined with motor inputs for a complete kinesthetic response for the safe operation of the aircraft in all phases of flight. The loss of visual horizon reference introduces illusory sensations in a pilot resulting in the potential for spatial disorientation. This case illustrates the importance of pilot awareness, recurrent training, and education to help mitigate the risks for spatial disorientation. Learning Objectives 1. The audience will learn of the unresolved problem of spatial disorientation and aircraft accidents within the US national airspace system. 2. The audience will leave with a better understanding of the challenges in mitigating spatial disorientation due to the human sensory inner ear systems functional biases. [ABSTRACT FROM AUTHOR]

BACKGROUND: Visually degraded environments hold the potential for pilots to misperceive the orientation of their aircraft. When visual information suddenly becomes available (or disappears), such as when flying out of (or into) clouds, the pilot must integrate that information to update their perception of vehicle orientation. Visual information may come in the form of naturalistic cues (e.g., the horizon) or artificial information (e.g., attitude indicator on the aircraft's instrument display). Further, orientation perception (i.e., the "sense" of orientation) may differ from a pilot's orientation "awareness" (i.e., best understanding of vehicle orientation). To our knowledge the temporal dynamics of spatial orientation perception and awareness have not been quantified following transitions in the availability of naturalistic or artificial visual information. OVERVIEW: We executed a series of human subject experiments in a motion device capable of roll tilt and lateral translation. Availability of visual cues was dynamically activated or removed on each trial, and presented either naturalistically (horizon and angular vection cues from a dot pattern, presented in virtual reality) or artificially (aircraft attitude indicator shown on a screen). Orientation perception was reported continuously using a subjective haptic horizontal psychophysical task. On separate trials, subjects were instructed to verbally report their orientation "awareness" at discrete moments. In summary, we found it took 3 seconds for subjects to integrate sudden naturalistic visual cues into their orientation perception. In contrast, it took roughly 7 seconds for the attitude indicator information to be integrated into perception. Orientation awareness became consistent with true orientation immediately after the attitude indicator appeared. When visual information disappeared, orientation perception and awareness both gradually transitioned over 7-9 seconds, whether naturalistic of artificial visual information was previously available. DISCUSSION: Sudden visual information can rapidly counteract disorientation (particularly instrumentation). Quantifying the temporal dynamics of how visual information affects both orientation perception and awareness is important for understanding pilot spatial disorientation. Further work should be done to examine the difference in impact between orientation awareness vs. perception on the manual operation of aerospace vehicles. Learning Objectives 1. Understand the influence of visual and vestibular cues on orientation perception. 2. Distinguish between spatial orientation perception and spatial orientation "awareness" contructs. [ABSTRACT FROM AUTHOR]

This paper introduces a novel visual landing system applicable to the accurate landing of commercial aircraft utilizing human depth perception algorithms, named a 3D Model Landing System (3DMLS). The 3DMLS uses a simulation environment for visual landing in the failure of navigation aids/avionics, adverse weather conditions, and limited visibility. To simulate the approach path and surrounding area, the 3DMLS implements both the inertial measurement unit (IMU) and the digital elevation model (DEM). While the aircraft is in the instrument landing system (ILS) range, the 3DMLS simulates more details of the environment in addition to implementing the DOF depth perception algorithm to provide a clear visual landing path. This path is displayed on a multifunction display in the cockpit for pilots. As the pilot's eye concentrates mostly on the runway location and touch-down point, "the runway" becomes the center of focus in the environment simulation. To display and evaluate the performance of the 3DMLS and depth perception, a landing auto test is also designed and implemented to guide the aircraft along the runway. The flight path is derived simultaneously by comparison of the current aircraft and the runway position. The Unity and MATLAB software are adopted to model the 3DMLS. The accuracy and the quality of the simulated environment in terms of resolution, the field of view, frame per second, and latency are confirmed based on FSTD's visual requirements. Finally, the saliency map toolbox shows that the depth of field (DOF) implementation increases the pilot's concentration resulting in safe landing guidance. [ABSTRACT FROM AUTHOR]

To support alternative positioning, navigation and timing (A‐PNT), multi‐DME with better geometry than distance measuring equipment (DME)/DME can be used to improve the performance. Different from the existing station selection methods that have been proposed for DME/DME, a station selection method for multi‐DME should be considered in order to prevent unnecessary emission of navigation signals because DME receivers have limited number of channels and constrained real‐time processing power, and also to limit DME to GNSS L5/E5a interference. A heuristic algorithm is constructed to determine the quasi‐optimal selection of DME stations based on geometrical and computational cost restrictions, which is different from a brute‐force method checking all possible subsets and selecting the best one. A station selection method for multi‐DME is proposed based on the heuristic search. Meanwhile, the degradation of GNSS L5/E5a signal processing that is caused by DME signals is discussed. An advanced station selection method where the DME to GNSS signal interference is taken into account is also proposed. The experimental results show that the methods based on heuristic search can effectively select the quasi‐optimal subset of DME stations with less computational expense. [ABSTRACT FROM AUTHOR]

Airborne lidar altimetry can measure the sea surface height (SSH) over scales ranging from hundreds of kilometers to a few meters. Here, we analyze the spectrum of SSH observations collected during an airborne lidar campaign conducted off the California coast. We show that the variance in the surface wave band can be over 20 times larger than the variance at submesoscales and that the observed SSH variability is sensitive to the directionality of surface waves. Our results support the hypothesis that there is a spectral gap between meso‐to‐submesoscale motions and small‐scale surface waves and also indicate that aliasing of surface waves into lower wavenumbers may complicate the interpretation of SSH spectra. These results highlight the importance of better understanding the contributions of different physics to the SSH variability and considering the SSH spectrum as a continuum in the context of future satellite altimetry missions. Plain Language Summary: Using unique measurements of the sea surface height (SSH) taken from an instrument onboard an airplane off the California coast, we examine how the variance of the SSH is distributed across different spatial scales, ranging from hundreds of kilometers to a few meters. We show that surface waves can be 20 times more energetic than motions with larger scales (known as submesocales) and that the direction of surface waves impacts the SSH variability depending on different sampling and averaging strategies. These results highlight the importance of better understanding the contributions of different types of motions and physics to the SSH variability. In particular, we advocate measuring scales from meters to hundreds of kilometers as a continuum to better inform future satellite altimetry missions. Key Points: We present unique broadband airborne lidar observations of sea surface height spanning scales from hundreds of kilometers to a few metersThe sea surface height variance due to surface waves can be over an order of magnitude larger than the variance at submesoscalesThe observed sea surface height is sensitive to the direction of waves which may impact the interpretation of remote sensing measurements [ABSTRACT FROM AUTHOR]

The paper considers the transition algorithm from incoherent models to partially coherent ones by the example of the problem of synthesizing a two‐dimensional partially coherent model of a distributed radar object by its five‐point and nine‐point incoherent models. The transition algorithm includes the analytical expressions which allow determining powers and correlation functions of emitting signals for both types of models. The result is confirmed by numerical modeling. The comparison of the precision reflection altimeter formation and correlation function of angular glint provided by equivalent incoherent and partially coherent models is carried out. Key Points: Matrix simulatorAngle noisePartially coherent model [ABSTRACT FROM AUTHOR]

The mei-yu season, typically occurring from mid-June to mid-July, on average, contributes to 32% of the annual precipitation over the Yangtze–Huai River Valley (YHRV) and represents one of the three heavy-rainfall periods in China. Here, we briefly review the large-scale background, synoptic pattern, moisture transport, and cloud and precipitation characteristics of the mei-yu frontal systems in the context of the ongoing Integrative Monsoon Frontal Rainfall Experiment (IMFRE) field campaign. Phase one of the campaign, IMFRE-I, was conducted from 10 June to 10 July 2018 in the middle reaches of the YHRV. Led by the Wuhan Institute of Heavy Rain (IHR) with primary support from the National Natural Science Foundation of China, IMFRE-I maximizes the use of our observational capacity enabled by a suite of ground-based and remote sensing instruments, most notably the IHR Mesoscale Heavy Rainfall Observing System (MHROS), including different wavelengths of radars, microwave radiometers, and disdrometers. The KA350 (Shanxi King-Air) aircraft participating in the campaign is equipped with Ka-band cloud radar and different probes. The comprehensive datasets from both the MHROS and aircraft instruments are combined with available satellite observations and model simulations to answer the three scientific questions of IMFRE-I. Some highlights from a previously published special issue are included in this review, and we also briefly introduce the IMFRE-II field campaign, conducted during June–July 2020, where the focus was on the spatiotemporal evolutions of the mei-yu frontal systems over the middle and lower reaches of the YHRV. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to lead to an improvement in pilot-aircraft interaction. The goal of the performed tests is an assessment of haptic feedback, which mediates flight parameters to the pilot. Pedals indicate side-slip angle by vibrations, whereas a sliding element inside the control stick is able to continuously indicate both angles of attack and side-slip. Design/methodology/approach: Haptic feedback applied on rudder pedals and control stick were tested on a flight simulator and flight tests in a couple of tasks. Pilot workload, readability of feedback and side-slip were then evaluated when the flight was turning. Findings: As a useful instrument for aircraft control, haptic feedback was assessed. The feedback settings were then individually perceived, and haptic feedback slightly improved side-slip while turning in a flight test; however, the results are not statistically significant. Practical implications: The tests provided promising results for human pilot performance. The training phase and personal settings of haptic feedback is an approach for improving the performance of human pilots. Originality/value: The designed and tested device is a unique tool for improving pilot-aircraft interaction. This study brings valuable experiences from its flight simulator and in-flight tests. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/AEAT-12-2019-0265/ [ABSTRACT FROM AUTHOR]

We have developed in situ and flask sampling systems for airborne measurements of variations in the O2/N2 ratio at the part per million level. We have deployed these instruments on a series of aircraft campaigns to measure the distribution of atmospheric O2 from 0-14km and 87°N to 85°S throughout the seasonal cycle. The NCAR airborne oxygen instrument (AO2) uses a vacuum ultraviolet (VUV) absorption detector for O2 and also includes an infrared CO2 sensor. The VUV detector has a precision in 5 seconds of ±1.25 per meg (1#963;) δ(O2/N2), but thermal fractionation and motion effects increase this to ±2.5-4.0 per meg when sampling ambient air in flight. The NCAR/Scripps airborne flask sampler (Medusa) collects 32 cryogenically dried air samples per flight under actively controlled flow and pressure conditions. For in situ or flask O2 measurements, fractionation and surface effects can be important at the required high levels of relative precision. We describe our sampling and measurement techniques, and efforts to reduce potential biases. We also present a selection of observational results highlighting the individual and combined instrument performance. These include vertical profiles, O2:CO2 correlations, and latitudinal cross sections reflecting the distinct influences of terrestrial photosynthesis, air-sea gas exchange, burning of various fuels, and stratospheric dynamics. When present, we have corrected the flask δ(O2/N2) measurements for fractionation during sampling or analysis, with the use of the concurrent δ(Ar/N2) measurements. We have also corrected the in situ δ(O2/N2) measurements for inlet fractionation and humidity effects by comparison to the corrected flask values. A comparison of Ar/N2-corrected Medusa flask δ(O2/N2) measurements to regional Scripps O2 Network station observations shows no systematic biases over 10 recent campaigns (+0.2±8.2 per meg, mean and standard deviation, n=86). For AO2, after resolving sample drying and inlet fractionation biases previously on the order of 10-100 per meg, independent AO2 δ(O2/N2) measurements over 6 more recent campaigns differ from coincident Medusa flask measurements by -0.3±7.2 per meg (mean and standard deviation, n=1361), with campaign-specific means ranging from -5 to +5 per meg. [ABSTRACT FROM AUTHOR]

Emissions of methane (CH4) from offshore oil and gas installations are poorly ground-truthed and quantification relies heavily on the use of emission factors and activity data. As part of the United Nations Climate and Clean Air Coalition (UN CCAC) objective to study and reduce short-lived climate pollutants (SLCP) a Twin Otter aircraft was used to survey CH4 emissions from UK and Dutch offshore oil and gas installations. The aims of the surveys were to i) identify installations that are significant CH4 emitters, ii) separate installation emissions from other emissions using carbon-isotopic fingerprinting and other chemical proxies, iii) estimate CH4 emission rates, and iv) improve flux estimation (and sampling) methodologies for rapid quantification of major gas leaks. In this paper, we detail the instrument and aircraft set up for two campaigns flown in the springs of 2018 and 2019 over the southern North Sea and describe the developments made in both planning and sampling methodology in order to maximise the quality and value of the data collected. We present example data collected from both campaigns to demonstrate the challenges encountered during offshore surveys, focussing on the complex meteorology of the marine boundary layer, and sampling discrete plumes from an airborne platform. The uncertainties of CH4 flux calculations from measurements under varying boundary layer conditions are considered, as well as recommendations for attribution of sources through either spot sampling for VOCs / Î'13CCH4 or using in-situ instrumental data to determine C2H6-CH4 ratios. A series of recommendations for both planning and measurement techniques for future offshore work within the marine boundary layers are provided. [ABSTRACT FROM AUTHOR]

Column-averaged dry-air mole fractions of carbon dioxide (XCO2) and methane (XCH4) measured by a solar viewing portable Fourier transform spectrometer (FTS, EM27/SUN) have been characterized and validated by comparison using in-situ profile measurements made during the transfer flights of two aircraft campaigns: Korea-United States Air Quality Study (KORUS-AQ) and Effect of Megacities on the Transport and Transformation of Pollutants on the Regional and Global Scale (EMeRGe). The aircraft flew over two Total Carbon Column Observing Network (TCCON) sites: Rikubetsu, Japan (43.46° N, 143.77° E) for the KORUS-AQ campaign and Burgos, Philippines (18.53° N, 120.65° E) for the EMeRGe campaign. The EM27/SUN was deployed at the corresponding TCCON sites during the overflights. The mole fraction profiles obtained by the aircraft over Rikubetsu differed between the ascending and the descending flights above approximately 8 km for both CO2 and CH4. Because the spatial pattern of tropopause heights based on potential vorticity values from the ERA5 reanalysis show that the tropopause height over the Rikubetsu site was consistent with the descending profile, we used only the descending profile to compare with the EM27/SUN data. Both the XCO2 and XCH4 derived from the descending profiles over Burgos were lower than those from the ascending profiles. Output from the Weather Research and Forecast Model indicate that higher CO2 for the ascending profile originated in central Luzon, an industrialized and densely populated region about 400 km south of the Burgos TCCON site. Air masses observed with the EM27/SUN overlap better with those from the descending aircraft profiles than those from the ascending aircraft profiles with respect to their properties such as origin and atmospheric residence times. Consequently, the descending aircraft profiles were used for the comparison with the EM27/SUN data. The EM27/SUN XCO2 and XCH4 data were derived by using the GGG2014 software in which air mass independent correction factors utilized for the TCCON data (0.9898 for XCO2 and 0.9765 for XCH4) were not applied. The comparison of the EM27/SUN observations with the aircraft data revealed that on average, the EM27/SUN XCO2 data were biased low by 1.22 % and the EM27/SUN XCH4 data were biased low by 1.67 %. The resulting air mass independent correction factors of 0.9878 for XCO2 and 0.9833 for XCH4 were obtained for the portable FTS. [ABSTRACT FROM AUTHOR]

NASA's Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ, conducted in 2011–2014) campaign in the United States and the joint NASA and National Institute of Environmental Research (NIER) Korea–United States Air Quality Study (KORUS-AQ, conducted in 2016) in South Korea were two field study programs that provided comprehensive, integrated datasets of airborne and surface observations of atmospheric constituents, including nitrogen dioxide (NO2), with the goal of improving the interpretation of spaceborne remote sensing data. Various types of NO2 measurements were made, including in situ concentrations and column amounts of NO2 using ground- and aircraft-based instruments, while NO2 column amounts were being derived from the Ozone Monitoring Instrument (OMI) on the Aura satellite. This study takes advantage of these unique datasets by first evaluating in situ data taken from two different instruments on the same aircraft platform, comparing coincidentally sampled profile-integrated columns from aircraft spirals with remotely sensed column observations from ground-based Pandora spectrometers, intercomparing column observations from the ground (Pandora), aircraft (in situ vertical spirals), and space (OMI), and evaluating NO2 simulations from coarse Global Modeling Initiative (GMI) and high-resolution regional models. We then use these data to interpret observed discrepancies due to differences in sampling and deficiencies in the data reduction process. Finally, we assess satellite retrieval sensitivity to observed and modeled a priori NO2 profiles. Contemporaneous measurements from two aircraft instruments that likely sample similar air masses generally agree very well but are also found to differ in integrated columns by up to 31.9 %. These show even larger differences with Pandora, reaching up to 53.9 %, potentially due to a combination of strong gradients in NO2 fields that could be missed by aircraft spirals and errors in the Pandora retrievals. OMI NO2 values are about a factor of 2 lower in these highly polluted environments due in part to inaccurate retrieval assumptions (e.g., a priori profiles) but mostly to OMI's large footprint (>312 km 2). [ABSTRACT FROM AUTHOR]

The structure of the navigation and landing system for light-weight aviation tasks, its operation principle, potential technical parameters, and the configuration of the airborne and ground-based equipment are proposed in the article. The operating modes of the system airborne equipment and its communication and interaction with standard aircraft instruments have been developed. Based on the tactics of using such system, the parameters of its frequency-code channels and the principles of its controlling are determined, which allow to identify the multi-position components of its ground-based equipment. The ways to improve system characteristics are proposed. An analysis of the aircraft location determination errors for a mobile two-position radio rangefinder ground-based inquiry-response system is carried out. The possibility of providing a categorized landing of light aircrafts in the signal field of such system is shown. [ABSTRACT FROM AUTHOR]

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Background: The Kenz Lifecorder EX (KL) is a relatively new, moderately priced, user friendly accelerometer that tracks step counts and time spent in various intensity classifications. Thus, the KL is an attractive instrument for researchers and the public. However, there is limited research comparing the KL's output to other accelerometers during free-living conditions. Therefore the purpose of this study was to compare KL versus ActiGraph (AG) outputs of step counts and time spent in various intensity classifications during free-living conditions. Methods: Ten men and 10 women volunteers wore an AG (right side) and 2 KL (right side: KL-R vs. left side: KL-L) accelerometers on their waistline during waking hours for one day. Results: KL-R vs. KL-L yielded similar physical activity (PA) output. The AG recorded fewer steps compared with KL-L (P = .002) but was similar to the KL-R. The KL-R and KL-L yielded lower estimates of accumulated time spent in moderate PA compared with most AG intensity derivations (P < .003). There were no differences between KL-R and KL-L vs. the AG for time spent in vigorous PA. Conclusions: The KL provides similar estimates of step counts and time spent in vigorous PA compared with established AG intensity derivations. [ABSTRACT FROM AUTHOR]

Fatigue in offshore environments is a critical safety hazard, yet the utility of daily fatigue assessments has not been longitudinally examined in these environments. The aim of this exploratory longitudinal field study across two drillships in the Gulf of Mexico was to determine the changes in subjective, performance-based, and physiological fatigue measures over time across different shift types (day, night, and swing) and to identify correlations between these multimodal fatigue assessments. Repeated measures correlation analyses of daily fatigue data from seventy offshore workers revealed that while total sleep time remained unaffected by time on rig, workers' performances on the psychomotor vigilance test (PVT) deteriorated over time across all shift types. Several correlations between the various multimodal measures were consistent with the extant literature on worker fatigue symptoms and perceptual and physiological manifestations. These findings emphasize the utility of PVT and single item self-reports to capture worker fatigue in offshore shiftwork. • Daily multimodal fatigue assessments were collected for 28 days in offshore rigs. • PVT captures fatigue-related performance declines over time for all shift types. • Total sleep time and efficiency remained unchanged over time across all shift types. • Mental fatigue increased among swing shift but decreased among night shift workers. • PVT and short self-reports are suitable candidates to assess fatigue in offshore shiftwork. [ABSTRACT FROM AUTHOR]

Research has shown that timing is modulated by mental workload, making duration judgments a measure of cognitive demand, alongside subjective assessments, and physiological measurements. Yet, it is unclear whether such findings can be extended in less controlled setups. By employing air traffic controllers in a real aviation environment, we tested whether tasks with different levels of cognitive load can affect their timing behavior. Participants completed temporal production, verbal estimation, and passage of time judgments, while actively engaging in real flight control sessions. Subjective assessments of task demands, as well as physiological responses (cardiac and electrodermal activity) were also measured. Accuracy of the produced intervals was measured at two distinct phases of the flight (during low-load cruising vs. high-load landing) and under two different task load manipulations (controlling one vs. two helicopters and speaking in native vs. non-native language). Analysis of interval production accuracy showed that during the high-load landing phase significant overproductions were made, compared to the low-load cruising phase, and landing two helicopters led to greater overproductions compared to landing only one. The duration of the two-helicopter sessions was significantly overestimated compared to the single-helicopter ones, and the passage of time was felt significantly faster. Subjective assessments of workload were positively correlated with the temporal estimations and passage of time judgments, and skin responses were positively correlated with the produced intervals. Overall, our results are consistent with past research, suggesting that mental workload modulates time perception in complex, real-world environments, thus making timing behavior a reliable index of the workload changes. • The study assessed if workload manipulation in a primary aviation task affects air traffic controllers' time percept in a secondary timing task. • Significant overproductions were made during the high-load landing phase and when landing two helicopters, compared to the low-load conditions. • Significant overestimations were made for the high-load two-helicopter sessions, compared to the low-load conditions. • NASA TLX scores were positively correlated with time estimations and skin responses were positively correlated with time productions. • This is the first study to show that mental workload affects time perception in a real aviation scenario. [ABSTRACT FROM AUTHOR]