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At least 685 records · Page 38

Continuous snow depth and temperature measurements from dense network of above-ground distributed temperature profiling systems from 2021-09-23 to 2024-08-23, Seward Peninsula, Alaska

The dataset contains temperature measurements from distributed temperature profiling (DTP) systems (Dafflon et al., 2022; Wielandt et al., 2022; Wang et al., 2024a; Fiolleau et al., 2024) deployed vertically above the ground surface at a large number of locations from 2021 to 2024. The research is designed to improve understanding of the local heterogeneity in snow depth and snow thermal insulation dynamics, as well as their interactions in a discontinuous permafrost region (Wang et al., 2025). The DTP systems were deployed at 96 locations in a watershed along the Nome-Teller road at mile marker 27 (T27) and at 54 locations on a hillslope along the Kougarok road at mile marker 64 (K64) in the Seward Peninsula, Alaska. The probe location information is stored in Probe_locations_T27.csv and Probe_locations_K64.csv. Temperature measurements were recorded at 15-minute intervals using high-precision digital sensors (accuracy: ±0.1°C, resolution: 0.0078°C). The temperature probes, either 1.4 m or 1.6 m long, contain sensors spaced every 5 cm or 10 cm along their length. The temperature data are stored in compressed files following the format: DTP_snow_air_temperature_(site)_(start)_(end).zip, where site is either T27 or K64, and start and end represent the time series period. Within each ZIP file, individual CSV files are named by probe ID and contain temperature records at different heights above the ground surface.This dataset also includes derived snow depth time series over three snow seasons, estimated from temperature measurements. Snow depth was estimated by identifying the consecutive sensor pair that exhibited the largest drop in high-frequency temperature fluctuations (detailed in the methods). These data are stored in: Snow_depths_flags_(site)_(start)_(end).csv, which includes snow depth time series and corresponding quality flags (defined in the methods) from different probes. Additionally, the dataset includes derived metrics and supporting measurements at selected locations over two snow seasons, contributing to the manuscript of Wang et al., 2025. These locations were chosen based on the availability of high-quality snow depth time series during both seasons. The additional data include: (1) Air temperature proxies measured from the top sensors on the pole when they were not buried by snow, stored in Air_temperature_proxies_(site)_(start)_(end).csv (2) Ground interface temperature, recorded at 3 cm above the ground, stored in Ground_interface_temperature_(site)_(start)_(end).csv (3) Site characteristics, including vegetation height, elevation, and the topographic position index (TPI) within a 50 m radius, stored in Selected_probe_locations_gps_vegheight_tpi_elevation_(site).csv. These metrics were derived from 1 m resolution summer LiDAR-based digital elevation models and digital surface models from Singhania et al., 2023, DOI:10.5440/1832016. Metadata files include data descriptions (_dd.csv) for tabular data. All included files are listed and described in xxxx_flmd.csv.This dataset is an updated version of a previous archive (Wang et al., 2024b, DOI: 10.15485/2475020), incorporating multiple seasons and improved snow depth estimation. Please note that due to large amount of information present in this dataset, many specificities associated with the acquisition of snow temperature, air temperature proxy and estimation of snow depth, and the future archiving of additional datasets on the soil temperature, thaw depth and soil characteristics at these locations, the author would welcome being contacted by people planning to use this dataset.The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research.The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska.Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

54 ENVIRONMENTAL SCIENCES↗

AmeriFlux US-SB1 Sweet Briar Land-Atmosphere Research Station

This is the AmeriFlux version of the carbon flux data for the site US-SB1 Sweet Briar Land-Atmosphere Research Station. Site Description - The facility features a 36.5m (120') triangular tower and a climate-controlled shed laboratory with line power and high speed internet. The site is located in a 27 ha loblolly pine (Pinus taeda) plantation on the campus of Sweet Briar College. The average canopy height is approximately 20 meters in the immediate footprint of the tower, where the loblolly trees are approximately 25 years old. Beyond the loblolly plantation, the site is surrounded by regionally representative, middle-aged, mixed deciduous forest that is dominated by red maple (Acer rubrum), tulip poplar (Liriodendron tulipifera), white oak (Quercus alba), and chestnut oak (Quercus prinus)

Ahlswede, Benjamin [Virginia Tech]↗

Gas-phase hydrogen permeation through alpha-titanium - Surface film and dimensional effects

The two techniques normally used to determine diffusivity and permeability in metals are considered and a description is presented of experiments which had been conducted to determine the direct effect of oxide and nitride films on the membrane surface as a function of location and thickness. The test specimens used in the experiments has been machined from commercially pure titanium rod. The results of the experiments show that hydrogen transport in alpha-titanium is partially or completely controlled by surface reactions depending upon membrane wall thickness and the composition and thickness of the surface film.

Shah, K. K.↗

Aspects of clear air turbulence severity forecasting and detection

Factors influencing the accuracy of the forecasts of incidences of clear air turbulence (CAT) are discussed, along with techniques for improved verification. Descriptive ranking terms for the intensity of CAT events, ranging from light to extreme, are developed, and meteorological parameters used for predictions are reviewed, including jetstream core location, vertical and horizontal wind shears, stable layers, tropopause height, trough speed, 500-mb vorticity, surface fronts, pressure centers and cyclogenesis, and wind speeds near mountain ridges. Methods of remote detection of CAT, particularly by using radiometry sensitive to the IR water vapor band, are noted to have had some success in detecting actual CAT events and decreasing false alarms. Statistical aspects of CAT encounter severity are discussed, including the establishment of confidence intervals for thresholds of detection of CATs of varying intensities.

Ehernberger, L. J.↗

Evaluation of a total energy-rate sensor on a transport airplane

A sensor that measures the rate of change of total energy of an airplane with respect to the airstream has been evaluated. The sensor consists of two cylindrical probes located on the fuselage of a transport airplane, an in line acoustic filter, and a pressure sensing altitude rate transducer. Sections of this report include the sensor description and experimental configuration, frequency response tests, analytical model development, and flight test results for several airplane maneuvers. The results section includes time history comparisons between data generated by the total energy rate sensor and calculated data derived from independent sources.

Ostroff, A. J.↗

Can crop types be resolved using mixture distribution components - Some initial results and implications

For the analysis of remotely sensed data, it is frequently necessary to design a classifier in order to locate a ground cover class of interest or to estimate the proportion of this ground cover class. Advantages of a mixture distribution formulation are discussed, and a description is presented of the results of estimating the proportion of small grains in ten Landsat data segments using the mixture model. It is found that the mixture model proportion estimates have a very low variance and coefficient of variation. The discussed investigation implies that the mixtures model is a viable method for determining the distributions of classes of interest in remote sensing problems and in estimating the proportions of these classes directly.

Lennington, R. K.↗

Enhanced orbit determination filter: Inclusion of ground system errors as filter parameters

The theoretical aspects of an orbit determination filter that incorporates ground-system error sources as model parameters for use in interplanetary navigation are presented in this article. This filter, which is derived from sequential filtering theory, allows a systematic treatment of errors in calibrations of transmission media, station locations, and earth orientation models associated with ground-based radio metric data, in addition to the modeling of the spacecraft dynamics. The discussion includes a mathematical description of the filter and an analytical comparison of its characteristics with more traditional filtering techniques used in this application. The analysis in this article shows that this filter has the potential to generate navigation products of substantially greater accuracy than more traditional filtering procedures.

Masters, W. C.↗

Fundamental Test of a Hovering Rotor: Comprehensive Measurements for CFD Validation

A model-scale hover test of a 4-bladed, 11.08-ft diameter rotor was recently completed inside the National Full-Scale Aerodynamics Complex 80- by 120-Foot Wind Tunnel test section. The primary objective of the test was to acquire key experimental data for a hovering rotor of sufficient quality and quantity to allow validation of state-of-the-art analysis codes. A comprehensive measurement set has been acquired, including rotor performance, blade airloads, flow transition locations, blade deflections, and wake geometry for a range of tip Mach numbers and collective settings. The present paper provides an overview of the test, including detailed descriptions of the hardware, instrumentation, and measurement systems. In addition, the specific test objectives, approach, and sample results are presented. The full test database, as well as detailed rotor geometry information, will ultimately be shared openly on a NASA-sponsored website to serve as a benchmark validation dataset.

Hover↗

Descriptions and preliminary interpretations of cores recovered from the Manson Impact Structure (Iowa)

A core drilling program initiated by the Iowa Geological Survey Bureau and U.S. Geological Survey in 1991 and 1992 collected 12 cores totalling over 1200 m from the Manson Impact Structure, a probable K-T boundary structure located in north-central Iowa. Cores were recovered from each of the major structural terranes, with 2 cores (M-3 and M-4) from the Terrace Terrane, 4 cores (M-2, M-2A, M-6, and M-9) from the Crater Moat, and 6 cores (M-1, M-5, M-7, M-8, M-10, and M-11) from the Central Peak. These supplemented 2 central peak cores (1-A and 2-A) drilled in 1953. The cores penetrated five major impact lithologies: (1) sedimentary clast breccia; (2) impact ejecta; (3) central peak crystallite rocks; (4) crystalline clast breccia with sandy matrix; and (5) crystallite clast breccia with a melt matrix. Descriptions and preliminary interpretations of these cores are presented.

Anderson, R. R.↗

Kinetic description of ionospheric dynamics in the three-fluid approximation

Conservation equations are developed in the three-fluid approximation for general application problems of ionospheric dynamics in the altitude region 90 km to 800 km for all geographic locations. These equations are applied to a detailed study of auroral E region neutral winds and their relationship to ionospheric plasma motions.

Comfort, R. H.↗

AmeriFlux CA-DSM Delta Salt Marsh

This is the AmeriFlux version of the carbon flux data for the site CA-DSM Delta Salt Marsh. Site Description - This site is a tidal salt marsh on the eastern side of the Boundary Bay Wildlife Management Area (WMA) in Delta, British Columbia, Canada. This area is located on the southern front of the Fraser River. The total area of the Boundary Bay WMA is 11,470 ha, and the eastern part surrounding the flux tower accounts for 39 ha. This area is surrounded by farms and dikes. The Provincial Government purchased this area in 1974 limiting public access and designated it as WMA in 1995. This area has a mixed semidiurnal tidal cycle. The dominant species is Saltgrass (Distichlis spicata) with a canopy height of ~40 cm. The tower is in a high marsh system and was installed to analyze energy, H2O, CO2, and CH4 fluxes on September 3, 2021.

Knox, Sara↗

AmeriFlux FLUXNET-1F CA-DSM Delta Salt Marsh

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-DSM Delta Salt Marsh. This is the FLUXNET version of the carbon flux data for the site CA-DSM Delta Salt Marsh produced by applying the standard ONEFlux (1F) software. Site Description - This site is a tidal salt marsh on the eastern side of the Boundary Bay Wildlife Management Area (WMA) in Delta, British Columbia, Canada. This area is located on the southern front of the Fraser River. The total area of the Boundary Bay WMA is 11,470 ha, and the eastern part surrounding the flux tower accounts for 39 ha. This area is surrounded by farms and dikes. The Provincial Government purchased this area in 1974 limiting public access and designated it as WMA in 1995. This area has a mixed semidiurnal tidal cycle. The dominant species is Saltgrass (Distichlis spicata) with a canopy height of ~40 cm. The tower is in a high marsh system and was installed to analyze energy, H2O, CO2, and CH4 fluxes on September 3, 2021.

Knox, Sara [The University of British Columbia]↗

Stresses in pin-loaded orthotropic plates using photoelasticity

The stresses in transparent glass-epoxy plates loaded by a steel pin through a hole were determined by photoelasticity. The stresses around the hole edge, across the net section, along the shear out line, and on the centerline below the hole for quasiisotropic, unidirectional, and angle ply plates are outlined. Stresses in an isotropic comparison specimen are also presented. Stress concentration factors for several locations around the plates are tabulated. The experimental apparatus and the experimental technique are discussed. The isochromatic and isoclinic fringe patterns for the four plates are shown. A description of the necessary photoelastic theory is appended.

Hyer, M. W.↗

Aeroelastic model helicopter rotor testing in the Langley TDT

Wind-tunnel testing of a properly scaled aeroelastic model helicopter rotor is considered a necessary phase in the design development of new or existing rotor systems. For this reason, extensive testing of aeroelastically scaled model rotors is done in the Transonic Dynamics Tunnel (TDT) located at the NASA Langley Research Center. A unique capability of this facility, which enables proper dynamic scaling, is the use of Freon as a test medium. A description of the TDT and a discussion of the benefits of using Freon as a test medium are presented. A description of the model test bed used, the Aeroelastic Rotor Experimental System (ARES), is also provided and examples of recent rotor tests are cited to illustrate the advantages and capabilities of aeroelastic model rotor testing in the TDT. The importance of proper dynamic scaling in identifying and solving rotorcraft aeroelastic problems, and the importance of aeroelastic testing of model rotor systems in the design of advanced rotor systems are demonstrated.

Mantay, W. R.↗

Aeroelastic model helicopter rotor testing in the Langley TDT

Wind-tunel testing of a properly scaled aeroelastic model helicopter rotor is considered a necessary phase in the design development of new or existing rotor systems. For this reason, extensive testing of aeroelastically scaled model rotors is done in the Transonic Dynamics Tunnel (TDT) located at the NASA Langley Research Center. A unique capability of this facility, which enables proper dynamic scaling, is the use of Freon as a test medium. A description of the TDT and a discussion of the benefits of using Freon as a test medium are presented. A description of the model test bed used, the Aeroelastic Rotor Experimental System (ARES), is also provided and examples of recent rotor tests are cited to illustrate the advantages and capabilities of aeroelastic model rotor testing in the TDT. The importance of proper dynamic scaling in identifying and solving rotorcraft aeroelastic problems, and the importance of aeroelastic testing of model rotor systems in the design of advanced rotor systems are demonstrated.

Mantay, W. R.↗

AmeriFlux US-xTA NEON Talladega National Forest (TALL)

This is the AmeriFlux version of the carbon flux data for the site US-xTA NEON Talladega National Forest (TALL). Site Description - The TALL terrestrial field site covers 5300 hectares within the larger Oakmulgee District of the Talladega National Forest (475,000 hectares) in west-central Alabama. TALL is located within the Gulf Coastal Plain which is the dominant physiographic province (52%) of NEON's Domain 8: Ozarks Complex. It is also where the upper coastal plain gives rise to the Appalachian foothills. The lands of this region are rich a mosaic of forest types and habitats. Steep ridges to rolling hills fading to hardwood bottoms make up the diversity of forest conditions found in Oakmulgee. While known for its longleaf forests, over 40% of Oakmulgee is covered with a mixture of hardwoods and wetlands.

Network), NEON (National Ecological Observatory↗

AmeriFlux FLUXNET-1F US-xTA NEON Talladega National Forest (TALL)

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-xTA NEON Talladega National Forest (TALL). This is the FLUXNET version of the carbon flux data for the site US-xTA NEON Talladega National Forest (TALL) produced by applying the standard ONEFlux (1F) software. Site Description - The TALL terrestrial field site covers 5300 hectares within the larger Oakmulgee District of the Talladega National Forest (475,000 hectares) in west-central Alabama. TALL is located within the Gulf Coastal Plain which is the dominant physiographic province (52%) of NEON's Domain 8: Ozarks Complex. It is also where the upper coastal plain gives rise to the Appalachian foothills. The lands of this region are rich a mosaic of forest types and habitats. Steep ridges to rolling hills fading to hardwood bottoms make up the diversity of forest conditions found in Oakmulgee. While known for its longleaf forests, over 40% of Oakmulgee is covered with a mixture of hardwoods and wetlands.

Network), NEON (National Ecological Observatory↗

AmeriFlux US-TEF Tenderfoot Creek Experimental Forest

This is the AmeriFlux version of the carbon flux data for the site US-TEF Tenderfoot Creek Experimental Forest. Site Description - This site was established by Montana State University researchers in 2005 and re-instrumented in 2025 for above- and below-canopy eddy covariance. The tower is located in the Stringer Creek sub-watershed, which is maintained as an undisturbed lodgepole pine forest, and represents one of seven gaged sub-watersheds nested within the Tenderfoot Creek Experimental Forest. Historical data collection spanned the 2005-2012 (tall tower) and 2010-2012 (sub-canopy) time periods.

Stoy, Paul↗