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At least 1,405 records · Page 78
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Airborne Measurements and Emission Estimates of Greenhouse Gases and Other Trace Constituents From the 2013 California Yosemite Rim Wildfire

This paper presents airborne measurements of multiple atmospheric trace constituents including greenhouse gases (such as CO2, CH4, O3) and biomass burning tracers (such as CO, CH3CN) downwind of an exceptionally large wildfire. In summer 2013, the Rim wildfire, ignited just west of the Yosemite National Park, California, and burned over 250,000 acres of the forest during the 2-month period (17 August to 24 October) before it was extinguished. The Rim wildfire plume was intercepted by flights carried out by the NASA Ames Alpha Jet Atmospheric eXperiment (AJAX) on 29 August and the NASA DC-8, as part of SEAC4RS (Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys), on 26 and 27 August during its intense, primary burning period. AJAX revisited the wildfire on 10 September when the conditions were increasingly smoldering, with slower growth. The more extensive payload of the DC-8 helped to bridge key measurements that were not available as part of AJAX (e. g. CO). Data analyses are presented in terms of emission ratios (ER), emission factors (EF) and combustion efficiency and are compared with previous wildfire studies. ERs were 8.0 ppb CH4/(ppm CO2) on 26 August, 6.5 ppb CH4 (ppm CO2)1 on 29 August and 18.3 ppb CH4 (ppm CO2)1 on 10 September 2013. The increase in CH4 ER from 6.5 to 8.0 ppb CH4/(ppm CO2) during the primary burning period to 18.3 ppb CH4/(ppm CO2) during the fire's slower growth period likely indicates enhanced CH4 emissions from increased smoldering combustion relative to flaming combustion. Given the magnitude of the Rim wildfire, the impacts it had on regional air quality and the limited sampling of wildfire emissions in the western United States to date, this study provides a valuable dataset to support forestry and regional air quality management, including observations of ERs of a wide number of species from the Rim wildfire.

Yates, E. L.↗
NASA NTRS2016

Planning, Implementation, and Scientific Goals of the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) Field Missions

The Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field mission based at Ellington Field, Texas, during August and September 2013 employed the most comprehensive airborne payload to date to investigate atmospheric composition over North America. The NASA ER-2, DC-8, and SPEC Inc. Learjet flew 57 science flights from the surface to 20 km. The ER-2 employed seven remote sensing instruments as a satellite surrogate and eight in situ instruments. The DC-8 employed 23 in situ and five remote sensing instruments for radiation, chemistry, and microphysics. The Learjet used 11 instruments to explore cloud microphysics. SEAC4RS launched numerous balloons, augmented Aerosol RObotic NETwork, and collaborated with many existing ground measurement sites. Flights investigating convection included close coordination of all three aircraft. Coordinated DC-8 and ER-2 flights investigated the optical properties of aerosols, the influence of aerosols on clouds, and the performance of new instruments for satellite measurements of clouds and aerosols. ER-2 sorties sampled stratospheric injections of water vapor and other chemicals by local and distant convection. DC-8 flights studied seasonally evolving chemistry in the Southeastern U.S., atmospheric chemistry with lower emissions of NOx and SO2 than in previous decades, isoprene chemistry under high and low NOx conditions at different locations, organic aerosols, air pollution near Houston and in petroleum fields, smoke from wildfires in western forests and from agricultural fires in the Mississippi Valley, and the ways in which the chemistry in the boundary layer and the upper troposphere were influenced by vertical transport in convective clouds.

Toon, Owen B.↗
NASA NTRS2018

Building a QC Database of Meteorological Data From NASA KSC and the United States Air Force's Eastern Range

The National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC) Natural Environments Branch (EV44) has provided atmospheric databases and analysis in support of space vehicle design and day-of-launch operations for NASA and commercial launch vehicle programs launching from the NASA Kennedy Space Center (KSC), co-located on the United States Air Force's Eastern Range (ER) at the Cape Canaveral Air Force Station. The ER is one of the most heavily instrumented sites in the United States measuring various atmospheric parameters on a continuous basis. An inherent challenge with the large databases that EV44 receives from the ER consists of ensuring erroneous data are removed from the databases, and thus excluded from launch vehicle design analyses. EV44 has put forth great effort in developing quality control (QC) procedures for individual meteorological instruments; however, no standard QC procedures for all databases currently exist resulting in QC databases that have inconsistencies in variables, methodologies, and periods of record. The goal of this activity is to use the previous efforts by EV44 to develop a standardized set of QC procedures from which to build flags within the meteorological databases from KSC and the ER, while maintaining open communication with end users from the launch community to develop ways to improve, adapt and grow the QC database. Details of the QC checks are described. The flagged data points will be plotted in a graphical user interface (GUI) as part of a manual confirmation that the flagged data do indeed need to be removed from the archive. As the rate of launches increases with additional launch vehicle programs, more emphasis is being placed to continually update and check weather databases for data quality before use in launch vehicle design and certification analyses.

Brenton, James C.↗
NASA NTRSDate not supplied

Characteristics and Origins of Frontal Convection During IMPACTS on 25 January 2020

This presentation will discuss the characteristics of frontal convection and its estimation from the ER-2 multifrequency nadir reflectivity and Doppler velocity from a warm-occlusion frontal system that traversed across the Northeast U.S. on 25 January 2020. This system that occurred during the IMPACTS field deployment, brought widespread clouds and precipitation to the Northeast. The system brought primarily rain in most areas of more intense rainfall associated with embedded convection near the frontal band and some freezing rain and/or snowfall in the northern regions or higher terrain due to the pre-existing low-level cold air. The NASA ER-2 instrumented with multifrequency radar and the NASA P-3 with in situ microphysics measurements both collected data from this system. The focus of this presentation is on the estimation of vertical velocity in convective and non-convective regions using the ER-2 nadir Doppler measurements. Vertical velocities are inherently difficult to estimate in frontal systems at mesoscale and below other than from direct in situ measurement because of their small magnitudes and errors in the measurements. Estimates from nadir Doppler measurements such as from the ER-2 are challenging because of both Doppler velocity uncertainties and the need to estimate particle fallspeed since the Doppler measurement is the vertical velocity plus the hydrometeor fallspeed. In the presentation, the vertical velocity estimation, its associated errors, and a possible mitigation scheme are described. The characteristics of the convective and stratiform regions on 25 January 2020 are discussed. The vertical velocity estimated from the nadir Doppler measurements are compared with P-3 in situ measurements. Estimation of vertical velocity is one of the goals for upcoming spaceborne missions such as EarthCare and ACCP.

Gerald M. Heymsfield↗
NASA NTRSDate not supplied

Generation of Merged Radar-Lidar Data Products during the IMPACTS 2020 Field Campaign

A novel, composite lidar and radar data products was created using lidar and radar data products generated from the NASA ER-2 aircraft during the NASA IMPACTS 2020 field campaign. This product is intended to supplement the raw data sources, tease out additional aspects of the mechanisms underpinning wintertime cyclones, and enhance our understanding of microphysical properties in sensor overlap regions. Initial combined products focused on generating normalized fields of ER-2 based radar and lidar data to provide a more comprehensive visualization of storm structure (precipitation bands, cloud tops, melting levels, etc.) Ongoing work has focused on developing a combined radar-lidar reflectivity product and deriving hydrometeor particle properties (type, orientation, etc.) using ER-2-based depolarization data. To validate these hydrometeor properties, we leverage coincident overpasses of the high-altitude ER-2 aircraft with the suite of cloud particle probes on the in-situ P-3 aircraft during coincident flight overpasses. This work aims to provide vital information to help IMPACTS achieve its mission goal of improving microphysical properties retrievals from airborne and spaceborne platforms for these high-impact winter storm events.

Stephen D Nicholls↗
NASA NTRSDate not supplied

Evaluation of Present and Future Spaceborne Lightning Observations During the ALOFT Campaign

The ALOFT1 campaign took place during July 2023. The NASA ER-2 high-altitude aircraft was based in Tampa, Florida, and flew approximately 60 hours sampling tropical and sub-tropical thunderstorms that were mostly contained within the common fields of view of GLM4-16 and GLM-18. In addition, multiple underflights of the ISS LIS5 instrument occurred. The FEGS2 and LIP6 instrument suite on the ER-2 provided a combination of multispectral optical, slow and fast electric field change, and three-dimensional electric field measurements of lightning and thunderstorms. Notably, in addition to the 777-nm band used by GLM and LIS, FEGS also observed at 337 nm, 500 nm, 868 nm, wideband visible-to-infrared, and shortwave infrared. A spectrometer that spanned most major lightning bands from the ultraviolet to infrared was included. Observations of gamma-ray production by thunderstorms were also collected during ALOFT. Thus, the lightning-observing suite on the ER-2 during ALOFT provides an unprecedented suborbital dataset for direct optical-to-optical and indirect radio-to-optical validation of existing spaceborne lightning sensors like GLM and LIS. In addition, the multispectral observations from FEGS enables evaluation of current and future spaceborne lightning-observing concepts. For example, the 337-nm channel is relevant to both existing missions like ASIM7 as well as future concepts like the CubeSpark mission currently being formulated by NASA. Complementary to LIS, the ISS also carries the STP-H88 payload, which features microwave radiometers covering 18-182 GHz, while the ER-2 carried radiometers covering 10-684 GHz, enabling evaluation of spaceborne passive microwave measurements that are complementary to the lightning observations. 1. Airborne Lightning Observatory for FEGS2 and TGFs3 2. Fly’s Eye GLM4 Simulator 3. Terrestrial Gamma-ray Flashes 4. Geostationary Lightning Mapper 5. International Space Station Lightning Imaging Sensor 6. Lightning Instrument Package 7. Atmosphere-Space Interactions Monitor 8. 8th Space Test Program – Houston mission

Timothy Lang↗
NASA NTRSDate not supplied

Development of Luminescence Lifetime-Based Surface Temperature Mapping for Environmental Barrier Coatings

Luminescence lifetime-based temperature mapping for thermal barrier coatings (TBCs) has been previously demonstrated up to temperatures approaching 1200 °C. Advantages of this method include insensitivities to reflected radiation and emissivity uncertainties. Because of a push towards greater efficiency turbine engine operation using higher turbine inlet temperatures, there is an ongoing movement from TBC-coated superalloy turbine engine components to SiC/SiC ceramic matrix composite components protected by environmental barrier coatings (EBCs). The useful application of luminescence lifetime-based temperature mapping to EBCs requires a significant increase in high temperature capability from below 1200 °C up into the 1300 to 1500 °C temperature range where the much higher background thermal radiation is a challenging issue. In addition, the luminescing sensing layer must exhibit thermochemical compatibility with the EBC. To meet these requirements, Er-doped Y 2 SiO 5 was selected as the luminescing sensor layer material both for its enhanced temperature sensitivity above 1300 °C and its compatibility with rare-earth disilicate EBC topcoats. Both localized spot temperature measurements as well as luminescence lifetime imaging-based temperature mapping were demonstrated up to 1560 °C for Er-doped Y 2 SiO 5 disks. In addition, temperature mapping capability was demonstrated from a 15 µm thick Er-doped Y 2 SiO 5 layer at the surface of a Sc 2 Si 2 O 7 based EBC topcoat. Both localized spot and temperature mapping by luminescence lifetime imaging were demonstrated up to 1380 °C (upper temperature limit of this slurry-based layered EBC) with excellent suppression of background thermal radiation and no degradation of the Er-doped Y 2 SiO 5 temperature sensing surface layer. The source of the novel enhanced temperature sensitivity above 1300 °C will be discussed as well as a path towards compatibility between sensing layer and EBC topcoat to higher temperatures.

temperature measurement↗
DOE OSTI2024

Flame Flashback Investigations in Hydrogen-Enriched Low Swirl Flames using High-Speed Hydroxyl (OH) Planar Laser-Induced Fluorescence

This study reports flashback mechanism observed in hydrogen-enriched flames stabilized in a low swirl burner (LSB) at atmospheric pressure and temperature conditions. The fundamentals of hydrogen-rich stable flames and spatiotemporal investigation of flashback phenomena were observed experimentally using a high-repetition-rate nanosecond (ns)-duration hydroxyl radical planar laser-induced fluorescence (OH-PLIF) diagnostic. Testing was conducted in an optically accessible pre-mixing section of LSB with inlet pre-mixing velocities from 5 to 10 m/s for methane and hydrogen (50 – 90% by mole) blends. Swirlers with two different turning angles, 26 and 33 degrees and three different perforated plate hole diameters, 1.08, 1.12 and 1.16 mm with measured swirl numbers varying from 0.43 to 0.49 were used. The flashback propensity showed dependence on the proximity of the lifted flame to the burner exit which was dependent on pre-mixer velocity, hydrogen content and equivalence ratio (ER). High-speed OH-PLIF images revealed lifted flames were first observed at low ER condition which is changed to M-shaped flame attached to burner rim with the increase in ER. Then, further increase in ER triggers flame flashback into the nozzle. Flashback occurred when burning occurs in the outer shear layer and the leading flame brush ingresses into the nozzle.

Parajuli, Pradeep↗
DOE OSTI2020

Materials Data on Er3AlC by Materials Project

Er3AlC is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional and consists of one methane molecule and one Er3Al framework. In the Er3Al framework, Er is bonded in a linear geometry to two equivalent Al atoms. Both Er–Al bond lengths are 2.65 Å. Al is bonded to six equivalent Er atoms to form corner-sharing AlEr6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErBPd3 by Materials Project

ErPd3B is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Er is bonded to twelve equivalent Pd atoms to form ErPd12 cuboctahedra that share corners with twelve equivalent ErPd12 cuboctahedra, faces with six equivalent ErPd12 cuboctahedra, and faces with eight equivalent BPd6 octahedra. All Er–Pd bond lengths are 3.04 Å. Pd is bonded to four equivalent Er and two equivalent B atoms to form a mixture of distorted edge, corner, and face-sharing PdEr4B2 octahedra. The corner-sharing octahedra tilt angles range from 0–60°. Both Pd–B bond lengths are 2.15 Å. B is bonded to six equivalent Pd atoms to form BPd6 octahedra that share corners with six equivalent BPd6 octahedra and faces with eight equivalent ErPd12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er3GaC by Materials Project

Er3GaC is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional and consists of one methane molecule and one Er3Ga framework. In the Er3Ga framework, Er is bonded in a linear geometry to two equivalent Ga atoms. Both Er–Ga bond lengths are 2.63 Å. Ga is bonded to six equivalent Er atoms to form corner-sharing GaEr6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er3InC by Materials Project

Er3InC is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional and consists of one methane molecule and one Er3In framework. In the Er3In framework, Er is bonded in a linear geometry to two equivalent In atoms. Both Er–In bond lengths are 2.77 Å. In is bonded to six equivalent Er atoms to form corner-sharing InEr6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er2AlSi2 by Materials Project

Er2AlSi2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Er is bonded in a 10-coordinate geometry to six equivalent Si atoms. There are four shorter (2.97 Å) and two longer (2.99 Å) Er–Si bond lengths. Al is bonded in a 12-coordinate geometry to four equivalent Si atoms. All Al–Si bond lengths are 2.62 Å. Si is bonded in a 9-coordinate geometry to six equivalent Er, two equivalent Al, and one Si atom. The Si–Si bond length is 2.41 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErTl by Materials Project

ErTl is Tetraauricupride structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Er is bonded in a distorted body-centered cubic geometry to eight equivalent Tl atoms. All Er–Tl bond lengths are 3.29 Å. Tl is bonded in a distorted body-centered cubic geometry to eight equivalent Er atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErAu by Materials Project

ErAu is alpha-derived structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Er is bonded in a 7-coordinate geometry to seven equivalent Au atoms. There are a spread of Er–Au bond distances ranging from 2.96–3.10 Å. Au is bonded in a 7-coordinate geometry to seven equivalent Er atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErHg2 by Materials Project

ErHg2 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Er is bonded to twelve equivalent Hg atoms to form a mixture of distorted edge and face-sharing ErHg12 cuboctahedra. All Er–Hg bond lengths are 3.33 Å. Hg is bonded in a 9-coordinate geometry to six equivalent Er and three equivalent Hg atoms. All Hg–Hg bond lengths are 2.85 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErIn by Materials Project

ErIn is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Er is bonded in a body-centered cubic geometry to eight equivalent In atoms. All Er–In bond lengths are 3.23 Å. In is bonded in a body-centered cubic geometry to eight equivalent Er atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErInPd2 by Materials Project

ErPd2In is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Er is bonded in a body-centered cubic geometry to eight equivalent Pd atoms. All Er–Pd bond lengths are 2.93 Å. Pd is bonded in a body-centered cubic geometry to four equivalent Er and four equivalent In atoms. All Pd–In bond lengths are 2.93 Å. In is bonded in a distorted body-centered cubic geometry to eight equivalent Pd atoms.

36 MATERIALS SCIENCE↗