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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

A Variational Formalism for the Radiative Transfer Equation: Prelude to Model 3

The MODEL III variational data assimilation model is the third of four general assimilation models designed to blend weather data measured from space based platforms in the meteorological data mainstream in a way that maximizes the information content of the satellite data. Because there are many different observation locations and there are many instruments with different measurement error characteristics, it is also necessary to require that the blending be done to maximize the information content of the data and simultaneously to retain a dynamically consistent and reasonably accurate description of the state of the atmosphere. This is ideally a variational problem for which the data receive relative weights that are inversely proportional to measurement error and are adjusted to satisfy a set of dynamical equations that govern atmospheric processes. The advantage of MODEL III over the previous two models is that radiance, the atmospheric variable measured by satellite, becomes a dependent variable. In the previous versions, mean layer temperatures that had been retrieved from the radiances by some method, were included in the assimilation by substituting them in place of the rawinsonde temperatures. Now both rawinsonde temperatures and satellite radiances are included independently in the assimilation.

Achtemeier, Gary L.↗
NASA NTRS2009

A First Look at Carbon and Oxygen Stable Isotope Measurements of Martian Atmospheric C02 by the Phoenix Lander

Precise stable isotope measurements of the CO2 in the martian atmosphere have the potential to provide important constraints for our understanding of the history of volatiles, the carbon cycle, current atmospheric processes, and the degree of water/rock interaction on Mars. The isotopic composition of the martian atmosphere has been measured using a number of different methods (Table 1), however a precise value (<1%) has yet to be achieved. Given the elevated 13C values measured in carbonates in martian meteorites it has been supposed that the martian atmosphere was enriched in delta(sup 13)C. This was supported by measurements of trapped CO2 gas in EETA 79001[2] which showed elevated delta(sup 13)C values (Table 1). More recently, Earth-based spectroscopic measurements of the martian atmosphere have measured the martian CO2 to be depleted in delta(sup 13)C relative to CO2 in the terrestrial atmosphere. The spectroscopic measurements performed by Krasnopolsky et al. were reported with approx.2% uncertainties which are much smaller than the Viking measurements, but still remain very large in comparison to the magnitude of carbon and oxygen isotope fractionations under martian surface conditions. The Thermal Evolved Gas Analyzer (TEGA) instrument on the Mars Phoenix Lander included a magnetic sector mass spectrometer (EGA) which had the goal of measuring the isotopic composition of martian atmospheric CO2 to within 0.5%. The mass spectrometer is a miniature magnetic sector instrument intended to measure both the martian atmosphere as well as gases evolved from heating martian soils. Ions produced in the ion source are drawn out by a high voltage and focused by a magnetic field onto a set of collector slits. Four specific trajectories are selected to cover the mass ranges, 0.7 - 4, 7 - 35, 14 - 70, and 28 - 140 Da. Using four channels reduces the magnitude of the mass scan and provides simultaneous coverage of the mass ranges. Channel electron multiplier (CEM) detectors that operate in the pulse counting mode detect the ion beams.

Niles, P.B.↗
NASA NTRS1979

Proceedings: Workshop on the Need for Lightning Observations from Space

The results of the Workshop on the Need for Lightning Observations from Space held February 13-15, 1979, at the University of Tennessee Space Institute, Tullahoma, Tennessee are presented. The interest and active involvement by the engineering, operational, and scientific participants in the workshop demonstrated that lightning observations from space is a goal well worth pursuing. The unique contributions, measurement requirements, and supportive research investigations were defined for a number of important applications. Lightning has a significant role in atmospheric processes and needs to be systematically investigated. Satellite instrumentation specifically designed for indicating the characteristics of lightning are of value in severe storms research, in engineering and operational problem areas, and in providing information on atmospheric electricity and its role in meteorological processes.

Christensen, L. S.↗
NASA NTRS1984

Present state of knowledge of the upper atmosphere: An assessment report

A program of research, technology, and monitoring of the phenomena of the upper atmosphere, to provide for an understanding of and to maintain the chemical and physical integrity of the Earth's upper atmosphere was developed. NASA implemented a long-range upper atmospheric science program aimed at developing an organized, solid body of knowledge of upper atmospheric processes while providing, in the near term, assessments of potential effects of human activities on the atmosphere. The effects of chlorofluorocarbon (CFC) releases on stratospheric ozone were reported. Issues relating the current understanding of ozone predictions and trends and highlights recent and future anticipated developments that will improve our understanding of the system are summarized.

Source record↗
NASA NTRS2000

Advanced Concepts, Technologies and Flight Experiments for NASA's Earth Science Enterprise

Over the last 25 years, NASA Langley Research Center (LaRC) has established a tradition of excellence in scientific research and leading-edge system developments, which have contributed to improved scientific understanding of our Earth system. Specifically, LaRC advances knowledge of atmospheric processes to enable proactive climate prediction and, in that role, develops first-of-a-kind atmospheric sensing capabilities that permit a variety of new measurements to be made within a constrained enterprise budget. These advances are enabled by the timely development and infusion of new, state-of-the-art (SOA), active and passive instrument and sensor technologies. In addition, LaRC's center-of-excellence in structures and materials is being applied to the technological challenges of reducing measurement system size, mass, and cost through the development and use of space-durable materials; lightweight, multi-functional structures; and large deployable/inflatable structures. NASA Langley is engaged in advancing these technologies across the full range of readiness levels from concept, to components, to prototypes, to flight experiments, and on to actual science mission infusion. The purpose of this paper is to describe current activities and capabilities, recent achievements, and future plans of the integrated science, engineering, and technology team at Langley Research Center who are working to enable the future of NASA's Earth Science Enterprise.

Meredith, Barry D.↗
NASA NTRS2010

Carbon and Oxygen Stable Isotope Measurements of Martian Atmospheric CO2 by the Phoenix Lander

Precise stable isotope measurements of the CO2 in the martian atmosphere have the potential to provide important constraints for our understanding of the history of volatiles, the carbon cycle, current atmospheric processes, and the degree of water/rock interaction on Mars [1]. The isotopic composition of the martian atmosphere has been measured using a number of different methods (Table 1), however a precise value (<1%) has yet to be achieved. Given the elevated Delta(sup 13)C values measured in carbonates in martian meteorites [2-4] it has been proposed that the martian atmosphere was enriched in 13C [8]. This was supported by measurements of trapped CO2 gas in EETA 79001[2] which showed elevated Delta(sup 13)C values (Table 1). More recently, Earth-based spectroscopic measurements of the martian atmosphere have measured the martian CO2 to be depleted in C-13 relative to CO2 in the terrestrial atmosphere[ 7, 9-11]. The Thermal and Evolved Gas Analyzer (TEGA) instrument on the Mars Phoenix Lander [12] included a magnetic-sector mass spectrometer (EGA) [13] which had the goal of measuring the isotopic composition of martian atmospheric CO2 to within 0.5%. The mass spectrometer is a miniature instrument intended to measure both the martian atmosphere as well as gases evolved from heating martian soils.

Niles, Paul B.↗
NASA NTRS2014

Limb Correction of RGB Composite Imagery for Improved Interpretation

RGB (Red‐Green‐Blue) imagery, created by integrating several spectral channels into one composite image, is currently used by the operational weather community to aid in quick, real‐time analysis of atmospheric processes. However, the limb effect - a result of an increasing optical path length of the absorbing atmosphere between the satellite and the earth as scan angle increases - interferes with the qualitative interpretation of RGB composites at large scan angles. It also makes the comparison of similar products from multiple satellite sensors difficult. Recent work has indicated that correcting for the limb effect in the basic channel imagery using simple statistical relationships greatly improves the utility of the derived RGB imagery. However, it is hypothesized that the limb correction coefficients vary with respect to latitude, season, cloud cover, and surface albedo. This poster will highlight an improved approach to the limb correction of RGB imagery using varying coefficients. The Joint Center for Satellite and Data Assimilation (JCSDA) Community Radiative Transfer Model (CRTM) was used to simulate top of atmosphere brightness temperatures at varying scan angles for infrared channels corresponding to the Aqua and Terra Moderate Resolution Imaging Spectroradiometer (MODIS), Suomi NPP Visible Infrared Imaging Radiometer Suite (VIIRS), and Meteosat‐10 Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensors. A subset of European Center for Medium‐Range Weather Forecasts (ECMWF) temperature, specific humidity, and ozone mixing ratio profiles from March 2013 through February 2014 were used as input to the CRTM. The simulated brightness temperatures were used to determine the best fit slope of the linear relationship between the natural log of the cosine of the scan angle and the difference of the simulated brightness temperature at nadir and on the limb. The correction coefficients were then analyzed for variability with respect to latitude, season, cloud cover, and surface type and used to produce improved limb corrected imagery. Applications of the results will be presented.

Elmer, Nicholas↗
NASA NTRS2019

Coupled Modes of North Atlantic Ocean Atmosphere Variability and the Onset of the Little Ice Age

Hydroclimate extremes in North America, Europe, and the Mediterranean are linked to ocean and atmospheric circulation anomalies in the Atlantic, but the limited length of the instrumental record prevents complete identification and characterization of these patterns of covariability especially at decadal to centennial timescales. Here we analyze the coupled patterns of drought variability on either side of the North Atlantic Ocean basin using independent climate field reconstructions spanning the last millennium in order to detect and attribute epochs of coherent basinwide moisture anomalies to ocean and atmosphere processes. A leading mode of broadscale moisture variability is characterized by distinct patterns of North Atlantic atmosphere circulation and sea surface temperatures.

Kevin J Anchukaitis↗
NASA NTRS1993

NASA/MSFC FY92 Earth Science and Applications Program Research Review

A large amount of attention has recently been given to global issues such as the ozone hole, tropospheric temperature variability, etc. A scientific challenge is to better understand atmospheric processes on a variety of spatial and temporal scales in order to predict environmental changes. Measurement of geophysical parameters such as wind, temperature, and moisture are needed to validate theories, provide analyzed data sets, and initialize or constrain numerical models. One of NASA's initiatives is the Mission to Planet Earth Program comprised of an Earth Observation System (EOS) and the scientific strategy to analyze these data. This work describes these efforts in the context of satellite data analysis and fundamental studies of atmospheric dynamics which examine selected processes important to the global circulation.

Arnold, James E.↗
DOE OSTI2023

Sensitivities of subgrid-scale physics schemes, meteorological forcing, and topographic radiation in atmosphere-through-bedrock integrated process models: a case study in the Upper Colorado River basin

Abstract. Mountain hydrology is controlled by interacting processes extending from the atmosphere through the bedrock. Integrated process models (IPMs), one of the main tools needed to interpret observations and refine conceptual models of the mountainous water cycle, require meteorological forcing that simulates the atmospheric process to predict hydroclimate then subsequently impacts surface–subsurface hydrology. Complex terrain and extreme spatial heterogeneity in mountainous environments drive uncertainty in several key considerations in IPM configurations and require further quantification and sensitivity analyses. Here, we present an IPM using the Weather Research and Forecasting (WRF) model which forces an integrated hydrologic model, ParFlow-CLM, implemented over a domain centered over the East River watershed (ERW), located in the Upper Colorado River basin (UCRB). The ERW is a heavily instrumented 300 km2 region in the headwaters of the UCRB near Crested Butte, CO, with a growing atmosphere-through-bedrock observation network. Through a series of experiments in the water year 2019 (WY19), we use four meteorological forcings derived from commonly used reanalysis datasets, three subgrid-scale physics scheme configurations in WRF, and two terrain shading options within WRF to test the relative importance of these experimental design choices for key hydrometeorological metrics including precipitation and snowpack, as well as evapotranspiration, groundwater storage, and discharge simulated by the ParFlow-CLM. Our hypothesis is that uncertainty from synoptic-scale forcings produces a much larger spread in surface–subsurface hydrologic fields than subgrid-scale physics scheme choice. Results reveal that the WRF subgrid-scale physics configuration leads to larger spatiotemporal variance in simulated hydrometeorological conditions, whereas variance across meteorological forcing with common subgrid-scale physics configurations is more spatiotemporally constrained. Despite reasonably simulating precipitation, a delay in simulated discharge peak is due to a systematic cold bias across WRF simulations, suggesting the need for bias correction. Discharge shows greater variance in response to the WRF simulations across subgrid-scale physics schemes (26 %) rather than meteorological forcing (6 %). The topographic radiation option has minor effects on the watershed-average hydrometeorological processes but adds profound spatial heterogeneity to local energy budgets (±30 W m−2 in shortwave radiation and 1 K air temperature differences in late summer). This is the first presentation of sensitivity analyses that provide support to help guide the scientific community to develop observational constraints on atmosphere-through-bedrock processes and their interactions.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Molecular Characterization of Brown Carbon in Biomass Burning Aerosol Particles

Emissions from biomass burning are a significant source of brown carbon (BrC) in the atmosphere. In this study, we investigate the molecular composition of freshly-emitted biomass burning organic aerosol (BBOA) samples collected during test burns of selected biomass fuels: sawgrass, peat, ponderosa pine, and black spruce. We characterize individual BrC chromophores present in these samples using high performance liquid chromatography coupled to a photodiode array detector and a high-resolution mass spectrometer. We demonstrate that both the overall BrC absorption and the chemical composition of light-absorbing compounds depend significantly on the type of biomass fuels and burning conditions. Common BrC chromophores in the selected BBOA samples include nitro-aromatics, polycyclic aromatic hydrocarbon derivatives, and polyphenols spanning a wide range of molecular weights, structures, and light absorption properties. A number of biofuel-specific BrC chromophores are observed, indicating that some of them may be used as potential markers of BrC originating from different biomass burning sources. On average, ~50% of the light absorption above 300 nm can be attributed to a limited number of strong BrC chromophores, which may serve as representative light-absorbing species for studying atmospheric processing of BrC aerosol. The absorption coefficients of BBOA are affected by solar photolysis. Specifically, under typical atmospheric conditions, the 300 nm absorbance decays with a half-life of 16 hours. A “molecular corridors” analysis of the BBOA volatility distribution suggests that many BrC compounds in the fresh BBOA have low volatility (<1 g m-1) and will be retained in the particle phase under atmospherically relevant conditions.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2016

Current understanding of structure-processing-property relationships in BaTiO 3 -Bi( M )O 3 dielectrics

Here, as part of a continued push for high permittivity dielectrics suitable for use at elevated operating temperatures and/or large electric fields, modifications of BaTiO 3 with Bi( M )O 3 , where M represents a net-trivalent B-site occupied by one or more species, have received a great deal of recent attention. Materials in this composition family exhibit weakly coupled relaxor behavior that is not only remarkably stable at high temperatures and under large electric fields, but is also quite similar across various identities of M . Moderate levels of Bi content (as much as 50 mol%) appear to be crucial to the stability of the dielectric response. In addition, the presence of significant Bi reduces the processing temperatures required for densification and increases the required oxygen content in processing atmospheres relative to traditional X7R-type BaTiO 3 -based dielectrics. Although detailed understanding of the structure–processing–property relationships in this class of materials is still in its infancy, this article reviews the current state of understanding of the mechanisms underlying the high and stable values of both relative permittivity and resistivity that are characteristic of BaTiO 3 -Bi( M )O 3 dielectrics as well as the processing challenges and opportunities associated with these materials.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Atmospheric Radiation Measurement (ARM) Aerosol Observing Systems (AOS) for Surface-Based In Situ Atmospheric Aerosol and Trace Gas Measurements

Aerosols alter Earth’s radiative budget both directly and indirectly through interaction with clouds. Continuous observations are required to reduce the uncertainties in climate models associated with atmospheric processing and the interactions between aerosols and clouds. Field observations of aerosols are a central component of the Atmospheric Radiation Measurement (ARM) Facility’s global measurements. The ARM mission goal is to “provide the climate research community with strategically located in situ and remote sensing observatories designed to improve the understanding and representation, in climate and earth system models, of clouds and aerosols as well as their interactions and coupling with the Earth’s surface.” Since 1996, ARM has met this goal by operating Aerosol Observing Systems (AOS) for in situ measurement of aerosols. Currently the five ARM AOSs are the most comprehensive field deployable aerosol systems in the United States. The AOS suite includes seven measurement classes: number concentration, size distribution, chemical composition, radiative and optical properties, hygroscopicity, trace gases, and supporting meteorological conditions. AOSs are designed as standardized measurement platforms to enable intercomparison across the ARM Facility for regional process studies within a global context. The instrumentation and measurement capabilities of the ARM AOSs, along with a history of their design and field deployments are presented here.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Functionalization of polymer powders for SLS-processes using an atmospheric plasma jet in a fluidized bed reactor

Recently additive manufacturing processes such as selective laser sintering (SLS) of polymers have gained more importance for industrial applications [1]. Tailor-made modification of polymers is essential in order to make these processes more efficient and to cover the industrial demands. The so far used polymer materials show weak performance regarding the mechanical stability of processed parts. To overcome this limitation, a new route to functionalize the surface of commercially available polymer particles (PA12; PE-HD; PP) using an atmospheric plasma jet in combination with a fluidized bed reactor has been investigated. Consequently, an improvement of adhesion and wettability [2] of the polymer surface without restraining the bulk properties of the powder is achieved. The atmospheric plasma jet process can provide reactive species at moderate temperatures which are suitable for polymer material. The functionalization of the polymer powders improves the quality of the devices build in a SLS-process.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1984

Neutral Atmosphere Properties Determining D-region Electron Densities

The increasing discoveries of various manifestations of meteorological control of the D region ionization and the growth of techniques for its measurement provide a challenge to meteorologists to test their insight into middle atmosphere processes with the physical interpretation of D layer phenomena. Models for ion production due to photoionization of minor atmospheric nitric oxide by quasi-monochromatic solar Lyman-alpha radiation are presented. A ground based measuring technique using low frequency radio reflection heights is briefly described and an approach to the interpretation of data acquired by this method is discussed. It is shown that D region electron density variations can provide an efficient diagnostic tool for the detection of perturbations of the circulation state of the middle atmosphere.

Taubenheim, J.↗
NASA NTRS2019

Coupled Modes of North Atlantic Ocean Atmosphere Variability and the Onset of the Little Ice Age

Hydroclimate extremes in North America, Europe, and the Mediterranean are linked to ocean and atmospheric circulation anomalies in the Atlantic, but the limited length of the instrumental record prevents complete identification and characterization of these patterns of covariability especially at decadal to centennial timescales. Here we analyze the coupled patterns of drought variability on either side of the North Atlantic Ocean basin using independent climate field reconstructions spanning the last millennium in order to detect and attribute epochs of coherent basin-wide moisture anomalies to ocean and atmosphere processes. A leading mode of broad-scale moisture variability is characterized by distinct patterns of North Atlantic atmosphere circulation and sea surface temperatures. We infer a negative phase of the North Atlantic Oscillation and colder Atlantic sea surface temperatures in the middle of the 15th century, coincident with weaker solar irradiance and prior to strong volcanic forcing associated with the early Little Ice Age.

Kevin J Anchukaitis↗
NASA NTRSDate not supplied

Enabling Exchange and Adequate Use of Data for Observation Based Atmospheric Research

Systematic long-term field observations have played a vital role in advancing atmospheric research over the past several decades. The use of these observations has expanded from primarily characterizing atmospheric processes and trends to evaluating satellite measurements, assessing models, and improving air quality forecasts. Consequently, the demand for atmospheric chemistry observational data have dramatically increased in terms of scope and coverage of measurements (i.e., parameters/species, spatiotemporal extent). In addition to high quality measurements, certain data reporting standards need to be agreed to ensure the data can be readily exchanged and are sufficiently documented to enable adequate use in different research activities. To this end, WMO has developed and implemented measurement guidelines and community practices for meteorology, climatology, atmospheric and hydrological sciences. In addition, the WMO Expert Team on Metadata Standards manages and evolves the existing metadata standards for the WMO Information System WIS and WMO Integrated Global Observing System WIGOS to support consistent and interoperable data descriptions, ensure relevance to research, and to apply data science principles. This team draws on a wide range of expertise from the research community, including atmospheric measurements, modeling, data management, and data science. The current activities include development of key performance indicators, vocabularies for metadata and the evolution of metadata standards to lower the barrier of application to weather/climate/water/environment data for all communities and the weather enterprise. This presentation intends to promote awareness of ongoing progress and actively solicit community feedback.

Field Observations↗