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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Greater committed warming after accounting for the pattern effect

Our planet’s energy balance is sensitive to spatial inhomogeneities in sea surface temperature and sea ice changes, but this is typically ignored in climate projections. Here, we show the energy budget during recent decades can be closed by combining changes in effective radiative forcing, linear radiative damping and this pattern effect. The pattern effect is of comparable magnitude but opposite sign to Earth’s net energy imbalance in the 2000s, indicating its importance when predicting the future climate on the basis of observations. Additionally, after the pattern effect is accounted for, the best-estimate value of committed global warming at present-day forcing rises from 1.31 K (0.99–2.33 K, 5th–95th percentile) to over 2 K, and committed warming in 2100 with constant long-lived forcing increases from 1.32 K (0.94–2.03 K) to over 1.5 K, although the magnitude is sensitive to sea surface temperature dataset. Further constraints on the pattern effect are needed to reduce climate projection uncertainty.

58 GEOSCIENCES↗
DOE OSTI2022

Solitary Magnetic Structures Developed From Gyro-Resonance With Solar Wind Ions at Mars and Earth

We investigate solitary magnetic structures in the foreshock of Mars and Earth. The structures exhibit pulse-like magnetic field and density enhancements along with plasma heating and local solar wind (SW) ion reflection. The structures at Mars resemble the foreshock structures developed from ultra-low-frequency electromagnetic waves gyro-resonant with SW ions at Earth, and propagate toward the magnetosphere. We perform fully kinetic simulations to reproduce the solitary structures and the nonlinear evolution of ion distribution functions, illustrating their resonance with SW ions. The structures present self-induced foreshock turbulence that can have space weather effects. Our results advance the fundamental understanding of how SW interacts with planetary magnetospheres, and have potential impact on the current picture of planet-origin ion escape.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

The Dynamics of Interstellar Asteroids and Comets within the Galaxy: An Assessment of Local Candidate Source Regions for 1I/’Oumuamua and 2I/Borisov

The low velocity of interstellar asteroid 1I/’Oumuamua with respect to our galaxy’s local standard of rest implies that it is young. Adopting the young age hypothesis, we assess possible origin systems for this interstellar asteroid and for 2I/Borisov, though the latter’s higher speed means it is unlikely to be young. First, their past trajectories are modeled under gravitational scattering by galactic components (“disk heating”) to assess how far back one can trace them. The stochastic nature of disk heating means that a back integration can only expect to be accurate to within 15 pc and 2 km s{sup −1} at −10 Myr, dropping steeply to 400 pc and 10 km s{sup −1} at −100 Myr, sharply limiting our ability to determine a precise origin. Nevertheless, we show that ’Oumuamua’s origin system likely is currently within 1 kpc of Earth, in the local Orion Arm. Second, we back integrate ’Oumuamua’s trajectory in order to assess source regions, emphasizing young systems and moving groups. Though disk heating allows for only a statistical link to source regions, ’Oumuamua passed through a considerable subset of the Carina and Columba moving groups when those groups were forming. This makes them perhaps the most plausible source region, if ’Oumuamua was ejected during planet formation or via intra-cluster interactions. We find three stars in the Ursa Major group, one brown dwarf, and seven other stars to have plausible encounters with 2I/Borisov, within 2 pc and 30 km s{sup −1}. These encounters’ high relative speeds mean none are likely to be the home of 2I/Borisov.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Multi-Scale Land-Atmosphere Interactions: Modeling Convective Processes from Plants to Planet

Research accomplishments include: 1)Two case studies of the effects of heterogeneous soil moisture and surface energy budgets on organization and propagation of convective precipitation during MC3E. 2) Development and evaluation of a new approach for simulating the effect of heterogeneous soil moisture at ARM-SGP using an innovative modeling approach. 3) Investigation of the effects of spatial coupling scale using multidecade global simulations in CESM with the multiscale modeling framework. 4) Exploration of changes to future precipitation intensity resulting from two different climate change scenarios using the multiscale model. 5) Provision of the new cloud-scale coupled multiscale Earth System Model to the larger community through the CESM process.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Stability of hydrides in sub-Neptune exoplanets with thick hydrogen-rich atmospheres

Many sub-Neptune exoplanets have been believed to be composed of a thick hydrogen-dominated atmosphere and a high-temperature heavier-element-dominant core. From an assumption that there is no chemical reaction between hydrogen and silicates/metals at the atmosphere–interior boundary, the cores of sub-Neptunes have been modeled with molten silicates and metals (magma) in previous studies. In large sub-Neptunes, pressure at the atmosphere–magma boundary can reach tens of gigapascals where hydrogen is a dense liquid. A recent experiment showed that hydrogen can induce the reduction of Fe 2+ in (Mg,Fe)O to Fe 0 metal at the pressure–temperature conditions relevant to the atmosphere–interior boundary. However, it is unclear whether Mg, one of the abundant heavy elements in the planetary interiors, remains oxidized or can be reduced by H. Our experiments in the laser-heated diamond-anvil cell found that heating of MgO + Fe to 3,500 to 4,900 K (close to or above their melting temperatures) in an H medium leads to the formation of Mg 2 FeH 6 and H 2 O at 8 to 13 GPa. At 26 to 29 GPa, the behavior of the system changes, and Mg–H in an H fluid and H 2 O were detected with separate FeH x . The observations indicate the dissociation of the Mg–O bond by H and subsequent production of hydride and water. Therefore, the atmosphere–magma interaction can lead to a fundamentally different mineralogy for sub-Neptune exoplanets compared with rocky planets. The change in the chemical reaction at the higher pressures can also affect the size demographics (i.e., “radius cliff”) and the atmosphere chemistry of sub-Neptune exoplanets.

58 GEOSCIENCES↗
DOE OSTI2023

A mountain-induced moist baroclinic wave test case for the dynamical cores of atmospheric general circulation models

Idealized test cases for the dynamical cores of atmospheric general circulation models are informative tools to assess the accuracy of the numerical designs and investigate the general characteristics of atmospheric motions. A new test case is introduced that is built upon a baroclinically unstable base state with an added orographic barrier. The topography is analytically prescribed and acts as a trigger of both baroclinic Rossby waves and inertia–gravity waves on a rotating, regular-sized planet. Both dry and idealized moist configurations are suggested. The latter utilizes the Kessler warm-rain precipitation scheme. The test case enhances the complexity of the existing test suite hierarchy and focuses on the impacts of two midlatitudinal mountain ridges on the circulation. Selected simulation examples from four dynamical cores are shown. These are the Spectral Element and Finite Volume dynamical cores, which are part of the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM), versions 2.1.3 and 2.2, and the Cubed-Sphere Finite Volume dynamical cores, which is new to CESM version 2.2. In addition, the Model for Prediction Across Scales (MPAS) is tested. The overall flow patterns agree well in the four dynamical cores, but the details can vary greatly. The examples highlight the broad palette of use cases for the test case and reveal physics–dynamics coupling issues.

58 GEOSCIENCES↗
DOE OSTI2022

Life and death in the soil microbiome: how ecological processes influence biogeochemistry

We report soil microorganisms shape global element cycles in life and death. Living soil microorganisms are a major engine of terrestrial biogeochemistry, driving the turnover of soil organic matter — Earth’s largest terrestrial carbon pool and the primary source of plant nutrients. Their metabolic functions are influenced by ecological interactions with other soil microbial populations, soil fauna and plants, and the surrounding soil environment. Remnants of dead microbial cells serve as fuel for these biogeochemical engines because their chemical constituents persist as soil organic matter. This non-living microbial biomass accretes over time in soil, forming one of the largest pools of organic matter on the planet. In this Review, we discuss how the biogeochemical cycling of organic matter depends on both living and dead soil microorganisms, their functional traits, and their interactions with the soil matrix and other organisms. With recent omics advances, many of the traits that frame microbial population dynamics and their ecophysiological adaptations can be deciphered directly from assembled genomes or patterns of gene or protein expression. Thus, it is now possible to leverage a trait-based understanding of microbial life and death within improved biogeochemical models and to better predict ecosystem functioning under new climate regimes.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Observational Data for Next-Generation Climate Model Evaluation: Requirements, Considerations, and Best Practices

Climate model simulations are an important source of information about our planet’s climate system and also enable informed decision-making under different future scenarios. As a new archive of results from the next generation of climate models is anticipated to become available with the Coupled Model Intercomparison Project phase 7 (CMIP7), the need to develop efficient and robust methods to evaluate models is paramount. Observations are an integral part of model evaluation, providing a means to quantify and understand the degree to which climate models can faithfully reproduce Earth system processes. Such analysis is critical for constraining climate projections, identifying areas of focus for model development, and assisting analysts in deciphering the utility of models for specific applications. Observations of Earth system come from a diversity of sources, span different space–time domains, and are produced by different communities, and each dataset features different data structures and formats, metadata standards, and its own unique uncertainties. Uncertainties in an observational dataset may stem from gaps in temporal and spatial coverage, instrumentation errors, or assumptions in retrieval and processing methods. How then does one ensure that observational data are ready for use and utilized in the most appropriate way for robust, rapid, and routine climate model evaluation? The CMIP7 Model Benchmarking Task Team with input from the broader climate modeling, model evaluation, and observational data communities present a vision and considerations for best practices toward the optimal and appropriate use of observational data to support next-generation climate model evaluation.

Climate models↗
DOE OSTI2022

First-Principles Surface Characterization and Water Adsorption of Fe 3 P Schreibersite

We report the meteoritic mineral schreibersite, e.g., Fe 3 P, is a proposed abiotic source of phosphorus for phosphate ion (PO 4 – ) production, needed for nucleobases, phospholipids, and other life building materials. Schreibersite could have acted as both a source of elemental phosphorus and as a catalyst, and the hostile conditions on early Earth could have accelerated its degradation in different environments. Here, we present results from quantum calculations of bulk schreibersite and of its low Miller index surfaces. We also investigate water surface adsorption and identify possible dissociation pathways on the most stable facet. Our calculations provide useful chemical insights into schreibersite interactions in aqueous environments, paving the way for further detailed investigation on more reactive surfaces. Our results help provide a “bottom-up” understanding for phosphorylated organic synthesis on the primitive planet and its role in producing life building molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Chapter 5: Major Biological Innovations in the History of Life on Earth

All organisms living on Earth descended from a single, common ancestral population of cells, known as LUCA—the last universal common ancestor. Since its emergence, the diversity and complexity of life have increased dramatically. Here this chapter focuses on four key biological innovations throughout Earth's history that had a significant impact on the expansion of phylogenetic diversity, organismal complexity, and ecospace habitation. First is the emergence of the last universal common ancestor, LUCA, which laid the foundation for all life-forms on Earth. Second is the evolution of oxygenic photosynthesis, which resulted in global geochemical and biological transformations. Third is the appearance of a new type of cell—the eukaryotic cell—which led to the origin of a new domain of life and the basis for complex multicellularity. Fourth is the multiple independent origins of multicellularity, resulting in the emergence of a new level of complex individuality. A discussion of these four key events will improve our understanding of the intertwined history of our planet and its inhabitants and better inform the extent to which we can expect life at different degrees of diversity and complexity elsewhere.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

VLBI Data Processing on Coronal Radio-sounding Experiments of Mars Express

The ESA’s Mars Express solar corona experiments were performed at two solar conjunctions in the years 2015 and 2017 by a number of radio telescopes in the European VLBI Network. This paper presents the methods to measure the frequency and phase fluctuations of the spacecraft radio signal, and the applications to study the characteristics of the plasma turbulence effects on the signal at a single station and at multiple stations via cross correlation. The power spectra of the frequency fluctuations observed between 4.9 and 76.3 R {sub s} have a power-law shape close to a Kolmogorov spectrum over the frequency interval ν {sub lo} < ν < ν {sub up}, where the nominal value of ν {sub lo} is set to 3 mHz and ν {sub up} is in the range of 0.03–0.15 Hz. The rms of the frequency fluctuations is presented as a function of the heliocentric distance. Furthermore, we analyze the variations of the electron column density fluctuations at solar offsets 4.9 R {sub s} and 9.9 R {sub s} and the cross-correlation products between the VLBI stations. The power density of the differential fluctuations between different stations decreases at ν < 0.01 Hz. Finally, the fast flow speeds of solar wind >700 km s{sup -1} are derived from the cross correlation of frequency fluctuations at ν < 0.01 Hz. The fast flow speeds of solar wind correspond to the high heliolatitude of the coronal region that the radio rays passed. The VLBI observations and analysis methods can be used to study the electron column density fluctuations and the turbulence at multiple spatial points in the inner solar wind by providing multiple lines of sight between the Earth and the spacecraft.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Editorial: Plant-Soil Interactions Under Changing Climate

The health and well-being of plants and soil is crucial for all life on Earth. It is well-known that vegetation cover follows climatic zones, and plants respond to climatic drivers such as temperature and precipitation. It is also well-known that plant health depends on the properties and health of the soil, and that strong interactions among biota above and belowground dictate the functioning of both realms. Yet, soils and the processes occurring belowground are often considered a “black box,” and are treated very simplistically in our efforts to understand, quantify, and model the future of the planet. Our understanding of the interactions between plants and soils is also far from complete and offers some of the most important research frontiers in community ecology, biogeochemistry, and global change science.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Ab initio Geochemistry of Hydrous Phases (Final Report)

Hydrous phases are among the most important Earth components. They are important for a broad suite of Earth processes, including the origin of life. From both thermodynamic and structural perspectives, however, they represent some of the most complex naturally occurring materials: their bonding often includes a combination of covalent solid, weak ionic, van der Waals, and hydrogen bonding, all within large unit cells. Most are solid solutions, and many are prone to variations in layer packing. Thermodynamic modeling of these materials is fundamental for understanding present and past natural processes, including those that shaped—and continue to shape—the structure and evolution of our planet. Yet, the thermodynamic properties of these materials at appropriate conditions are challenging to measure. To make significant progress and attain a deep understanding of these materials requires an atomistic theoretical approach.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Detection Limits of Low-mass, Long-period Exoplanets Using Gaussian Processes Applied to HARPS-N Solar Radial Velocities

Radial velocity (RV) searches for Earth-mass exoplanets in the habitable zone around Sun-like stars are limited by the effects of stellar variability on the host star. In particular, suppression of convective blueshift and brightness inhomogeneities due to photospheric faculae/plage and starspots are the dominant contribution to the variability of such stellar RVs. Gaussian process (GP) regression is a powerful tool for statistically modeling these quasi-periodic variations. We investigate the limits of this technique using 800 days of RVs from the solar telescope on the High Accuracy Radial velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph. These data provide a well-sampled time series of stellar RV variations. Into this data set, we inject Keplerian signals with periods between 100 and 500 days and amplitudes between 0.6 and 2.4 m s{sup −1}. We use GP regression to fit the resulting RVs and determine the statistical significance of recovered periods and amplitudes. We then generate synthetic RVs with the same covariance properties as the solar data to determine a lower bound on the observational baseline necessary to detect low-mass planets in Venus-like orbits around a Sun-like star. Our simulations show that discovering planets with a larger mass (∼0.5 m s{sup −1}) using current-generation spectrographs and GP regression will require more than 12 yr of densely sampled RV observations. Furthermore, even with a perfect model of stellar variability, discovering a true exo-Venus (∼0.1 m s{sup −1}) with current instruments would take over 15 yr. Therefore, next-generation spectrographs and better models of stellar variability are required for detection of such planets.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

ARES. V. No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b

We present a study on the spatially scanned spectroscopic observations of the transit of GJ 1132 b, a warm (∼500 K) super-Earth (1.13 R {sub ⊕}) that was obtained with the G141 grism (1.125–1.650 μm) of the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. We used the publicly available Iraclis pipeline to extract the planetary transmission spectra from the five visits and produced a precise transmission spectrum. We analyzed the spectrum using the TauREx3 atmospheric retrieval code, with which we show that the measurements do not contain molecular signatures in the investigated wavelength range and are best fit with a flat-line model. Our results suggest that the planet does not have a clear primordial, hydrogen-dominated atmosphere. Instead, GJ 1132 b could have a cloudy hydrogen-dominated atmosphere, have a very enriched secondary atmosphere, be airless, or have a tenuous atmosphere that has not been detected. Due to the narrow wavelength coverage of WFC3, these scenarios cannot be distinguished yet, but the James Webb Space Telescope may be capable of detecting atmospheric features, although several observations may be required to provide useful constraints.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Straight lightning as a signature of macroscopic dark matter

Macroscopic dark matter (macros) is a broad class of alternative candidates to particle dark matter. These candidates would transfer energy to matter primarily through elastic scattering. A sufficiently large macro passing through the atmosphere would produce a straight channel of ionized plasma. If the cross-section of the macro is σx ≳ 6 × 10 –9 cm 2 , then under atmospheric conditions conducive to lightning (eg. a thunderstorm) the plasma channel would be sufficient to seed a lightning strike with a single leader. This is entirely unlike ordinary bolt lightning in which a long sequence of hundreds or thousands of few-meter-long leaders are strung together. This macro-induced lightning would be extremely straight, and thus highly distinctive. Neither wind shear nor magnetohydrodynamic instabilities would markedly spoil its straightness. The only photographically documented case of a straight lightning bolt is probably not straight enough to have been macro-induced. We estimate the region of macro parameter space that could be probed by a search for straight lightning from the number of thunderstorms happening on Earth at any time. In conclusion, we also estimate the parameter space that can be probed by carefully monitoring Jupiter, e.g. using the Hubble Space Telescope.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Advancing Energy Justice in Alaska

NREL works with remote and rural communities across Alaska and the world to develop energy and building technologies that enhance culture, strengthen economies, and improve resilience in a changing environment. Alaska and Arctic communities not only face one of the harshest climates on earth; they also pay some of the highest energy and housing costs in the nation. NREL's Alaska Campus collaborates with communities and tribes to develop affordable, culturally appropriate homes and buildings that combine traditional knowledge and twenty-first century technology. Demonstration homes deployed all over Alaska prove out new technologies in energy efficiency, foundations, indoor air quality, and clean energy. Local workforce development is incorporated into every project: new homes are built by local workers, often including the home's future occupant. With the Arctic warming twice as fast as the rest of the planet, coastal erosion and thawing permafrost are wreaking havoc on roads, buildings, and infrastructure across Alaska. With an inclusive approach to R&D, NREL is helping communities adapt to a changing environment and advancing energy justice in the world's extremes.

Alaska housing prototypes↗
DOE OSTI2021

The First Detection of an Earthquake From a Balloon Using Its Acoustic Signature

Extreme temperature and pressure conditions on the surface of Venus present formidable technological challenges against performing ground-based seismology. Efficient coupling between the Venusian atmosphere and the solid planet theoretically allows the study of seismically generated acoustic waves using balloons in the upper atmosphere, where conditions are far more clement. However, earthquake detection from a balloon has never been demonstrated. We present the first detection of an earthquake from a balloon-borne microbarometer near Ridgecrest, CA in July 2019 and include a detailed analysis of the dependence of seismic infrasound, as measured from a balloon on earthquake source parameters, topography, and crustal and atmospheric structure. Our comprehensive analysis of seismo-acoustic phenomenology demonstrates that seismic activity is detectable from a high-altitude platform on Earth, and that Rayleigh wave-induced infrasound can be used to constrain subsurface velocities, paving the way for the detection and characterization of such signals on Venus.

58 GEOSCIENCES↗