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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Physics or Knob‐Tuning? Tropical Anvil Peak Is Captured by GCMs

Tropical anvil clouds peak near 200 hPa and significantly impact Earth's climate, yet its physical realism in coarse‐resolution General Circulation Models (GCMs) remains debated. We examine anvil cloud formation by performing simulations with a GCM with a hierarchy of cloud fraction schemes ranging from a complex prognostic Tiedtke scheme to a simple binary scheme. All schemes consistently reproduce the anvil peak. The robust anvil peak arises because extremely cold temperatures at the upper troposphere facilitate frequent saturation events, producing clouds that disproportionately influence mean cloud fraction. Sensitivity experiments with enhanced evaporation of cloud condensate unexpectedly show increased anvil coverage, highlighting how slight evaporative moistening reinforces local saturation in cold upper‐tropospheric conditions. These results demonstrate that the tropical anvil cloud peak emerges from fundamental thermodynamic constraints, rather than specific cloud fraction parameterization choices.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1990

Physical retrieval of precipitation water contents from Special Sensor Microwave/Imager (SSM/I) data. Part 2: Retrieval method and applications (report version)

A physical retrieval method for estimating precipitating water distributions and other geophysical parameters based upon measurements from the DMSP-F8 SSM/I is developed. Three unique features of the retrieval method are (1) sensor antenna patterns are explicitly included to accommodate varying channel resolution; (2) precipitation-brightness temperature relationships are quantified using the cloud ensemble/radiative parameterization; and (3) spatial constraints are imposed for certain background parameters, such as humidity, which vary more slowly in the horizontal than the cloud and precipitation water contents. The general framework of the method will facilitate the incorporation of measurements from the SSMJT, SSM/T-2 and geostationary infrared measurements, as well as information from conventional sources (e.g., radiosondes) or numerical forecast model fields.

Olson, William S.↗
DOE OSTI2024

Volatiles and Redox Along the East African Rift

Abstract The upper mantle under the Afar Depression in the East African Rift displays some of the slowest seismic wave speeds observed globally. Despite the extreme nature of the geophysical anomaly, lavas that erupted along the East African Rift record modest thermal anomalies. We present measurements of major elements, H 2 O, S, and CO 2 , and Fe 3+ /ΣFe and S 6+ /ΣS in submarine glasses from the Gulf of Aden seafloor spreading center and olivine‐, plagioclase‐, and pyroxene‐hosted melt inclusions from Erta Ale volcano in the Afar Depression. We combine these measurements with literature data to place constraints on the temperature, H 2 O, andfO 2 of the mantle sources of these lavas as well as the initial and final pressures of melting. The Afar mantle plume is C/FOZO/PHEM in isotopic composition, and we suggest that this mantle component is damp, with 852 ± 167 ppm H 2 O, not elevated infO 2 compared to the depleted MORB mantle, and has temperatures of ∼1401–1458°C. This is similar infO 2 and H 2 O to the estimates of C/FOZO/PHEM in other locations. Using the moderate H 2 O contents of the mantle together with the moderate thermal anomaly, we find that melting begins at around 93 km depth and ceases at around 63 km depth under the Afar Depression and at around 37 km depth under the Gulf of Aden, and that ∼1%–29% partial melts of the mantle can be generated under these conditions. We speculate that the presence of melt, and not elevated temperatures or high H 2 O contents, are the cause for the prominent geophysical anomaly observed in this region.

Geochemistry & Geophysics↗
NASA NTRS1987

The Magellan mission to Venus

The Magellan mission will be the next NASA mission to Venus. This paper describes the mission as it is currently planned, showing how the design of the science payload, the spacecraft, and the mission satisfies the science objectives and requirements as well as other programmatic constraints. The Magellan mission is dedicated to obtaining SAR images of at least 70 percent of the surface of Venus at a resolution of 1 km per line-pair, or better, which is comparable to the coverage and resolution of the Mars Mariner 9 mission. Other investigations will study the geophysical characteristics of the planet using altimetric data and gravity field measurements, and measurements to determine global surface emissivity.

Dallas, S. S.↗
NASA NTRS2010

Comparing Global Atmospheric CO2 Flux and Transport Models with Remote Sensing (and Other) Observations

We report recent progress derived from comparison of global CO2 flux and transport models with new remote sensing and other sources of CO2 data including those from satellite. The overall objective of this activity is to improve the process models that represent our understanding of the workings of the atmospheric carbon cycle. Model estimates of CO2 surface flux and atmospheric transport processes are required for initial constraints on inverse analyses, to connect atmospheric observations to the location of surface sources and sinks, to provide the basic framework for carbon data assimilation, and ultimately for future projections of carbon-climate interactions. Models can also be used to test consistency within and between CO2 data sets under varying geophysical states. Here we focus on simulated CO2 fluxes from terrestrial vegetation and atmospheric transport mutually constrained by analyzed meteorological fields from the Goddard Modeling and Assimilation Office for the period 2000 through 2009. Use of assimilated meteorological data enables direct model comparison to observations across a wide range of scales of variability. The biospheric fluxes are produced by the CASA model at 1x1 degrees on a monthly mean basis, modulated hourly with analyzed temperature and sunlight. Both physiological and biomass burning fluxes are derived using satellite observations of vegetation, burned area (as in GFED-3), and analyzed meteorology. For the purposes of comparison to CO2 data, fossil fuel and ocean fluxes are also included in the transport simulations. In this presentation we evaluate the model's ability to simulate CO2 flux and mixing ratio variability in comparison to remote sensing observations from TCCON, GOSAT, and AIRS as well as relevant in situ observations. Examples of the influence of key process representations are shown from both forward and inverse model comparisons. We find that the model can resolve much of the synoptic, seasonal, and interannual variability in the observations, although reasons for persistent discrepancies in northern hemisphere vegetation uptake are examined. At this time, we do not find any serious shortcomings in the model transport representation, but this is still the subject of close scrutiny. In general, the fidelity of these simulations leads us to anticipate incorporation of real-time, highly resolved remote sensing and other observations into quantitative analyses that will reduce uncertainty in CO2 fluxes and revolutionize our understanding of the key processes controlling atmospheric CO2 and its evolution with time.

Kawa, S. R.↗
NASA NTRS1984

The Venus radar mapper mission

The Venus Radar Mapper (VRM) Mission, in 1988, will be the next NASA mission to Venus. This paper describes the mission as it is currently planned, showing how the design of the science payload, the spacecraft, and the mission satisfies the science objectives and requirements as well as other programmatic constraints. The VRM mission is dedicated to obtaining Synthetic Aperture Radar (SAR) images of at least 70 percent of the surface of Venus at a resolution of 1 km per line pair or better (comparable to the coverage and resolution of the Mars Mariner 9 mission). Additional investigations will study the interior geophysical characteristics of the planet using altimetric data and gravity field measurements of the planet.

Dallas, S. S.↗
NASA NTRS2014

Bulk Composition of Vesta as Constrained by the Dawn Mission and the HED Meteorites

Of the objects in the main asteroid belt, Vesta is of particular interest as it is large enough to have experienced internal differentiation (520 km diameter), and it is known to have a basaltic surface dominated by FeO-bearing pyroxenes. Furthermore, visible-IR spectra of Vesta and associated Vestoids are remarkably similar to laboratory spectra of Howardite-Eucrite-Diogenite (HED) meteorites, leading to the paradigm that the HEDs ultimately came from Vesta. Geochemical and petrological studies of the HEDs confirm the differentiated nature of the near-surface region of their parent body, and imply that crust extraction occurred well within the first 10 Ma of solar system history Vesta is therefore a prime target for studies that aim to constrain the earliest stages of planet building, and it is within this context that the NASA Dawn spacecraft orbited Vesta from July 2011 to September 2012. The results of the Dawn mission so far have significantly reinforced the HED-Vesta connection, confirming a significant degree of internal differentiation, a surface mineralogy compatible with that of the HEDs, and near-surface ratios of Fe/O and Fe/Si consistent with HED lithologies. The combination of data from the HED meteorites and the Dawn mission thus presents an unprecedented opportunity to use Vesta as a natural laboratory of early differentiation processes in the early solar system. However, the bulk composition of Vesta remains a significant unknown parameter, but one that plays a key role on the physical and chemical properties of the internal and surface reservoirs (core, mantle, crust). Several attempts have been made to constrain the bulk composition of the eucrite parent body, early endeavours relying on petrological or cosmochemical constraints. More recently, individual chondrite class compositions, or mixtures thereof, have been considered, constrained by considerations such as O-isotopes, trace-element ratios and siderophile element concentrations of the eucrites. The work presented here builds upon these latter studies, with the primary aims of: i) illustrating the potential diversity of the geochemical and geophysical properties of a fully differentiated Vesta-sized parent body, and ii) assessing which, if any, of the known chondritic bulk compositions are plausible analogues for proto-Vesta.

Toplis, M. J.↗
NASA NTRS1985

The impact of tropical wind data on the analysis and forcasts of the GLA GCM for the global weather experiment

It is well-known that divergent wind estimates are much more dependent upon the analysis system than are estimates of the rotational wind. This conclusion is supported in recent analyses of FGGE SOP1 data produced by the Goddard Laboratory for Atmospheres (GLA), the Geophysical Fluid Dynamics Laboratory (GFDL) and the European Center for Medium Range Weather Forecasting (ECMWF). These analyses differ in the forecast models that are used for the four-dimensional assimilation, in the data rejection criteria, and, to a certain extent, in the data density. Because the final divergent wind is a product of both model constraints and observation, it is relevant to inquire how much of each goes into the final product. We presently investigate this question through a systematic analysis of tropical data that are sampled at different densities by the GLA GCM.

Paegle, Jan↗
DOE OSTI2024

ML-Based Rock Properties and Seismic Volume Enhancement

This project aims to improve field-scale Carbon Capture and Storage (CCS) assessments by enhancing petrophysical and geophysical log predictions through machine learning and neural networks. In our work during EY23, we applied Conditional Variational Autoencoders (CVAEs) to predict compressional velocity (Vp) and assess CO2 saturation levels in geological formations at the Illinois Basin Decatur Project (IBDP). In another task, we improved full-waveform inversion (FWI) methods with machine-learning approaches using lithological constraints. Full-waveform inversion (FWI) of seismic data estimates the elastic properties of subsurface rocks with high spatial resolution.

Nathanail, Athanasios↗
NASA NTRS1992

Ice tracking techniques, implementation, performance, and applications

Present techniques of ice tracking make use both of cross-correlation and of edge tracking, the former being more successful in heavy pack ice, the latter being critical for the broken ice of the pack margins. Algorithms must assume some constraints on the spatial variations of displacements to eliminate fliers, but must avoid introducing any errors into the spatial statistics of the measured displacement field. We draw our illustrations from the implementation of an automated tracking system for kinematic analyses of ERS-1 and JERS-1 SAR imagery at the University of Alaska - the Alaska SAR Facility's Geophysical Processor System. Analyses of the ice kinematic data that might have some general interest to analysts of cloud-derived wind fields are the spatial structure of the fields, and the evaluation and variability of average deformation and its invariants: divergence, vorticity and shear. Many problems in sea ice dynamics and mechanics can be addressed with the kinematic data from SAR.

Rothrock, D. A.↗
DOE OSTI2023

Ecosystems and Networks Integrated with Genes and Molecular Assemblies (Final Scientific/Technical Report)

The ENIGMA science focus area (SFA) is a multi-disciplinary, multi-institutional research effort focused on addressing foundational knowledge gaps in environmental microbial communities by studying groundwater and sediment microbiomes in the shallow subsurface at the contaminated Oak Ridge Field Research Site (FRC). We seek to discover and characterize the reciprocal interactions between the microbial communities and the geochemical and geophysical parameters of the shallow subsurface within the contamination plume. The goal of the Fields lab is to help manage and conduct laboratory experiments informed by field observations using ecological and physiological approaches to study microbial populations in situ as well as ex situ (in the laboratory). In particular, we aim to study and characterize the impact of hydrological constraints on free-living and biofilm biomass and activity with increasing spatial and temporal resolution under static and flow conditions. We also aim to help characterize novel microbial groups that are present and active under relevant field conditions, including the development of molecular techniques for in situ detection as well as metabolic interactions that underlie pertinent physiology and ecology.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1985

Application of shock wave data to earth and planetary science

It is pointed out that shock wave data for: (1) low temperature condensable gases H2 and He, (2) H2O, CH4, NH3, CO, CO2, and N2 ices, and (3) silicates, metals, oxides and sulfides have many applications in geophysics and planetary science. The present paper is concerned with such applications. The composition of planetary interiors is discussed, taking into account the division of the major constituent of the planets in three groups on the basis of 'cosmic abundance' arguments, the H-He mixtures in the case of Jupiter and Saturn, shock wave data for hydrogen, and constraints on the internal structure of Uranus and Neptune. Attention is also given to the earth's mantle, shock wave data for mantle materials, the earth's core, impacts on planetary surfaces, elastic wave velocities as a function of pressure along the Hugoniot of iron, and reactions which yield the CO2 bearing atmospheres for Venus, earth, and Mars.

Ahrens, T. J.↗
NASA NTRS2013

Pneumatic Proboscis Heat-Flow Probe

Heat flow is a fundamental property of a planet, and provides significant constraints on the abundance of radiogenic isotopes, the thermal evolution and differentiation history, and the mechanical properties of the lithosphere. Heat-flow measurements are also essential in achieving at least four of the goals set out by the National Research Council for future lunar exploration. The heat-flow probe therefore directly addresses the goal of the Lunar Geophysical Network, which is to understand the interior structure and composition of the Moon. A key challenge for heat flow measurement is to install thermal sensors to the depths approximately equal to 3 m that are not influenced by the diurnal, annual, and longer-term fluctuations of the surface thermal environment. In addition, once deployed, the heat flow probe should cause little disturbance to the thermal regime of the surrounding regolith. A heat-flow probe system was developed that has two novel features: (1) it utilizes a pneumatic (gas) approach, excavates a hole by lofting the lunar soil out of the hole, and (2) deploys the heat flow probe, which utilizes a coiled up tape as a thermal probe to reach greater than 3-meter depth. The system is a game-changer for small lunar landers as it exhibits extremely low mass, volume, and simple deployment. The pneumatic system takes advantage of the helium gas used for pressurizing liquid propellant of the lander. Normally, helium is vented once the lander is on the surface, but it can be utilized for powering pneumatic systems. Should sufficient helium not be available, a simple gas delivery system may be taken specifically for the heat flow probe. Either way, the pneumatic heat flow probe system would be much lighter than other systems that entirely rely on the electrical power of the lander.

Zacny, Kris↗
DOE OSTI2022

Automatic Calibration of a Geomechanical Model from Sparse Data for Estimating Stress in Deep Geological Formations

Summary In this study, we demonstrate geomechanical modeling with fully automatic parameter calibration to estimate the full geomechanical stress fields of a prospective US carbon dioxide (CO2) storage site, based on sparse measurement data. The goal is to compute full stress tensor field estimates (principal stresses and orientations) that are maximally compatible with observations within the constraints of the model assumptions, thereby extending pointwise, incomplete partial stress measurement to a simulated full formation stress field, as well as a rough assessment of the associated error. We use the Perch site, located in Otsego County, Michigan, USA, as our case study. The input data consist of partial stress tensor information inferred from in-situ borehole tests, geophysical well logs, and processing of seismic data. A static earth model (SEM) of the site was developed, and geomechanical simulation functionality of the open-source MATLAB Reservoir Simulation Toolbox (MRST) was used to model the stress field. Adjoint-based nonlinear optimization was used to adjust boundary conditions and material properties to calibrate simulated results of observations. Results were interpreted through a Bayesian framework. The focus of this paper is to demonstrate how the fully automatic calibration procedure works and discuss the results obtained; it does not attempt a detailed analysis of the stress field in the context of the proposed CO2 storage initiatives. Our work is part of a larger effort to noninvasively determine in-situ stresses in deep formations considered for CO2 storage. Guided by previously published research on geomechanical model calibration, our work presents a novel calibration approach supporting a potentially large number of linear or nonlinear calibration parameters to produce results optimally agreeing with available measurements and thus extend partial pointwise estimates to full tensor fields compatible with the physics of the site.

Engineering↗
NASA NTRS1990

Satellite laser ranging and geological constraints on plate motion

Satellite laser ranging (SLR) observed baseline rates of change were measured and compared with rates determined from sea floor spreading rates and directions, and earth-quake solutions. With the number of years of observation now over six for many of the baselines, the inaccuracy of determining baseline rates of change has diminished so that in some cases it is less than a few mm per year. Thus, a direct comparison between baseline rates of change and rates of change established using geophysical information (called geological rates) is now feasible. In most cases, there is good agreement between the rates determined from SLR and geological rates, but in some cases there appear to be discrepancies. These discrepancies involve many of the data for which one end of the baseline is either Quincy (California), Huahine (French Polynesia), or Simosato (Japan). A method for looking at the discrepancies for these SLR observatories has been devised which makes it possible to calculate the motion not modeled by the geologic information.

Harrison, C. G. A.↗
DOE OSTI2022

Magmatic water content controls the pre-eruptive depth of arc magmas

We report that vanguard efforts in forecasting volcanic eruptions are turning to physics-based models, which require quantitative estimates of magma conditions during pre-eruptive storage. Below active arc volcanoes, observed magma storage depths vary widely (~0 to 20 kilometers) and are commonly assumed to represent levels of neutral buoyancy. Here we show that geophysically observed magma depths (6 ± 3 kilometers) are greater than depths of neutral buoyancy, ruling out this commonly assumed control. Observed depths are instead consistent with predicted depths of water degassing. Intrinsically wetter magmas degas water and crystallize deeper than dry magmas, resulting in viscosity increases that lead to deeper stalling of ascending magma. The water–depth relationship provides a critical constraint for forecasting models by connecting depth of eruption initiation to its volatile fuel.

58 GEOSCIENCES↗
NASA NTRS2000

Towards Solving the Mixing Problem in the Decomposition of Geophysical Time Series by Independent Component Analysis

The use of the Principal Component Analysis technique for the analysis of geophysical time series has been questioned in particular for its tendency to extract components that mix several physical phenomena even when the signal is just their linear sum. We demonstrate with a data simulation experiment that the Independent Component Analysis, a recently developed technique, is able to solve this problem. This new technique requires the statistical independence of components, a stronger constraint, that uses higher-order statistics, instead of the classical decorrelation a weaker constraint, that uses only second-order statistics. Furthermore, ICA does not require additional a priori information such as the localization constraint used in Rotational Techniques.

Aires, Filipe↗