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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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A Rapidly Moving Shell in the Orion Nebula
A well-resolved elliptical shell in the inner Orion Nebula has been investigated by monochromatic imaging plus high- and low-resolution spectroscopy. We find that it is of low ionization and the two bright ends are moving at -39 and -49 km/s with respect to OMC-1. There is no central object, even in the infrared J bandpass although H2 emission indicates a possible association with the nearby very young pre-main-sequence star J&W 352, which is one of the youngest pre-main-sequence stars in the inner Orion Nebula. Many of the characteristics of this object (low ionization, blue shift) are like those of the Herbig-Haro objects, although the symmetric form would make it an unusual member of that class.
Walter, Donald K.↗
Polarimetric Scanning Radiometer C and X Band Microwave Observations During SMEX03
Soil Moisture Experiments 2003 (SMEX03) was the second in a series of field campaigns using the NOAA Polarimetric Scanning Radiometer (PSR/CX) designed to validate brightness temperature data and soil moisture retrieval algorithms for the Advanced during SMEX03 were: calibration and validation of AMSR-E brightness temperature observations over different climate/vegetation regions of the US. (Alabama, Georgia, Oklahoma), identification of possible sources of Radio Frequency Interference (RFI), comparison of X-band observations from TRMM Microwave Imager (TMI), AMSR-E and PSR/CX, and exploring the potential of soil moisture retrieval algorithms using C and X band imagery in diverse landscapes. In the current investigation, more than one hundred flightlines of PSR/CX data were extensively processed to produce gridded brightness temperature products for the four study regions. Variations associated with soil moisture were not as large as hoped for due to the lack of significant rainfall in Oklahoma. Observations obtained over Alabama include a wide range of soil moisture and vegetation conditions for C and X band frequencies. These results clearly showed a lack of sensitivity to rainfall/soil moisture under forest canopy cover. Quantitative comparisons made between the PSR/CX, AMSR-E for validated that both the PSR/CX and AMSR-E data were well calibrated. X band comparisons of the PSR/CX high resolution and AMSR-E and TMI low-resolution data indicated a linear scaling for the range of conditions studied in SMEX03. These results will form the basis for further soil moisture investigations.
Jackson, Thomas J.↗
Impact of Resolution and Parameterized Convection on the Diurnal Cycle of Precipitation in a Global Nonhydrostatic Model
A series of 40-day non-hydrostatic global simulations was run with the NASA Goddard Earth Observing System (GEOS) model with horizontal grid spacing ranging from 50 km to 3.5 km. Here we evaluate the diurnal cycle of precipitation and organized convection as a function of resolution. For validation we use the TRMM 3B42 and IMERG precipitation products and 4 km Merged Infrared brightness temperature, focusing on three regions: the contiguous United States (CONUS), the Maritime Continent, and Amazonia. We find that higher resolution has mixed impacts on diurnal phase. Regions dominated by non-local propagating convection show the greatest improvement, with better representation of organized convective systems. Precipitation in regions dominated by local thermodynamic forcing tends to peak too early at high resolution. Diurnal amplitudes in all regions develop unrealistic small-scale variability at high resolution, while amplitudes tend to be underestimated at low resolution. The GEOS model uses the Grell-Freitas scale-aware convection scheme, which smoothly reduces parameterized deep convection with increasing resolution. We find that some parameterized convection is beneficial for the diurnal amplitude and phase even with a 3.5 km model grid, but only when throttled with the scale-aware approach. An additional 3.5 km experiment employing the GFDL microphysics scheme and higher vertical resolution shows further improvement in propagating convection, but an earlier rainfall peak in locally forced regions.
Nathan P. Arnold↗
The NASA Ames Mars Global Climate Model: Benchmarking Publicly Released Source Code and Model Output
We have recently publicly released source code from the new NASA Ames Mars Global Climate Model (MGCM), which is based on NOAA/GFDL cubed-sphere finite volume (FV3-based) dynamical core (https://github.com/nasa/AmesGCM). We also we have a manuscript in preparation that aims to document the status of the new MGCM, and present selected simulations generated from it with interpretations and comparisons to both observations and the Ames Legacy MGCM. Output from our reference simulation will be made publicly available as well. One of our ongoing goals is to understand the underlying causes for differences between results produced with the new FV3-based dynamical core compared to the Legacy C-grid dynamical core. While the thermal and dynamical fields predicted with the new and Legacy GCMs are broadly similar for much of the year, there are key differences at low resolution when no external drag is applied to the new MGCM. This is particularly clear during a seasonal window of ~100 degrees of Ls surrounding southern summer solstice, when the predicted northern hemisphere polar warming is significantly over-predicted in the new MGCM. When we apply Rayleigh drag throughout much of the tropics and sub-tropics to the new MGCM, the simulated zonal mean structure of the atmosphere is much more consistent with both MCS observations and Legacy MGCM simulations. We note that the Kling et al. (2023; this meeting) study demonstrates that the behavior that we see with Rayleigh drag here can be recovered with high resolution simulations (in the horizontal and in the vertical) or with parameterized orographic and non-orographic gravity waves at lower resolution. While this work is still in progress, our preliminary conclusion is that the new dynamical core is less dissipative than the Legacy dynamical core. At low to moderate resolution, users of the new MGCM will need to be careful to use some sort of external drag, either in the form of gravity wave drag parameterizations or the simpler Rayleigh drag.
Melinda April Kahre↗
Midlatitude cyclone processes as a key to understanding climate sensitivity
Global climate models (GCMs) differ greatly in their shortwave cloud feedback. One feature that is consistent across GCMs is a positive shortwave cloud feedback in the subtropics, and a negative shortwave cloud feedback across the midlatitudes. Confidence has grown in the mechanisms that lead to, and the strength of, the subtropical shortwave cloud feedback, but the midlatitude negative shortwave cloud feedback is not well-constrained or well-understood. It is critical to reduce uncertainty in midlatitude shortwave cloud feedback. A more positive midlatitude shortwave cloud feedback in the sixth coupled model intercomparison project (CMIP6) has been found to be one of the primary causes of the increased climate sensitivity of CMIP6 models relative to CMIP5. We show that changes in midlatitude cyclones in future climates are the primary cause of the negative shortwave cloud feedback and are thus key to understanding the high climate sensitivity in the most recent GCMs. Warming-induced changes in cloud liquid water path in midlatitude cyclones can almost entirely be explained by Clausius-Clapeyron increasing moisture convergence into cyclones. One concern with simulating midlatitude cyclones is the lack of predictive skill at low resolution. A more realistic relationship between moisture flux and cyclone liquid content is found at high horizontal resolution (∆x<25km), but the cloud feedback within cyclones can be explained by increased moisture convergence across low- and high-resolution models. Observations and models agree that the extratropical shortwave cloud feedback is moderated by precipitation processes in cyclones. This rules out a large contribution from ice-to-liquid transitions, as has been hypothesized in previous studies. Understanding and constraining these precipitation processes is crucial to constraining the response of midlatitude cyclones to warming and by extension climate sensitivity.
Cyclones↗
Detection of gravity-induced polarity of cytoplasmic streaming in Chara
Gravity induces a polarity of cytoplasmic streaming in vertically-oriented internodal cells of characean algae. The motive force that powers cytoplasmic streaming is generated at the ectoplasmic/endoplasmic interface. The velocity of streaming, which is about 100 micrometers/s at this interface, decreases with distance from the interface on either side of the cell to 0 micrometers/s near the middle. Therefore, when discussing streaming velocity it is necessary to specify the tangential plane through the cell in which streaming is being measured. This is easily done with a moderate resolution light microscope (which has a lateral resolution of 0.6 micrometers and a depth of field of 1.4 micrometers), but is obscured when using any low resolution technique, such as low magnification light microscopy or laser Doppler spectroscopy. In addition, the effect of gravity on the polarity of cytoplasmic streaming declines with increasing physiological age of isolated cells. Using a classical mechanical analysis, we show that the effect of gravity on the polarity of cytoplasmic streaming cannot result from the effect of gravity acting directly on individual cytoplasmic particles. We suggest that gravity may best be perceived by the entire cell at the plasma membrane-extracellular matrix junction.
Non-NASA Center↗
The HadGEM3-GA7.1 radiative kernel: the importance of a well-resolved stratosphere
We present top-of-atmosphere and surface radiative kernels based on the atmospheric component (GA7.1) of the HadGEM3 general circulation model developed by the UK Met Office. We show that the utility of radiative kernels for forcing adjustments in idealised CO2 perturbation experiments is greatest where there is sufficiently high resolution in the stratosphere in both the target climate model and the radiative kernel. This is because stratospheric cooling to a CO2 perturbation continues to increase with height, and low-resolution or low-top kernels or climate model output are unable to fully resolve the full stratospheric temperature adjustment. In the sixth phase of the Coupled Model Intercomparison Project (CMIP6), standard atmospheric model data are available up to 1 hPa on 19 pressure levels, which is a substantial advantage compared to CMIP5. We show in the IPSL-CM6A-LR model where a full set of climate diagnostics are available that the HadGEM3-GA7.1 kernel exhibits linear behaviour and the residual error term is small, as well as from a survey of kernels available in the literature that in general low-top radiative kernels underestimate the stratospheric temperature response. The HadGEM3-GA7.1 radiative kernels are available at https://doi.org/10.5281/zenodo.3594673 (Smith, 2019).
radiative kernels↗
The Impact of High-Resolution Sea Surface Temperatures on the Simulated Nocturnal Florida Marine Boundary Layer
High- and low-resolution sea surface temperature (SST) analysis products are used to initialize the Weather Research and Forecasting (WRF) Model for May 2004 for short-term forecasts over Florida and surrounding waters. Initial and boundary conditions for the simulations were provided by a combination of observations, large-scale model output, and analysis products. The impact of using a 1-km Moderate Resolution Imaging Spectroradiometer (MODIS) SST composite on subsequent evolution of the marine atmospheric boundary layer (MABL) is assessed through simulation comparisons and limited validation. Model results are presented for individual simulations, as well as for aggregates of easterly- and westerly-dominated low-level flows. The simulation comparisons show that the use of MODIS SST composites results in enhanced convergence zones. earlier and more intense horizontal convective rolls. and an increase in precipitation as well as a change in precipitation location. Validation of 10-m winds with buoys shows a slight improvement in wind speed. The most significant results of this study are that 1) vertical wind stress divergence and pressure gradient accelerations across the Florida Current region vary in importance as a function of flow direction and stability and 2) the warmer Florida Current in the MODIS product transports heat vertically and downwind of this heat source, modifying the thermal structure and the MABL wind field primarily through pressure gradient adjustments.
LaCasse, Katherine M.↗
Satellite snowcover and runoff monitoring in central Arizona
The author has identified the following significant results. Although the very high resolution experimental LANDSAT imagery permits rapid snow cover mapping at low cost, only one observation is available very 9 days. In contrast, low resolution operational imagery acquired by the ITOS and SMS/GOES satellites provide the daily synoptic observations necessary to monitor the rapid changes in snow covered areas in the entire Salt-Verde watershed. Geometric distortions in meteorological satellite imagery require specialized optical equipment or digital image processing for snow cover mapping.
Schumann, H. H.↗
Interaction of the solar wind with interstellar neutral hydrogen - Three-fluid model
It is commonly assumed in models of the solar wind-interstellar neutral hydrogen interaction that the ionized interstellar particles are quickly assimilated into the solar wind proton population and 'become indistinguishable' from the original solar wind. This assumption leads to the prediction that the solar wind proton temperature should increase with radius in the outer heliosphere. This temperature increase has not been observed. It is pointed out that assimilation of the interstellar particles to the point of indistinguishability takes place on the very long Coulomb collision time scale, and is not expected to occur within the heliosphere. Results are presented of a three-fluid model of the solar wind which consists of comoving thermal populations of protons of solar origin, protons produced by ionization of interstellar hydrogen, and electrons. The steady-state results yield a solar wind with a 'core' proton distribution which cools adiabatically, and a 'halo' of interstellar pickup protons which is maintained near 10 to the 7th K by the energy input of continued ionization and pickup. Such a distribution will not be observed to manifest the temperature increase at large heliocentric distances which is predicted from a one-fluid analysis. Further time-dependent calculations show a strong correlation between the densities of the solar wind and the interstellar pickup protons. It is suggested that the interstellar pickup population may be observable by the Voyager plasma instruments in low resolution mode during periods of high solar wind density and low solar wind temperature.
Isenberg, P. A.↗
The Growth of Protein Crystals Using McDUCK
Most of the current microgravity crystal growth hardware is optimized to produce crystals within the limited time available on orbit. This often results in the actual nucleation and growth process being rushed or the system not coming to equilibrium within the limited time available. Longer duration hardware exists, but one cannot readily pick out crystals grown early versus those which nucleated and grew more slowly. We have devised a long duration apparatus, the Multi-chamber Dialysis Unit for Crystallization Kinetics, or McDUCK. This apparatus-is a series of protein chambers, stacked upon a precipitant reservoir chamber. All chambers are separated by a dialysis membrane, which serves to pass small molecules while retaining the protein. The volume of the Precipitant chamber is equal to the sum of the volumes of the protein chamber. In operation, the appropriate chambers are filled with precipitant solution or protein solution, and the McDUCK is placed standing upright, with the precipitant chamber on the bottom. The precipitant diffuses upwards over time, with the time to reach equilibration a function of the diffusivity of the precipitant and the overall length of the diffusion pathway. Typical equilibration times are approximately 2-4 months, and one can readily separate rapid from slow nucleation and growth crystals. An advantage on Earth is that the vertical precipitant concentration gradient dominates that of the solute, thus dampening out solute density gradient driven convective flows. However, large Earth-grown crystals have so far tended to be more two dimensional. Preliminary X-ray diffraction analysis of lysozyme crystals grown in McDUCK have indicated that the best, and largest, come from the middle chambers, suggesting that there is an optimal growth rate. Further, the improvements in diffraction resolution have been better signal to noise ratios in the low resolution data, not an increase in resolution overall. Due to the persistently large crystals grown we are currently proposing McDUCK for the growth of macromolecule crystals for use in neutron diffraction studies.
Ewing, Felicia↗
The Magnetospheric Multiscale Magnetometers
The success of the Magnetospheric Multiscale mission depends on the accurate measurement of the magnetic field on all four spacecraft. To ensure this success, two independently designed and built fluxgate magnetometers were developed, avoiding single-point failures. The magnetometers were dubbed the digital fluxgate (DFG), which uses an ASIC implementation and was supplied by the Space Research Institute of the Austrian Academy of Sciences and the analogue magnetometer (AFG) with a more traditional circuit board design supplied by the University of California, Los Angeles. A stringent magnetic cleanliness program was executed under the supervision of the Johns Hopkins University,s Applied Physics Laboratory. To achieve mission objectives, the calibration determined on the ground will be refined in space to ensure all eight magnetometers are precisely inter-calibrated. Near real-time data plays a key role in the transmission of high-resolution observations stored onboard so rapid processing of the low-resolution data is required. This article describes these instruments, the magnetic cleanliness program, and the instrument pre-launch calibrations, the planned in-flight calibration program, and the information flow that provides the data on the rapid time scale needed for mission success.
Magnetosphere↗
Next-Generation Optical Sensing Technologies for Exploring Ocean Worlds - NASA FluidCam, MiDAR, and NeMO-Net
We highlight three emerging NASA optical technologies that enhance our ability to remotely sense, analyze, and explore ocean worlds–FluidCam and fluid lensing, MiDAR, and NeMO-Net. Fluid lensing is the first remote sensing technology capable of imaging through ocean waves without distortions in 3D at sub-cm resolutions. Fluid lensing and the purpose-built FluidCam CubeSat instruments have been used to provide refraction-corrected 3D multispectral imagery of shallow marine systems from unmanned aerial vehicles (UAVs). Results from repeat 2013 and 2016 airborne fluid lensing campaigns over coral reefs in American Samoa present a promising new tool for monitoring fine-scale ecological dynamics in shallow aquatic systems tens of square kilometers in area. MiDAR is a recently-patented active multispectral remote sensing and optical communications instrument which evolved from FluidCam. MiDAR is being tested on UAVs and autonomous underwater vehicles (AUVs) to remotely sense living and non-living structures in light-limited and analog planetary science environments. MiDAR illuminates targets with high-intensity narrowband structured optical radiation to measure an object’s spectral reflectance while simultaneously transmitting data. MiDAR is capable of remotely sensing reflectance at fine spatial and temporal scales, with a signal-to-noise ratio 10-10(exp 3) times higher than passive airborne and spaceborne remote sensing systems, enabling high-framerate multispectral sensing across the ultraviolet, visible, and near-infrared spectrum. Preliminary results from a 2018 mission to Guam show encouraging applications of MiDAR to imaging coral from airborne and underwater platforms whilst transmitting data across the air-water interface. Finally, we share NeMO-Net, the Neural Multi-Modal Observation & Training Network for Global Coral Reef Assessment. NeMO-Net is a machine learning technology under development that exploits high-resolution data from FluidCam and MiDAR for augmentation of low-resolution airborne and satellite remote sensing. NeMO-Net is intended to harmonize the growing diversity of 2D and 3D remote sensing with in situ data into a single open-source platform for assessing shallow marine ecosystems globally using active learning for citizen-science based training. Preliminary results from four-class Q17 coral classification have an accuracy of 94.4%. Together, these maturing technologies present promising scalable, practical, and cost-efficient innovations that address current observational and technological challenges in optical sensing of marine systems.
Ved Chirayath↗
The structure of chromospheres around late-type giants and supergiants
Observations alpha Tau (K5III) and beta Gru (M2II) made at high resolution are used to confirm line identifications of features blended at low resolution. The high resolution spectra allow selected pairs of lines to be used to find the electron density and the opacity. Methods for determining these factors and the usual emission measure are presented. The electron density and opacity can be used together with the emission measure to place constraints on the structure of the atmosphere. The line formation processes are briefly discussed. Photo-excitation by strong lines appears to be important in these late type atmospheres.
Brown, A.↗
High-resolution land/ice imaging using Seasat scatterometer measurements
A new method for obtaining high-resolution images (to 4 km) of the land backscatter from low-resolution Seasat-A scatterometer (SASS) measurements is introduced. The method utilizes the measurement cell overlap in multiple spacecraft passes over the region of interest and signal processing techniques to generate high-resolution images of the radar backscatter. The overlap is exploited to estimate the underlying high-resolution surface radar backscatter characteristics using a robust multivariate image reconstruction algorithm. The algorithm has been designed to operate in the high-noise environment typical of scatterometer measurements. The ultimate resolution obtainable is a function of the number of measurements and the measurement overlap. Sample results based on SASS data are provided.
Long, D. G.↗
Incidence angle and resolution - Potential effects on interpreting Venusian impact craters in Magellan radar images
The effects of incidence angle and spatial resolution are analyzed in order to evaluate the types of information that Magellan imaging radar may provide about impact craters on Venus. Seasat synthetic-aperture radar images of small terrestrial craters at high resolution (about 25 m) and Soviet Venera images of comparatively large Venusian craters at low resolution (1000 to 2000 m) and shorter wavelength show comparable radar responses to crater morphology. At low incidence angles, it is difficult to locate the precise position of crater rims on images, while at higher incidence angles, images show less distortion of crater morphology. Magellan will obtain images through a range of incidence angles varying from about 45 deg at low latitudes to 16 deg at polar latitudes. Radially symmetrical landforms such as impact craters are expected to show outlines that vary with the incidence angle and to appear bilaterally symmetrical and increasingly compressed at higher latitude.
Ford, J. P.↗
Applications of GOES-8/9 data to hurricane analysis
GOES-8 was successfully launched in 1994, and has performed up to expeditions and in some cases has actually exceeded pre-launch specifications. A similar geostationary satellite, GOES-9, was launched in May of 1995. This new generation of NOAA's geostationary satellites carry a superior design and instrumentation package that allow for greater detection of meteorological features and parameters. The new GOES imager has a 5 band multispectral capability with high spatial resolution, while the sounder contains 18 thermal infrared (IR) bands plus a low resolution visible band. The imager carries a visible channel with 1 10-bit quantization and increased sampling frequency, a short-wave and long-wave window channel, and a water vapor band with a twofold increase in spatial resolution and a factor of 3 improvement in signal-to-noise over that obtained from previous GOES sensors. The advances in observing the earth's atmospheric system anticipated from these improvements are outlined in Menzel and Purdom (1994). The specific impact of this improved remote sensing capability on the analysis of tropical cyclones is discussed here.
Velden, Christopher S.↗