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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

A UNIFORM CATALOG OF MOLECULAR CLOUDS IN THE MILKY WAY

The all-Galaxy CO survey of Dame et al. is by far the most uniform, large-scale Galactic CO survey. Using a dendrogram-based decomposition of this survey, we present a catalog of 1064 massive molecular clouds throughout the Galactic plane. This catalog contains 2.5 × 10{sup 8} solar masses, or 25{sub −5.8}{sup +10.7}% of the Milky Way's estimated H{sub 2} mass. We track clouds in some spiral arms through multiple quadrants. The power index of Larson's first law, the size-linewidth relation, is consistent with 0.5 in all regions—possibly due to an observational bias—but clouds in the inner Galaxy systematically have significantly (∼30%) higher linewidths at a given size, indicating that their linewidths are set in part by the Galactic environment. The mass functions of clouds in the inner Galaxy versus the outer Galaxy are both qualitatively and quantitatively distinct. The inner Galaxy mass spectrum is best described by a truncated power law with a power index of γ = −1.6 ± 0.1 and an upper truncation mass of M {sub 0} = (1.0 ± 0.2) × 10{sup 7} M {sub ⊙}, while the outer Galaxy mass spectrum is better described by a non-truncating power law with γ = −2.2 ± 0.1 and an upper mass of M {sub 0} = (1.5 ± 0.5) × 10{sup 6} M {sub ⊙}, indicating that the inner Galaxy is able to form and host substantially more massive GMCs than the outer Galaxy. Additionally, we have simulated how the Milky Way would appear in CO from extragalactic perspectives, for comparison with CO maps of other galaxies.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Microparticle cloud imaging and tracking for data-driven plasma science

Oceans of image and particle track data encountered in plasma interactions with microparticle clouds motivate development and applications of machine-learning (ML) algorithms. A local-constant-velocity tracker, a Kohonen neural network or self-organizing map, the feature tracking kit, and U-Net are described and compared with each other for microparticle cloud datasets generated from exploding wires, dusty plasmas, and atmospheric plasmas. Particle density and the signal-to-noise ratio have been identified as two important factors that affect the tracking accuracy. Fast Fourier transform is used to reveal how U-Net, a deep convolutional neural network developed for non-plasma applications, achieves the improvements for noisy scenes. Viscous effects are revealed in the ballistic motions of the particles from the exploding wires and atmospheric plasmas. Subdiffusion of microparticles satisfying Δr 2 ∝t k (k=0.84±0.02) is obtained from the dusty plasma datasets. Microparticle cloud imaging and tracking, when enhanced with data and ML models, present new possibilities for plasma physics.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Ka-Band ARM Zenith Radar (KAZR) Active Remote Sensing of Clouds (ARSCL) CloudSat Calibration (KAZRARSCL-CLOUDSAT) (Value-Added Product Report)

The Ka-band ARM Zenith Radar Active Remote Sensing of CLouds CloudSat-aligned (KAZRARSCL-CLOUDSAT) Value-Added Product (VAP) applies satellite-based reflectivity calibrations to KAZRARSCL data sets. The Atmospheric Radiation Measurement (ARM) user facility has primarily used radar subsystem calibration monitoring to track cloud radar reflectivity drift over time, since reliable external calibration sources or other absolute references (such as corner reflectors) have historically been unavailable or impracticable. A study by Kollias et al. (2019) examined cloud reflectivity profiles observed with a well-characterized spaceborne downward-pointing millimeter cloud radar, operating as part of NASA’s CloudSat satellite mission (Tanelli et al. 2008). The Kollias team derived monthly statistical reflectivity offsets between CloudSat and the various generations of ARM cloud radars (millimeter wavelength cloud radar [MMCR], W-Band ARM Cloud Radar [WACR[, and Ka-band ARM Zenith Radar [KAZR]) for many, but not all, months at most fixed and mobile ARM sites over the period 2007-2017. These offsets, when available, are applied to the existing KAZRARSCL VAP products using the KAZRARSCL-CLOUDSAT VAP.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1975

Man-Computer Interactive Data Access System (McIDAS). Continued development of McIDAS and operation in the GARP Atlantic tropical experiment

The complete output of the Synchronous Meteorological Satellite was recorded on one inch magnetic tape. A quality control subsystem tests cloud track vectors against four sets of criteria: (1) rejection if best match occurs on correlation boundary; (2) rejection if major correlation peak is not distinct and significantly greater than secondary peak; (3) rejection if correlation is not persistent; and (4) rejection if acceleration is too great. A cloud height program determines cloud optical thickness from visible data and computer infrared emissivity. From infrared data and temperature profile, cloud height is determined. A functional description and electronic schematics of equipment are given.

Suomi, V. E.↗
NASA NTRS1977

Analysis of satellite derived winds for April 24, 1975

Cumulus cloud tracking based on short-interval GOES satellite imagery provided a representation of the low-level wind fields existing prior to the outbreak of severe thunderstorms. Through use of the satellite-derived winds and surface mixing ratios, moisture convergence fields were estimated. The effect of the spatial distribution of trackable clouds on the computed dynamic fields was also investigated.

Maddox, R. A.↗
NASA NTRS1981

Supernova remnant revolution in an inhomogeneous medium. I - Numerical models

The first numerical simulations of supernova remnant evolution in an inhomogeneous gas are presented. Evolution in the lowest density substrate (the intercloud) is assumed to be spherically symmetric with a large intercloud filling factor and many dense regions (clouds) within the remnant; however, mass momentum and energy transfer between cloud and intercloud are included and the position and morphology of individual clouds tracked. Evolution is considered in several different models of the interstellar medium, both those in which the intercloud gas is diffuse (0.001 to 0.01/cu cm) and those in which it is relatively dense (n approximately 0.3/cu cm) under a variety of assumptions about the efficiency of thermal evaporation from the clouds into the intercloud medium.

Cowie, L. L.↗
DOE OSTI2016

Understanding the Varied Influence of Midlatitude Jet Position on Clouds and Cloud Radiative Effects in Observations and Global Climate Models

This study examines the dynamical mechanisms responsible for changes in midlatitude clouds and cloud radiative effects (CRE) that occur in conjunction with meridional shifts in the jet streams over the North Atlantic, North Pacific, and Southern Oceans. When the midlatitude jet shifts poleward, extratropical cyclones and their associated upward vertical velocity anomalies closely follow. As a result, a poleward jet shift contributes to a poleward shift in high-topped storm-track clouds and their associated longwave CRE. However, when the jet shifts poleward, downward vertical velocity anomalies increase equatorward of the jet, contributing to an enhancement of the boundary layer estimated inversion strength (EIS) and an increase in low cloud amount there. Because shortwave CRE depends on the reflection of solar radiation by clouds in all layers, the shortwave cooling effects of midlatitude clouds increase with both upward vertical velocity anomalies and positive EIS anomalies. Over midlatitude oceans where a poleward jet shift contributes to positive EIS anomalies but downward vertical velocity anomalies, the two effects cancel, and net observed changes in shortwave CRE are small. Global climate models generally capture the observed anomalies associated with midlatitude jet shifts. However, there is large intermodel spread in the shortwave CRE anomalies, with a subset of models showing a large shortwave cloud radiative warming over midlatitude oceans with a poleward jet shift. In these models, midlatitude shortwave CRE is sensitive to vertical velocity perturbations, but the observed sensitivity to EIS perturbations is underestimated. Consequently, these models might incorrectly estimate future midlatitude cloud feedbacks in regions where appreciable changes in both vertical velocity and EIS are projected

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2001

Recent Developments in DAO's Finite-Volume Data Assimilation System

The Physical-space/Finite-volume Data Assimilation System (fvDAS) is the next generation global atmospheric data assimilation system in development at the Data Assimilation Office at NASA's Goddard Space Flight Center. It is based on a new finite-volume general circulation model jointly developed by NASA and NCAR and on the Physical-Space Statistical Analysis System (PSAS) developed at the DAO. The data assimilation method implemented in CODAS incorporates a simplified version of the model bias estimation and correction algorithm, as described by Dee and da Silva (1998). In this talk we will briefly describe the general system formulation, and focus on the impact of 3 data types recently introduced, namely: 1) cloud tracks winds from the Multi-angle Imaging Spectrometer by the US Air Force, and 3) temperature and moisture information derived from GPS refractivity occultation measurements. The impact of these data types on observation-minus-6hr forecast (O-F) statistics, as well as 5-day forecast skills will be discussed. In addition we will assess the impact of cloud assimilation on top of the atmosphere radiation fields estimated from CERES measurements.

daSilva, Arlindo↗
DOE OSTI2022

The Influence of Shallow Cloud Populations on Transitions to Deep Convection in the Amazon

Abstract In this study, a pair of convection-permitting (2-km grid spacing), month-long, wet-season Weather Research and Forecasting (WRF) Model simulations with and without the eddy-diffusivity mass-flux (EDMF) scheme are performed for a portion of the Green Ocean Amazon (GoAmazon) 2014/15 field campaign period. EDMF produces an ensemble of subgrid-scale convective plumes that evolve in response to the boundary layer meteorological conditions and can develop into shallow clouds. The objective of this study is to determine how different treatments of shallow cumulus clouds (i.e., with and without EDMF) impact the total cloud population and precipitation across the Amazonian rain forest, with emphasis on impacts on the likelihood of shallow-to-deep convection transitions. Results indicate that the large-scale synoptic conditions in the EDMF and control simulations are nearly identical; however, on the local scale their rainfall patterns diverge drastically and the biases decrease in EDMF. The EDMF scheme significantly increases the frequency of shallow clouds, but the frequencies of deep clouds are similar between the simulations. Deep convective clouds are tracked using a cloud-tracking algorithm to examine the impact of shallow cumulus on the surrounding ambient environment where deep convective clouds initiate. Results suggest that a rapid increase of low-level cloudiness acts to cool and moisten the low to midtroposphere during the day, favoring the transition to deep convection.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

VENUS CLOUD MORPHOLOGY AND MOTIONS FROM GROUND-BASED IMAGES AT THE TIME OF THE AKATSUKI ORBIT INSERTION

We report Venus image observations around the two maximum elongations of the planet at 2015 June and October. From these images we describe the global atmospheric dynamics and cloud morphology in the planet before the arrival of JAXA’s Akatsuki mission on 2015 December 7. The majority of the images were acquired at ultraviolet wavelengths (380–410 nm) using small telescopes. The Venus dayside was also observed with narrowband filters at other wavelengths (890 nm, 725–950 nm, 1.435 μ m CO{sub 2} band) using the instrument PlanetCam-UPV/EHU at the 2.2 m telescope in Calar Alto Observatory. In all cases, the lucky imaging methodology was used to improve the spatial resolution of the images over the atmospheric seeing. During the April–June period, the morphology of the upper cloud showed an irregular and chaotic texture with a well-developed equatorial dark belt (afternoon hemisphere), whereas during October–December the dynamical regime was dominated by planetary-scale waves (Y-horizontal, C-reversed, and ψ -horizontal features) formed by long streaks, and banding suggesting more stable conditions. Measurements of the zonal wind velocity with cloud tracking in the latitude range from 50°N to 50°S shows agreement with retrievals from previous works.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Evaluating Sea Breezes and Associated Convective Cloud Evolution in the Model Gray Zone

We characterize convective clouds associated with sea‐breeze circulations (SBC) using multi‐agency observations and multi‐case ensemble model simulations. The focus is on assessing convective cloud lifecycle properties and their merging behavior, as well as the environmental conditions they are embedded in, particularly SBC features. In total, 46 SBC days over the Houston‐Galveston region are selected and simulated using the Weather Research and Forecasting (WRF) model at a gray zone scale with a forecast‐like parameterization setup. Advanced techniques, including change‐point detection, a Lagrangian cloud tracking method, and a newly developed cell merging and splitting detection algorithm, are applied and/or developed for this study. Our findings indicate that the WRF model at 1 km grid spacing well represents the thermodynamic conditions over the region, as well as SBC timing and intensity. However, for the associated convective cells, WRF overestimates the 30‐dBZ echo top height, cell area, and maximum radar reflectivity compared to radar observations. This overestimation is potentially due to under‐resolved entrainment processes, an overestimated merging frequency, and the overestimation of updraft intensity. Furthermore, the model exhibits a deficiency in simulating congestus clouds, showing a more rapid transition from shallow to deep convection compared to observed behavior. Moreover, observations indicate stronger, deeper, and wider clouds when merging happens. Conversely, in simulations, the merging process does not necessarily lead to higher or longer‐lived cells, as many cases experience rapid and frequent merging and splitting which may result in more variance in convective updraft velocity during the convection lifetime.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

MEANDERING SHALLOW ATMOSPHERIC JET AS A MODEL OF SATURN'S NORTH-POLAR HEXAGON

The Voyager flybys of Saturn in 1980–1981 revealed a circumpolar Hexagon at ∼78° north planetographic latitude that has persisted for over 30 Earth years, more than one Saturn year, and has been observed by ground-based telescopes, Hubble Space Telescope and multiple instruments on board the Cassini orbiter. Its average phase speed is very slow with respect to the System III rotation rate, defined by the primary periodicity in the Saturn Kilometric Radiation during the Voyager era. Cloud tracking wind measurements reveal the presence of a prograde jet-stream whose path traces the Hexagon’s shape. Previous numerical models have produced large-amplitude, n = 6, wavy structures with westward intrinsic phase propagation (relative to the jet). However, the observed net phase speed has proven to be more difficult to achieve. Here we present numerical simulations showing that instabilities in shallow jets can equilibrate as meanders closely resembling the observed morphology and phase speed of Saturn’s northern Hexagon. We also find that the winds at the bottom of the model are as important as the winds at the cloud level in matching the observed Hexagon’s characteristics.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRSDate not supplied

Preparing for Europa Clipper Jupiter Observations: Multi-Wavelength Zonal Winds During the New Horizons and Cassini Flybys

We present Jovian zonal wind speeds measured during the Cassini and New Horizons Jupiter flybys in 2000 and 2007, respectively. We performed our cloud tracking wind measurements using an automated, two-dimensional correlation imaging velocimetry technique. We analyzed all LORRI panchromatic images from the New Horizons Jupiter flyby dataset. This LORRI measurement documents the state of Jupiter’s zonal mean wind speed in 2007 and extends the historical record of Jupiter’s winds. Among the Cassini ISS images, we processed the CL1CL2, CB2, UV3, BL1, BL2, GRN, RED, IR1, IR2, IR3, IR4, MT2, and MT3 filters. Our Cassini measurements provide valuable context to understand the altitudes probed by LORRI. Comparing the panchromatic LORRI measurements against past wind measurements using images captured with various narrow and wide-band camera filters is not straightforward. Because the Cassini ISS CL1CL2 “clear” filter’s performance is similar to that of LORRI, comparing CL1CL2 winds against LORRI results will help determine if the New Horizons measurements represent Jupiter’s cloud-top zonal wind speeds or if they are sensitive to different altitudes. In addition to placing our New Horizons measurements in altitudinal context, the Cassini ISS's IR4, IR2, RED, GRN, and BL1 filters are similar to those on Europa Clipper EIS camera. Wind measurements performed using those ISS filters will enable comparison to future missions, including anticipated observations to be taken by Europa Clipper

Jupiter↗
NASA NTRS2016

Fast Track to the Cloud: Design Patterns for 12-Factor Earth Sciences Applications

As expanding service offerings and decreasing prices make the cloud increasingly attractive to Earth Science applications, there are nontrivial practical considerations which can hinder its meaningful use. In this talk, we will discuss architectural recommendations and lessons learned while working on EOSDIS' cloud efforts, particularly the NASA-compliant General Application Platform (NGAP) and its associated applications. Prominent in our findings is the importance of 12-factor design patterns and the powerful "wins" they enable in the cloud. We will share our strategies for "fast-tracking" applications to the cloud --whether they be legacy, planned for the future, or somewhere in between.

cloud↗
NASA NTRSDate not supplied

Multi-Wavelength Comparison of Jupiter’s Zonal Winds During the New Horizons and Cassini Flybys

We present Jovian zonal wind speeds measured during the Cassini and New Horizons Jupiter flybys in 2000 and 2007, respectively. We performed our cloud tracking wind measurements using an automated, two-dimensional correlation imaging velocimetry technique. We analyzed all LORRI panchromatic images from the New Horizons Jupiter flyby dataset. This LORRI measurement documents the state of Jupiter’s zonal mean wind speed in 2007 and extends the historical record of Jupiter’s winds that serve as useful points of comparison for Juno observations. Among the Cassini ISS images, we analyzed the CL1CL2, CB2, UV3, BL1, BL2, GRN, RED, IR1, IR2, IR3, IR4, MT2, and MT3 filters. Our Cassini measurements provide valuable context to understand the altitudes probed by LORRI. Comparing the panchromatic LORRI measurements against past wind measurements using images captured with various narrow and wide-band camera filters is not straightforward. Because the Cassini ISS CL1CL2 “clear” filter’s performance is similar to that of LORRI, comparing CL1CL2 winds against LORRI results will help determine if the New Horizons measurements represent Jupiter’s cloud-top zonal wind speeds or if they are sensitive to different altitudes. In addition to placing our New Horizons measurements in altitudinal context, the Cassini ISS's IR4, IR2, RED, GRN, and BL1 filters are similar to those on Europa Clipper EIS camera. Wind measurements performed using those ISS filters will enable comparison to future missions, including anticipated observations to be taken by Europa Clipper.

Jupiter↗
DOE OSTI2023

Flow of the normal component of He-II about bluff objects observed with He$^*_2$ excimers

Flow of the normal fluid component of He II about a cylinder and flat plate in a channel with a square cross-section was observed by tracking clouds of He$^*_2$ excimers. Flow was produced using a lithographically patterned heater. The direction and speed of flow projected onto a plane parallel to the axis of the channel and perpendicular to the heater exhibited significant change with time even after the heater was turned off. Flow was recorded in movies. Excimers moved at least as fast as could be recorded by the camera. Velocity vector field maps of flow suggest formation of structures downstream of the cylinder object that are consistent with parts of eddies. Here, in this paper, we establish a foundation to observe normal component flow of a quantum fluid over centimeters.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1976

Preliminary evaluation of Nimbus-6 sounding data

Preliminary results on Nimbus-6 moisture and temperature soundings are discussed. The satellite takes readings of cloud-tracked winds and temperatures (with vertical resolution) in microwave and IR (15 micron and 4 micron) channels. The data are compared with ground-based radiosonde data. Isotherm patterns and thickness patterns derived from satellite data and radiosonde data are compared, as well as data on precipitable water. Satellite soundings are found to present a realistic picture of thermal and moisture fields in the vicinity of large-scale disturbances, and can be useful in initialization for large-scale numerical prediction models when properly combined with data from other sources. Limitations in vertical resolution are noted.

Tracton, M. S.↗