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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Application of satellite data in variational analysis for global cyclonic systems

The goal of the research is a variational data assimilation method that incorporates as dynamical constraints, the primitive equations for a moist, convectively unstable atmosphere and the radiative transfer equation. Variables to be adjusted include the three-dimensional vector wind, height, temperature, and moisture from rawinsonde data, and cloud-wind vectors, moisture, and radiance from satellite data. In order to facilitate thorough analysis of each of the model components, four variational models that divide the problem naturally according to increasing complexity were defined. The research performed during the second year fall into four areas: sensitivity studies involving Model 1; evaluation of Model 2; reformation of Model 1 for greater compatibility with Model 2; development of Model 3 (radiative transfer equation); and making the model more responsive to the observations.

Achtemeier, G. L.↗
NASA NTRS1974

Interhemispheric comparison of atmospheric circulation features as evaluated from Nimbus satellite data. A comparison of the structure and flow characteristics of the upper troposphere and stratosphere of the Northern and Southern Hemispheres

The general circulations of the Northern and Southern Hemispheres are compared with regard to the upper troposphere and stratosphere, using atmospheric structure obtained from multi-channel radiance data from the satellite infrared spectrometer instrument aboard the Nimbus 3 spacecraft. The inter-hemispheric comparisons are based on two months of data (one summer month and one winter month) in each hemisphere. Topics studied include: (1) mean meridional circulation in the Southern Hemisphere stratosphere; (2) magnitude and distribution of tropospheric eddy heat flux; (3) relative importance of standing and transient eddies in the two hemispheres; (4) magnitudes of energy cycle components; and (5) the relation of vortex structure to the breakdown climatology of the Antarctic stratospheric polar vortex.

Reiter, E. R.↗
NASA NTRS1981

Methodologies for initialization experiments with NWP mesoscale model and geostationary satellite data

An algorithm is developed for the initialization of a mesoscale NWP model with geostationary satellite data and conventional data. The algorithm is a blend of the four-dimensional assimilation technique (Charney, Jastrow and Halem, 1969) for large-scale NWP models and the variational techniques used in cloud models (Gal-Chen, 1978) and large-scale models (Sasaki, 1969). The model's generated winds are combined with rawinsonde measurements.

Gal-Chen, T.↗
NASA NTRS2021

Seawater Debye Model Function at L-Band and Its Impact on Salinity Retrieval From Aquarius Satellite Data

A model function of seawater, which specifies the dielectric constant of seawater as a function of salinity, temperature, and frequency, is important for the retrieval of sea surface salinity using satellite data. In 2017, a model function has been developed based on measurement data at 1.4134 GHz using a third-order polynomial expression in salinity ( S ) and temperature ( T ). Although the model showed improvements in salinity retrieval, it had an inconsistent behavior between partitioned salinities. To improve the stability of the model, new dielectric measurements of seawater have been made recently over a broad range of salinities and temperatures to expand the data set used for developing the model function. The structure of the model function has been changed from a polynomial expansion in S and T to a physics-based model consisting of a Debye molecular resonance term plus a conductivity term. Each unknown parameter is expressed in S and T based on the expanded measurement data set. Physical arguments have been used to limit the number of unknown coefficients in these expressions to improve the stability of the model function. The new model function has been employed in the retrieval algorithm of the Aquarius satellite mission to obtain a global salinity map. The retrieved salinity using a different model function is compared with in situ data collected by Argo floats to evaluate the impact and the performance of model functions. The results indicate that the new model function has significant improvements in salinity retrieval compared with other existing models.

Seawater↗
NASA NTRS1984

Multisensor satellite data integration for sea surface wind speed and direction determination

Techniques to integrate meteorological data from various satellite sensors to yield a global measure of sea surface wind speed and direction for input to the Navy's operational weather forecast models were investigated. The sensors were launched or will be launched, specifically the GOES visible and infrared imaging sensor, the Nimbus-7 SMMR, and the DMSP SSM/I instrument. An algorithm for the extrapolation to the sea surface of wind directions as derived from successive GOES cloud images was developed. This wind veering algorithm is relatively simple, accounts for the major physical variables, and seems to represent the best solution that can be found with existing data. An algorithm for the interpolation of the scattered observed data to a common geographical grid was implemented. The algorithm is based on a combination of inverse distance weighting and trend surface fitting, and is suited to combing wind data from disparate sources.

Glackin, D. L.↗
NASA NTRS2000

Sea Ice Motion from Wavelet Analysis of Satellite Data

Wavelet analysis of NASA scatterometer (NSCAT) backscatter and Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I) radiance data can be used to obtain daily sea ice drift information for the Arctic region. This technique provides improved spatial coverage over the existing array of Arctic Ocean buoys and better temporal resolution over techniques utilizing data from satellite synthetic aperture radars. Comparisons with ice motion derived from ocean buoys give good quantitative agreement. Both comparison results from NSCAT and SSM/I are compatible, and the results from NSCAT can definitely complement that from SSM/I when there are cloud or surface effects. Then three sea-ice drift daily results from NSCAT, SSM/I, and buoy data can be merged as a composite map by some data fusion techniques. The ice flow streamlines are highly correlated with surface air pressure contours. Examples of derived ice-drift maps in December 1996 illustrate large-scale circulation reversals over a period of four days. A method for deriving divergence and shear at the large-scale has been developed and comparison between buoys and satellite results shows a good agreement. These calibrated/validated results indicate that NSCAT, SSM/I merged daily ice motion are suitably accurate to identify and closely locate sea ice processes, and to improve our current knowledge of sea ice drift and related processes through the data assimilation of ocean-ice numerical model. For demonstration purpose, the ice velocities derived from satellite data are compared with the ice velocities derived from a coupled ice-ocean interaction model. The comparison reveals that the general circulation patterns of the two are quite similar but the ice velocity differences between the two are quite significant. In order to quantify the wind effects on ice motion, empirical orthogonal functions (EOF) are used in the principal component analysis for both ice motion and pressure field. Some preliminary results of sea-ice motion from QuikScat will also be presented.

Liu, Antony K.↗
NASA NTRS1990

Estimates of radiative flux divergence in the atmosphere from satellite data

Several options for the inference of the atmospheric radiative flux divergence (ARD) on the basis of satellite data are discussed. Attention is given to the clear-sky case and the cloudy-sky case. LW ARD profiles for different climatological regimes are presented and the effect of cloud base height on LW ARD divergence at various heights is illustrated.

Smith, G. L.↗
NASA NTRS1980

Applications of HCMM satellite data

The thermal properties of Lake Ontario as they relate to water equality, lake hydrology and energy exchange were investigated as well as the urban heat island problem in selected areas adjacent to the lake. The HCMM thermal sensor was fully calibrated for several underflight data. Actual surface water temperature maps were generated for all of Lake Ontario using the calibration procedure developed. Major water quality changes associated with the thermal bar as located by HCMM thermal data were observed from satellite and aerial data and verified by ground truth.

Source record↗
NASA NTRSDate not supplied

Increasing Discovery and Usability of Earth Science Satellite Data with My NASA Data

For 20 years, the My NASA Data project at NASA Langley Research Center has developed innovative approaches to increase the use of NASA’s satellite data by learners. My NASA Data offers a variety of authentic Earth Science datasets and a data visualization tool, eliminating the need for educators and/or learners to obtain specialized knowledge of GIS data formats and software to access and use authentic Earth Science data. While there is no shortage of available data, as federal government agencies such as NASA house petabytes of freely accessible Earth Science datasets, much of the data are only available for download and visualization in specialized formats and software, limiting their accessibility to educators and learners, especially those in primary and secondary school. Using the Google Earth Engine platform, the My NASA Data team has recently reinvented their data visualization tool, called the Earth System Data Explorer (ESDE). The ESDE gives users the capability to explore over 60 Earth Science satellite datasets in a multitude of formats such as maps, graphs, and data table Its new and improved user interface design was developed based on the preferences of educators, whom the My NASA Data project has over 20 years’ experience working with. Earth Science and GIS Subject Matter Experts (SMEs) structured the data in a professional and scientific manner. During Fiscal Year 2023, the My NASA Data website received over 1 million digital engagements, with over one-third being visitors to the data visualization tool. These metrics highlight the interest in a visualization tool that is simple and free to use with reliable and trusted datasets. The ESDE empowers users to readily relate and analyze NASA Earth Science data within their area of interest. The team used a user-centered design (UCD) framework to receive and incorporate feedback into the application’s design. Core requested features include the ability to create time series graphs, comparative analysis of maps, and download the data as CSV file. Responses indicate that advances in data visualization tools such as the ESDE make authentic Earth Science data more accessible. This presentation will cover how the My NASA Data project develops tools to enhance data discovery and accessibility, as well as how SME and user suggestions are incorporated.

Desiray Wilson↗
NASA NTRS2012

NASA In Situ Data Needs to Support the Operational Calibration and Validation of Ocean Color Satellite Data Products

Calibrating ocean color satellite instruments and validating their data products requires temporal and spatial abundances of high quality in situ oceanographic data. The Consortium for Ocean Leadership Ocean Observing Initiative (OOl) is currently implementing a distributed array of in-water sensors that could provide a significant contribution to future ocean color activities. This workshop will scope the optimal way to use and possibly supplement the planned OOl infrastructure to maximize its utility and relevance for calibration and validation activities that support existing and planned NASA ocean color missions. Here, I present the current state of the art of NASA validation of ocean color data products, with attention to autonomous time-series (e.g., the AERONET -OC network of above-water radiometers), and outline NASA needs for data quality assurance metrics and adherence to community-vetted data collection protocols

Werdel, P. Jeremy↗
NASA NTRS1984

Satellite Data Transmission (SDT) requirement

An 85 Mb/s modem/codec to operate in a 34 MHz C-band domestic satellite transponder at a system carrier to noise power ratio of 19.5 dB is discussed. Characteristics of a satellite channel and the approach adopted for the satellite data transmission modem/codec selection are discussed. Measured data and simulation results of the existing 50 Mbps link are compared and used to verify the simulation techniques. Various modulation schemes that were screened for the SDT are discussed and the simulated performance of two prime candidates, the 8 PSK and the SMSK/2 are given. The selection process that leads to the candidate codec techniques are documented and the technology of the modem/codec candidates is assessed. Costs of the modems and codecs are estimated.

Chie, C. M.↗
NASA NTRS1988

A satellite data processing and analysis software system for earth's atmosphere and surface research

The OASIS (Oceanic and Atmospheric Satellite Imaging System) is a satellite data processing and analysis software system being developed by the California Space Institute (Cal Space) for support of interdisciplinary and integrated earth sciences research programs. The system's software applications are integrated under a common executive, NASA's Transportable Application Executive (TAE). In this paper, TAE and the system software and hardware are described, and specific techniques used for ingesting, processing, analyzing, and graphically displaying data from many of the sensors presently being flown are presented. Scientific uses of these capabilities that are, or will shortly be, running under TAE at Cal Space are described.

Dealy, B.↗
NASA NTRS1990

Residual circulations calculated from satellite data: Their relations to observed temperature and ozone distributions

Monthly mean residual circulations were calculated from eight years of satellite data. The diabatic circulation is usually found to give a good approximation to the residual circulation, but this is not always the case. In particular, an example is shown at 60 deg S and 30 mbar where the diabatic and residual circulations show very different annual variations. Correlations between the vertical component of the residual circulation and temperature and ozone were computed. The computations indicate that yearly variations of temperatures in the tropics are under radiative control, except during stratospheric warmings. Interannual variations in seasonal mean temperatures are shown to be under dynamical control everywhere. Correlations between seasonal means of the vertical component of the residual circulation and ozone mixing ratios are consistent with what would be expected from the ozone variations being due to differences in the ozone transport, although transport effects cannot easily be distinguished from photochemical effects above the altitude of the ozone mixing ratio peak. Finally, variations in total ozone are examined in comparison with residual circulation variations. A one to two month phase lag is seen in the annual variation in the total ozone at 60 deg N with respect to the maximum downward residual motions. This phase lag is greater at 60 deg N than at 60 deg S. There is evidence at 60 deg S of a greater downward trend in the mean zonal ozone maxima than there is in the minima. A decreasing trend in the maximum descending motion is seen to accompany the ozone trend at 60 deg S.

Geller, Marvin A.↗