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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Thermospheric neutral wind signatures dependent on the east-west component of the interplanetary magnetic field for Northern and Southern Hemispheres as measured from Dynamics Explorer-2

DE-2 neutral-wind measurements obtained between November and January 1981-1982 and 1982-1983 were analyzed to investigate the effect of the sign of the IMF By component on neutral thermosphere dynamics at F-region altitudes. Maps of the mean neutral circulation for the northern (winter) and southern (summer) polar regions were derived for By positive and negative using polar geomagnetic coordinates. The mean neutral winds demonstrate clear By-dependent neutral wind signatures in both hemispheres.

Thayer, J. P.↗
NASA NTRS1988

Geodetic measurement of deformation east of the San Andreas Fault in Central California

The shear strain rates in the Diablo Range of California have been calculated, and the slip rate along the Calaveras and Paicines faults in Central California have been estimated, on the basis of triangulation and trilateration data from two geodetic networks located between the western edge of the Great Valley and the San Andreas Fault. The orientation of the principal compressive strain predicted from the azimuth of the major structures in the region is N 25 deg E, leading to an average shear strain value that corresponds to a relative shortening rate of 4.5 + or - 2.4 mm/yr. It is inferred that the measured strain is due to compression across the fold of this area. The hypothesized uniform, fault-normal compression within the Coast Ranges is not supported by these results.

Sauber, Jeanne↗
NASA NTRS1988

Nature of local magma storage zones and geometry of conduit systems below balsatic eruption sites - Pu'u 'O'o, Kilauea East Rift, Hawaii, example

The fluid dynamics of the well-documented eruptive episodes at Pu'u 'O'o, Kilauea are used to investigate quantitatively the size and shape of the shallow conduit system beneath the vent. The possible geometry of this region is considered. The dynamics of the eruptive episodes is used to place restrictions on the size and shape of the region and thermal calculations are used to show that the geometry is consistent with the region being the fluid residue of the partially cooled, major preepisode 1 dike. The Pu'u 'O'o example is used to illustrate some general properties of shallow magma storage zones.

Wilson, Lionel↗
NASA NTRS1989

Viewing zenith angle dependence of cloudiness determined from coincident GOES East and GOES West data

The effect of the viewing zenith angle (VZA) on the cloudiness values observed by a satellite was investigated using a combination of two cloud-amount data sets derived from nearly simultaneous collocated GOES-E and GOES-W radiance measurements over the Pacific Ocean during May 1979 and July 1983. A hybrid bispectral threshold method was used to analyze data for single-layer and total cloudiness. It was found that the cloud fraction values increased with increasing VZA for almost all cases. Low clouds exhibited the greatest increases with a VZA increase for cloud amounts in the 0.1 range, whereas high clouds showed greatest increases for cloud amounts around 0.5. Midlevel clouds showed only a slight dependence on VZA. Total cloudiness increased the most, reflecting its predominantly low-cloud composition.

Minnis, Patrick↗
NASA NTRS1989

Characterization and evaluation of acid rain in East Central Florida from 1978 to 1987: Ten year summary report

Rainfall was collected on the University of Central Florida (UCF) campus near Orlando since July 1977 and at the Kennedy Space Center (KSC), Florida since August 1977. Since November 1983, the KSC site has been affiliated with the National Atmospheric Deposition Network. Annual volume weighted pH was slightly above the 10 year mean of 4.58 during four of the past five years. Nitrate concentrations have risen somewhat during recent years while excess sulfate concentrations have remained below the 10 year mean during four of the past years. These observations hold for both the UCF and KSC data. The distribution of individual sample pH was nearly identical at UCF and KSC. Stepwise regression suggests that sulfate, nitrate, ammonium ion, and calcium play major roles in the description of rainwater acidity. Annual acid deposition and annual rainfall have varied from 30 to 50 meq/m2-yr and 100 to 180 cm/yr, respectively. Sea salt comprises about 25 percent (UCF) and greater than 50 percent (KSC) of total ionic composition.

Madsen, Brooks C.↗
NASA NTRS1990

The Interpretation of Crustal Dynamics Data in Terms of Plate Interactions and Active Tectonics of the Anatolian Plate and Surrounding Regions in the Middle East

During the past 6 months, efforts were concentrated on the following areas: (1) Continued development of realistic, finite element modeling of plate interactions and associated deformation in the Eastern Mediterranean; (2) Neotectonic field investigations of seismic faulting along the active fault systems in Turkey with emphasis on identifying seismic gaps along the North Anatolian fault; and (3) Establishment of a GPS regional monitoring network in the zone of ongoing continental collision in eastern Turkey (supported in part by NSF).

Toksoz, M. Nafi↗
NASA NTRS1992

The interpretation of crustal dynamics data in terms of plate interactions and active tectonics of the Anatolian plate and surrounding regions in the Middle East

A detailed study was made of the consequences of the Arabian plate convergence against Eurasia and its effects on the tectonics of Anatolia and surrounding regions of the eastern Mediterranean. A primary source of information is time rates of change of baseline lengths and relative heights determined by repeated SLR measurements. These SLR observations are augmented by a network of GPS stations in Anatolia, Aegea, and Greece, established and twice surveyed since 1988. The existing SLR and GPS networks provide the spatial resolution necessary to reveal the details of ongoing tectonic processes in this area of continental collision. The effort has involved examining the state of stress in the lithosphere and relative plate motions as revealed by these space based geodetic measurements, seismicity, and earthquake mechanisms as well as the aseismic deformations of the plates from conventional geodetic data and geological evidence. These observations are used to constrain theoretical calculations of the relative effects of: (1) the push of the Arabian plate; (2) high topography of Eastern Anatolia; (3) the geometry and properties of African-Eurasian plate boundary; (4) subduction under the Hellenic Arc and southwestern Turkey; and (5) internal deformation and rotation of the Anatolian plate.

Toksoz, M. Nafi↗
NASA NTRS1990

Acid rain monitoring in East-Central Florida from 1977 to present

Rainfall has been collected on the University of Central Florida campus and at the Kennedy Space Center over a 12 year period. The chemical composition has been determined and summarized by monthly, annual periods, and for the entire 12 year period at both locations. The weighted average pH at each site is 4.58; however, annual weighted average pH has been equal to or above the 12 year average during six of the past eight years. Nitrate concentrations have increased slightly during recent years while excess sulfate concentrations have remained below the 12 year weighted average during six of the past seven years. Stepwise regression suggests that sulfate, nitrate, ammonium ion and calcium play major roles in the description of rainwater acidity. Annual acid deposition and annual rainfall have varied from 20 to 50 meg/(m(exp 2) year) and 100 to 180 cm/year, respectively. Sea salt comprises at least 25 percent of the total ionic composition.

Madsen, B. C.↗
NASA NTRS1992

A numerical investigation of East Coast cyclogenesis during the cold-air damming event of 27-28 February 1982. II - Importance of physical mechanisms

This study presents a series of numerical experiments designed to examine the role of several physical processes on the evolution of and interaction between atmospheric phenomena having different scales, each of which contributed to the development of the storm of February 27-28, 1982 along a Carolina coastal front. The physical processes include: the role of diabatic heating associated with convective and grid-scale precipitation, the role of a thermally direct transverse circulation about the entrance region of a strong polar jet streak, and modification of the marine planetary boundary layer by fluxes of heat and moisture over the Gulf Stream. The diabatic heating associated with precipitation is found to have the most significant impact on storm development. Without latent heating, cyclogenesis does not occur along the Carolina coastal front despite the presence of strong low-level baroclinicity and cyclonic vorticity. A less dramatic but still important relationship is found between storm formation and the other two physical mechanisms.

Lapenta, William M.↗
NASA NTRS1991

Settlement patterns, GIS, remote sensing, and the late prehistory of the Black Prairie in east central Mississippi

Data recovered as the result of a recent field project designed to test a model of the distribution of protohistoric settlement in an unusual physiographic zone in eastern Mississippi are examined using GIS based techniques to manipulate soil and stream distance information. Significant patterning is derived. The generally thin soils and uniform substratum of the Black Prairie in combination with a distinctive settlement pattern offer a promising opportunity for the search for site specific characteristics within airborne imagery. Landsat TM data provide information on modern ground cover which is used as a mask to select areas in which a multivariate search for archaeological site signatures within a TIMS image is most likely to prove fruitful.

Johnson, Jay K.↗
NASA NTRS1993

Special Investigation Report: Commercial Space Launch Incident, Launch Procedure Anomaly Orbital Sciences Corporation PEGASUS/SCD-1, 80 Nautical Miles East of Cape Canaveral, Florida, February 9, 1993

This report explains the procedural anomaly that occurred during the launch sequence of an Orbital Sciences Corporation Pegasus expendable launch vehicle, which was subsequently deployed successfully from an NB-52B airplane, on 9 Feb. 1993. The safety issues discussed in the report include command, control and communications responsibility, launch crew fatigue, launch interphone procedures, efficiency of launch constraints, and the lack of common launch documents. Safety recommendations concerning these issues were made to the Department of Transportation, the National Aeronautics and Space Administration, and the Orbital Sciences Corporation.

Source record↗
NASA NTRS1993

Thermal and rheological controls on magma migration in dikes: Examples from the east rift zone of Kilauea volcano, Hawaii

Long-lived eruptions from basaltic volcanoes involving episodic or steady activity indicate that a delicate balance has been struck between the rate of magma cooling in the dike system feeding the vent and the rate of magma supply to the dike system from a reservoir. We describe some key factors, involving the relationships between magma temperature, magma rheology, and dike geometry that control the nature of such eruptions.

Parfitt, E. A.↗
NASA NTRS1990

Waterbird use of coastal impoundments and management implications in east-central Florida

Monthly surveys were conducted on Kennedy Space Center for one year to determine densities of waterbirds within impounded salt marshes that were predominantly open water with little emergent vegetation. The objective was to assess the importance of these impoundments to waterbirds, particularly wading birds, which are species of special conservation concern. Water-level management for mosquito control and waterfowl provided habitat for an abundance of ducks, shorebirds, coots, and wading birds. Average densities throughout the year for these groups were 5.26, 412, 2.80, and 2.20 birds/ha, respectively. The majority of waterfowl were present during the winter. Shorebirds were most common during spring migration. Wading bird densities increased with declining water level. Due to the extensive alteration and development of coastal wetlands in central Florida, properly managed impoundments may provide important feeding areas for maintaining certain waterbird populations.

Breininger, David R.↗
NASA NTRS1996

Some Operational Aspects of the International Two-Way Satellite Time and Frequency Transfer (TWSTFT) Experiment Using INTELSAT Satellites at 307 Degrees East

Eight laboratories are participating in an international two-way satellite time and frequency transfer (TWSTFT) experiment. Regular time and frequency transfers have been performed over a period of almost two years, including both European and transatlantic time transfers. The performance of the regular TWSTFT sessions over an extended period has demonstrated conclusively the usefulness of the TWSTFT method for routine international time and frequency comparisons. Regular measurements are performed three times per week resulting in a regular but unevenly spaced data set. A method is presented that allows an estimate of the values of delta (sub y)(gamma) to be formed from these data. In order to maximize efficient use of paid satellite time an investigation to determine the optimal length of a single TWSTFT session is presented. The optimal experiment length is determined by evaluating how long white phase modulation (PM) instabilities are the dominant noise source during the typical 300-second sampling times currently used. A detailed investigation of the frequency transfers realized via the transatlantic TWSTFT links UTC(USNO)-UTC(NPL), UTC(USNO)-UTC(PTB), and UTC(PTB)-UTC(NPL) is presented. The investigation focuses on the frequency instabilities realized, a three cornered hat resolution of the delta (sub y) (gamma) values, and a comparison of the transatlantic and inter-European determination of UTC(PTB)-UTC(NPL). Future directions of this TWSTFT experiment are outlined.

DeYoung, J. A.↗
NASA NTRS1998

Local Data Integration in East Central Florida Using the ARPS Data Analysis System

This paper describes the Applied Meteorology Unit's (AMU) efforts to configure, implement, and test a version of the Advanced Regional Prediction System (ARPS) Data Analysis System (ADAS; Brewster 1996) that assimilates all available data within 250 km of the Kennedy Space Center (KSC) and the Eastern Range at Cape Canaveral Air Station (CCAS). The objective for running a Local Data Integration System (LDIS) such as ADAS is to generate products which may enhance weather nowcasts and short-range (less than 6 h) forecasts issued in support of ground and aerospace operations at KSC/CCAS. A LDIS such as ADAS has the potential to provide added value because it combines observational data to produce gridded analyses of temperature, wind, and moisture (including clouds) and diagnostic quantities such as vorticity, divergence, etc. at specified temporal and spatial resolutions. In this regard, a LDTS along with suitable visualization tools may provide users with a ignore complete and comprehensive understanding of evolving weather than could be developed by individually examining the disparate data sets over the same area and time. The AMU implemented a working prototype of the ADAS which does not run in real-time. Instead, the AMU is evaluating ADAS through post-analyses of weather events for a warm and cool season case. The case studies were chosen to investigate the capabilities and limitations of a LDIS such as ADAS including the impact of non-incorporation of specific data sources on the utility of the subsequent analyses.

Case, Jonathan↗
NASA NTRS1999

East Asian Summer Monsoon Rainfall: A Historical Perspective of the 1998 Flood over Yangtze River

One of the main factors that might have caused the disastrous flood in China during 1998 summer is long-term variations that include a trend indicating increasing monsoon rainfall over the Yangtze River Valley. China's 160-station monthly rainfall anomaly for the summers of 1955-98 is analyzed for exploring such long-term variations. Singular value decomposition (SVD) between the summer rainfall and the global sea surface temperature (SST) anomalies reveals that the rainfall over Yangtze River Valley is closely related to global and regional SST variabilities at both interannual and interdecadal timescales. SVD1 mode links the above normal rainfall condition in central China to an El Nino-like SSTA distribution, varying on interannual timescale modified by a trend during the period. SVD3 mode links positive rainfall anomaly in Yangtze River Valley to the warm SST anomaly in the subtropical western Pacific, varying on interannual timescales modified by interdecadal timescales. This link tends to be stronger when the Nino3 area becomes colder and the western subtropical Pacific becomes warmer. The 1998 summer is a transition season when the 1997/98 El Nino event was in its decaying phase, and the SST in the Nino3 area emerged below normal anomaly while the subtropical western Pacific SST above normal. Thus, the first and third SVD modes become dominant in 1998 summer, favoring more Asian summer monsoon rainfall over the Yangtze River Valley.

Weng, H.-Y.↗
NASA NTRS1999

Late Pleistocene Interstadial Environment on Faddeyevskiy Island, East-Siberian Sea, Russia

Pollen, plant macrofossil, LOI and radiocarbon analyses of a 1.4-m section from Faddeyevskiy Island, Novosibirskie Ostrova archipelago (75 deg 20 min N, 143 deg 50 min E, 30m elevation) provide new information on the Late Pleistocene interstadial environmental history of this high Arctic region. Bulk radiocarbon dates of 25,700 +/- 1000, 32,780 +/- 500, 35,200 +/- 650 and two AMS dates of 29,950 +/- 660 and 42,990 +/- 1280 indicate that the deposits accumulated during the Kargian (Boutellier) interval. Numerous mammoth (Mammuthus primigenius) remains collected in the vicinity of the site were radiocarbon dated to 36,700-18,500 yr. BP. Rare bison (Bison priscus) bones were dated to 32,200 +/- 600 and 33,100 +/- 320. Poaceae, Cyperaceae, and Artemisia pollen dominate the pollen spectra with some Ranunculaceae, Caryophyllaceae, Rosaceae, and Compositae. These pollen spectra reflect a tundra-steppe vegetation which probably was dominant on the exposed shelf of the Arctic Ocean. The presence of Carex macrofossils infer a summer climate two degrees warmer than today. The productivity of this local vegetation during the Kargian interstadial was apparently high enough to feed the grass-eater herds.

Andreev, Andrei A.↗