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At least 1,063 records · Page 59
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Flight test measurements and analysis of sonic boom phenomena near the shock wave extremity

The sonic boom flight test program conducted at Jackass Flats, Nevada, during the summer and fall of 1970 consisted of 121 sonic-boom-generating flights over the 1500 ft instrumented BREN tower. This test program was designed to provide information on several aspects of sonic boom, including caustics produced by longitudinal accelerations, caustics produced by steady flight near the threshold Mach number, sonic boom characteristics near lateral cutoff, and the vertical extent of shock waves attached to near-sonic airplanes. The measured test data, except for the near-sonic flight data, were analyzed in detail to determine sonic boom characteristics for these flight conditions and to determine the accuracy and the range of validity of linear sonic boom theory. The caustic phenomena observed during the threshold Mach number flights and during the transonic acceleration flights are documented and analyzed in detail. The theory of geometric acoustics is shown to be capable of predicting shock wave-ground intersections, and current methods for calculating sonic boom pressure signature away from caustics are shown to be reasonably accurate.

Haglund, G. T.↗
NASA NTRS1973

Iron absorption band analysis for the discrimination of iron rich zones

The author has identified the following significant results. A lineament study of the Nevada test site is near completion. Two base maps (1:500,000) have been prepared, one of band 7 lineaments and the other of band 5 lineaments. In general, more lineaments and more faults are seen on band 5. About 45% of the lineaments appear to be faults and contacts, the others being predominantly streams, roads, railway tracks, and mountain crests. About 25% of the lineaments are unidentified so far. Special attention is being given to unmapped extensions of faults, groups of unmapped lineaments, and known mineralized areas and alteration zones. Earthquake epicenters recorded from 1869 to 1963 have been plotted on the two base maps. Preliminary examination as yet indicates no basic correlation with the lineaments. Attempts are being made to subtract bands optically, using an I2S viewer, an enlarger, and a data color viewer. Success has been limited so far due to technical difficulties, mainly vignetting and poor light sources, within the machines. Some vegetation and rock type differences, however, have been discerned.

Rowan, L. C.↗
NASA NTRS1973

Use of satellite imagery for wildland resource evaluation in the Great Basin

The author has identified the following significant results. Color composites and diazachrome transparencies of ERTS-1 imagery have greatly increased interpretation capabilities. Vegetation green-up and flooding due to late summer precipitation has been identified on such imagery. MSS imagery in all bands has not proven as valuable for similar determinations. Snow cover has been found to be valuable in the identification of fire scars, pinyon/juniper chainings, and subtle ecotones not previously identified with any other type of imagery. It is felt that a greater understanding of the effects of snow cover on vegetation remote sensing will enable investigators to extend capabilities relating to the mapping and identification of these resources. Highly reflective phreatophytic vegetation has been mapped and quantified using the MSS 5 and 7 bands and diazachrome color composites. Approximately 10 man-hours were required to complete the entire state. Native meadow and hay meadow vegetation has been mapped in Elko County, Nevada, using ERTS-1 imagery. Future plans include a statewide inventory of this resource.

Tueller, P. T.↗
NASA NTRS1973

Recognition of the geologic framework of porphyry deposits on ERTS-1 imagery

The author has identified the following significant results. Photointerpretation methods have been most successfully applied in the less vegetated test sites where several previously unknown geologic features have been recognized and known ones extended. Northwest mid-Tertiary faults in the ELY, Nevada area are observed to offset north-trending ranges and abruptly terminate older Mesozoic structures. In the Ray, Arizona area the observed patterns of fault and fracture systems appear to be related to the locations of known porphyry copper deposits. In the Tanacross, Alaska area a number of regional circular features observed may represent near surface intrusions and, therefore, permissive environments for copper porphyries.

Wilson, J. C.↗
NASA NTRS1973

Use of satellite imagery for wildland resource evaluation in the Great Basin

The author has identified the following significant results. Most major vegetation types of Nevada have been mapped with success. The completed set of mosaic overlays will be more accurate and detailed than previous maps compiled by various State and Federal agencies due to the excellent vantage point that ERTS-1 data affords. This new vegetation type map will greatly aid resource agencies in their daily work. Such information as suitable grazing areas, wildlife habitat, forage production, and approximate wildland production potentials can be inferred from such a map. There has been some success in detecting vegetational changes with the use of ERTS-1 MSS imagery, but exposure differences have somewhat confounded the results. Future plans include work to solve this problem.

Tueller, P. T.↗
NASA NTRS1973

ERTS-1 evaluation of natural resources management applications in the Great Basin

The relatively cloud free weather in the Great Basin has allowed the accumulation of several dates of excellent ERTS-1 imagery. Mountains, valleys, playas, stream courses, canyons, alluvial fans, and other landforms are readily delineated on ERTS-1 imagery, particularly with MSS-5. Each band is useful for identifying and studying one or more natural resource features. For example, crested wheatgrass seedings were most easily identified and measured on MSS-7. Color enhancements simulating CIR were useful for depicting meadow and phreatophytic vegetation along water bodies and stream courses. Work is underway to inventory and monitor wildfire areas by age and successional status. Inventories have been completed on crested wheatgrass seedings over the entire State of Nevada, and inventories of playa surfaces, water surfaces, phreatophytic vegetation, snow cover, meadows, and other features is continuing. Vegetation ecotones are being delineated for vegetation mapping. The pinyon/juniper-northern desert shrub ecotone has been identified with considerable success. Phenology changes can be used to describe vegetation changes for management.

Tueller, P. T.↗
NASA NTRS1973

Regional Tectonic Control of Tertiary Mineralization and Recent Faulting in the Southern Basin-Range Province, an Application of ERTS-1 Data

Research based on ERTS-1 MSS imagery and field work in the southern Basin-Range Province of California, Nevada and Arizona has shown regional tectonic control of volcanism, plutonism, mineralization and faulting. This paper covers an area centered on the Colorado River between 34 15' N and 36 45' N. During the mid-Tertiary, the area was the site of plutonism and genetically related volcanism fed by fissure systems now exposed as dike swarms. Dikes, elongate plutons, and coeval normal faults trend generally northward and are believed to have resulted from east-west crustal extension. In the extensional province, gold silver mineralization is closely related to Tertiary igneous activity. Similarities in ore, structural setting, and rock types define a metallogenic district of high potential for exploration. The ERTS imagery also provides a basis for regional inventory of small faults which cut alluvium. This capability for efficient regional surveys of Recent faulting should be considered in land use planning, geologic hazards study, civil engineering and hydrology.

Bechtold, I. C.↗
NASA NTRS1973

ERTS Applications in earthquake research and mineral exploration in California

Examples that ERTS imagery can be effectively utilized to identify, locate, and map faults which show geomorphic evidence of geologically recent breakage are presented. Several important faults not previously known have been identified. By plotting epicenters of historic earthquakes in parts of California, Sonora, Mexico, Arizona, and Nevada, we found that areas known for historic seismicity are often characterized by abundant evidence of recent fault and crustal movements. There are many examples of seismically quiet areas where outstanding evidence of recent fault movements is observed. One application is clear: ERTS-1 imagery could be effectively utilized to delineate areas susceptible to earthquake recurrence which, on the basis of seismic data alone, may be misleadingly considered safe. ERTS data can also be utilized in planning new sites in the geophysical network of fault movement monitoring and strain and tilt measurements.

Abdel-Gawad, M.↗
NASA NTRS1973

ERTS-1 image enhancement by optically combining density slices

The technique of density slicing using a photographic film and its application to enhancement of ERTS-1 imagery has proved to be useful for mapping varigated areal phenomena and provides a useful supplement ot the I2S MiniAddcol viewing system. The intial experiments conducted with this film were encouraging, and indicated that this technique of density slicing using readily accessible darkroom facilities and simple darkroom procedures allows rapid, accurate, and facile interpretation of certain areal phenomena to be made from the imagery. The distribution of the tree yucca, Yucca brevifolia Jaegeriana, in the eastern Mojave Desert of Southern California and southern Nevada was used as an example to test the accuracy of the technique for mapping purposes. The distribution was mapped at a relatively high level of accuracy.

Tapper, G. O.↗
NASA NTRS1973

Photointerpretation of Skylab 2 multispectral camera (S-190A) data: Advance report of significant results

The author has identified the following significant results. A significant and possible major economic example of the practical value of Skylab photographs was provided by locating on Skylab Camera Station Number 4, frame 010, SL-2, an area of exposures of limestone rocks which were thought to be completely covered by volcanic rocks based upon prior mapping. The area is located less than 12 miles north of the Ruth porphyry copper deposit, White Pine County, Nevada. This is a major copper producing open pit mine owned by Kennecott Copper Corporation. Geophysical maps consisting of gravity and aeromagnetic studies have been published indicating three large positive magnetic anomalies located at the Ruth ore deposits, the Ward Mountain, not a mineralized area, and in the area previously thought to be completely covered by post-ore volcanics. Skylab photos indicate, however, that erosion has removed volcanic cover in specific sites sufficient to expose the underlying older rocks suggesting, therefore, that the volcanic rocks may not be the cause of the aeromagnetic anomaly. Field studies have verified the initial interpretations made from the Skylab photos. The potential significance of this study is that the large positive aeromagnetic anomaly suggests the presence of cooled and solidified magma below the anomalies, in which ore-bearing solutions may have been derived forming possible large ore deposits.

Jensen, M. L.↗
NASA NTRS1973

Study to develop improved spacecraft snow survey methods using Skylab/EREP data

The author has identified the following significant results. The initial analysis of EREP data from the SL-2 mission has been undertaken. Snow distributions are being mapped from the S190A photography for three mountain areas: the Sierra Nevadas; the Cascades near Washington-Oregon border; and the Wasatch Range in Utah. In the S192 screening film, a dramatic reversal in the reflectance of the snow in the Wasatch Range is observed between the visible and near IR channels. In channel 2 (0.46 - 0.51 microns) the snow has a high reflectance, whereas in channel 11 (1.55 - 1.75 microns) the snow appears almost black, having a much lower reflectance than the surrounding terrain. The sharp drop in reflectance in the near IR channel is believed to be due to the existence of melt water on the snow surface. Although investigators have reported this effect previously using ERTS-1 imagery, the S192 data provides the first opportunity to study quantitatively the snow reflectance in several visible and near IR channels. The results will have direct application for developing a technique to determine the condition of the snow surface (i.e., dry of melting), a significant parameter in snow hydrology.

Barnes, J. C.↗
NASA NTRS1973

Evaluate the application of ERTS-A data for detecting and mapping snow cover

The author has identified the following significant results. It is concluded from data analysis that the amount of information in ERTS-1 imagery with practical application to snow mapping is substantial. For the Arizona and California test sites, it appears that the extent of the mountain snowpacks can be mapped from ERTS-1 data in more detail than is depicted in aerial survey snow charts. In the Salt-Verde watershed, the agreement between the percentage of the area snow covered as measured from the ERTS-1 data and from aerial survey charts is generally well within 10%. In nearly all of the areas in which greater discrepancies occur, the differences can be explained by changes in snow cover during the interval between the two observations. In the southern Sierra Nevada, the agreement between ERTS-1 data and aerial survey charts is of the order of 5% in all cases, except for the Kaweah Basin on one date. In addition to comparative analysis with aerial snow charts, the ERTS-1 data have also been compared with high altitude aircraft photography. The ERAP data have provided an excellent source of correlative information. The results of the comparative analysis indicate that although small details in the snow line that cannot be detected in the ERTS-1 data can be mapped from higher resolution aircraft data, the boundaries of snow cover can be mapped just as accurately from ERTS-1 data.

Barnes, J. C.↗
NASA NTRS1973

An investigation of mountain waves with lidar observations.

In March and April of 1969 and 1970, lidar (laser radar) observations of the atmospheric structure were made in the lee of the Sierra Nevada during the occurrence of mountain lee waves. Rawinsonde ascents and, on some occasions, research aircraft flights supported the lidar observations. The objective of the program was to explore the applicability of the lidar technique to atmospheric turbulence detection. The observations demonstrate that a ground-based lidar can delineate significant features of the atmospheric flow pattern by monitoring echoes from concentrations of particulate matter that characterize the airflow structure in the form of either visible or subvisible clouds and dust.

Viezee, W.↗
NASA NTRS1974

The application of ERTS imagery to mapping snow cover in the western United States

The author has identified the following significant results. In much of the western United States a large part of the utilized water comes from accumulated mountain snowpacks; thus, accurate measurements of snow distributions are required for input to streamflow prediction models. The application of ERTS-1 imagery for mapping snow has been evaluated for two geographic areas, the Salt-Verde watershed in central Arizona and the southern Sierra Nevada in California. Techniques have been developed to identify snow and to differentiate between snow and cloud. The snow extent for these two drainage areas has been mapped from the MSS-5 (0.6 - 0.7 microns) imagery and compared with aerial survey snow charts, aircraft photography, and ground-based snow measurements. The results indicate that ERTS imagery has substantial practical applications for snow mapping. Snow extent can be mapped from ERTS-1 imagery in more detail than is depicted on aerial survey snow charts. Moreover, in Arizona and southern California cloud obscuration does not appear to be a serious deterrent to the use of satellite data for snow survey. The costs involved in deriving snow maps from ERTS-1 imagery appear to be very reasonable in comparison with existing data collection methods.

Barnes, J. C.↗
NASA NTRS1974

Study to develop improved spacecraft snow survey methods using Skylab/EREP data

The author has identified the following significant results. A segment of the interim S192 film product from the SL-2 mission has been examined. The film covers the White Mountains area near the California-Nevada border and contains useable data for spectral bands: band 3, band 7, band 9, and band 11. Whereas the snow surface exhibits wide variations in reflectance, no significant change in the reflectance of the clouds occurs over the spectral range of these four bands. In band 11 the clouds appear white and snow appears black; in the band 3 data, both the clouds and the snow appear white. Two potential applications are possible, based on these results. First, because the reflectance of the snow surface in the band 9 data is much lower at the lower elevation terrain of the White Mountains, it appears that the drop in reflectance in the near-IR portion of the spectrum may be related to the wetness of the snow surface. Secondly, the complete reversal in reflectance that is observed in band 11 data indicates that in this portion of the spectrum snow surfaces have a low reflectance regardless of the condition of the snow. Because clouds do not exhibit a similar drop in reflectance, measurements in this spectral band have potential use for automatically distinguishing snow from clouds.

Barnes, J. C.↗
NASA NTRS1974

Multispectral signatures in relation to ground control signature using nested sampling approach

The author has identified the following significant results. In a cooperative study with USGS personnel, it has been possible to detect a 1.5 by 1 mile anomaly on ERTS CCT data, in the pine-covered mountains of western Nevada. This anomalous area is about 3-5 times larger than that of the known geobotanical anomaly which lies centrally within the area. The site has been studied on the ground and bi-directional reflectances, relative to BaS04 obtained for 40 trees, using both in-vivo techniques (similar to cherry picker operations) and field determinations of cut branches. The anomaly can be seen best by color transparencies made from 5/4, 6/4, 7/4 ratioed digital data, the 3 ratios each being coded by one of 3 colors (blue, green, and red).

Lyon, R. J. P.↗
NASA NTRS1974

Natural resource inventories and management applications in the Great Basin

ERTS-1 resolution capabilities and repetitive coverage have allowed the acquisition of several statewide inventories of natural resource features not previously completed or that could not be completed in any other way. Familiarity with landform, tone, pattern and other converging factors, along with multidate imagery, has been required. Nevada's vegetation has been mapped from ERTS-1. Dynamic characteristics of the landscape have been studied. Sequential ERTS-1 imagery has proved its usefulness for mapping vegetation, following vegetation phenology changes, monitoring changes in lakes and reservoirs (including water quality), determining changes in surface mining use, making fire fuel estimates and determining potential hazard, mapping the distribution of rain and snow events, making range readiness determinations, monitoring marshland management practices and other uses. Feasibility has been determined, but details of incorporating the data in management systems awaits further research and development. The need is to accurately define the steps necessary to extract required or usable information from ERTS imagery and fit it into on-going management programs.

Tueller, P. T.↗
NASA NTRS1974

Mapping of hydrothermal alternation zones and regional rock types using computer enhanced ERTS MSS images

A combination of digital computer processing and color compositing of ERTS MSS images has been used to map hydrothermal alternation zones and regional rock types in south-central Nevada. The technique is based on enhancement of subtle visible and near infrared reflectivity differences between mineralogically dissimilar rocks, especially unaltered and altered rocks. MSS spectral bands are ratioed, pixel by pixel, in the computer and subsequently stretched. These ratio values are used to produce a new black and white image which shows the subtle spectral reflectivity differences. Additional enhancement is achieved by preparing color composites of two or more stretched ratio images. The choice of MSS bands for rationing depends on the spectral reflectance properties of the rocks to be discriminated. Although this technique is in the initial stage of development and is untested in other areas, it already appears to have considerable potential for targeting mineral prospects and for regional geologic mapping.

Rowan, L. C.↗