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At least 55 records · Page 3

Satellite Relaying of Geophysical Data

Data Collection Platforms (DCPs) for transmitting surface data to an orbiting satellite for relaying to a central data distribution center are being used in a number of geophysical applications. "Off-the-shelf" DCP's, transmitting through Landsat or GOES satellites, are fully capable of relaying data from low-data-rate instruments, such as tiltmeters or tide gauges. In cooperation with the Lamont-Doherty Geological Observatory, Goddard has successfully installed DCP systems on a tide gauge and tiltmeter array on Anegada, British Virgin Islands. Because of the high-data-rate requirements, a practical relay system capable of handling seismic information is not yet available. Such a system could become the basis of an operational hazard prediction system for reducing losses due to major natural catastrophies such as earthquakes, volcanic eruptions, landslides or tsunamis.

Allenby, R. J.↗

Petrologic model of the northern Mississippi embayment based on satellite magnetic and ground based geophysical data

Magnetization, derived from gravity-seismic data from the northern Mississippi Embayment, is evaluated relative to magnetization values obtained from satellite magnetic data. A magnetization contrast of approximately -0.54 A/m determined from the geophysical model compares favorably to a value of approximately -0.47 A/m from MAGSAT United States Apparent Magnetization contrast map. The negative magnetization contrast, required by the MAGSAT data, is unusual as rift zones with the exception of those which are currently active are associated with positive magnetization. The model presented favors an intrusion of low Curie temperature mafic rock at the base of the crust. Alternate possibilities, a shallow Curie isotherm or remanence in a direction other than that of the current main field, seem less likely as reported regional heat flow values are too low and remanence is attenuated at depth.

Thomas, H. H.↗

An array processing system for lunar geochemical and geophysical data

A computerized array processing system has been developed to reduce, analyze, display, and correlate a large number of orbital and earth-based geochemical, geophysical, and geological measurements of the moon on a global scale. The system supports the activities of a consortium of about 30 lunar scientists involved in data synthesis studies. The system was modeled after standard digital image-processing techniques but differs in that processing is performed with floating point precision rather than integer precision. Because of flexibility in floating-point image processing, a series of techniques that are impossible or cumbersome in conventional integer processing were developed to perform optimum interpolation and smoothing of data. Recently color maps of about 25 lunar geophysical and geochemical variables have been generated.

Eliason, E. M.↗

Microwave spectrometer on the Nimbus 5 satellite - Meteorological and geophysical data

The Nimbus 5 microwave spectrometer has been used to measure thermal radiation in five frequency bands between 22.235 and 58.8 gigahertz, and has yielded both the temperature profile and, over ocean, the vapor and liquid water content of the terrestrial atmosphere, even in overcast conditions. Information has also been obtained on geophysical parameters that affect the surface emissivity, such as ice type, sea roughness, and snow cover. The experiment demonstrates the considerable potential of passive microwave sensing of meteorological and geophysical parameters.

Staelin, D. H.↗

Solar-geophysical data number 496, December 1985. Part 2: (Comprehensive reports). Data for June 1985, January-May 1985 and miscellanea

Contents include the detailed index for 1985; data for June 1985 (solar flares, solar radio bursts at fixed frequencies, solar X-ray radiation from GOES satellite graphs, mass ejections from the sun, and active prominences and filaments); data for January to May 1985 (solar flares January 1985, solar flares February 1985, solar flares March 1985, solar flares April 1985, solar flares May 1985, and number of flares August 1966 to June 1985); and the international geophysical calendar 1986.

Coffey, H. E.↗

CT and Geophysical Data of Clinton Sandstone Cores from Ohio

Collection of computed tomography and multi-sensor core logger data of 12 wells in Ohio that intersect the Clinton Sandstone formation. This data is described along with well information in a technical report series document: Paronish, T.; Holleran, A.; Pohl, M.; Crandall, D.; Jarvis, K.; Workman, S.; Drosche, J.; McKisic, T.; Collins, C.; Thomas, M.; McDonald, J. Computed Tomography Scanning and Geophysical Measurements of the Clinton Sandstone in Ohio; DOE.NETL-2025.4949; NETL Technical Report Series; U.S. Department of Energy, National Energy Technology Laboratory, Morgantown, WV, 2025; p 68. https://doi.org/10.2172/2589262

AS↗

High latitude geophysical data

Cosmic noise, telluric currents, and geomagnetic activity for Alaska, April-June 1967 - Tables and charts

Hessler, V. P.↗

Geophysical data base

A general data-management system that provides a random-access capability for large amounts of data is described. The system operates on a CDC 6400 computer using a combination of magnetic tape and disk storage. A FORTRAN subroutine package is provided to simplify the maintenance and use of the data.

Williamson, M. R.↗

Low-power portable geophysical data acquisition system and its use in geomagnetic measurements

A low-power portable data acquisition system presently in use for geomagnetic measurements is described. The system is composed of a data-processing system containing a low-power microprocessor, a 9-track digital tape recorder, and a rechargeable battery pack. The magnetometer is a low-power three axis fluxgate design. Under program control the data processing system keeps track of time of day and date, samples three analog magnetometer outputs at intervals of either 0.4 or 2 s, digitizes the data to 15-bit resolution, and, depending upon relative magnetic activity, decides upon data compression to increase the tape storage capacity. It also monitors and records internal voltages and provides self-checking functions which may be monitored through a visual readout on the control panel. The system is mounted in a rugged, weather-tight carrying case suitable for use outdoors with minimal protection. The system, including magnetometer, uses 1.6-W power and can store 5.7 Mbytes of data.

Medford, L. V.↗

Investigation of Antarctic crust and upper mantle using MAGSAT and other geophysical data

Progress in processing and analysis of Investigator B MAGSAT data is reported. Data processing tasks required prior to data analysis, including translation and reformatting of tapes and development of computer routines, were performed. A scalar anomaly map of Antarctica is near completion. Data analysis included a qualitative correlation of NASA's 4/81 scalar map of Antarctica with other geopotential data and correlation of POGO and continental scale gravity data with MAGSAT data. A magnetic high was found to exist over the Ross Embayment.

Bentley, C. R.↗

Investigation of antarctic crust and upper mantle using MAGSAT and other geophysical data

The isolation of the crustal magnetic anomaly field is discussed. Slowly spatially varying ring current fields were modeled as a least squares fit to each MAGSAT pass over Antarctica. Selection criteria were applied to data from 3000 MAGSAT passes to remove field aligned currents, yielding 87 data sets used to construct a scalar magnetic anomaly map for regions south of 55 S latitude. Internal tests performed on MAGSAT data and comparisons with the POGO map indicated that the general anomaly features are of crustal origin. The sources of anomalies generated in continental and in oceanic regions are discussed. Correlations were found between crustal magnetic anomalies and known geologic features over West and East Antarctica and over the surrounding oceanic regions.

Bentley, C. R.↗

Investigation of Antarctic crust and upper mantle using MAGSAT and other geophysical data

Development of a spectral analysis technique to determine the depth to the Curie Isotherm from MAGSAT data over Antarctica is reported. The analysis of the power spectra of a number of MAGSAT passes over Antarctica indicates on the average two power maxima for each flight pass, one with spatial wavelength of approximately 2000 km and the other with a wavelength of approximately 700 km. It was not determined whether these spectral peaks are geological or mathematical in origin.

Bentley, C. R.↗

Investigation of Antarctic crust and upper mantle using MAGSAT and other geophysical data

Plans to create an improved version of the MAGSAT magnetic anomaly map by more carefully scrutinizing the accepted data for field-aligned current effects are discussed. Data are continued to a 300 km surface for the compilation of a final map. Based on this set of data, vector anomaly maps over Antarctica are planned. A high-pass anomaly map with a cut-off wavelength of approximately 1500 km is also envisioned. It is suspected that longer-wavelength features have their origin outside the crust.

Bentley, C. R.↗

Investigation of Antarctic crust and upper mantle using MAGSAT and other geophysical data

Antarctica is the perfect proving ground for testing data reduction procedures which are alternatives to the standard procedure employing polynomial fitting. Unreduced data (observed values minus corefield model theo each pass) were averaged in 3 degree bins. The resulting map was then high pass filtered using a finite Fourier transform filter so that spectral peaks between 4200 km and 5280 km were diminished by 1/3, peaks corresponding to wavelengths greater than or equal to 5280 km were diminished by 1/2, and the d.c. component was set equal to zero. The surface subtracted in this way differs from the polynomials used in the standard method in that it is static over the 5 north data window. The map produced is presented and the effects of the static model are compared to those of the dynamic mode.

Bentley, C. R.↗