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  • GEOPHYSICS  (1,636)
  • 1995-1999
  • 1985-1989  (1,636)
  • 1950-1954
  • 1987  (668)
  • 1985  (968)
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  • 1995-1999
  • 1985-1989  (1,636)
  • 1950-1954
Year
  • 101
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    Detailed spectral structure of magnetospheric electron bursts precipitated by lightning (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The temporal structure of electron fluxes precipitated by lightning that was measured at night over Wallops Island, Virginia, during August 1984 has been analyzed. A component of the precipitating electrons is almost certainly due to equatorial wave-particle interactions involving equatorial electron cyclotron resonance (EECR) with whistlers which produce pitch angle scattering. Precipitated electron fluxes of equatorial origin are characterized by a very steep spectral power exponent of about -20 above 100 keV. A second electron distribution from some other origin is also found whose time-integrated energy flux appears to be about equal in magnitude to the fluxes identified with the EECR processes.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 2505-251
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  • 102
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    Balloon-borne observations of the development and vertical structure of the Antarctic ozone hole in 1986 (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The vertical distribution of ozone measured at McMurdo Station, Antarctica using balloon-borne sensors on 33 occasions during November 6, 1986 - August 25, 1986 is described. These observations suggest a highly structured cavity confined to the 12-20 km altitude region. In the 17-19 km altitude range, the ozone volume mixing ratio declined from about 2 ppm at the end of August to about 0.5 ppm by mid-October. The average decay in this region can be described as exponential with a half life of about 25 days. While total ozone, as obtained from profile integration, declined only about 35 percent, the integrated ozone between 14 and 18 km declined more than 70 percent. Vertical ozone profiles in the vortex revealed unusual structure with major features from 1 to 5 km thick which had suffered ozone depletions as great as 90 percent.
    Keywords: GEOPHYSICS
    Type: Nature (ISSN 0028-0836); 326; 59-62
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  • 103
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    The influence of lower stratospheric forcing on the October Antarctic ozone decrease (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A pattern correlation is found between the 30-mb zonal average ozone and temperature at 70 deg S during the October months and the 100-mb Eliassen-Palm (E-P) fluxes for the seven Septembers of 1979 to 1985, suggesting a dynamical influence on the long term trend of ozone and temperature values in the Southern Hemisphere for this period. For the August E-P fluxes and September values, this relationship is found to hold for temperature while not being strong for ozone. No explanation is found for the anomalously warm temperature values noted for both September and October 1982.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 14; 202-205
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  • 104
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    Satellite sensing of aerosol absorption (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A method is developed for remote sensing of aerosol absorption from satellite images of the earth's surface. The method is based on the measurement of the change in the upward radiances between a clear and a hazy day over a varying surface reflectance. For a zero change balance between brightening due to scattering and darkening due to absorption and scattering is reached. This balance is utilized via a radiative transfer model to derive the aerosol single-scattering albedo. A sensitivity study is performed, and the method is tested against laboratory measurements. It is suggested that for the case of haze introduced on top of an existing background aerosol and with a fair estimate of the scattering phase function, the error in the remotely sensed single-scattering albedo is in the range of 0.03-0.05. The main errors in the method arise from variations in the surface reflectance between the clear and the hazy days, uncertainty in the scattering phase function, and variation of the aerosol and gaseous absorption between these two days. If the satellite calibration varies with time, the measurements of single-scattering albedo can be substantially affected.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 4307-431
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  • 105
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    Polar stratospheric optical depth observed between 1978 and 1985 (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Observations of the stratospheric optical depth at 1.0 micron obtained for high latitudes are presented for a 7-year period. Weekly averaged data determined from measurements made by the Stratospheric Aerosol Measurement experiment from October 1978-1985 show that the overall yearly values in both polar regions are controlled by volcanic perturbations, with most volcanic effects being experienced in Arctic latitudes. Conservatively, peak values found in the Antarctic region were approximately 0.02 and in the Arctic region about 0.55. Probable values for these regions are estimated to be 0.26 and 0.11, respectively. The weekly averaged data also show the seasonal fluctuations due to microphysical and dynamical processes. Comparison of the optical depth record with a weekly averaged 50-mbar temperature record indicates that polar stratospheric clouds are present in the southern high latitudes each year near this level from early June to early September. A depression observed in the optical depth record each austral spring season is believed to be the result of the downward displacement of particles caused by subsidence and sedimentation during the course of winter. Following the breakup of the vortex, optical depth values increase as aerosol is transported poleward. These features are noted to be present in the Arctic region as well, but on a smaller scale because of the satellite sampling methodology and the averaging scheme employed.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 4297-430
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  • 106
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    High latitude currents in the 0600 to 0900 MLT sector - Observations from Viking and DMSP-F7 (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: High-resolution magnetic field and charged-particle data acquired on March 25, 1986 by the Viking and DMSP-F7 satellites, as they traversed the dawn sector auroral zone on nearly antiparallel trajectories within 40 min of each oher, are analyzed. Magnetic field measurements by Viking at 0850 MLT and by DMSP at 0630 MLT indicate the presence of a large-scale earthward-directed region 1 Birkeland current and an upward-flowing region 2 current. Both satellites also observed a third Birkeland current adjacent to and poleward of the region 1 system with opposite flow. This poleward system is about 0.5 deg invariant latitude wide and has a current density comparable to the region 1 and 2 systems. The highest-latitude current is identified as region 0. Its charged-particle signatures were used to infer field line mapping to the equatorial plane.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 14; 423-426
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  • 107
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    The cause of high-intensity long-duration continuous AE activity (HILDCAAS) - Interplanetary Alfven wave trains (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: It is shown that high intensity (AE of greater than 1,000 nT), long duration (T of greater than 2d) continuous auroral activity events are caused by outward (from the sun) propagating interplanetary Alfven wave trains. The Alfven waves are often (but not always) detected several days after major interplanetary events, such as shocks and solar wind density enhancements. Presumably, magnetic reconnection between the southward components of the Alfven wave magnetic fields and magnetospheric fields is the mechanism for transfer of solar wind energy to the magnetosphere.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science (ISSN 0032-0633); 35; 405-412
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  • 108
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    Vertical profiles of ozone, carbon monoxide, and dew-point temperature obtained during GTE/CITE 1, October-November 1983 (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A set of 14 pairs of vertical profiles of ozone and carbon monoxide, obtained with fast-response instrumentation, is presented. Most of these profiles, which were measured in the remote troposphere, also have supporting fast-response dew-point temperature profiles. The data suggest that the continental boundary layer is a source of tropospheric ozone, even in October and November, when photochemical activity should be rather small. In general, the small-scale vertical variability between CO and O3 is in phase. At low latitudes this relationship defines levels in the atmosphere where midlatitude air is being transported to lower latitudes, since lower dew-point temperatures accompany these higher CO and O3 concentrations. A set of profiles which is suggestive of interhemispheric transport is also presented. Independent meteorological analyses support these interpretations.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 2083-209
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  • 109
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    Airborne intercomparison of nitric oxide measurement techniques (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Results from an airborne intercomparison of techniques to measure tropospheric levels of nitric oxide (NO) are discussed. The intercomparison was part of the National Aeronautics and Space Administration's Global Tropospheric Experiment and was conducted during missions flown in the fall of 1983 and spring of 1984. Instruments intercompared included a laser-induced fluorescence (LIF) system and two chemiluminescence instruments (CL). NO mixing ratios from below 5 pptv (parts per trillion by volume) to greater than 100 pptv were reported, with the majority less than 20 pptv. Good correlation was observed between the measurements reported by the CL and LIF techniques. The general level of agreement observed for the ensemble of measurements obtained during the two missions provides the basis from which one can conclude that equally 'valid' measurements of background levels of NO can be expected from either CL or LIF instruments. At the same time the periods of disagreement that were observed between the CL and LIF instruments as well as between the two CL instruments highlight the difficulty of obtaining reliable measurements with NO mixing ratios in the 5-20 pptv range and emphasize the vigilance that should be maintained in future NO measurements.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 1995-200
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  • 110
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    The electromagnetic ion cyclotron beam anisotropy instability (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Electromagnetic instabilities driven by an anisotropic, relatively cool ion beam are studied for the case in which both the beam and the instabilities propagate parallel or antiparallel to a uniform magnetic field. At modest beam-core relative drift speeds, sufficiently large perpendicular-to-parallel beam temperature ratios and sufficiently large plasma beta, the mode of fastest growth rate is the ion cyclotron beam anisotropy instability. Because the right-hand polarized waves observed upstream of slow shocks in the earth's magnetotail can lead to the appropriate beam anisotropy, the ion cyclotron instability may be present and account for the left-hand polarized magnetic waves observed there. Also, because of its relatively low phase speed, the ion cyclotron beam anisotropy instability may provide the scattering necessary for ion Fermi acceleration at slow shocks of sufficiently high plasma beta.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science (ISSN 0032-0633); 35; 51-59
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  • 111
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    Dynamic substorm injections - Similar magnetospheric phenomena at earth and Mercury (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Correlations between energetic electrons, plasma electrons, and magnetic fields during the Mercury 1 energetic particle events are examined and comparisons are made with several well-documented substorm injections at the earth. The data reveal that the B and B-prime events possess the same characteristics as single-point observations of terrestrial dynamic injections. Several recently discovered correlations between the energetic electrons, plasma electrons, and magnetic fields at Mercury are discussed.
    Keywords: GEOPHYSICS
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  • 112
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    Plasma and magnetic field variations in the distant magnetotail associated with near-earth substorm effects (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Examination of many individual event periods in the ISEE 3 deep-tail data set has suggested that magnetospheric substorms produce a characteristic pattern of effects in the distant magnetotail. During the growth, or tail-energy-storage phase of substorms, the magnetotail appears to grow diametrically in size, often by many earth radii. Subsequently, after the substorm expansive phase onset at earth, the distant tail undergoes a sequence of plasma, field, and energetic-particle variations as large-scale plasmoids move rapidly down the tail following their disconnection from the near-earth plasma sheet. ISEE 3 data are appropriate for the study of these effects since the spacecraft remained fixed within the nominal tail location for long periods. Using newly available auroral electrojet indices (AE and AL) and Geo particle data to time substorm onsets at earth, superposed epoch analyses of ISEE 3 and near-earth data prior to, and following, substorm expansive phase onsets have been performed. These analyses quantify and extend substantially the understanding of the deep-tail pattern of response to global substorm-induced dynamical effects.
    Keywords: GEOPHYSICS
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  • 113
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    Magnetic configuration of the distant plasma sheet - ISEE 3 observations (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The influence of the IMF orientation and magnitude and substorm activity on the magnetic configuration of the central plasma sheet at 20-240 earth radii down the geomagnetic tail is investigated on the basis of ISEE-3 data. The results are presented graphically, and high-speed antisolar bulk flows threaded by southward magnetic fields are shown to be present in the distant plasma sheet after periods of substorm activity and southward IMF Bz. The effective dayside reconnection efficiency is estimated as 25 + or - 4 percent, in good agreement with theoretical models.
    Keywords: GEOPHYSICS
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  • 114
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    Structure of the geomagnetic tail (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Observational data on the structure of the earth magnetotail are summarized and discussed, with reference to theoretical models. Particular attention is given to the interplanetary control of the tail, the magnetic-field structure, the plasma-sheet boundary layer, the magnetotail plasma parameters, the chemical composition of the tail, and the evidence indicating that a steady-state magnetotail cannot exist. Extensive diagrams and graphs are provided.
    Keywords: GEOPHYSICS
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  • 115
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    Bidirectional electron anisotropies in the distant tail - ISEE 3 observations of polar rain (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A detailed observational treatment of bidirectional electrons (50 approx. 500 eV) in the distant magnetotail (or greater than or equal to 100 R sub E) is presented. It is found that electrons in this energy range commonly exhibit strong, field aligned anisotropies in the tail lobes. Because of large tail motions, the ISEE-3 data provide extensive sampling of both the north and south lobes in rapid succession, demonstrating directly the strong asymetries that exist between the north and south lobes at any one time. The bidirectional fluxes are found to occur predominantly in the lobe directy connected to the sunward IMF in the open magnetosphere model (north lobe for away sectors and south lobe for toward sectors). Electron anisotropy and magnetic field data are presented which show the transition from unidirectional (sheath) electron populations to bidirectional (lobe) populations. Taken together, the present evidence suggests that the bidirectional electrons that we observe in the distant tail are closely related to the Polar rain electrons observed previously at lower altitudes. Furthermore, these data provide strong evidence that the distant tail is comprised largely of open magnetic field lines in contra distinction to some recently advanced models.
    Keywords: GEOPHYSICS
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  • 116
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    Magnetotail research - The early years (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The history of observations and theoretical modeling of the geomagnetic tail in the period 1961-1971 is reviewed. Particular attention is given to the contributions of the IMP-1 (Explorer 18) satellite (launched in 1963) and the Pioneer 7 and 8 probes. Typical data are presented in extensive graphs and diagrams and discussed in detail. Major topics considered include the discovery of the permanent tail and the imbedded plasma and neutral sheet, the determination of the average configuration and dynamical changes, estimates of the tail length, and the characterization of interplanetary-charged-particle access to the polar caps.
    Keywords: GEOPHYSICS
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  • 117
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    The roles of direct input of energy from the solar wind and unloading of stored magnetotail energy in driving magnetospheric substorms (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The contributions to the substorm expansive phase of direct energy input from the solar wind and from energy stored in the magnetotail which is released in an unpredictable manner are considered. Two physical processes for the dispensation of the energy input from the solar wind are identified: (1) a driven process in which energy supplied from the solar wind is directly dissipated in the ionosphere; and (2) a loading-unloading process in which energy from the solar wind is first stored in the magnetotail and then is suddenly released to be deposited in the ionosphere. The pattern of substorm development in response to changes in the interplanetary medium has been elucidated for a canonical isolated substorm.
    Keywords: GEOPHYSICS
    Type: Space Science Reviews (ISSN 0038-6308); 46; 1-2,; 93-111
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  • 118
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    Changes in the earth's rotation and low-degree gravitational field induced by earthquakes (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Analytical formulas based on the normal-mode theory are used together with a spherically symmetric earth model and the centroid-moment tensor solutions for earthquake sources to compute the earthquake-induced changes in the earth's rotation and low-degree harmonics of the gravitational field for the period 1977-1985. Spectral and statistical analyses are conducted on these changes. It is found that the earthquake-induced changes are two orders of magnitude smaller than those observed; most of these changes show strong evidence of nonrandomness either in their polarity or in their directions.
    Keywords: GEOPHYSICS
    Type: Geophysical Journal (ISSN 0016-8009); 91; 569-596
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  • 119
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    Cross-system comparisons of soil nitrogen transformations and nitrous oxide flux in tropical forest ecosystems (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Soil nitrogen transformations and nitrous oxide flux across the soil-air interface have been measured in a variety of tropical forest sites and correlated with patterns of nitrogen circulation. Nitrogen mineralizaton and nitrification potentials were found to be high in the relatively fertile Costa Rica sites and the Amazonian oxisol/ultisols, intermediate in Amazonian white sand soils, and low in the Hawaiian montane sites. Nitrous oxide fluxes ranged from 0 to 6.2 ng/sq cm per h, and the mean flux per site was shown to be highly correlated with mean nitrogen mineralization.
    Keywords: GEOPHYSICS
    Type: Global Biogeochemical Cycles (ISSN 0886-6236); 1; 163-170
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  • 120
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    Middle atmosphere abundances of water vapor and ozone during MAP/WINE (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: GEOPHYSICS
    Type: Journal of Atmospheric and Terrestrial Physics (ISSN 0021-9169); 49; 827-841
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  • 121
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    A quartic dispersion equation for internal gravity waves in the thermosphere (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A new quartic dispersion equation in the square of the complex vertical wave number is derived by employing the 'shallow atmosphere' approximation and an ion drag approximation. These approximations allow the coefficients of the quartic equation to be given in terms of the corresponding cubic equation (which neglects the Coriolis force and the zonal ion drag component), but modified to take into account these neglected effects. Coupling between the extraordinary viscosity wave mode and the other three wave modes is highlighted and numerical solutions are compared for this quartic equation, an exact eighth order equation and the cubic equation. For the first time the validity of using the 'shallow atmosphere' approximation to describe internal gravity wave motions is demonstrated.
    Keywords: GEOPHYSICS
    Type: Journal of Atmospheric and Terrestrial Physics (ISSN 0021-9169); 49; 889-899
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  • 122
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    The magnetic field of the equatorial magnetotail - AMPTE/CCE observations at R less than 8.8 earth radii (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The MPTE/CCE magnetic field experiment has been used to obtain a quantitative evaluation of the frequency and extent of magnetic field distortion in the near-tail region at less than 8.8 earth radii. The variation of this distortion with Kp, radial distance, longitude, and near-equatorial latitude is reported. It has been found that taillike distortions from the dipole field direction may reach 80 deg near the MPTE/CE apogee of 8.8 earth radii. The Bz field component in dipole coordinates was always positive within 0.5 earth radii of the equatorial current sheet, indicating the neutral lines were never seen inside of 8.8 earth radii. Fields were most taillike near midnight and during times of high Kp. At 8.5 earth radii the equatorial field magnitude depressions were roughly half the dipole field strength of 51 nT. These depressions are larger at lesser distances, reaching -40 nT at 3.4 earth radii for Kp of 2- or less and -80 nT and Kp of 3+ and greater.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 7432-744
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  • 123
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    A model of ionospheric image structure underneath a braking, cross-field plasma jet (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A plasma jetting across the geomagnetic field above the ionosphere tends to brake by ohmic dissipation of Pedersen currents. The braking can affect the ionosphere underneath if the associated Pedersen drifts are intense and prolonged enough to cause cumulative image structuring. Here, such image structuring is studied for the parameter regime of forthcoming releases from the Combined Release and Radiation Effects Satellite, involving photoionization of kilograms of barium vapor moving at orbital velocity. The resultant structuring in the upper E-region offers possible diagnostic telltales of the braking process.
    Keywords: GEOPHYSICS
    Type: Journal of Atmospheric and Terrestrial Physics (ISSN 0021-9169); 49; 6, Ju; 599-605
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  • 124
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    Joule heating in the mesosphere and thermosphere during the July 13, 1982, solar proton event (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The solar proton event of July 13, 1982 produced considerable ionization in the polar-cap mesosphere. Energetic solar proton fluxes were measured by the NOAA-6 satellite. The DE-2 satellite measured the low-energy electrons, the ion drift velocity, and other atmospheric and ionospheric properties during the event in the region of the measured maximum electric field (189 mV/m at 2215 UT near 60 deg N), a Joule heating rate of 1-3 K/day is calculated between 70 and 80 km, exceeding the heating due to ozone absorption at noon in the summer hemisphere in that altitude range. The Joule heating rate above 90 km greatly exceeded 20 K/day. The calculated height-integrated Joule heating rate above 100 km in the same region exceeded 400 ergs/sq cm sec, and DE-2 near 350 km measured neutral winds of nearly 1000 m/s and neutral gas temperatures of over 2000 K. The overall ionospheric structure calculated below the DE-2 satellite is described.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 6083-609
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  • 125
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    The ionosphere as a fully adequate source of plasma for the earth's magnetosphere (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The ionospheric contribution of the polar wind and cleft ion fountain at energies less than 10 eV has been added to previously measured sources; this total ion outflow has then been used to calculate the resulting ion density in the different internal regions of the earth's magnetosphere: plasmasphere, plasma trough, plasma sheet, and magnetotail lobes. Using estimated volumes for these regions and an ion residence time characteristic of each region, it is found that the observed magnetospheric densities can be attained in all cases with no contribution from the solar wind plasma. In the case of the plasma sheet the ionospherically supplied density is more than enough to match the observations and even suggests an invisible component of low-energy plasma (less than 10 eV) which has never been observed. A detailed comparison between the calculated ionospheric source effects in the plasma sheet and those recently measured by ISEE shows excellent agreement and suggests a direct polar low-energy ion source for the plasma sheet which has remained unmeasured because of spacecraft potential effects. Although the solar wind is clearly the earth's magnetospheric energy source and energetic solar wind ions are observed in the magnetosphere, these calculations suggest the possibility that the ionospheric source alone is sufficient to supply the entire magnetospheric plasma content under all geomagnetic conditions.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 5896-591
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  • 126
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    Compound streams, magnetic clouds, and major geomagnetic storms (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Data from ISEE 3, Helios A, and Helios B were used to identify the components of two compound streams and to determine their configurations. In one case, ejecta containing a magnetic cloud associated with a disappearing quiescent filament were interacting with a corotating stream. In the second case, ejecta containing a magnetic cloud associated with a 2B flare were overtaking ejecta from a different source. Each of these compound streams produced an unusually large geomagnetic storm, on April 3, 1979, and on April 25, 1979, respectively. The largest geomagnetic storm in the period 1968-1986, which occurred on July 13, 1982, was associated with a compound stream. Thirty geomagnetic storms with A(p) greater than 90 occurred between 1972 and 1983, and there are interplanetary magnetic field and plasma data for 17 of these events. The data suggest that most large geomagnetic storms are associated with compound streams and/or magnetic clouds.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 5725-573
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  • 127
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    The initiation of grain movement by wind (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: When air blows across the surface of dry, loose sand, a critical shear velocity must be achieved to initiate motion. Since most natural sediments consist of a range of grain sizes, fluid threshold for any sediment cannot really be defined by a finite value but should be viewed as a threshold range which is a function of the mean size, sorting, and packing of the sediment. In order to investigate the initiation of particle movement by wind, a series of wind tunnel tests were carried out on a range of screened sands and commercially available glass beads of differing size, sorting, and shape characteristics. In addition, individual samples of the glass beads were mixed to produce rather poorly sorted bimodal distributions. Test results suggest the when velocity is slowly increased over the sediment surface the smaller or more exposed grains are first engrained by the fluid drag of the air either in surface creep or in saltation. As velocity continues to rise, the larger more protected grains may also be moved by fluid drag. The data also indicate that predicted values based on the modified Bagnold equation fall within the range of threshold values defined by the transition section of the grain movement/shear velocity plots. Moreover, the predicted values are very similar to the threshold values derived for the point maximum inflection on the curves.
    Keywords: GEOPHYSICS
    Type: NASA, Lyndon B. Johnson Space Center, Experiments in Planetary and Related Sciences and the Space Station; 2 p
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    Electrostatic aggregation of finely-comminuted geological materials (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Electrostatic forces are known to have a significant effect on the behavior of finely comminuted particulate material: perhaps the most prevalent expression of this being electrostatic aggregation of particles into relatively coherent clumps. However, the precise role of electrostatic attraction and repulsion in determining the behavior of geological materials (such as volcanic ash and aeolian dust) is poorly understood. Electrostatic aggregation of fine particles is difficult to study on earth either in the geological or laboratory environment principally because the material in an aggregated state remains airborne for such a short period of time. Experiments conducted in the NASA/JSC - KC135 aircraft are discussed. The aircraft experiments are seen as precursors to more elaborate and scientifically more comprehensive Shuttle or Space Station activities.
    Keywords: GEOPHYSICS
    Type: NASA, Lyndon B. Johnson Space Center, Experiments in Planetary and Related Sciences and the Space Station; 2 p
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  • 129
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    On the wave excitation in the turbulent meteor trace (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The solution to the problem of excitation of longitudinal and transverse electromagnetic waves in randomly inhomogeneous media is reduced to the derivation of a complex effective dielectric constant (EDC) tensor which nonlocally connects together the average macroscopic electromagnetic fields in continuous media, it is implied that the field values which are rapidly fluctuating on a microscopic scale in space and time become smoothed out in a specified way due to the inhomogeneous mixing of diffusion. Proceedings from the derived general expression for the EDC tensor new modes of longitudinal and transverse electromagnetic wave generation due to fluctuation in the parameters of the medium was predicted. In this connection, it is of interest to investigate the peculiarities of electromagnetic longitudinal and transverse wave propagation in such randomly inhomogeneous media where, apart from the charged particle concentration change, the random spatial and temporal changes of natural frequency of closely located oscillators take place.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 207-210
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  • 130
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    Atmosphere dynamic processes structure at 80-105 km altitude (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Determination of wind velocity by means of Doppler meteor radars is based on the assumption that an ionized meteor trail drifts together with the neutral atmosphere. From the Doppler frequency shift it is possible to estimate the radial velocity of the trail drift. Conversion of the recorded radial velocity to the true wind velocity vector in the given space region depends both on the radar technical parameters and the chosen atmospheric motion model. The atmospheric dynamic processes structure is considered.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 194-199
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  • 131
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    Volcanic eruption detection with TOMS (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) is designed for mapping of the atmospheric ozone distribution. Absorption by sulfur dioxide at the same ultraviolet spectral wavelengths makes it possible to observe and resolve the size of volcanic clouds. The sulfur dioxide absorption is discriminated from ozone and water clouds in the data processing by their spectral signatures. Thus, the sulfur dioxide can serve as a tracer which appears in volcanic eruption clouds because it is not present in other clouds. The detection limit with TOMS is close to the theoretical limit due to telemetry signal quantization of 1000 metric tons (5-sigma threshold) within the instrument field of view (50 by 50 km near the nadir). Requirements concerning the use of TOMS in detection of eruptions, geochemical cycles, and volcanic climatic effects are discussed.
    Keywords: GEOPHYSICS
    Type: Scientific and Operational Requirements for TOMS Data; p 54-56
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  • 132
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    TOMS ozone data compared at mesoscale resolution to tropopause heights from the AVE radiosonde network and to VAS radiances over the south-central United States (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Observations from 1982 are being compared between the Total Ozone Mapping Spectrometer (TOMS), the Atmospheric Variability Experiment (AVE), and the VISSR Atmospheric Sounder (VAS) across Texas and Oklahoma. TOMS data show a significant ozone maximum over northeastern Texas. AVE radiosonde analysis shows tropopause heights with the highest pressure (lowest altitudes) over central Oklahoma accompanied by a mid-level jet across northern Mexico exiting above the Texas-Gulf coast. Corresponding VAS radiances show a dry slot in the middle tropopause across central Texas accompanied by a secondary slot over Oklahoma. The maxima are separated by 100 to 500 km. The impact of TOMS data on tropopause analysis is preliminarily seen as insignificant because TOMS data is not registered with respect to AVE tropopause heights.
    Keywords: GEOPHYSICS
    Type: Scientific and Operational Requirements for TOMS Data; p 39
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  • 133
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    An analysis of tropopause pressure and total ozone correlations (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A study of the relationship between total ozone and tropopause pressure was carried out using Total Ozone Mapping Spectrometer (TOMS) data and National Meteorological Center (NMC) global analyses. The medium scales generally show correlations greater than 0.6 throughout the middle latitudes of both hemispheres with some regions exceeding 0.8. The areas of highest correlations seem to be associated with the storm track regions of both the Northern and Southern Hemispheres. A detailed spectral analysis is performed for the medium scales on five pairs of time series of area averaged tropopause pressure and total ozone. In middle latitudes, total ozone and tropopause pressure exhibit generally similar distributions in the power spectrum. In the subtropics and tropics the power in ozone drops off more rapidly with increasing frequency than the power in tropopause pressure. Only in the Northern Hemisphere middle latitudes does one find a clear association between increased power in ozone and tropopause pressure and maxima in the coherency spectrum. Results for large scales are more complicated, showing generally positive correlations at middle latitudes.
    Keywords: GEOPHYSICS
    Type: Scientific and Operational Requirements for TOMS Data; p 38
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  • 134
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    Transform fault earthquakes in the North Atlantic: Source mechanisms and depth of faulting (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The centroid depths and source mechanisms of 12 large earthquakes on transform faults of the northern Mid-Atlantic Ridge were determined from an inversion of long-period body waveforms. The earthquakes occurred on the Gibbs, Oceanographer, Hayes, Kane, 15 deg 20 min, and Vema transforms. The depth extent of faulting during each earthquake was estimated from the centroid depth and the fault width. The source mechanisms for all events in this study display the strike slip motion expected for transform fault earthquakes; slip vector azimuths agree to 2 to 3 deg of the local strike of the zone of active faulting. The only anomalies in mechanism were for two earthquakes near the western end of the Vema transform which occurred on significantly nonvertical fault planes. Secondary faulting, occurring either precursory to or near the end of the main episode of strike-slip rupture, was observed for 5 of the 12 earthquakes. For three events the secondary faulting was characterized by reverse motion on fault planes striking oblique to the trend of the transform. In all three cases, the site of secondary reverse faulting is near a compression jog in the current trace of the active transform fault zone. No evidence was found to support the conclusions of Engeln, Wiens, and Stein that oceanic transform faults in general are either hotter than expected from current thermal models or weaker than normal oceanic lithosphere.
    Keywords: GEOPHYSICS
    Type: The Interpretation of Crustal Dynamics Data in Terms of Plate Motions and Regional Deformation Near Plate Boundaries; 119 p
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  • 135
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    Spectral radiometry and tropospheric aerosols: Report of panel (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The term aerosols, as used here, refers to the haze, smoke, and dust that appear in the troposphere. The term does not refer to the hydrometeors in cumulus and stratus clouds but does include the sulfuric acid-water droplets which are assumed to predominate in the stratospheric aerosol layer. The aerosol properties that were measured from satellites and those which can be made in the near term (up to 1992) will be reviewed. The capabilities that will exist in the years 1992 to 2000, with implementation of EOS, are then discussed. Finally, a few words will be said concerning the potential for aerosol measurements for the decade after 2000.
    Keywords: GEOPHYSICS
    Type: Space Opportunities for Tropospheric Chemistry Research; p 33-42
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  • 136
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    Statistical analysis of total ozone and stratospheric Umkehr data for trends and solar cycle relationship (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Dobson total ozone data from 1970-1984 and stratospheric Umkehr profile ozone data from 1970-1981 are analyzed. The relationship between ozone and long-term solar cycle activity is examined using 10.7 cm solar flux data. From the Dobson data it is estimated that the overall global trend in total ozone is -0.26 + or -0.92 percent per decade, which indicates no significant overall trend; and for the total ozone-solar flux relationship there is a 1.18 + or - 0.66 percent change in total ozone from solar cycle minimum to maximum that reveals a positive relationship. Analysis of the Umkehr data reveals a negative trend of -0.30 + or - 0.17 percent per year in the layers 7 snd 8. The relationship between Umkehr data and solar flux in layers 6 and 7 is 2.57 + or - 1.25 percent and 3.40 + or - 2.16 percent change from solar cycle minimum to maximum; however, no significant relationship is detected in the higher layers 8 and 9. These estimates are compared with theoretical model calculations. It is noted that the estimated effects of solar cycle activity on total ozone and stratospheric ozone agree with calculations of photochemical models.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 2201-220
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  • 137
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    Three-dimensional analysis of potential vorticity associated with tropopause folds and observed variations of ozone and carbon monoxide (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The usability and reliability of potential vorticity as a meteorological stratospheric tracer are evaluated. The concept of potential vorticity conservation during transport in which stratospheric and tropospheric air are mixing is tested. Aircraft data collected on April 20, 1984 in the western and southwestern U.S. are analyzed in order to derive potential vorticity data; vertical cross sections of constant-pressure data and temperature and wind speed gradients are examined. The tropopause fold observed during the April 20, 1984 aircraft flights is described. The potential vorticity, ozone mixing ratio, and carbon monoxide mixing ratio are compared; a positive correlation between potential vorticity and the ozone mixing ratio and a negative correlation between the potential vorticity and the carbon monoxide mixing ratio are detected. The data support the concepts of the conservation of potential vorticity, the entrainment and mixing of tropospheric air across the boundaries of the fold, and the applicability of potential vorticity as a stratospheric tracer.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 2103-211
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  • 138
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    Measurements of nitric oxide in the boundary layer and free troposphere over the Pacific Ocean (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Measurements of NO and O3 are presented from 13 aircraft flights made over the Pacific Ocean in the autumn of 1983 during one phase of the NASA Global Tropospheric Experiment. All of the flights were made between 15 deg and 42 deg N and from the coast of California to west of the Hawaiian Islands. Within the upper marine boundary layer the median daytime mixing ratio of NO was near 1 part per trillion by volume (pptv). Values of NO less than 10 pptv were often observed up to altitudes near 6 km. Thus for the location and season of the measurements, a net photochemical destruction of O3 would be anticipated for the boundary layer region and to altitudes of 2-3 km. At higher altitudes of 7-11 km in the free troposphere, larger mixing ratios and greater variability were usually observed for NO. Both features are consistent with observed examples of injection of NO and O3 from the lower stratosphere and with the injection of NO from towering, electrically active, cumulonimbus clouds.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 2025-204
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  • 139
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    Operational overview of NASA GTE/CITE 1 airborne instrument intercomparisons - Carbon monoxide, nitric oxide, and hydroxyl instrumentation (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: An overview of the airborne intercomparisons of CO, NO, and OH instrumentation is presented in this first paper of the series on the NASA Global Tropospheric Experiment/Chemical Instrumentation Test and Evaluation (GTE/CITE 1). This paper provides the reader with background information about several important characteristics of the project. These include the overall objectives and approach, the measurements taken, the intercomparison protocol, aircraft platform, profiles of each aircraft flight, and the participants. A synopsis of the overall results of the CO, NO, and OH instrument intercomparisons is also included. Companion papers discuss the detailed results of the CO and NO intercomparison tests as well as pertinent scientific findings.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 92; 1977-198
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  • 140
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    Infrared spectroscopy of the lower stratosphere with a balloon-borne cryogenic Fourier spectrometer (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The IR limb emission of the lower stratosphere has been measured using a balloon-borne liquid nitrogen-cooled Michelson interferometer with liquid helium-cooled Si:Ga detectors. Portions of the thermal emission spectrum have been recorded between 650 and 2000/cm with an unapodized spectral resolution of 0.03/cm. This is the highest spectral resolution limb emission thus far obtained. A preliminary description is given of these data along with a discussion of the significant features. Species identified to date include CO2, O3, CFCl3, CF2Cl2, H2O, CH4, HNO3, N2O, NO2, and ClONO2. A tentative identification is made for NO, representing the first direct spectroscopic detection of NO in emission.
    Keywords: GEOPHYSICS
    Type: Applied Optics (ISSN 0003-6935); 26; 545-553
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  • 141
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    Some considerations on measuring the Newtonian gravitational constant G in an orbiting laboratory (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: No fundamental reason has been identified for rejecting the notion of measuring the Newtonian gravitational constant G by observing an artificial binary in a near-Earth orbiting laboratory.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center, Research Reports: 1987 NASA(ASEE Summer Faculty Fellowship Program; 7 p
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  • 142
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    Ozone formation due to interaction of meteoroids with Earth's atmosphere (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: In a previous paper, it was shown that concentration of atomic oxygen in overdense meteor trails may exceed that of the normal atmosphere by a factor of several hundred times. This may lead to the formation of meteoric ozone. Therefore, it is imperative to estimate the concentration of ozone in the trails of meteor bodies with different masses. It seems that meteoric ozone must be taken into account when studying the balance of ionization in the meteor trails formed by particles with masses more than .01 g. The predicted levels of atomic oxygen and ozone seem sufficient to greatly influence the rate of meteoric plasma deionization.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 258-260
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  • 143
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    Characteristics of atmospheric disturbances with a quasi-two day period (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: In 1968 the Soviet equatorial meteor expedition measured, at an altitude of 80 to 105 km, wind velocity disturbances in the equatorial atmosphere with a quasi-two day period. An example of such disturbances is provided which shows time series of wind velocity in the meridional and zonal directions. The results of the time series analysis are discussed.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 112-118
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  • 144
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    On the dependence of the lower thermospheric wind regime on the solar cycle (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The lower thermosphere occupies the intermediate position between the overlying thermospheric layers, for which direct correlation of its parameters with solar variety variations is well established, and the underlying ones, where this correlation is mainly of an indirect character. Therefore, for understanding the mechanism of solar terrestrial correlation it is important to investigate the dependence of different atmospheric parameters in the lower troposphere, and of wind regime parameters in particular, on the solar activity. Several series of observations were used which include the results of meteor radar wind velocity measurements carried out in Obninsk complemented by the data obtained using the same technique at Jodrell Bank from 1953 to 1958 and in Kharkov from 1960 to 1963. The interannual variations of values averaged over these periods for prevailing wind velocities and semidiurnal harmonic amplitudes and also results for some months are presented. These results are discussed.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 180-185
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  • 145
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    On connection between evolution of troposphere fronts and changes of circulation regime in meteor zone (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The interactions between the thermobaric fields at heights from 5 to 95 km at the beginning of a winter period are considered, based on experimental radar measurements of meteor drifts obtained in Frunze in November to December 1983. During this period the high atmosphere readily responds to even slight changes in the thermal regime of the stratosphere. The interdiurnal variations of average daily values of wind u, v, U, and azimuth phi are shown.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 143-145
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  • 146
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    Main results of atmospheric fine structure parameter observation in the lower thermosphere (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The capabilities of the radiometeor method of wind measurement increase with the increase of the transmitted power of radar stations fitted with goniometric systems which enables the observation of shower meteors along with sporadic background. In shower observations the meteor zone reflecting area narrows to the echo surface which is perpendicular to the flux radiant. Favorable conditions are created for singling out atmospheric disturbances in which the wave front is parallel to the echo surface which plays, in this case, the role of a frequency filter. For the first time this technique allowed wave disturbances with periods of approx. greater than 4 min. to be measured, with about a 99 percent probability of exceeding the level of the turbulence noise, during the Geminid and Perseid showers. Maximum values of such wave disturbance amplitudes were about 15 to 20 m/s, with lifetimes up to 2 hrs.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 138-142
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  • 147
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    Tidal activity in the meteor zone over Budrio, Italy (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A brief survey is presented of the variations with time and height of atmospheric tides observed at Budrio (45 deg N, 12 deg E) in the wind field between 80 and 110 km altitude during the 1978 to 1982 year period. Variations of amplitude maxima mainly of the semidiurnal tide in the winter data of 1979 and 1980 show periodicities of a few days throughout the observing period. Upward propagation of tidal energy during a stratospheric warming in January 1982 is proposed to be inhibited because of instabilities in atmospheric conditions.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 121-137
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  • 148
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    Circulation in the mesosphere and lower thermosphere during the MAP (Middle Atmosphere Program)/WINE (Winter in the Northern Europe) period (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: One of the scientific programs in the MAP project, Winter in the Northern Europe (WINE) 1983 to 1984 involved an analysis of circulation processes in the middle atmosphere which characterized that winter period. Rocket soundings were conducted at many stations. In order to investigate deviations of the mean winds for the MAP/WINE period from the circulation conditions of other winters and from the climatic norm, rocket sounding data of Churchill and Barrow stations was well as the Pressure Modulated Radiometer channel 3000 data enabled the compilation of geopotential fields and the calculation of winds in the geostrophic approximation for comparison with the meteor winds. The large scale processes of the winter which determined the circulation in the period of the experiment were analyzed briefly. The analysis and results are discussed.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 101-111
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  • 149
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    Numerical modeling of troposphere-induced gravity wave propagation (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Sources of internal gravity waves (IGW) in the upper atmosphere are assumed to be meteorological processes in the troposphere. These sources are vertically and horizontally inhomogeneous and time dependent. In order to describe the IGW propagation from such sources, a numerical solution of a system of hydrodynamical equations is required. In addition, it is necessary to take into account the influence of the altitude latitude inhomogeneity of the temperature and wind fields on the IGW propagation as well as the processes of dissipation. An algorithm is proposed for numerical modelling of the IGW propagation over a limited area from tropospheric local sources to the upper atmosphere. The algorithm takes into account all the above features. A spectral grid method is used with the expansion of wave fields into the Fourier series over longitude. The upper limit conditions were obtained from the requirement of a limited energy dissipation rate in an atmospheric column. The no slip (zero velocity) condition was used at the Earth's surface.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 167-172
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  • 150
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    TOMS and the NOAA/FAA volcano support plan (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A plan to detect volcanic ash clouds that are aircraft hazards is discussed. The plan utilizes NOAA satellite data and trajectory analysis. Because current operational satellite sensors cannot unambiguously distinguish volcanic eruptions from meteorological clouds, the plan is designed to react to known eruptions rather than detect eruptions. However, the Total Ozone Mapping Spectrometer (TOMS) instrument has been used to detect sulfur dioxide clouds from volcanic eruptions regardless of cloudiness. If TOMS was flown on an operational NOAA satellite, NOAA would have an automated volcanic eruption detection system which could more effectively support the Federal Aviation Administration.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center, Scientific and Operational Requirements for TOMS Data; p 70
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  • 151
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    Comparison of ground based and TOMS measurements of SO2 from volcanic emissions (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Brewer Ozone Spectrometer is being used in the World Ozone Network to monitor ozone and SO sub 2. SO sub 2 from natural as well as anthropogenic sources are measured. It has been demonstrated that SO sub 2 interferes with total ozone values as measured by the Dobson Spectrophotometer and the Total Ozone Mapping Spectrometer (TOMS). A small amount of manmade SO sub 2 is difficult to detect and quantify by TOMS because it is located near the surface. However, larger amounts of SO sub 2 injected into the stratosphere from volcanic emissions are detected by TOMS.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center, Scientific and Operational Requirements for TOMS Data; p 60-69
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  • 152
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    The use of TOMS-modified VAS data for large-scale NWP (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Collocation statistics obtained by comparing VISSR Atmospheric Sounder (VAS) temperature soundings with those from nearby rawinsondes indicate good agreement. However, the VAS soundings exhibited a substantial cold bias in the middle and upper troposphere. The error makes promising the use of the Total Ozone Mapping Spectrometer (TOMS) to obtain an independent estimate of tropopause pressure for use in the retrieval program. Good agreement is found between TOMS data and tropopause pressure. A quantitative assessment for the correlation of tropopause pressure, obtained from TOMS by regression and from rawinsondes over Europe, is reported.
    Keywords: GEOPHYSICS
    Type: Scientific and Operational Requirements for TOMS Data; p 40-45
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  • 153
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    Insights into the general circulation of the lower stratosphere from TOMS (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Total ozone is controlled by dynamical advection as well as chemistry. At least for day-to-day variations, dynamical processes appear to be in control of total ozone. There also appears to be good evidence that seasonal and secular changes in total ozone are also dynamically controlled. For example, the zonal mean changes in total ozone in the two hemispheres in spring appear to be quite different. The TOMS total ozone data suggest a south polar spring upwelling while the Northern Hemisphere shows a clear downwelling in the same period. Radiative transfer computations support this conclusion. The secular changes in total ozone over the South Pole in spring indicate a change in dynamics rather than chemistry.
    Keywords: GEOPHYSICS
    Type: Scientific and Operational Requirements for TOMS Data; p 14
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    Systematic stratospheric-tropospheric exchange viewed from isentropic coordinates (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Within the atmosphere's stratification, stratospheric-tropospheric exchange of mass and other properties occurs primarily through quasi-horizontal transport processes within baroclinic wave regimes and through diabatic processes either in the form of deep convection or through systematic meridional variation of incoming and outgoing radiation. These exchange processes include both extrusions of stratospheric air into the troposphere and intrusions of tropospheric air into the stratosphere. The physical processes that govern both meridional and vertical exchange processes within isentropic coordinates are summarized for the global circulation.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center, Scientific and Operational Requirements for TOMS Data; p 10
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    Lower-stratospheric/upper-tropospheric exchange processes associated with tropical cyclones as observed by TOMS (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Total ozone associated with western Atlantic and Pacific tropical cyclones at various stages of development were analyzed for the purpose of monitoring storm intensity and/or intensity changes. The analysis is based on total ozone measurements from the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS). Since ozone may be considered a passive tracer in the lower stratosphere and the ozone gradients are strongest just above the tropopause, fluctuations of total ozone are due to variations in tropopause height and/or changes in concentration within the column caused by vertical and horizontal advection. In the subtropical northern Pacific during August and September 1981, a negative correlation greater than 0.60 was found between upper-tropospheric geopotential heights near the tropopause level and total ozone. Preliminary results suggest that TOMS can be used to resolve the upper-troposphere structure in and around tropical cyclones and can provide an indication of those processes that help to intensify and maintain these storms.
    Keywords: GEOPHYSICS
    Type: Scientific and Operational Requirements for TOMS Data; p 21-22
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  • 156
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    Use of satellite data in volcano monitoring (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: It is argued that Total Ozone Mapping Spectrometer (TOMS) data, especially data on sulfur dioxide detection in volcanic clouds, and weather satellite data complement each other. TOMS data is most useful for discovering previously unknown eruptions and indicating a minimum volume of SO sub 2 produced by a given eruption. Once an eruption has been reported, weather satellite data can be used to accurately monitor its progress. To be used effectively, these data need to be analyzed jointly and in real time. Toward this end, it is hoped that full and timely utilization can be made of existing TOMS data, a polar orbiting TOMS can be launched in the near future, and that TOMS type instruments can be included on future geostationary satellites.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center, Scientific and Operational Requirements for TOMS Data; p 71-76
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  • 157
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    The effect of overburden thickness on tension fracture patterns above an uplifting dome (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Four experiments demonstrate that tension-fracture patterns above an uplifting dome depend on the thickness of the overburden layer being deformed. Four layers of increasing thicknesses (4.92 cm, 6.92 cm, 9.05 cm, and 11.12 cm) of a very fine sand (85%) and silt-clay (15%) mixture were updomed by slowly inflating a 1.22 m-diameter circular rubber pillow. The upper 2 cm of each layer was wetted and air dried to make it brittle and susceptible to fracture. The fractures that formed during these experiments exhibited a continuum of patterns from dominantly arcuate to dominantly radial as the overburden thickness increased. However, fracture density remained constant in each case for a given amount of surface deformation.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 497-498
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  • 158
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    Natural fracture systems on planetary surfaces: Genetic classification and pattern randomness (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: One method for classifying natural fracture systems is by fracture genesis. This approach involves the physics of the formation process, and it has been used most frequently in attempts to predict subsurface fractures and petroleum reservoir productivity. This classification system can also be applied to larger fracture systems on any planetary surface. One problem in applying this classification system to planetary surfaces is that it was developed for ralatively small-scale fractures that would influence porosity, particularly as observed in a core sample. Planetary studies also require consideration of large-scale fractures. Nevertheless, this system offers some valuable perspectives on fracture systems of any size.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 499-501
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  • 159
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    Secular cooling of Earth as a source of intraplate stress (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The once popular idea that changes in planetary volume play an important role in terrestrial orogeny and tectonics was generally discarded with the acceptance of plate tectonics. It is nonetheless likely that the Earth has been steadily cooling over the past 3-4 billion years, and the global contraction that accompanied such cooling would have led to a secular decrease in the radius of curvature of the plates. The implications of this global cooling and contraction are explored here for the intraplate stress field and the evolution of continental plates.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 455-457
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  • 160
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    A test of the hypothesis that impact-induced fractures are preferred sites for later tectonic activity (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Impact cratering has been an important process in the solar system. The cratering event is generally accompanied by faulting in adjacent terrain. Impact-induced faults are nearly ubiquitous over large areas on the terrestrial planets. The suggestion is made that these fault systems, particularly those associated with the largest impact features are preferred sites for later deformation in response to lithospheric stresses generated by other processes. The evidence is a perceived clustering of orientations of tectonic features either radial or concentric to the crater or basin in question. An opportunity exists to test this suggestion more directly on Earth. The terrestrial continents contain more than 100 known or probable impact craters, with associated geological structures mapped to varying levels of detail. Prime facie evidence for reactivation of crater-induced faults would be the occurrence of earthquakes on these faults in response to the intraplate stress field. Either an alignment of epicenters with mapped fault traces or fault plane solutions indicating slip on a plane approximately coincident with that inferred for a crater-induced fault would be sufficient to demonstrate such an association.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 458-460
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  • 161
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    Shatter cones in Illinois: Evidence for metoeritic impacts at Glasford and Des Plaines (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Shatter cone fragments were recovered from rock cores at two previously suspected, but heretofore unverified, impact structures in Illinois. Both sites are buried features known from geophysical surveys and drill holes. Shatter cones are accepted widely as field criteria of meteoritic impact. Detection of these shock indicators in both the Glasford Structure and the Des Plains Disturbance upgrades these sites in Earth's inventory of known and suspected impact structures from possible impact sites with compatible structure and morphology to probable impact structures which possess also evidence of shock metamorphism.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 438
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  • 162
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    Centrifuge impact cratering experiments: Scaling laws for non-porous targets (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: This research is a continuation of an ongoing program whose objective is to perform experiments and to develop scaling relationships for large body impacts onto planetary surfaces. The development of the centrifuge technique has been pioneered by the present investigator and is used to provide experimental data for actual target materials of interest. With both powder and gas guns mounted on a rotor arm, it is possible to match various dimensionless similarity parameters, which have been shown to govern the behavior of large scale impacts. Current work is directed toward the determination of scaling estimates for nonporous targets. The results are presented in summary form.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 396-398
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  • 163
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    Experimental evidence for non-proportional growth of large craters (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Evidence from laboratory impact experiments is indicating that increasing crater aspect ratios (diameter:depth) can result from increasing both velocity and projectile size without invoking unusual impactor conditions. An extensive data base of experimental impact cratering was analyzed for a variety of impactors and impact velocities for low strength targets. These data indicate a change in cratering efficiency that appears to be related to the onset of projectile deformation or rupture. When all projectile types and sizes are considered, one finds two contrasting relationships between crater aspect ratio and impactor parameter. These relationships are briefly considered.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 394-395
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  • 164
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    Impact crater scaling laws (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Impact craters are numerous on planetary bodies and furnish important information about the composition and past histories of those bodies. The interpretation of that information requires knowledge about the fundamental aspects of impact cratering mechanics. Since the typical conditions of impacts are at a size scale and velocity far in excess of experimental capabilities, direct simulations are precluded. Therefore, one must rely on extrapolation from experiments of relatively slow impacts of very small bodies, using physically based scaling laws, or must study the actual cases of interest using numerical code solutions of the fundamental physical laws that govern these processes. A progress report is presented on research on impact cratering scaling laws, on numerical studies that were designed to investigate those laws, and on various applications of the scaling laws developed by the author and his colleagues. These applications are briefly reviewed.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 392-393
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  • 165
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    Centrifuge impact cratering experiments: Scaling laws for non-porous targets (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A geotechnical centrifuge was used to investigate large body impacts onto planetary surfaces. At elevated gravity, it is possible to match various dimensionless similarity parameters which were shown to govern large scale impacts. Observations of crater growth and target flow fields have provided detailed and critical tests of a complete and unified scaling theory for impact cratering. Scaling estimates were determined for nonporous targets. Scaling estimates for large scale cratering in rock proposed previously by others have assumed that the crater radius is proportional to powers of the impactor energy and gravity, with no additional dependence on impact velocity. The size scaling laws determined from ongoing centrifuge experiments differ from earlier ones in three respects. First, a distinct dependence of impact velocity is recognized, even for constant impactor energy. Second, the present energy exponent for low porosity targets, like competent rock, is lower than earlier estimates. Third, the gravity exponent is recognized here as being related to both the energy and the velocity exponents.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 391
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  • 166
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    Momentum transfer from oblique impacts (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A completely satisfactory experiment would be in a low gravity environment where the effect of momentum imparted by ejecta impacting the surface can be removed or controlled from momentum transfer during impact. Preliminary estimates can be made using a ballistic pendulum. Such experiments were initiated at the NASA-Ames Vertical Gun Range in order to examine momentum transfer due to impact vaporization for oblique impacts. The preliminary results indicate that momentum from oblique impacts is very inefficient: decreasing with increasing impact velocity and perhaps size; increasing with decreasing density; and increasing with increasing impact angle. At face value, such results minimize the effect of momentum transfer by grazing impact; the more probable impact angles of 30 deg would have a greater effect, contrary to the commonly held impression.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 386-387
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  • 167
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    Experimental studies of collision and fragmentation phenomena (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The reduction and publication of an extensive data set collected in experiments over several years at Ames and PSI is briefly examined. Hartmann has been assembling data sets from his experiments on catastrophic fragmentation of various materials, including basalt, other igneous rock, ice, and weak dirt clods. Weidenschilling and Davis have continued to gather and reduce data on oblique impacts. The data indicate a power law distribution of ejecta mass vs. velocity, with a slope that is independent of azimuth, and does not vary with impact angle from normal impacts to at least 75 deg from vertical. In order to improve models of coagulation of dust aggregates in the solar nebula, SJW developed an apparatus for drop tests of fragile projectiles. Davis and Weidenschilling continued to collect and analyze experimental data on collisional catastrophic disruption at the Ames Vertical Gun Range.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 388-390
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  • 168
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    Oblique impact: Projectile richochet, concomitant ejecta and momentum transfer (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Experimental studies of oblique impact indicate that projectile richochet occurs for trajectory angles less than 30 deg and that the richocheted projectile, accompanied by some target material, are ejected at velocities that are a large fraction of the impact velocity. Because the probability of occurrence of oblique impact less than 30 deg on a planetary body is about one out of every four impact events, oblique impacts would seem to be a potential mechanism to provide a source of meteorites from even the largest atmosphere-free planetary bodies. Because the amount of richocheted target material cannot be determined from previous results, additional experiments in the Ames Vertical Gun laboratory were undertaken toward that purpose using pendulums; one to measure momentum of the richocheted projectile and concomitant target ejecta, and a second to measure the momentum transferred from projectile to target. These experiments are briefly discussed.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 384-385
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  • 169
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    Impact vaporization: Late time phenomena from experiments (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: While simple airflow produced by the outward movement of the ejecta curtain can be scaled to large dimensions, the interaction between an impact-vaporized component and the ejecta curtain is more complicated. The goal of these experiments was to examine such interaction in a real system involving crater growth, ejection of material, two phased mixtures of gas and dust, and strong pressure gradients. The results will be complemented by theoretical studies at laboratory scales in order to separate the various parameters for planetary scale processes. These experiments prompt, however, the following conclusions that may have relevance at broader scales. First, under near vacuum or low atmospheric pressures, an expanding vapor cloud scours the surrounding surface in advance of arriving ejecta. Second, the effect of early-time vaporization is relatively unimportant at late-times. Third, the overpressure created within the crater cavity by significant vaporization results in increased cratering efficiency and larger aspect ratios.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 382-383
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  • 170
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    The geology of Picacho Butte, a silicic volcanic dome in northwest Arizona (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The purpose of this investigation was to determine the geologic history of Picacho Butte and vicinity through careful mapping of a 38 square kilometer area surrounding the peak. A detailed analysis of the geochemistry and petrology will aid in the development of a petrogenetic model for the area. The relationship of Picacho Butte to regional volcanism in Arizona, and more specifically to nearby volcanic centers can thus be established. Furthermore, in conjunction with this study a search will be made for possible planetary analogs exhibiting photogeologic characteristics similar to those in northern Arizona.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 371-373
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  • 171
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    Impacts of hemispherical granular targets: Implications for global impacts (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: As impact excavation diameters subtend a nontrivial fraction of a planetary body, both the excavation process and ejecta emplacement may depart form the classical description of impacts into a planar surface. Hemispherical particulate targets were impacted at the NASA-Ames Vertical Gun Range in order to trace the evolution of the ejecta curtain and to document the effects of slope and surface curvature on crater shape and cratering efficiency. The experiments suggest that basin size impacts or large craters on small bodies may be shallower than their counterparts on a planar surface but may have displaced a larger relative mass. Moreover, the increased ejecta curtain angle with distance may result in a change in ejecta emplacement style with distance. Although the ejecta curtain is vertical, ejecta within the curtain impact the surface at 45 deg and the time between first and last arrival within the curtain increases. This increased interaction time as the ejecta curtain density decreases should result in a more chaotic style of implacement.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 380-381
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  • 172
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    Computer simulations of 10-km-diameter asteroid impacts into oceanic and continental sites: Preliminary results on atmospheric passage, cratering and ejecta dynamics (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A series of analytical calculations of large scale cratering events for both oceanic and continental sites were made in order to examine their effects on the target media and atmosphere. The first analytical studies that were completed consists of computer simulations of the dynamics of: (1) the passage of a 10 km diameter asteroid moving at 20 km/sec through the Earth's atmosphere, and (2) the impact cratering events in both oceanic and continental environments. Calculation of the dynamics associated with the passage of the asteroid through the atmosphere showed strong effects on the surrounding air mass. The calculations of the impact cratering events showed equally dramatic effects on the oceanic and continental environments. These effects are briefly discussed.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 377-379
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  • 173
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    The geology of Pine and Crater Buttes: Two basaltic constructs on the far eastern Snake River Plain (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The emplacement history and petrochemical evolution of the volcanics associated with Pine Butte, Crater Butte, and other nearby vents are developed and described. Four major vents were identified in the study area and their associated eruptive products were mapped. All of the vents show a marked physical elongation or linear orientation coincident with the observed rift set. Planetary exploration has revealed the importance of volcanic processes in the genesis and modification of extraterrestrial surfaces. Interpretation of surface features has identified plains-type basaltic volcanism in various mare regions of the Moon and the volcanic provinces of Mars. Identification of these areas with features that appear analogous to those observed in the Pine Butte area suggests similar styles of eruption and mode of emplacement. Such terrestrial analogies serve as a method to interpret the evolution of volcanic planetary surfaces on the inner planets.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 368-370
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  • 174
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    Geology of the Mohon Mountain volcanic field, Yavapai and Mohave Counties, Arizona: A preliminary report (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Field mapping has produced a preliminary picture of Mohon Mountain as a composite volcano, in which pyroclastic ash and larger tephra erupted alternately with flows of rhyodacite and dacite. An analog study which uses imagery of lunar and Martian features will compare the overall shape of the vent complex, including its breached southern flank and satellite vents, to similar landforms found on Mars and the Moon which are believed to have formed similar processes. Ash flow sheets were hypothesized to comprise the outer slopes of Olympus Mons suggesting that explosive eruptions which are more volatile-rich than those which produce basalt flows are not confined to terrestrial settings but may also be found on bodies such as Mars, which have a thicker crust and deeper magma source in the mantle. The analog study will explore further evidence for explosive eruptions on Mars and the Moon.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 365-367
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  • 175
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    Crustal and subcrustal nodules in ejecta from Kilbourne Hole Maar, New Mexico (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Nodules retrieved from the ejecta of volcanic craters serve as the source of two major items of information. The first is in providing details of the geochemistry and mineralogy of the Earth's interior by supplying samples of materials that cannot be obtained by existing drilling techniques. The other is in providing information regarding the process which led to their transport from the Earth's interior to the surface. The primary purpose of the present study was to examine the morphology of the nodules in an attempt to place some constraints on the process that brought them to the surface. This attempt is briefly discussed.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 362-364
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  • 176
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    Toward a model for leveed lava flows (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Many lava flows have two distinct volumetric components during emplacement. First, there is a component actively flowing in accordance with Newtonian or other constitutive relations. Second, there may be an inactive, stationary component that is no longer participating in the forward movement of the flow. Such passive components may take the form of flow-confining levees, solidified lateral margins, overspilling, plating, small ponds and sidestreams, or a lava tube. To describe the conservation of flow volume for the active component, governing equations are given and discussed.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 357-359
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  • 177
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    Studies of vesicle distribution patterns in Hawaiian lavas (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Basaltic lava flows are generally vesicular, and the broader facts relating to vesicle distribution have long been established; few studies have yet been made with a view to determining how and when vesicles form in the cooling history of the lava, explaining vesicle shape and size distribution, and gaining enough understanding to employ vesicles as a geological tool. Various avenues of approach exist by which one may seek to gain a better understanding of these ubiquitous structures and make a start towards developing a general theory, and three such avenues have recently been explored. One avenue involves the study of pipe vesicles; these are a well known feature of lava flows and are narrow pipes which occur near the base of many pahoehoe flow units. Another avenue of approach is that presented by the distinctive spongy pahoehoe facies of lava that is common in distal locations on Hawaiian volcanoes. A third avenue of approach is that of the study of gas blisters in lava. Gas blisters are voids, which can be as much as tens of meters wide, where the lava split along a vesicle-rich layer and the roof up-arched by gas pressure. These three avenues are briefly discussed.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 360-361
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  • 178
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    Calculated viscosity-distance dependence for some actively flowing lavas (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The importance of viscosity as a gauge of the various energy and momentum dissipation regimes of lava flows has been realized for a long time. Nevertheless, despite its central role in lava dynamics and kinematics, it remains among the most difficult of flow physical properties to measure in situ during an eruption. Attempts at reconstructing the actual emplacement viscosities of lava flows from their solidified topographic form are difficult. Where data are available on the position of an advancing flow front as a function of time, it is possible to calculate the effective viscosity of the front as a function of distance from the vent, under the assumptions of a steady state regime. As an application and test of an equation given, relevant parameters from five recent flows on Mauna Loa and Kilauea were utilized to infer the dynamic structure of their aggregate flow front viscosity as they advanced, up to cessation. The observed form of the viscosity-distance relation for the five active Hawaiian flows examined appears to be exponential, with a rapid increase just before the flows stopped as one would expect.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 354-356
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  • 179
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    The 1984 Mauna Loa eruption and planetary geolgoy (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: In planetary geology, lava flows on the Moon and Mars are commonly treated as relatively simple systems. Some of the complexities of actual lava flows are illustrated using the main flow system of the 1984 Mauna Loa eruption. The outline, brief narrative, and results given are based on a number of sources. The implications of the results to planetary geology are clear. Volume flow rates during an eruption depend, in part, on the volatile content of the lava. These differ from the volume flow rates calculated from post eruption flow dimensions and the duration of the eruption and from those using models that assume a constant density. Mass flow rates might be more appropriate because the masses of volatiles in lavas are usually small, but variable and sometimes unknown densities impose severe restrictions on mass estimates.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 351-353
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  • 180
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    Studies of fluid instabilities in flows of lava and debris (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: At least two instabilities have been identified and utilized in lava flow studies: surface folding and gravity instability. Both lead to the development of regularly spaced structures on the surfaces of lava flows. The geometry of surface folds have been used to estimate the rheology of lava flows on other planets. One investigation's analysis assumed that lava flows have a temperature-dependent Newtonian rheology, and that the lava's viscosity decreased exponentially inward from the upper surface. The author reviews studies by other investigators on the analysis of surface folding, the analysis of Taylor instability in lava flows, and the effect of surface folding on debris flows.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 345-347
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    Long, paired A'A/Pahoehoe flows of Mauna Loa: Volcanological significance and insights they provide into volcano plumbing systems (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The long lava flows of Mauna Loa, Hawaii have been cited as Earth's closed analogs to the large Martian flows. It is therefore important to understand the flow mechanics and characteristics of the Mauna Loa flows and to make use of these in an attempt to gain insights into Martian eruptive processes. Two fundamentally different kinds of long lava flows can be distinguished on Hawaiian volcanoes as in Martian flows. The two kinds may have identical initial viscosities, chemical compositions, flow lengths, and flow volumes, but their flow mechanisms and thermal energy budgets are radically different. One travels a distance set by the discharge rate as envisaged by Walker and Wadge, and the other travels a distance set mainly by the eruption duration and ground slope. In the Mauna Loa lavas, yield strength becomes an important flow morphology control only in the distal part of a'a lavas. The occurrence of paired flows on Mauna Loa yields insights into the internal plumbing systems of the volcano, and it is significant that all of the volume of the a'a flow must be stored in a magma chamber before eruption, while none of the volume of the pahoehoe needs to be so stored. Differentiation between the two kinds of flows on images of Martian volcanoes is possible and hence an improved understanding of these huge structures is acquired.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 348-350
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  • 182
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    Valley development on Hawaiian volcanoes (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Work in progress on Hawaiian drainage evolution indicates an important potential for understanding drainage development on Mars. Similar to Mars, the Hawaiian valleys were initiated by surface runoff, subsequently enlarged by groundwater sapping, and eventually stabilized as aquifers were depleted. Quantitative geomorphic measurements were used to evaluate the following factors in Hawaiian drainage evolution: climate, stream processes, and time. In comparing regions of similar climate, drainage density shows a general increase with the age of the volcani island. With age and climate held constant, sapping dominated valleys, in contrast to runoff-dominated valleys, display the following: lower drainage densities, higher ratios of valley floor width to valley height, and more positive profile concavities. Studies of stream junction angles indicate increasing junction angles with time on the drier leeward sides of the major islands. The quantitative geomorphic studies and earlier field work yielded important insights for Martian geomorphology. The importance of ash mantling in controlling infiltration on Hawaii also seems to apply to Mars. The Hawaiian valley also have implications for the valley networks of Martian heavily cratered terrains.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 297-299
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  • 183
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    The steady state toroidal magnetic field at the core-mantle boundary (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Recent measurements indicate that the strength of the toroidal magnetic field at Earth's core-mantle boundary is comparable in strength to the poloidal field - 5 to 10 gauss. Calculations are given to show that this is an inevitable result of the external boundary condition on the core, in which the mantle electrical conductivity is several orders of magnitude lower than that of the core. The measurements are shown to imply that the internal core magnetic field is in the range of several hundred gauss. Thus the measurements imply that the Earth's core contains a strong toroidal magnetic field. They also support the idea that Earth's dynamo, and by implication, other planetary magnetic fields, involves efficient toroidal magnetic field generation through strong differential rotation.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 148
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  • 184
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    The origin of polarity asymmetries in the history of the geomagnetic field (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The behavior of magnetohydrodynamic stationary modes in the presence of an imposed weak magnetic field originating separately from the dynamo is studied. A rare class of stationary states is found that exhibit high sensitivity to the presence of weak imposed fields. The amplitude of the difference between the total fields of opposite polarity is much larger than the amplitude of the imposed nondynamo fields. It is proposed that Earth's magnetic field operates in such a mode, highly sensitive to the presence of an ambient field. An argument is given to explain why the terrestrial dynamo should choose to operate in one of these rare states. Implications are discussed for the general mechanism of dynamo magnetic field equilibrium in planets.
    Keywords: GEOPHYSICS
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986; p 147
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  • 185
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    Electric potential distributions at the interface between plasmasheet clouds (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: At the interface between two plasma clouds with different densities, temperatures, and/or bulk velocities, there are large charge separation electric fields which can be modeled in the framework of a collisionless theory for tangential discontinuities. Two different classes of layers were identified: the first one corresponds to (stable) ion layers which are thicker than one ion Lamor radius; the second one corresponds to (unstable) electron layers which are only a few electron Larmor radii thick. It is suggested that these thin electron layers with large electric potential gradients (up to 400 mV/m) are the regions where large-amplitude electrostatic waves are spontaneously generated. These waves scatter the pitch angles of the ambient plasmasheet electron into the atmospheric loss cone. The unstable electron layers can therefore be considered as the seat of strong pitch angle scattering for the primary auroral electrons.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Double Layers in Astrophysics; p 287-294
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  • 186
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    Particle simulation of auroral double layers (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Work on the simulation of auroral double layers (DLs) with realistic particle-in-cell models is presented. An early model simulated weak DLs formed in a self-consistent circuit but under conditions subject to the ion-acoustic instability. Recent work has focused on strong DLs formed when currentless jets are injected into a dipole magnetic field.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Double Layers in Astrophysics; p 247-263
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  • 187
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    Effect of double layers on magnetosphere-ionosphere coupling (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The Earth's auroral zone contains dynamic processes occurring on scales from the length of an auroral zone field line which characterizes Alfven wave propagation to the scale of microscopic processes which occur over a few Debye lengths. These processes interact in a time-dependent fashion since the current carried by the Alfven waves can excite microscopic turbulence which can in turn provide dissipation of the Alfven wave energy. This review will first describe the dynamic aspects of auroral current structures with emphasis on consequences for models of microscopic turbulence. A number of models of microscopic turbulence will be introduced into a large-scale model of Alfven wave propagation to determine the effect of various models on the overall structure of auroral currents. In particular, the effects of a double layer electric field which scales with the plasma temperature and Debye length is compared with the effect of anomalous resistivity due to electrostatic ion cyclotron turbulence in which the electric field scales with the magnetic field strength. It is found that the double layer model is less diffusive than in the resistive model leading to the possibility of narrow, intense current structures.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Double Layers in Astrophysics; p 147-166
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  • 188
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    Petrogenesis of basalts from the Archean Matachewan Dike Swarm Superior Province of Canada (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The Matachewan Dike swarm of eastern Ontario comprises Archean age basalts that were emplaced in the greenstone, granite-greenstone, and metasedimentary terrains of the Superior Province of Canada. The basalts are Fe-rich tholeiites, characterized by the near ubiquitos presence of large, compositionally uniform, calcic plagioclase. Major and trace element whole-rock compositions, along with microprobe analyses of constituent phases, from a group of dikes from the eastern portion of the province, were evaluated to constrain petrological processes that operated during the formation and evolution of the magmas. Three compositional groupings, were identified within the dikes. One group has compositional characteristics similar to modern abyssal tholeiites and is termed morb-type. A second group, enriched in incompatible elements and light-REE enriched, is referred to as the enriched group. The third more populated group has intermediate characteristics and is termed the main group. The observation of both morb-type and enriched compositions within a single dike strongly argues for the contemporaneous existence of magmas derived through different processes. Mixing calculations suggest that two possibilities exist. The least evolved basalts lie on a mixing line between the morb-type and enriched group, suggesting mixing of magmas derived from heterogeneous mantle. Mixing of magmas derived from a depleted mantle with heterogeneous Archean crust can duplicate certain aspects of the Matachewan dike composition array.
    Keywords: GEOPHYSICS
    Type: NASA. Johnson Space Center, NASA(ASEE Summer Faculty Fellowship Program, 1987, Volume 2; 20 p
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  • 189
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    Mid-tertiary volcano-tectonic development of the Southwestern Cordillera of North America (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: In the Southwestern Cordillera (SC) of North America, volcanic style changed from dominantly calcalkaline stratovolcanoes to caldera-related magmatism during the mid-Tertiary. The dominant tectonic process affecting the region during this time was convergence of the Farallon and North American Plates. The change in style of volcanism indicates a change in the operative stress regime: compressional for the earlier calcalkaline volcanism and tensional for development of the calderas. The development of the centers were compared to evaluate the volcano-tectonic relationship of caldera development within and between centers and determine the relationships between the earlier calcalkaline and later caldera-style volcanisms. The calderas exhibit three distinct stages of development that are closely associated with the East Pacific Rise/trench collision. The spatial and temporal association of the calcalkaline and caldera-related volcanism argues for the SC representing a region of continued arc magnetism in which the style of volcanism varied in response to differences in regional stresses.
    Keywords: GEOPHYSICS
    Type: NASA. Johnson Space Center, NASA(ASEE Summer Faculty Fellowship Program, 1987, Volume 2; 19 p
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  • 190
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    Longitudinal peculiarities of meridional circulation in lower thermosphere and mesosphere (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Average monthly longitudinal profiles of geostrophic wind in winter are presented. Positive values correspond to meridional movements from north to south. It is concluded that the normal longitudinal meridional circulation is characterized by the presence of sectors where meridional flows do not change their direction in the course of time comparable with synoptic periods. The longitudinal distribution of meridional wind in middle latitudes taken from the analysis results of radiometeor and ionospheric stations observational data obtained in 1976 to 1980 are presented. Meridional winds have a longitudinal variability that is equivalent to both the warm and cold half years.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 186-188
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  • 191
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    A study of the mechanism of internal gravity wave generation by quasigeostrophic meteorological motions (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Numerous experiments on the detection of atmospheric waves in the frequency range from acoustic to planetary at meteor heights have revealed that important wave sources are meteorological processes in the troposphere (cyclones, atmospheric fronts, jet streams, etc.). A dynamical theory based on the others work include describing the adaptation of meteorological fields to the geostropic equilibrium state. According to this theory, wave motions appear as a result of constant competition between the maladjustment of the wind and pressure fields due to nonlinear effects and the tendency of the atmosphere to establish a quasi-geostrophic equilibrium of these fields. These meteorological fields are discussed.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 146-152
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  • 192
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    Some aspects of metallic ion chemistry and dynamics in the mesosphere and thermosphere (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The relationship between the formation of sporadic layers of metallic ion and the dumping of these ions into the upper mesosphere is discussed in terms of the tidal wind, classical (i.e., windshear) and other more complex, perhaps highly nonlinear layer formation mechanisms, and a possible circulation mechanism for these ions. Optical, incoherent scatter radar, rocket, and satellite derived evidence for various layer formation mechanisms and for the metallic ion circulation system is reviewed. The results of simple one dimensional numerical model calculations of sporadic E and intermediate layer formation are presented along with suggestions for more advanced models of intense or blanketing sporadic E. The flux of metallic ions dumped by the tidal wind system into the mesosphere is estimated and compared with estimates of total particle flux of meteoric origin. Possible effects of the metallic ion flux and of meteoric dust on D region ion chemistry are discussed.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 228-254
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  • 193
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    The lower thermosphere wind regime from simultaneous observations over Euroasia (Collm, Dushanbe, Frunze) (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The circulation in the lower thermosphere as determined from the results of measurements in 1984 is considered. Ionospheric drift measurements were taken using the method of spaced reception in the long wave range. Other measurements were taken using the D2 method. Average daily values of wind velocity were used. Discontinuity of measurements ranged from a day to a week. Preliminary data were reduced to the common average height of 93 km with the help of vertical profiles of wind velocity components. The results of measurements of zonal and meridional wind velocity components are presented. Zonal circulation changes from westerly to easterly winds were observed in winter, in periods of spring time reversal and during stratomesospheric rises in temperature.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 62-65
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  • 194
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    The nonlinear thermodynamics of meteors, noctilucent clouds, enhanced airglow and global atmospheric circulation (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Two types of fundamental topological junctions of elements are deduced from a nonlinear thermodynamical model. Using this scheme, the possibility of a causal relation between fireballs and faint meteors as nonlinear sources on the one hand, and noctilucent clouds (NC) and Hoffmeister's enhanced airglow (EA) as complementary formative processes in the middle atmosphere and ionosphere, on the other hand, is examined. The principal role of the global atmospheric circulation in this relation is demonstrated. Such circulation in the mesosphere appears to prevent the neutral dust dissipated by fireballs from becoming an efficient agent in NLC generation. In this case, the behavior of ionized material deposited by both the bright and faint meteors is more probably controlled, as shown from the annual variation of the E sub s layer by the darkness of lunar eclipses and the global circulation of the lower thermosphere. The role of fireballs and neutral dust might be more significant as a source of EA phenomenon.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 266-271
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  • 195
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    Internal gravity waves in the meteor zone in the Tbilisi Region (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The study of wave disturbances (WD) in the upper part of the meteor zone (90 to 110 km) was made in the Tbilisi region. Observations were conducted using three ionospheric vertical sounders located at the corners of a triangle spaced from each other at a distance of 50 km, a four azimuth electrophotometer by the method of space reception with a small distance and a recording unit. These disturbances are measured and the results are given.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 200-206
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  • 196
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    Lower thermosphere wind regime according to radiometeor measurements in Kazan (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Research in dynamic processes in the lower thermosphere has been carried out in Kazan using the meteor radar facilities of the Kazan State University under the MAP-GLOBMET international program. Presented is experimental data on seasonal dependences of the wind for anomalous winter circulation periods, spring and autumn reconstructions and stable summer circulation from observations conducted in 1978 to 1984. Prevailing wind parameters are shown: zonal and meridional component amplitudes and A sub 0 and azimuth of the prevailing wind vector. The values are also presented for semidiurnal zonal and meridional tidal components, their correlation coefficient and zonal component amplitude maximum time.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 189-193
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  • 197
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    A statistical study of variations of internal gravity wave energy characteristics in meteor zone (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Internal gravity wave (IGW) parameters obtained by the radiometer method have been considered by many other researchers. The results of the processing of regular radiometeor measurements taken during 1979 to 1980 in Obninsk (55.1 deg N, 36.6 deg E) are presented.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 173-180
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  • 198
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    Study of internal gravity waves in the meteor zone (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: An important component of the dynamical regime of the atmosphere at heights near 100 km are internal gravity waves (IGW) with periods from about 5 min to about 17.5 hrs which propagate from the lower atmospheric layers and are generated in the uppermost region of the atmosphere. As IGW propagate upwards, their amplitudes increase and they have a considerable effect on upper atmospheric processes: (1) they provide heat flux divergences comparable with solar heating; (2) they influence the gaseous composition and produce wave variations of the concentrations of gaseous components and emissions of the upper atmosphere; and (3) they cause considerable acceleration of the mean stream. It was concluded that the periods, wavelengths, amplitudes and velocities of IGW propagation in the meteor zone are now measured quite reliably. However, for estimating the influence of IGW on the thermal regime and the circulation of the upper atmosphere these parameters are not as important as the values of wave fluxes of energy, heat, moment and mass.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 153-166
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  • 199
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    Variations of the semi-diurnal tidal wind in the meteor region with periods of about 27 and 13.5 days (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Daily values of sunspot number and solar radio emission at 10.7 cm wavelength show a well known strong modulation with a period of 27 days, the Sun's rotation period. Recent satellite measurements revealed the same modulation of the ultraviolet irradiance at wavelength below 300 nm. These UV variations can influence the thermal heating of the ozone layer by altering the chemical composition. Therefore, one can also expect a corresponding variation in the middle atmosphere of the semi-diurnal tide, which is thermally excited essentially by absorption of UV between 200 and 370 nm in the upper ozone layer. Results of radar meteor wind measurements were used to detect a presumable very weak 27 day modulation within the natural and artificial noise of the daily values of the semi-diurnal wind amplitude. The summer period was chosen because of its relatively steady conditions and the maximum amplitudes during the year. The results of this investigation are given and discussed.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 119-120
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  • 200
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    Mean pressure distribution and geostrophic circulation in the meteor zone (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Boutko et al., used available satellite radiometer data to estimate 0.1 mb constant pressure heights in the mesosphere and Koshelkov and Kovshova derived, 0.1 to 0.005 mb or 0.1 to 0.001 mb layer thickness from which were compiled height fields of the 0.005 mb and 0.001 mb levels. The close relationship discovered between mean thicknesses and zonal values of atmospheric radiances observed in channel 3000 of the pressure modulated radiometer was used. An analysis of the geopotential height fields in the lower thermosphere of the Southern Hemisphere was carried out by others. The Northern Hemisphere patterns are analyzed herein. The analysis was limited to regions north of 20 N due to poor reliability of the thickness estimates from the radiometer data at low latitudes. These analyses are discussed.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 76-100
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