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  • Other Sources  (9,942)
  • NASA Technical Reports  (9,942)
  • GEOPHYSICS  (7,240)
  • INSTRUMENTATION AND PHOTOGRAPHY  (2,702)
  • 1985-1989  (5,540)
  • 1980-1984  (4,402)
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  • Other Sources  (9,942)
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  • NASA Technical Reports  (9,942)
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  • 1
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    Proposed uses of laser light scattering instruments for polymerization studies (1989)
    In:  CASI
    Details
    Publication Date: 2006-06-11
    Description: Microgravity offers a unique environment for studying polymer diffusion and polymer polymerization reactions. The absence of convection currents, which are the major mode of mixing at the molecular level on Earth, are eliminated or reduced in the microgravity environment. More importantly, the prediction of unique copolymer composition development in microgravity allows controlled formation of new compositions of matter. The absence of mixing at the molecular level should produce unique short block copolymers available for the first time for comonomer compositions which normally lead to random or long block copolymer under good mixing. The investigation of fundamental polymer diffusion and polymer polymerization processes in microgravity is proposed. This effort will involve fundamental studies of monomer and polymer diffusion; their effects on initiation, propagation, and especially termination kinetics rate constant; and the accurate evaluation of copolymerization reactivity ratios in microgravity. The experimental design is presented for these studies along with an evaluation technique for in situ monitoring of polymer diffusion and polymerization kinetics.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA, Lewis Research Center, NASA Laser Light Scattering Advanced Technology Development Workshop, 1988; p 215-227
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  • 2
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    Light scattering instrumentation for micro gravity research (1989)
    In:  CASI
    Details
    Publication Date: 2006-06-11
    Description: The analysis of light scattered from an ensemble of particles has long been a preferred method for characterizing their physical properties. Instrumentation to perform the measurements which forms the basis for such analysis is available in many forms based upon a variety of different experimental techniques. A system is presented which is singularly applicable for making many types of measurements in a microgravity environment. The commercial version of this device, the DAWN-F, has been used in many labs throughout the world to perform analyses of particular importance for both research and production. Light scattering theory is reviewed and the structure and function of the system is described.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA, Lewis Research Center, NASA Laser Light Scattering Advanced Technology Development Workshop, 1988; p 165-172
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  • 3
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    Photon counting modules using RCA silicon avalanche photodiodes (1989)
    In:  CASI
    Details
    Publication Date: 2006-06-11
    Description: Avalanche photodiodes (APD) are excellent small area, solid state detectors for photon counting. Performance possibilities include: photon detection efficiency in excess of 50 percent; wavelength response from 400 to 1000 nm; count rate to 10 (exp 7) counts per sec; afterpulsing at negligible levels; timing resolution better than 1 ns. Unfortunately, these performance levels are not simultaneously available in a single detector amplifier configuration. By considering theoretical performance predictions and previous and new measurements of APD performance, the anticipated performance of a range of proposed APD-based photon counting modules is derived.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA, Lewis Research Center, NASA Laser Light Scattering Advanced Technology Development Workshop, 1988; p 65-80
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  • 4
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    Miniature instrumentation for laser light scattering experiments (1989)
    In:  CASI
    Details
    Publication Date: 2006-06-11
    Description: Traditional optical systems for photon correlation spectroscopy and laser anemometry have relied upon physically large and fairly expensive lasers, bulk-optics such as lenses of a few inches diameter, large mechanical mounts and carefully selected, fragile and bulky photon counting photomultiplier detectors. In some cases, experimental fluid dynamics at a desired position in a flow, perhaps deep inside complex machinery, is physically impossible or very difficult. Similar problems exist with photon correlation spectroscopy, e.g., remote and heterodyne experiments. Various optical and electro optical components were investigated and characterized with the aim of replacing existing photon correlation laser spectroscopy and anemometry techniques in miniaturized form, and with significant cost reduction. Very recently, a range of miniature, modular light scattering systems were constructed from little solid state optical and electro optical components, and experimentally verified measurement performance comparable to standard lab photon correlation spectroscopy and laser anemometry equipment.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA, Lewis Research Center, NASA Laser Light Scattering Advanced Technology Development Workshop, 1988; p 45-63
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  • 5
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    Satellite/rocket ozone comparisons at Natal, Brazil (1989)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: Comparisons are presented of satellite, rocket, and balloon ozone profiles near Natal, Brazil (5.9 deg S, 35.2 deg W). The low variability of stratospheric ozone at Natal during March and April of 1985 has allowed intercomparisons of reasonably large data sets, rather than a small number of paired satellite/in situ comparisons. There are sharp differences between the profile from the SBUV instrument on Nimbus 7 and the in situ measurements. These results support the conclusions of the NASA Ozone Trends Panel that there is an instrumental cause for the very large changes in upper stratospheric ozone seen by SBUV. Along with other comparisons, these results are being used in a reassessment of the SBUV instrument and its data reduction procedures. The agreement between the ozone profiles from the SAGE II instrument on the ERBS satellite and the rocket values is excellent over the full range of comparisons. Both SAGE II and ROCOZ-A must convert from altitude to pressure for intercomparisons with SME and with SBUV-type instruments. The conversion between pressure and altitude is as important as the ozone measurements, especially in the upper stratosphere where the scale height for ozone is approximately half that for pressure.
    Keywords: GEOPHYSICS
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  • 6
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    Millimeter-wave sensor image enhancement (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Images from an airborne, scanning radiometer operating at a frequency of 98 GHz have been analyzed. The millimeter-wave images were obtained in 1985-1986 using the JPL millimeter-wave imaging sensor. The goal of this study was to enhance the information content of these images and make their interpretation easier. A visual-interpretative approach was used for information extraction from the images. This included application of nonlinear transform techniques for noise reduction and for color, contrast, and edge enhancement. Results of using the techniques on selected millimeter-wave images are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 7
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    1960 Chile - New estimate of polar motion excitation (1989)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A recent reanalysis of the International Latitude Serivce (ILS) polar motion data-day has been processed using Kalman filtering techniques to generate the polar motion excitation function over the time-span from 1960 to 1965. The resulting excitation function has been examined for the effects of 1960 Chile in an attempt to determine experimentally how large earthquake affect polar motion. The resulting upper bound of about 75 x 10 to the 22nd N-m for a 10-deg dip (about 36 x 10 to the 22nd N-m for 20-deg dip) is consistent with results obtained from previous seismic studies, including a recent normal mode excitation result. Following future great earthquakes, monitoring of polar motion by space-based techniques such as VLBI should continue at high temporal resolution for several weeks in order to directly measure the rheological parameters of the upper mantle.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 16; 1193-119
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  • 8
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    Lithology and structure within the basement terrain adjacent to Clark Mountains, California, mapped with calibrated data from the airborne visible/infrared imaging spectrometer (1989)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The Clark Mountains in eastern California form a rugged, highly dissected area nearly 5000 ft above sea level, with Clark Mountain rising to 8000 ft. The rocks of the Clark Mountains and the Mescal Range just to the south are Paleozoic carbonate and clastic rocks, and Mesozoic clastic and volcanic rocks standing in pronounced relief above the fractured Precambrian gneisses to the east. The Permian Kaibab Limestone and the Triassic Moenkopi and Chinle Formations are exposed in the Mescal Range, which is the only place in California where these rocks, which are typical of the Colorado Plateau, are found. To the west, the mountains are bordered by the broad alluvial plains of Shadow Valley. Cima Dome, which is an erosional remnant carved on a batholithic intrusion of quartz monzonite, is found at the south end of the valley. To the east of the Clark and Mescal Mountains is found the Ivanpah Valley, in the center of which is located the Ivanpah Play. Studies of the Clark Mountains with the airborne visible/infrared imaging spectrometer are briefly described.
    Keywords: GEOPHYSICS
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  • 9
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    Microwave limb-sounding of earth's upper atmosphere (1989)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Microwave limb-sounding can be used to improve understanding of earth's upper atmosphere. This paper summarizes general features of the technique. An experiment being developed for the Upper Atmosphere Research Satellite is described. Plans for the future Earth Observing System are discussed.
    Keywords: GEOPHYSICS
    Type: Atmospheric Research (ISSN 0169-8095); 23; 391-410
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  • 10
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    Uncertainty estimates in geomagnetic field modeling (1989)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: This paper presents an extension of the conventional uncertainty analysis which characterizes the sources of uncertainty in the coefficients of the geomagnetic field models. The new formalism accounts for the systematic errors introduced by the omission of such sources as the presence of crustal fields, the external fields, and the field from the truncated terms. The usefulness of this formalism depends on two critical conditions. The first of these is the knowledge of the statistical properties of the fields whose parameters are not solved in the analysis, i.e., the crustal field and the external field. The second critical point in the practical use of the method is the approximation used for the weight matrix.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 12281-12
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  • 11
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    Indicators of transport and vertical motion from correlations between in situ measurements in the Airborne Antarctic Ozone Experiment (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Analysis of small-scale structure in the in situ measurements made from the ER-2 during the Airborne Antarctic Ozone Experiment shows the existence of a region at the boundary of the chemiclly perturbed region where the mixing ratios and small-scale structure of trace gases are influenced by transport across the boundary. This transition region is characterized by horizontal interchange and vertical layering of air parcels from within and outside of the chemically perturbed region and negative small-scale correlations between ClO and ozone. The horizontal transport in this region creates large surface areas between dissimilar air masses, providing the potential for substantial mixing. Correlations between ClO and O3 show that the transition region extends to 2-4 deg of latitude to either side of the boundary of the chemically perturbed region. A + or - 4-deg-wide transition region would contain nearly as much air as the chemically perturbed region proper. Analysis of water vapor and nitrous oxide data suggests that diabatic descent is associated with dehydration. This could be caused by strong radiative cooling of those polar stratospheric clouds in which enough water condenses for the particles to fall and dehydrate the air.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11669-11
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  • 12
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    Potential vorticity and mixing in the south polar vortex during spring (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Fluid dynamic aspects of the Antarctic ozone hole phenomena are studied. Data collected by the ER-2 aircraft as part of the Airborne Antarctic Ozone Experiment (AAOE) are used to calculate the potential vorticity distribution on potential temperature surfaces. Most of the ER-2 flights show a monotonic decrease in potential vorticity and nitrous oxide toward the pole on isentropic surfaces.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11625-11
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  • 13
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    Diagnostic studies of the Antarctic vortex during the 1987 Airborne Antarctic Ozone Experiment - Ozone miniholes (1989)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Localized rapid reductions in total ozone (miniholes), which were observed during the Airborne Antarctic Ozone Experiment, are studied with particular attention given to meteorological aspects. It is suggested that miniholes are forced by tropospheric weather features and that they are largely reversible distortions to the airflow around the vortex. The relationship between the miniholes and upper tropospheric and lower stratospheric synoptic-scale disturbances is studied. Trajectory calculations are presented which demonstrate the exchange of air from low latitudes with air from within the vortex, with the vortex air subsequently moving to lower latitudes.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11641-11
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  • 14
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    Trace gases in the Antarctic Atmosphere (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Whole-air samples collected aboard the NASA ER-2 and DC-8 aircraft as part of the Airborne Antarctic Ozone Experiment were analyzed in a field laboratory set up at Punta Arenas, Chile. Mixing ratios obtained from gas chromatographic analyses of these samples are presented for CH4, CO, N2O, CFCl3, CF2Cl2, C2F3Cl3, CH3CCl3, and CCl4. A comparison of CFCl3/N2O mixing ratios from the flights of September 16-29, 1987 provides evidence of sustained subsidence.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11599-11
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  • 15
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    Ground-based infrared measurements of tropospheric source gases over Antarctica during the 1986 austral spring (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Simultaneous measurements of the atmospheric burdens of CH4, N2O, CO2, CF2Cl2, and CO above McMurdo Station, Antarctica, have been derived from solar absorption spectra obtained by the Jet Propulsion Laboratory high-resolution Fourier transform spectrometer. In all cases the burdens are smaller than midlatitude values. Furthermore, retrievals of N2O and CH4 indicate that the tropospheric mixing ratios were normal and that the depletion of the burdens can best be accounted for by a downward shift of the volume mixing ratio profiles by some 6-8 km. This rules out the possibility of large-scale upwelling of ozone-poor tropospheric air into the stratosphere being the cause of the Antarctic springtime ozone depletion.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11613-11
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  • 16
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    Nitrous oxide as a dynamical tracer in the 1987 Airborne Antarctic Ozone Experiment (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: In situ N2O measurements were made using an airborne tunable laser absorption spectrometer (ATLAS) on 12 flights into the Antarctic vortex, as well as on five transit flights outside the vortex region in August and September 1987, as part of the Airborne Antartic Ozone Experiment. Vertical profiles of N2O were obtained within the vortex on most of these flights and were obtained outside the vortex on several occasions. Flights into the vortex region show N2O decreasing southward between 53 and 72 S latitude on constant potential temperature surfaces in the lower stratosphere. The data lead to two important conclusions about the vortex region: (1) the lower stratosphere in August/September 1987 was occupied by 'old' air, which had subsided several kilometers during polar winter; (2) the N2O profile in the vortex was in an approximately steady state in August/September 1987, which indicates that the spring upwelling, suggested by several theories, did not occur.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11589-11
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  • 17
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    Quasi-biennial modulation of the Antarctic ozone depletion (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The quasi-biennial oscillation (QBO) in total ozone and temperature has been extracted from 9 years of Total Ozone Mapping Spectrometer (TOMS) observations and National Meteorological Center (NMC) analyses. Years in which QBO-related variations in the total ozone and temperature are positive are found to correspond to years with smaller September Antarctic total ozone hole decline rates and vice versa. The QBO appears to be responsible for September decline rate deviations up to 0.4 Dobson units (DU) per day. Also, the QBO at mid-latitudes appears to be better correlated with the 30-mbar tropical QBO winds than with those at 50 mbar. Possible mechanisms that would explain these phenomena are discussed.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11559-11
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  • 18
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    Lagrangian photochemical modeling studies of the 1987 Antarctic spring vortex. I - Comparison with AAOE observations (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Results from the Lagrangian photochemical model integrated along computed air parcel trajectories intersected by the ER-2 aircraft are presented and compared with AAOE observations. According to the model, the BrO observations made from the ER-2 within the dehydrated denitrified region are consistent with there being approximately 5 parts per trillion by volume of BrO(y) at 428 K in spring. Within the high ClO region, ozone destruction rates are expected to exceed 2 percent/d with approximately 80 percent due to the ClO dimer mechanism.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11529-11
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  • 19
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    A chemical definition of the boundary of the Antarctic ozone hole (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A program designed to study the Antarctic ozone hole using ER-2 high-altitude and DC-8 aircraft was conducted out of Punta Arenas, Chile during August 17-September 22, 1987. Graphs are presented of ozone and chlorine monoxide when crossing the boundary of the chemically perturbed region on August 23 and on September 21. Interpretations of ClO, H2O, and N2O measurements are presented, indicating ongoing diabetic cooling and advective poleward transport across the boundary.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11437-11
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  • 20
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    Measurements of ozone in the Antarctic atmosphere during August and September 1987 (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Mixing ratios changed dramatically for ozone in the austral polar stratosphere during August and September 1987. Data were obtained with an ultraviolet photometer mounted in the equipment bay of an ER-2 aircraft. Measurements were made between the latitudes of 53 and 72 deg S at pressure altitudes (U.S. Standard Atmosphere, 1976) up to 21 km in a series of flights from Punta Arenas, Chile, over the Palmer Peninsula. Additional data were obtained between 37 N and 53 deg S on the ferry flights leaving from and returning to Moffett Field, California. The sampling-collecting system and the analytical techniques are described. In September the mixing ratios for ozone at pressure altitudes above 15 km in the southernmost part of the flights over the Palmer Peninsula were significantly lower than values for midlatitudes. The various latitudes of the ER-2 aircraft's encounters with the boundary of the region of depleted ozone lie between 59 and 71 deg S. Near the 425 K potential temperature surface and well within the vortex, the measured mixing ratio of ozone declined from about 2 parts per million by volume (ppmv) to about 0.6 ppmv during the period of the ER-2 flights. The distributions of ozone as a function of altitude indicate the presence of layering of ozone.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11449-11
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  • 21
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    Airborne measurements of stratospheric constituents over Antarctica in the austral spring 1987. I - Method and ozone observations (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A Fourier transform spectrometer was flown aboard a DC-8 on 10 flights over Antarctica during August and September, 1987, as part of the Airborne Antarctic Ozone Experiment (AAOE). Observing the sun at infrared wavelengths, it was possible to determine the integrated column amount above the flight altitude for ozone and a number of other chemical species that are believed to be important in the perturbed chemistry of the 'ozone hole'. The paper describes the method, the observations, the data analysis procedure, and the ozone results. During the observation period, ozone developed a steep gradient near the edge of the polar vortex; deep within the vortex, the average ozone column decreased by about 1.6 percent per day during September.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11413-11
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  • 22
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    Filter measurement results from the Airborne Antarctic Ozone Experiment (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Filter samples obtained as part of the AAOE to determine the total nitrate, sulfate, acidic chloride, and acidic fluoride content along the flight path of the NASA ER-2 are studied. These compounds were obtained in the aerosol and vapor phase. The ratio of particulate sulfate observed outside the chemically perturbed region (CPR) of the vortex to that inside the CPR was 2.6. The ratio of total acidic chloride to total acidic flouride within the CPR is near 1, indicating the removal of chloride from the air mass or the partitioning of chloride into an unmeasured species.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11285-11
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  • 23
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    Condensed nitrate, sulfate, and chloride in Antarctic stratospheric aerosols (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The 1987 Airborne Antarctic Ozone Experiment, in which the NO3, Cl, and SO4 contents of stratospheric aerosols were estimated, is discussed. The aerosol size and chemical composition measurements were carried out on samples collected during August 17 to September 4, 1987. The data indicate that condensed nitrate is found below a threshold temperature of 193.6 + or - 3.0 K, which is generally found at latitudes exceeding 64 deg S. A negative correlation exists between condensed nitrate and ozone correlation.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11271-11
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  • 24
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    Balloon-borne measurements of aerosol, condensation nuclei, and cloud particles in the stratosphere at McMurdo Station, Antarctica, during the spring of 1987 (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Measurements of the vertical profile of particles with condensation nuclei counters and eight channel aerosol detectors at McMurdo Station, Antarctica, in 1987 verified observations made in 1986 concerning the absence of upwelling in the polar vortex and the presence of a condensation nuclei layer in conjunction with the ozone hole region. New observations of a bimodal aerosol size distribution, consisting of a large-particle mode mixed in with the small-particle sulfate mode, at temperatures below -79 C are consistent with the presence of nitric acid-water particles at low concentrations. Higher concentrations of large particles were observed in association with nacreous clouds. An unusual particle layer which contained enhanced concentrations of both the small-particle (sulfate) mode and the large-particle (nitric acid) mode was detected at temperatures below -85 C, suggesting simultaneous nucleation and growth phenomena. The vortex condensation nuclei layer was observed to form at the same time as the ozone hole, indicating that formation of the layer is triggered by photochemical processes and may be important in controlling ozone depletion above 22 km.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11253-11
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  • 25
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    Observational results using the microwave temperature profiler during the Airborne Antarctic Ozone Experiment (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The Microwave Temperature Profiler (MTP) measures profiles of air temperature versus altitude. The altitude coverage is about 5 km at a flight altitude of 20 km (66,000 feet), and the profiles are obtained every 14 s. The MTP instrument is installed on NASA's ER-2 aircraft, which flew 13 missions over Antarctica during the Airborne Antarctic Ozone Experiment. Altitude temperature profiles were used to derive potential temperature cross sections. These cross sections have been useful in detecting atmospheric waves. Many wave encounters have been identified as 'mountain waves'. The mountain waves are found to extend from the lowest altitudes measured to the highest (about 24 km). The southern part of the Palmer Peninsula was found to be associated with mountain waves more than half the time. Altitude temperature profiles were also used to measure the lapse rate along the flight track. Lapse rate versus latitude plots do not show significant changes at the ozone hole boundary.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11223-11
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  • 26
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    A method for using a time interval counter to measure frequency stability (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: It is shown how a commercial time interval counter can be used to measure the relative stability of two signals that are offset in frequency and mixed down to a beat note of about 1 Hz. To avoid the dead-time problem, the counter is set up to read the time interval between each beat note upcrossing and the next pulse of a 10 Hz reference pulse train. The actual upcrossing times are recovered by a simple algorithm whose outputs can be used for computing residuals and Allan variance. A noise floor-test yielded a delta f-f Allan deviation of 1.3 times 10 to the minus 9th power/tau relative to the beat frequency.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control (ISSN 0885-3010); 36; 478-480
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  • 27
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    Morphology of calcite crystals in clast coatings from four soils in the Mojave desert region (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Pedogenic calcite-crystal coatings on clasts were examined in four soils along an altitudinal gradient on Kyle Canyon alluvium in southern Nevada. Clast coatings were studied rather than matrix carbonate to avoid the effects of soil matrix on crystallization. Six crystal sizes and shapes were recognized and distinguished. Equant micrite was the dominant crystal form with similar abundance at all elevations. The distributions of five categories of spar and microspar appear to be influenced by altitudinally induced changes in effective moisture. In the drier, lower elevation soils, crystals were equant or parallel prismatic with irregular, interlocking boundaries while in the more moist, higher elevation soils they were randomly oriented, euhedral, prismatic, and fibrous. There was little support for the supposition that Mg(+2) substitution or increased (Mg + Ca)/HCO3 ratios in the precipitating solution produced crystal elongation.
    Keywords: GEOPHYSICS
    Type: Soil Science Society of America, Journal (ISSN 0038-0776); 53; 211-219
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    Silicification of holocene soils in northern Monitor Valley, Nevada (1989)
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    Publication Date: 2011-08-19
    Description: Chemical, physical, and microscopic data for three soils in the northern Monitor Valley are analyzed. The soils ranked in order of increasing age are: Mule, Rotinom, and Nayped. The procedures and techniques used to obtain and study that data are described. It is observed that: (1) redistribution of carbonate is detectable in all soils; (2) clay illuviation is insignificant in the Mule soil, weak but identifiable in the Rotinom soil, and significant in the Nayped soil; and (3) the maximum sodium adsorption ratio (SAR) and electrical conductivity (EC) for the Mule soil is between 64-89 cm, for the Rotinom soil the values are below 100 cm, and for Nayped the maximum SAR values range from 51-117 cm and maximum EC values are between 117-152 cm. The relationship between volcanic glass weathering and the amount of silica cementation in the soils is studied. It is noted that silicification of Monitor Valley holocene soils is due to there being enough moisture to release silica from volcanic glass, but not enough to leach the weathering products from the profile.
    Keywords: GEOPHYSICS
    Type: Soil Science Society of America, Journal (ISSN 0038-0776); 53; 158-164
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    Self-limiting physical and chemical effects in volcanic eruption clouds (1989)
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    Publication Date: 2011-08-19
    Description: One-dimensional aerosol microphysical and photochemical models are used to study the chemistry of stratospheric volcanic clouds. The results indicate that the aerosol microphysical processes of condensation and coagulation produce larger particles as the SO2 injection rate is increased. Larger particles have a smaller optical depth per unit mass and settle out of the stratosphere at a faster rate than smaller ones, restricting the total number of particles in the stratosphere. The microphysical processes moderate the impact of volcanic clouds on the earth's radiation budget and climate, suggesting that volcanic effects may be self limiting. It is noted that the injection of HCl into the stratosphere, which could lead to large ozone changes, is limited by a cold trap effect in which HCl and water vapor condense on ash particles in the rising volcanic plume and fall out as ice.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11165-11
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    Stratospheric ozone measurements from the 1985 MAP/GLOBUS NO(x) campaign (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Nine experiments obtained stratospheric ozone measurements during the fall 1985 Middle Atmosphere Program (MAP) Global Budget of Stratospheric Trace Constituents (GLOBUS) NO(x) campaign. Measurements are grouped into four sets from four air masses and compared. Agreement between individual experiments and weighted mean profiles is generally within 10 percent and within absolute accuracies. Dobson Umkehr values in layer 5 differ by more than absolute accuracies from weighted mean profiles. Brewer sonde values for one data set are outside absolute accuracies near the ozone peak. Solar UV occultation measurements are 30-35 percent less than the weighted mean profile and outside absolute accuracies. Measurements from the Exospheric Satellite backscattered ultraviolet experiment, not previously compared with other techniques, agree within 10-15 percent of weighted mean profiles. Results of the campaign are generally consistent with those of four previous intercomparison campaigns.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11074-11
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  • 31
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    Secular increase of the total vertical column abundance of carbon monoxide above central Europe since 1950 (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The secular increase of the total vertical column abundance of carbon monoxide has been derived from sets of infrared solar spectra recorded from an altitude of 3.58 km at the Jungfraujoch Station, Switzerland, in 1950-1951 and in 1985-1987. The results are based on equivalent width measurements of the R3 line of the 1-0 vibration-rotation band of (C-12)(0-16) at 2159.30/cm. The set of 1985-1987 observations indicates a strong seasonal cycle in the total column abundance of CO, with a + or - 25 percent modulation between minimum values in late summer and the maximum values in late winter. Variability on shorter time scales is also present in both the old and recent data sets. The mean cumulative rate of increase of the total column abundance of CO above the Jungfraujoch is found to be (0.85 + or - 0.20) percent/yr between 1950-1951 and 1985-1987. The present findings are compared with trends reported in earlier studies.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 11021-11
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  • 32
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    The morphology of strike-slip faults - Examples from the San Andreas Fault, California (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The dilatational strains associated with vertical faults embedded in a horizontal plate are examined in the framework of fault kinematics and simple displacement boundary conditions. Using boundary element methods, a sequence of examples of dilatational strain fields associated with commonly occurring strike-slip fault zone features (bends, offsets, finite rupture lengths, and nonuniform slip distributions) is derived. The combinations of these strain fields are then used to examine the Parkfield region of the San Andreas fault system in central California.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 10204-10
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    Carrier phase ambiguity resolution for the Global Positioning System applied to geodetic baselines up to 2000 km (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A technique for resolving the ambiguities in the GPS carrier phase data (which are biased by an integer number of cycles) is described which can be applied to geodetic baselines up to 2000 km in length and can be used with dual-frequency P code receivers. The results of such application demonstrated that a factor of 3 improvement in baseline accuracy could be obtained, giving centimeter-level agreement with coordinates inferred by very-long-baseline interferometry in the western United States. It was found that a method using pseudorange data is more reliable than one using ionospheric constraints for baselines longer than 200 km. It is recommended that future GPS networks have a wide spectrum of baseline lengths (ranging from baselines shorter than 100 km to those longer than 1000 km) and that GPS receivers be used which can acquire dual-frequency P code data.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 10187-10
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    A search for five month solar induced periodicity in the stratosphere (1989)
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    Publication Date: 2011-08-19
    Description: Recent studies of solar UV spectra and various indices of solar activity indicate a strong period at about 5 months. In the 10.7 cm solar radio flux (F10.7), a conventional index for the solar EUV and UV variabilities, the spectral power of the 5 month period is comparable to the well known 27 day solar period. However, in the solar UV flux at 205 nm, directly measured from the Nimbus-7 SBUV spectrometer, the (spectral) power of the 5 month period is about half that of the 27 day period. This paper examines the possible impact of the 5 month solar period on ozone and temperature at various pressure levels in the stratosphere and discusses the implications of differences in solar forcing at the 27 day and 5 month periods. It is shown that ozone, both in the lower and the upper stratosphere, has a measurable response to solar UV forcing at 27 days. Such a solar response is not observed at 5 month period because of a relatively weaker 5 month solar UV component in the solar signal and a strong interference from dynamical signals associated with planetary wave activity.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 16; 711-714
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  • 35
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    Experimental comparison of two hot-wire techniques in supersonic flow (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA Journal (ISSN 0001-1452); 27; 1074-108
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  • 36
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    SAGE II inversion algorithm (1989)
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    Publication Date: 2011-08-19
    Description: The operational Stratospheric Aerosol and Gas Experiment II multichannel data inversion algorithm is described. Aerosol and ozone retrievals obtained with the algorithm are discussed. The algorithm is compared to an independently developed algorithm (Lenoble, 1989), showing that the inverted aerosol and ozone profiles from the two algorithms are similar within their respective uncertainties.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 8339-835
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    SAGE II aerosol validation - Selected altitude measurements, including particle micromeasurements (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The validity of particulate extinction coefficients derived from limb path solar radiance measurements obtained during the Stratospheric Aerosol and Gas Experiment (SAGE) II is tested. The SAGE II measurements are compared with correlative aerosol measurements taken during January 1985, August 1985, and July 1986 with impactors, laser spectrometers, and filter samplers on a U-2 aircraft, an upward pointing lidar on a P-3 aircraft, and balloon-borne optical particle counters. The data for July 29, 1986 are discussed in detail. The aerosol measurements taken on this day at an altitude of 20.5 km produce particulate extinction values which validate the SAGE II values for similar wavelengths.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 8367-838
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    SAGE II aerosol data validation and initial data use - An introduction and overview (1989)
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    Publication Date: 2011-08-19
    Description: The process of validating data from the Stratospheric Aerosol and Gas Experiment (SAGE) II and the initial use of the validated data are reviewed. The instruments developed for the SAGE II, the influence of the eruption of El Chichon on the global stratospheric aerosol, and various data validation experiments are discussed. Consideration is given to methods for deriving aerosol physical and optical properties from SAGE II extinction data and for inferring particle size distribution moments from SAGE II spectral extinction values.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 8335-833
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  • 39
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    Application of internal gravitational field equations to geophysical measurement of G (1989)
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    Publication Date: 2011-08-19
    Description: The spherical harmonic equation for the gravitational potential inside the earth is presented. The equation satisfies Poisson's equation and converges uniformly. It obviates the need for downward continuation of the exterior potential with its attendant convergence difficulties but of course requires some knowledge of the earth's density distribution. The equation is used to derive the general expression for the geophysical measurement of the gravitational constant G made inside the earth, such as in boreholes and mine shafts. Numerical evidence is also presented to show that the long- to intermediate-wavelength gravity anomalies can masquerade as the 'fifth force' if not properly corrected for.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 7563-756
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  • 40
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    An improved correction algorithm for number density measurements made with the forward scattering spectrometer probe (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A correction factor to the number density measured by the Forward Scattering Spectrometer Probe (FSSP) which compensates for dead time and coincidence errors was determined by calculating the probabilities of, and the average number of particles in, the six possible types of dead time and coincidence events. These probabilities and averages were calculated by means of a probabilistic model based on Poisson statistics. A Monte Carlo computer simulation of the FSSP operation was also carried out and the number density correction factor was compared with the Monte Carlo data. For an actual number density of 2000/cu cm, it was found that the measured number density was of the order of 300/cu cm.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments (ISSN 0034-6748); 60; 1143-115
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    Denitrification in the Antarctic stratosphere (1989)
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    Publication Date: 2011-08-19
    Description: Rapid loss of ozone over Antarctica in spring requires that the abundance of gaseous nitric acid be very low. Precipitation of particulate nitric acid has been assumed to occur in association with large ice crystals, requiring significant removal of H2O and temperatures well below the frost point. However, stratospheric clouds exhibit a bimodal size distribution in the Antarctic atmosphere, with most of the nitrate concentrated in particles with radii of 1 micron or greater. It is argued here that the bimodal size distribution sets the stage for efficient denitrification, with nitrate particles either falling on their own or serving as nuclei for the condensation of ice. Denitrification can therefore occur without significant dehydration, and it is unnecessary for temperatures to drop significantly below the frost point.
    Keywords: GEOPHYSICS
    Type: Nature (ISSN 0028-0836); 339; 525-527
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  • 42
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    Operational aspects of CASA UNO '88-The first large scale international GPS geodetic network (1989)
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    Publication Date: 2011-08-19
    Description: For three weeks, from January 18 to February 5, 1988, scientists and engineers from 13 countries and 30 international agencies and institutions cooperated in the most extensive GPS (Global Positioning System) field campaign, and the largest geodynamics experiment, in the world to date. This collaborative eperiment concentrated GPS receivers in Central and South America. The predicted rates of motions are on the order of 5-10 cm/yr. Global coverage of GPS observations spanned 220 deg of longitude and 125 deg of latitude using a total of 43 GPS receivers. The experiment was the first civilian effort at implementing an extended international GPS satellite tracking network. Covariance analyses incorporating the extended tracking network predicted significant improvement in precise orbit determination, allowing accurate long-baseline geodesy in the science areas.
    Keywords: GEOPHYSICS
    Type: IEEE Transactions on Instrumentation and Measurement (ISSN 0018-9456); 38; 648-651
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    Acoustic temperature profile measurement technique for large combustion chambers (1989)
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    Publication Date: 2011-08-19
    Description: Measurement of times of flight of sound waves can be used to determine temperatures in a gas. This paper describes a system, based on this principle, that is capable of giving the temperature profile in a nonisothermal gas volume, for example, prevalent in a large furnace. The apparatus is simple, rugged, accurate, and capable of being automated for process control applications. It is basically an acoustic waveguide where the outside temperature profile is transferred to a chosen gas contained inside the guide.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: ASME, Transactions, Journal of Heat Transfer (ISSN 0022-1481); 111; 461-466
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    Ellipsometric method for the measurement of temperature and optical constants of incandescent transition metals (1989)
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    Publication Date: 2011-08-19
    Description: The development of a unique noncontact temperature measurement device utilizing rotating analyzer ellipsometry is described. The technique circumvents the necessity of spectral emissivity estimation by direct measurement concomitant with radiance brightness. Simultaneous determinations of dielectric constants and refractive indices allow changes in the physical and chemical state of a heated surface to be monitored. The results of optical property measurements at 633 nm as functions of temperature between 1000 and 2500 K for eight transition metals including Hf, Ir, Mo, Nb, Pd, Pt, Ta, and V are presented together with preliminary results of oxidation studies on iridium.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 28; 1885-189
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    Relation between increasing methane and the presence of ice clouds at the mesopause (1989)
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    Publication Date: 2011-08-19
    Description: The possiblity is investigated that a substantial change has occurred in middle-atmospheric water vapor as a result of the increase in atmospheric methane over the past century and a half. It is shown from modeling of mesospheric ice-particle formation that noctilucent cloud brightness should be a sensitive indicator of the water content at the high-latitude summertime mesopause. From an examination of the historical record of noctilucent cloud occurrence, it is found that such clouds are absent from the record before 1885, a finding which is consistent with the hypothesis proposed in this paper.
    Keywords: GEOPHYSICS
    Type: Nature (ISSN 0028-0836); 338; 490-492
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    Impact of heterogeneous reactions on stratospheric chemistry of the Arctic (1989)
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    Publication Date: 2011-08-19
    Description: The possible depletion of ozone due to heterogeneous reactions occurring in Arctic polar stratospheric clouds (PSCs) is fundamentally different from the Antarctic situation. PSCs in the Arctic are relatively short-lived and occur over limited regions of the Arctic stratosphere. The Arctic situation is examined using a model which calculates photochemical processes as a function of longitude in air circulating with fixed velocity around the pole at fixed pressure level and latitude. The model allows sunlight to vary diurnally and PSCs to occur in specified subregions of the domain. Measurements of chemical species including HCl, ClO, NO2 and HNO3 downwind from a PSC should show obvious changes compared to measurements in air unaffected by clouds. These species concentrations are found to be sensitive to sticking coefficients, cloud characteristics including particle number density and surface area, and to the PSC exposure time.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 16; 131-134
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    Design of the polarimeter for the Solar Activity Measurements Experiments (SAMEX) vector magnetograph (1989)
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    Publication Date: 2011-08-19
    Description: A design concept developed for a polarimeter on the vector magnetograph of the SAMEX satellite that would be very sensitive to solar vector magnetic fields is described. A description of the Poincare sphere is presented, along with the instrument scientific requirements, to provide an understanding of how the polarimeter design has been selected. It is shown that the design goal of a polarimetric sensitivity of 0.0001 can be achieved in the linear measurements using a hybrid analyzer. It is also noted that the systematic errors that produce linear crosstalk into the circular measurement will require the use of the redundant polarization measurements for in-flight calibrations and corrections of the data.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optical Engineering (ISSN 0091-3286); 28; 131-140
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  • 48
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    Improved method of analyzing hot-wire measurements in supersonic turbulence (1989)
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    Publication Date: 2011-08-19
    Description: The present analysis method for hot-wire data in supersonic turbulence takes sound field effects into account and yields greater accuracy in its treatment of flow variable fluctuations than existing methods despite requiring only a moderately accurate estimate of static pressure fluctuations. The method demonstrates the way in which neglecting pressure fluctuations will affect hot-wire data analysis, as well as indicating the probable direction the errors will take.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA Journal (ISSN 0001-1452); 27; 115-117
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    False-color display of special sensor microwave/imager (SSM/I) data (1989)
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    Publication Date: 2011-08-19
    Description: Displays of multifrequency passive microwave data from the Special Sensor Microwave/Imager (SSM/I) flying on the Defense Meteorological Satellite Program (DMSP) spacecraft are presented. Observed brightness temperatures at 85.5 GHz (vertical and horizontal polarizations) and 37 GHz (vertical polarization) are respectively used to 'drive' the red, green, and blue 'guns' of a color monitor. The resultant false-color images can be used to distinguish land from water, highlight precipitation processes and structure over both land and water, and detail variations in other surfaces such as deserts, snow cover, and sea ice. The observations at 85.5 GHz also add a previously unavailable frequency to the problem of rainfall estimation from space. Examples of mesoscale squall lines, tropical and extra-tropical storms, and larger-scale land and atmospheric features as 'viewed' by the SSM/I are shown.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: American Meteorological Society, Bulletin (ISSN 0003-0007); 70; 146-151
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    Chemistry and transport in a three-dimensional stratospheric model - Chlorine species during a simulated stratospheric warming (1989)
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    Publication Date: 2011-08-19
    Description: The distributions in the stratosphere of a variety of chemical species were calculated for a 6-day period during the February 1979 stratospheric major warming, using winds derived from a spectral forecast model which included O(x), NO(x), HO(x), and ClO(x) chemistries as well as longitudinally varying reaction rate coefficients and photolysis rates for these molecules. The results obtained indicate a particular importance of chemistry and transport for the Cl-containing species ClO, ClONO2, HCl, and HOCl. Dynamical effects dominate the variability of HCl, while diurnal effects dominate that of ClONO2 and ClO. The effects of strong planetary wave activity may be seen in terms of large longitudinal variability of the total HCl and ClONO columns in the stratosphere; in the middle and high northern latitudes, it is sufficiently large to exceed the diurnal variability of the column.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 1057-108
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    A tenfold increase in the abundance of large solid particles in the stratosphere, as measured over the period 1976-1984 (1989)
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    Publication Date: 2011-08-19
    Description: Representative chemical, structural, and morphological analyses of the large (greater than 1 micron diameter) solid particles from three impaction collection surfaces have been performed. These collections sampled the stratosphere at approximately 17-19 km in altitude during 1976, 1981, and 1984. For these sampling periods, the stratospheric solid-particle number densities have been determined to be 0.089, 0.16, and 1.7 particles/cu m of air, respectively, for particles of greater than 1 micron diameter. This rise in solid-particle number density for the stratosphere over the collection period is likely due to the influx of solid rocket exhaust and rocket and satellite debris into the atmosphere in increasingly larger amounts with time. Some of this material is shed from spacecraft during ascent through the atmosphere, but the majority is probably provided during the descent of material from earth's growing belt of debris in low-earth orbit.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 1047-105
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    Postdispersion system for astronomical observations with Fourier transform spectrometers in the thermal infrared (1989)
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    Publication Date: 2011-08-19
    Description: A postdispersion system for astronomical observations with Fourier transform spectrometers in the thermal infrared has been developed which improves the sensitivity of radiation noise limited observations by reducing the spectral range incident on the detector. Special attention is given to the first-generation blocked impurity band detector. Planetary, solar, and stellar observations are reported.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 28; 139-145
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    Inspecting our upper atmosphere (1989)
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    Publication Date: 2011-08-19
    Description: The Upper Atmosphere Research Satellite (UARS) has been proposed for intensive studies of the 15-100 km-altitude region of the earth's atmosphere, begining in 1991. This 14,000-lb satellite will carry a suite of 10 instruments able to study the energy input and loss, photochemistry, and circulation of the upper atmosphere, as well as the extensive web of interactions among these three processes. UARS's remote sensors will give attention to the atmospheric molecular species of the nitrogen, hydrogen, and chlorine families.
    Keywords: GEOPHYSICS
    Type: Aerospace America (ISSN 0740-722X); 27; 24-26
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    Geometric bias and time coincidence in 3-dimensional laser Doppler velocimeter systems (1989)
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    Publication Date: 2011-08-19
    Description: The measurement by a three-dimensional laser Doppler velocimeter of a turbulent flow has been numerically simulated. Errors associated with the probe volume geometry and the coincidence time window concept are revealed. One type of error occurs for high system data rates when multiple particles lead to system realizations. Another error occurs associated with a geometric bias discovered in the present study. This three-dimensional ldv geometric bias exists even for single-particle realizations and regardless of the system data rate. A technique for the elimination of the geometric bias is presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Experiments in Fluids (ISSN 0723-4864); 7; 1, 19
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    Computer processing of tunable diode laser spectra (1989)
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    Publication Date: 2011-08-19
    Description: A computer-controlled tunable diode laser spectrometer and spectral analysis software are described. The three-channel system records simultaneously the transmission of a subject gas, a temperature-stabilized etalon, and a calibration gas. The software routines are applied to diode laser spectra of HNO3 and NO2 to illustrate the procedures adopted for conversion of raw spectral data to useful transmission and harmonic spectra. Extraction of line positions, absorption intensities, collisional broadening coefficients, and gas concentrations from recorded spectra is also described.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Spectroscopy (ISSN 0003-7028); 43; 834-839
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    A high-speed GaAs MESFET optical controller (1989)
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    Publication Date: 2011-08-19
    Description: Optical interconnects are being considered for control signal distribution in phased array antennas. A packaged hybrid GaAs optical controller with a 1:16 demultiplexed output that is suitable for this application is described. The controller, which was fabricated using enhancement/depletion mode MESFET technology, operates at demultiplexer-limited input data rates up to 305 Mb/s and requires less than 200 microW optical input power.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Photonics Technology Letters (ISSN 1041-1135); 1; 389-391
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    PC based graphic display real-time particle beam uniformity (1989)
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    Publication Date: 2011-08-19
    Description: A technique has been developed to support the study of the effects of cosmic rays on integrated circuits. The system is designed to determine the particle distribution across the surface of an integrated circuit accurately while the circuit is bombarded by a particle beam. The system uses photomultiplier tubes, an octal discriminator, a computer-controlled NIM quad counter, and an IBM PC. It provides real-time operator feedback for fast beam tuning and monitors momentary fluctuations in the particle beam. The hardware, software, and system performance are described.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 36; 1738-174
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    Applications of ground-based radiometric observations of millimeter wave radiation (1989)
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    Publication Date: 2011-08-19
    Description: A three-channel transportable radiometer that operates at 20.6, 31.65, and 90.0 GHz has been developed. The design of the radiometer is described and the results of various experimental applications of the radiometer are presented. The experiments include a comparison of brightness temperature measurements at various frequencies with the water vapor absorption models of Waters (1976) and Lieve (1989). Measurements of absorption ratios for cloud attenuation are given and the radiometer measurements are compared with oxygen absorption calculated using the Rasenkranz (1988) model.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: (ISSN 0002-6557); 58; 467-474
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    Passive millimeter-wave imaging - A tool for remote sensing (1989)
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    Publication Date: 2011-08-19
    Description: This paper describes a program of airborne radiometric imaging at 90 GHz and 140 GHz. Using high sensitivity (below 1 K) and high angular resolution (0.5-1.0 degree), high quality images have been made. The following measurements are discussed: cloud and fog penetration at 90 GHz, discrimination between agricultural and urban areas, discrimination between different vegetation types, detection of vehicles on roads, detection and classification of airports and airplanes, ship detection and quantitative oil spill sensing. The application of information enhancement techniques with automatic and real time application aspects is also described, and results of applied techniques for contrast and contour enhancement are shown.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: (ISSN 0002-6557); 58; 457-465
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    The interannual variability of polar stratospheric clouds and related parameters in Antarctica during September and October (1989)
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    Publication Date: 2011-08-19
    Description: Antarctic polar stratospheric cloud (PSC) sightings by the orbiting SAM II sensor during September and October show a pronounced quasi-biennial oscillation (QBO) signal, and October sightings have increased markedly over the past 10 years in years of westerly QBO phase. The QBO in PSC frequency is likely to affect the rate of Antarctic heterogeneous chemical processes and, hence, ozone depletion. Studies of the observed long-term temperature trend suggest that the decadal PSC trend probably results from the ozone decline, through its effect on stratospheric heating rates. A more detailed analysis of data from 1986 to 1987 shows that there were more PSCs in 1987, and that they persisted much later into the spring season as compared to 1986. Qualitatively similar behavior was found for the OClO column abundances and 18-km ozone depletion observed at McMurdo Station during these 2 years. These observations suggest that both the intensity and duration of heterogeneous chemical processes are likely greater during colder OBQ-westerly phase years.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 16; 1157-116
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    Electron density profile description in the international reference ionosphere (1989)
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    Publication Date: 2011-08-19
    Description: Problems encountered during efforts to reformulate the IRI description of the electron density profile are examined. Consideration is given to Booker's (1979) proposal that the unique, analytic profile functions should cover the entire ionospheric height range. The IRI topside model is reviewed and the electron density profile of the middle and lower ionosphere are discussed. Rawer's (1983) procedure for combining the topside, middle, and lower ionospheric profiles into one analytic profile is reviewed.
    Keywords: GEOPHYSICS
    Type: Journal of Atmospheric and Terrestrial Physics (ISSN 0021-9169); 51; 781-790
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    Growth of Greenland ice sheet - Interpretation (1989)
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    Publication Date: 2011-08-19
    Description: An observed 0.23 m/year thickening of the Greenland ice sheet indicates a 25 percent to 45 percent excess ice accumulation over the amount required to balance the outward ice flow. The implied global sea-level depletion is 0.2 to 0.4 mm/year, depending on whether the thickening is only recent (5 to 10 years) or longer term (less than 100 years). If there is a similar imbalance in the northern 60 percent of the ice-sheet area, the depletion is 0.35 to 0.7 mm/year. Increasing ice thickness suggests that the precipitation is higher than the long-term average; higher precipitation may be a characteristic of warmer climates in polar regions.
    Keywords: GEOPHYSICS
    Type: Science (ISSN 0036-8075); 246; 1589-159
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    Concentrations and size distributions of Antarctic stratospheric aerosols (1989)
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    Publication Date: 2011-08-19
    Description: Particle Measuring Systems laser particle spectrometer (ASAS-X and FSSP) probes were used to measure aerosol particle concentrations and size distributions during 11 ER-2 flights between Punta Arenas (53 deg S) and Antarctica (up to 72 deg S) from August 17 to September 22, 1987. The time resolution was 10 s, corresponding to a spatial resolution of 2 km. The data were divided into two size classes (0.05-0.25 and 0.53-5.5 micron radius) to separate the small particle from the coarse particle populations. Results show that the small-particle concentrations are typical for a background aerosol during volcanic quiescence. This concentration is generally constant along a flight track; in only one instance a depletion of small particles during a polar stratospheric cloud (PSC) encounter was measured, suggesting a nucleation of type I PSC particles on background aerosols. Temporary increases of the coarse particle concentrations indicated the presence of tenuous polar stratospheric clouds that were encountered most frequently at the southernmost portion of a flight track and when the aircraft descended to lower altitudes. During 'particle events', particle modes were found at 0.6-micron radius, corresponding to type I PSCs, and occasionally, at 2.0-micron radius corresponding to type II PSCs.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16459-16
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    A video atlas of TOMS ozone data, 1978-88 (1989)
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    Publication Date: 2011-08-19
    Description: The Total Ozone Mapping Spectrometer (TOMS), on-board NASA's Nimbus-7 weather satellite, has been observing ozone over the earth once daily for the last 10 yr. A time-lapse atlas of 3440 color-coded images drawn from the TOMS archive from 1978 to 1988 has been visualized on a standard VHS videotape that is now available from NASA. The rapid and complex ozone variations presented demonstrate the difficulty of separating man-induced climate changes from natural variability. This article presents a few images from the atlas and describes interesting features in the animation, such as the correlation between ozone and 'the weather', and the recent deepening of the annual ozone hole over the South Pole. Originally intended as a browsing tool for the TOMS digital database, the videotape is a vivid presentation of the earth's atmospheric dynamics and chemistry that is recommended for scientists, educators, policy makers, and citizens concerned about the global environment.
    Keywords: GEOPHYSICS
    Type: American Meteorological Society, Bulletin (ISSN 0003-0007); 70; 1564-156
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    An overview af SAGE I and II ozone measurements (1989)
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    Publication Date: 2011-08-19
    Description: The stratospheric Aerosol and Gas Experiments (SAGE) I and II measure Mie, Rayleigh, and gaseous extinction profiles using the solar occultation technique. These global measurements yield ozone profiles with a vertical resolution of 1 km which have been routinely obtained for the periods from February 1979 to November 1981 (SAGE I) and October 1984 to the present (SAGE II). The long-term periodic behavior of the measured ozone is presented as well as case studies of the observed short-term spatial and temporal variability. A linear regression shows annual, semiannual, and quasi-biennial oscillation features at various altitudes and latitudes which, in general, agree with past work. Also, ozone, aerosol, and water vapor data are described for the Antarctic springtime, showing large variation relative to the vortex. Cross-sections in latitude and altitude and polar plots at various altitudes clearly delineate the ozone hole vertically and areally.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science (ISSN 0032-0633); 37; 1567-158
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    The global distribution on total ozone - Toms satellite measurements (1989)
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    Publication Date: 2011-08-19
    Description: The general behavior of total ozone by season and latitude was known before 1930 through the pioneering observations by Dobson. The ozone record at Oxford and other European stations was dominated by an annual cycle and by irregular short term fluctuations. The amplitude and phase of the annual cycle were determined at representative latitudes in both hemispheres. However, the short term variations appeared to be meteorological origin, although the specific cause could not be identified. Data from the Total Ozone Mapping Spectrometer (TOMS) on the Nimbus 7 spacecraft, with global coverage at an average spatial resolution of 66 km, can now be used to completely map the total ozone field. These maps demonstrate that troughs and ridges in the upper troposphere are responsible for the large, short term ozone variations found at middle latitudes, while in the tropics, the steady, low ozone levels show broad scale structure associated with the Hadley circulation.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science (ISSN 0032-0633); 37; 1555-156
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    Practical application of HgI2 detectors to a space-flight scanning electron microscope (1989)
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    Publication Date: 2011-08-19
    Description: Mercuric iodide X-ray detectors have been undergoing tests in a prototype scanning electron microscope system being developed for unmanned space flight. The detector program addresses the issues of geometric configuration in the SEM, compact packaging that includes separate thermoelectric coolers for the detector and FET, X-ray transparent hermetic encapsulation and electrical contacts, and a clean vacuum environment.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Nuclear Instruments and Methods in Physics Research, Section A - Accelerators, Spectrometers, Detectors, and Associated Equipment (ISSN 0168-9002); 283; 348-351
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    Growth of Greenland ice sheet - Measurement (1989)
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    Publication Date: 2011-08-19
    Description: Measurements of ice-sheet elevation change by satellite altimetry show that the Greenland surface elevation south of 72 deg north latitude is increasing. The vertical velocity of the surface is 0.20 + or - 0.06 meters/year from measured changes in surface elevations at 5906 intersections between Geosat paths in 1985 and Seasat in 1978, and 0.28 + or - 0.02 meters/year from 256,694 intersections of Geosat paths during a 548-day period of 1985 to 1986.
    Keywords: GEOPHYSICS
    Type: Science (ISSN 0036-8075); 246; 1587-158
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    Sampling stratospheric aerosols with impactors (1989)
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    Publication Date: 2011-08-19
    Description: Derivation of statistically significant size distributions from impactor samples of rarefield stratospheric aerosols imposes difficult sampling constraints on collector design. It is shown that it is necessary to design impactors of different size for each range of aerosol size collected so as to obtain acceptable levels of uncertainty with a reasonable amount of data reduction.
    Keywords: GEOPHYSICS
    Type: Aerosol Science and Technology (ISSN 0278-6826); 11; 65-79
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    New spectral features of stratospheric trace gases identified from high-resolution infrared balloon-borne and laboratory spectra (1989)
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    Publication Date: 2011-08-19
    Description: A new Michelson-type interferometer system operating in the infrared at very high resolution has been used to record numerous balloon-borne solar absorption spectra of the stratosphere, ground-based solar absorption spectra, and laboratory spectra of molecules of atmospheric interest. In the present work results obtained for several important stratospheric trace gases, HNO3, CIONO2, HO2NO2, NO2, and COF2, in the 8- to 12-micron spectral region are reported. Many new features of these gases have been identified in the stratospheric spectra. Comparison of the new spectra with line-by-line simulations shows that previous spectral line parameters are often inadequate and that new analysis of high-resolution laboratory and atmospheric spectra and improved theoretical calculations will be required for many bands. Preliminary versions of several sets of improved line parameters under development are discussed.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 14945-14
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    Electron tunnel sensor technology (1989)
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    Publication Date: 2011-08-19
    Description: The recent development of Scanning Tunneling Microscopy technology allows the application of electron tunneling to position detectors for the first time. The vacuum tunnel junction is one of the most sensitive position detection mechanisms available. It is also compact, simple, and requires little power. A prototype accelerometer based on electron tunneling, and other sensor applications of this promising new technology are described.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: British Interplanetary Society, Journal (ISSN 0007-084X); 42; 474-477
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    Hydrogen-isotope evidence for extrusion mechanisms of the Mount St Helens lava dome (1989)
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    Publication Date: 2011-08-19
    Description: Hydrogen isotope analyses were used to determine water content and deuterium content for 18 samples of the Mount St Helens dome dacite in an attempt to identify the triggering mechanisms for periodic dome-building eruptions of lava. These isotope data, the first ever collected from an active lava dome, suggest a steady-state process of magma evolution combining crystallization-induced volatile production in the chamber with three different degassing mechanisms: closed-system volatile loss in the magma chamber, open-system volatile release during ascent, and kinetically controlled degassing upon eruption at the surface. The data suggest the future dome-building eruptions may require a new influx of volatile-rich magma into the chamber.
    Keywords: GEOPHYSICS
    Type: Nature (ISSN 0028-0836); 341; 521-523
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    Earth Radiation Budget Experiment (ERBE) archival and April 1985 results (1989)
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    Publication Date: 2011-08-19
    Description: This paper describes the Earth Radiation Budget Experiment (ERBE) data products being made available to the community. The Science Team used ten validation criteria to judge the acceptability of the data for archival. These criteria are listed, and uncertainty estimates based on them for four typical data products are presented. A brief description of the radiation budget for April 1985 from the combined data of ERBE and NOAA-9 concludes this paper.
    Keywords: GEOPHYSICS
    Type: American Meteorological Society, Bulletin (ISSN 0003-0007); 70; 1254-126
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    Diurnal variations of mesospheric ozone obtained by ground-based microwave radiometry (1989)
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    Publication Date: 2011-08-19
    Description: From December 1986 until April 1987 ground-based microwave observations of the diurnal variation of mesospheric ozone were made over Bern, Switzerland. These data were of sufficient quality to define the characteristics diurnal behavior of the ozone mixing ratio during winter and equinoctial conditions. The observed diurnal variation of ozone peaks at about 74 km, where its amplitude is about a factor of 6. At 65 km the observed diurnal variation is a factor of 3, whereas at 55 km it is only a factor of 1.4. One-dimensional model calculations accurately reproduce the relative diurnal variation of ozone at equinox, suggesting that the model value of the ozone photolysis rate coefficient is accurate to better that 10 percent. For winter conditions, however, the model underpredicts the observed relative diurnal variation by a factor of 2; a major part of this discrepancy is due to an observed postmidnight increase in ozone. Various suggested changes in model parameters to better produce the ozone abundance vertical profile result in only small differences in the relative diurnal variation, indicating that these observations do not provide a sensitive test of the mesospheric chemistry controlling the abundance of odd oxygen.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 12819-12
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    Nonlocal thermodynamic equilibrium effects in stratospheric HF by collisional energy transfer from electronically excited O2 and implications for infrared remote sensing (1989)
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    Publication Date: 2011-08-19
    Description: A possible nonlocal thermodynamic equilibrium (non-LTE) effect involving stratospheric HF arising from the direct photochemical excitation of vibrationally excited HF by collisional energy transfer from electronically excited O2 is presented. Although this non-LTE effect is smaller that one associated with the direct solar excitation of both HF(nv = 1) and HF(nv = 2), calculations show that inclusion of the mechanism into retrieval algorithms is necessary if correct daytime upper stratosphere HF profiles are to be inferred in future IR thermal emission measurements.
    Keywords: GEOPHYSICS
    Type: Applied Optics (ISSN 0003-6935); 28; 4161-416
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  • 76
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    An electron tunneling sensor (1989)
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    Publication Date: 2011-08-19
    Description: New methods have been developed to implement position sensors based on electron tunneling. The electron tunneling methods enable position to be detected with sub-Angstrom resolution using a compact mechanical structure and simple electronic control elements. A prototype accelerometer is the first sensor based on these principles; it shows reliable operation with a noise-limited sensitivity and a bandwidth of approximately 3 kHz. Based on these results, it is expected that tunnel sensors optimized for many applications will enable an entirely new class of sensors to be developed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Sensors and Actuators (ISSN 0250-6874); 19; 201-210
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    Topographic and volcanic asymmetry around the Red Sea - Constraints on rift models (1989)
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    Publication Date: 2011-08-19
    Description: This paper describes a model which explains the topographic and volcanic asymmetry around the Red Sea. The model involves asthenospheric upwelling beneath a lithosphere of laterally variable strength in which a weak zone (e.g., a suture or a region with quartz-bearing lower crust) may have controlled the location of rifting. In this model, Tertiary volcanism in Saudi Arabia marks the location of initial upwelling, and uplift is due to crustal thickening associated with magmatic underplating and crustal intrusion. The model predicts that the incipient crustal rift and the locus of mantle upwelling will tend to align as rifting continues and stable seafloor spreading develops, implying relative migration of the lithosphere and asthenosphere.
    Keywords: GEOPHYSICS
    Type: Tectonics (ISSN 0278-7407); 8; 1193-121
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    Large-scale transport of a CO-enhanced air mass from Europe to the Middle East (1989)
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    Publication Date: 2011-08-19
    Description: On November 14, 1981, the shuttle-borne Measurement of Air Pollution from Satellites (MAPS) experiment observed a carbon monoxide (CO) enhanced air mass in the middle troposphere over the Middle East. The primary source of this polluted air was estimated by constructing adiabatic isentropic trajectories backwards from the MAPS measurement location over a 36 h period. The isentropic diagnostics indicate that CO-enhanced air was transported southeastward over the Mediterranean from an organized synoptic-scale weather regime, albeit of moderate intensity, influencing central Europe on November 12. Examination of the evolving synoptic scale vertical velocity and precipitation patterns during this period, in conjuction with Meteosat visible, infrared, and water vapor imagery, suggests that the presence of this disturbed weather system over Europe may have created upward transport of CO-enhanced air between the boundary-layer and midtropospheric levels, and subsequent entrainment in the large-scale northwesterly jet stream flow over Europe and the Mediterranean.
    Keywords: GEOPHYSICS
    Type: Journal of Atmospheric Chemistry (ISSN 0167-7764); 9; 479-496
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    A small-scale plasmoid formed during the May 13, 1985, AMPTE magnetotail barium release (1989)
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    Publication Date: 2011-08-19
    Description: Plasmoids are closed magnetic-loop structures with entrained hot plasma which are inferred to occur on large spatial scales in space plasma systems. A model is proposed here to explain the brightening and rapid tailward movement of the barium cloud released by the AMPTE IRM spacecraft on May 13, 1985. The model suggests that a small-scale plasmoid was formed due to a predicted development of heavy-ion-induced tearing in the thinned near-tail plasma sheet. Thus, a plasmoid may actually have been imaged due to the emissions of the entrained plasma ions within the plasma bubble.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 17084-17
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    Correlation of N2O and ozone in the southern polar vortex during the Airborne Antarctic Ozone Experiment (1989)
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    Publication Date: 2011-08-19
    Description: The correlation of N2O and ozone in the Antarctic stratosphere during the late austral winter was investigated using measurements of N2O mixing ratios obtained by an airborne laser spectrometer and in situ measurements of ozone for latitudes between 53 and 72 deg S. In addition, airborne N2O and O3 measurements taken between 13 and 20 km in the mid-latitudes (37 deg N and 53 deg S) were correlated. It was found that, while the mid-latitude ozone-N2O corelation was negative, poleward of 53 deg S, the N2O and O3 mixing ratios often showed a strong positive correlation, which approximately coincided with the edge of the polar vortex as defined by the wind-speed maximum. Inside the vortex, in lower wind speed regions, the N2O-O3 correlation became negative again, with the lowest ozone mixing ratios usually found near the boundary with the positively correlated region.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16749-16
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    Measurements of nitric oxide and total reactive nitrogen in the Antarctic stratosphere - Observations and chemical implications (1989)
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    Publication Date: 2011-08-19
    Description: Results are presented on measurements of NO and the sum of reactive nitrogen species, NO(y), which include NO, NO2, NO3, N2O5, HNO3, and ClONO2 (in addition to ClO, O3, H2O, and N2O measurements), obtained aboard the NASA ER-2 aircraft flying over the Antarctica between the latitudes of 53 and 72 deg S during the Airborne Antarctic Ozone Experiment. The boundary of the chemically perturbed region (CPR), as indicated by a sharp increase in the level of ClO, occurred near 66 deg S; outside or equatorward of the CPR, the NO(y) mixing ratios ranged between 6 and 12 ppbv, with values decreasing poleward and reaching total NO(y) levels of 4 ppbv or less within 5-deg poleward of the boundary. Data presented in this paper clearly associate the Antarctic ozone decrease with perturbed conditions of ClO, NO(y), and H2O, which are in turn associated with processes defined as nonstandard heterogeneous chemistry, denitrification, and dehydration, respectively.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16665-16
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    Airborne measurements of stratospheric constituents over Antarctica in the austral spring, 1987. II - Halogen and nitrogen trace gases (1989)
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    Publication Date: 2011-08-19
    Description: The IR absorption spectra of the polar stratosphere, recorded by a Fourier transform spectrometer aboard the NASA DC-8 aircraft during the Airborne Antarctic Ozone Experiment, were used to derive vertical column amounts above flight altitude of HCl, HF, NO, NO2, ClONO2, and HNO3 in the region of disturbed ozone chemistry during September 1987. Significant reductions in the amounts of HCl, NO, NO2, and HNO3 were observed within the confines of the polar vortex, compared with amounts outside the vortex. When compared with the springtime observations by the same instrument in the Northern Hemisphere, the HCl and NO2 species displayed the most dramatic depletions. The results obtained are generally in agreement with the earlier ground measurements conducted at the McMurdo Station.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16597-16
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    In situ ozone measurements within the 1987 Antarctic ozone hole from a high-altitude ER-2 aircraft (1989)
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    Publication Date: 2011-08-19
    Description: In situ ozone measurements were made from the ER-2 aircraft during the 1987 Airborne Antarctic Ozone Experiment both inside and outside the ozone hole. Midday measurements from late August until late September during aircraft ascent near 53 deg S latitude indicate no clear temporal trend in ozone mixing ratio but instead reflect the distance of the measurement from the chemically perturbed region. The measurements made within the ozone hole at 72 deg S show altitude-dependent decreases in ozone of 61 percent at a potential temperature of 425 K down to 39 percent at 365 K. Temporal trends are also calculated at various positions relative to the boundary of the chemically perturbed region to locate the region of large ozone decreases and thereby accurately locate the boundary of the ozone hole.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16547-16
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    Tropospheric ozone in the vicinity of the ozone hole - 1987 Airborne Antarctic Ozone Experiment (1989)
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    Publication Date: 2011-08-19
    Description: Results are presented on ozone measurements in the upper troposphere/lower stratosphere over Antarctica, obtained by NASA DC-8 aircraft during the August/September 1987 Airborne Antarctic Ozone Experiment. The ozone mixing ratios as high as several hundred ppbv were measured, but in all cases these ratios were observed in pockets of upper atmospheric air, both in the vicinity of and away from the location of the ozone hole. The background ozone values in the surrounding troposphere were typically in the range of 20-50 ppbv. Correlation of tropospheric ozone observations with the boundaries of the ozone hole differed in the course of the experiment. During the August 28 - September 2 flights, encounters with ozone-rich air were limited, and the background tropospheric ozone appeared to decrease beneath the hole. For the later flights, and as the ozone hole deepened, the ozone-rich air was frequently observed in the vicinity of the hole, and the average ozone values at the flight altitude were frequently higher than the background values.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16537-16
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  • 85
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    Calibration of the Forward Scattering Spectrometer Probe used on the ER-2 during the Airborne Antarctic Ozone Experiment (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The Particle Measuring Systems (PMS) Forwared Scattering Spectrometer Probe (FSSP-100) which was flown on the ER-2 during the Airborne Antarctic Ozone Experiment for the measurement of particles in polar stratospheric clouds has been evaluated and calibrated. The sample volume of the probe per 10-s sampling period increases from 257 cu cm for 1-micron particles to 412 for 15-micron particles, but there is substantial uncertainty in this value. Limitations in the measurements from this instrument and possible corrections are discussed. The uncertainty in the total particle mass measured by the probe may be as large as + or - 100 percent. Recommendations are given for the processing of data from the FSSP used in this project.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16475-16
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  • 86
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    Stratospheric nitrous oxide distribution in the Southern Hemisphere (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Nitrous oxide measurements were made in the Southern Hemisphere as part of the Airborne Antarctic Ozone Experiment in late winter and early spring 1987, covering the altitude range 14-21 km. This paper reports on N2O measurements made by the airborne tunable laser absorption spectrometer, which was flown onboard the NASA ER-2 aircraft. Average vertical N2O profiles at latitudes 72 deg S, 54 deg S, and 42 deg S are presented and compared, when possible, with equivalent summer profiles. Latitudinal gradients of N2O on isentropic surfaces are presented and discussed in terms of their implications about the inhibition of horizontal mixing near the polar vortex. Finally, a large-scale distribution of N2O for the region 72 deg S to 42 deg S latitude is presented.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16767-16
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  • 87
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    Nitrogen and chlorine species in the spring Antarctic stratosphere - Comparison of models with Airborne Antarctic Ozone Experiment observations (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The concentrations and the time development of chlorine and nitrogen trace gases in the Antarctic stratosphere before, during, and after the Airborne Antractic Ozone Experiment (AAOE) were simulated using photochemical models of the Antractic stratosphere during winter/spring. The initial conditions in the calculations were constrained using observations by the AAOE instrument. The comparison of calculated results with the AAOE measurements of HCl and ClO suggest that heterogeneous chemistry was maintained throughout the month of September 1987.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16683-16
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  • 88
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    Intercomparison of ozone measurements over Antarctica (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Measurements of the abundances of ozone over Antarctica in August and September 1987 obtained during the Airborne Antarctic Ozone Experiment are intercompared. These measurements of ozone concentrations and total column abundance were obtained by three satellite instruments, two IR and one UV column-measuring instruments aboard the DC-8, one in situ DC-8, and two in situ ER-2 instruments, an upward looking lidar aboard the DC-8, and ozone sondes from four sites in Antarctica. This paper presents a summary of the ozone data, using the data and accuracies given by the individual investigators in the individual papers in this issue, without any attempt to critically review or evaluate the data. In general, very good agreement (within about 10-20 percent, limited by natural variability) among the various techniques was found, with no systematic biases detected. These observations confirm the low ozone amounts reported in the Antarctic stratosphere.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16557-16
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  • 89
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    Ozone profile measurements of McMurdo Station, Antarctica, during the spring of 1987 (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Ozone and temperature profiles were measured in 50 balloon flights at McMurdo Station (78 deg S) during the spring of 1987. Compared to similar data obtained in 1986, stratospheric temperatures were lower and the spring time Antarctic ozone reduction was greater in magnitude, extended to higher altitude, and proceeded at a higher rate in 1987. Ozone partial pressures reached values as low as 3 nbar (as compared to about 10 nbar in 1986) in the 16- to 18-km region in early and late October, down from about 150 nbar in late August. These low values suggest essentially complete removal of ozone in this region. The upper boundary of the depletion region was observed to be 2-3 km higher than in 1986, extending to altitudes as high as 24 km in mid-September. When averaged over September, the ozone mixing ratio at 18 km decayed with a half-life of only 12.4 days, as compared to about 28 days in 1986. Adiabatic vertical motions over 1- to 2-km intervals between 12 and 20 km with consequent ozone reductions were observed in association with the formation of nacreous clouds, indicating these to be rare events on a local scale probably associated with mountain lee waves.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16527-16
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  • 90
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    Antarctic stratospheric ice crystals (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Ice crystals were replicated over the Palmer Peninsula at approximately 72 deg S on six occasions during the 1987 Airboirne Antarctic Ozone Experiment. The sampling altitude was between 12.5 and 18.5 km (45-65 thousand ft pressure altitude) with the temperature between 190 and 201 K. The atmosphere was subsaturated with respect to ice in all cases. The collected crystals were predominantly solid and hollow columns. The largest crystals were sampled at lower altitudes where the potential temperature was below 400 K. While the crystals were larger than anticipated, their low concentration results in a total surface area that is less than one tenth of the total aerosol surface area. The large ice crystals may play an important role in the observed stratospheric dehydration processes through sedimentation. Evidence of scavenging of submicron particles further suggests that the ice crystals may be effective in the removal of stratospheric chemicals.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 94; 16449-16
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  • 91
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    Ground-level detection of LF and MF high latitude terrestrial emissions (1989)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Two brief experimental campaigns have been conducted in Norway and in Alaska, using four commercial comunications receivers, to confirm the suspected existence of auroral phenomena-associated radio noise in the 100 kHz range. While the Alaskan experiment yielded signals attributable to auroral processes on nearly one-half of the nights monitored, the Norway data identified only one such event. A proposed geophysical observatory in Antarctica is noted to furnish an ideal platform for experiments of this type.
    Keywords: GEOPHYSICS
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  • 92
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    Development of fiber-based laser anemometer for SSME application (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A recent study by Rocketdyne for NASA identified laser anemometry, using a compact optical head, as a feasible diagnostic instrument for the Space Shuttle Main Engine (SSME) Model Verification experiments. Physical Research, Inc. (PRI) is presently under contract from NASA Lewis to develop and deliver such a laser anemometer system. For this application, it is desired to place the laser at a remote distance from the engine, and use single mode polarization preserving fiber optics for the transmission of the laser light to and from the measurement head. Other requirements are given. Analytical and experimental tools are being used to develop the technologies required for the laser anemometer. These include finite element analysis of the optical head and vibration tests for various optical and mechanical components. Design of the optical head and the fiber optic connectors are driven by the temperature and vibration requirements for the measurement environment. Results of the finite element analysis and the vibration tests of the components are included. Conceptual design of the fiber optic launcher and the optical probe has also been complete. Detailed design of the probe as well as the fabrication and assembly of the components is in progress.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Lewis Research Center, Structural Integrity and Durability of Reusable Space Propulsion Systems; p 105-112
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  • 93
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    On the relation between the electron content of the ionospheric D-region, variations of the riometer absorption, and the H-component of the geomagnetic field (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The correlation between lower ionosphere disturbances, geomagnetic variations and radiowave absorption is an important geophysical problem. The correlation is investigated between the electron density profile structure and riometer absorption, and between the absorption and the H-component magnetic field, in order to determine the relation between the (e)-profile parameters and the geomagnetic field variations.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 29. Part 1: Extended Abstracts, International Symposium on Solar Activity Forcing of the Middle Atmosphere. Part 2: MASH Workshop, Williamsburg, 1986; p 236-239
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  • 94
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    Influence of non-stationary field of magnetospheric convection on the D-region (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Perturbations of F region electron density caused by the extension of magnetospheric convection electric field to middle latitudes are already well known. For the D region of the first observations are believed to be reported by Eliseyev, Kashpar and Nikitin (1988). On several occasions, following the southward turning of the Bz-component of interplanetary magnetic field (IMF) small disturbances of the D region electron density were detected at night by steep-incidence VLF sounding, which may be attributed to the influence of the penetrated convection electric field (CEF). Some evidence is given of a local time dependence of the CEF effect in the D region and a rather good correlation is demonstrated at the initial stage of disturbance between high latitude magnetic field variations and simultaneous perturbation of the midlatitude ionospheric reflection height.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 29. Part 1: Extended Abstracts, International Symposium on Solar Activity Forcing of the Middle Atmosphere. Part 2: MASH Workshop, Williamsburg, 1986; p 240-244
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  • 95
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    The probability of SWF occurrence in relation to solar activity (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Solar terrestrial researches have revealed substantial meaning of nonsteady events on the Sun, mainly solar flares, for the processes taking place in ionosphere. Solar flares result in the numerous consequences, account and prediction of which become necessary in our days. It is well known, that ionospheric disturbances following solar flares cause strong disturbances in the ionosphere, which severely violate radio systems (communication, navigation, etc.). Possibilities of sudden short wave fadeouts (SWF) prediction are considered.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 29. Part 1: Extended Abstracts, International Symposium on Solar Activity Forcing of the Middle Atmosphere. Part 2: MASH Workshop, Williamsburg, 1986; p 219-222
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  • 96
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    Ionospheric effects of the extreme solar activity of February 1986 (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: During February 1986, near the minimum of the 11 year Solar sunspot cycle, after a long period of totally quiet solar activity (R sub z = 0 on most days in January) a period of a suddenly enhanced solar activity occurred in the minimum between solar cycles 21 and 22. Two proton flares were observed during this period. A few other flares, various phenomena accompanying proton flares, an extremely severe geomagnetic storm and strong disturbances in the Earth's ionosphere were observed in this period of enhanced solar activity. Two active regions appeared on the solar disc. The flares in both active regions were associated with enhancement of solar high energy proton flux which started on 4 February of 0900 UT. Associated with the flares, the magnetic storm with sudden commencement had its onset on 6 February 1312 UT and attained its maximum on 8 February (Kp = 9). The sudden enhancement in solar activity in February 1986 was accompanied by strong disturbances in the Earth's ionosphere, SIDs and ionospheric storm. These events and their effects on the ionosphere are discussed.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 29. Part 1: Extended Abstracts, International Symposium on Solar Activity Forcing of the Middle Atmosphere. Part 2: MASH Workshop, Williamsburg, 1986; p 231-235
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  • 97
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    Post-flare effects in the lower ionosphere of middle latitudes (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Beginning in the 1960s, records were made of noise from the region around the Polar Star on 29 MHz (Krivsky and Tlamicha, 1960) at the Ondrejov Observatory near Prague. Since the aerial characteristic was not too narrow, radio bursts were received of solar origin (of flares) at the noise level, SCNA effects (sudden cosmic noise absorption) at the time of intensive flare X-emission and in some rare cases, after large proton flares, small absorption effects of a few hours duration (Krivsky, 1969). These post-flare absorption effects in cosmic noise are evidently analogous with PCA effects (polar cap absorption) and are connected with ionospheric absorption of radio cosmic noise, caused by fast particles of subcosmic radiation. The recording of long term absorption effects after large particle flares at European midlatitudes was reported at the beginning of the 1960s. It was then usual to record radio cosmic noise with riometers at frequencies of about 18 MHz in the polar or subpolar regions in an effort to record PCA effects of subcosmic radiation (Hakura, 1968). An attempt was made to record the complex of emissions mentioned as well as the effects in a new frequency range (30 MHz), which did not agree with the ideas of the contemporaneous representatives of the Ionospheric Department of the Geophysical Institute in Prague. In recent years radio cosmic noise has been recorded at the Upice Observatory. These long term after flare effects of cosmic radio noise absorption (AF-CNA) at middle latitudes are reported to the geophysical and ionospheric community for the first time.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 29. Part 1: Extended Abstracts, International Symposium on Solar Activity Forcing of the Middle Atmosphere. Part 2: MASH Workshop, Williamsburg, 1986; p 223-226
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  • 98
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    Solar or meteorological control of lower ionospheric fluctuations (2-15 and 27 days) in middle latitudes (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Several types of short and long term effects of solar activity on the lower ionosphere are related to solar flares, the sector structure of the interplanetary magnetic field and some periodicities in sunspots or solar radio flux. The most evident periodicities of the Sun are the 11 year cycle of its activity and the differential rotation period near 27 days (25 to 30 days). Here, the following questions are discussed: which periods between 2 and 15 days and near 27 days occur in ionospheric absorption during the interval July 1980 to July 1985 and are these periods related to similar periods in solar Ly-alpha flux, geomagnetic activity, or neutral wind near 95 km observed in Collm (GDR). Day-time absorption data obtained by the A3 method was used for the following radio-paths: (164 kHz), (1539 kHz), (6090 kHz). With the use of these data the electron density variations in the lower ionosphere can be analyzed. An attempt was made to clarify the nature of the observed fluctuations in absorption.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 29. Part 1: Extended Abstracts, International Symposium on Solar Activity Forcing of the Middle Atmosphere. Part 2: MASH Workshop, Williamsburg, 1986; p 210-214
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  • 99
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    The 27-day versus 13.5-day variations in the solar Lyman-alpha radiation and the radio wave absorption in the lower ionosphere over Europe (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: In order to clarify the question of solar periods in absorption, the pattern was studied of the solar Lyman-alpha radiation (the principal ionizing agent of the lower ionosphere) and of the radio wave absorption at five widely spaced places in Europe. When the solar Lyman-alpha flux variability is very well developed, then it dominates in the lower ionospheric variability. The most pronounced Lyman-alpha variation on time scale day-month is the solar rotation variation (about 27 days). When the Lyman-alpha variability is developed rather poorly, as it is typical for periods dominated by the 13.5 day variability, then the lower ionospheric variability appears to be dominated by variations of meteorological origin. The conclusions hold for all five widely spaced placed in Europe.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 29. Part 1: Extended Abstracts, International Symposium on Solar Activity Forcing of the Middle Atmosphere. Part 2: MASH Workshop, Williamsburg, 1986; p 215-218
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  • 100
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    The influence of IMF on the lower ionosphere plasma in high and middle latitudes (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: As shown by ground-based absorption measurements, the lower ionospheric plasma is markedly controlled by the structure of the IMF. Whereas in high auroral and subauroral latitudes this effect is very pronounced, in midlatitudes its influence is less important. A comparison of these results with satellite data of the IMF and the solar wind speed confirms the important role of these components, not only during special events but also for the normal state of the ionospheric D region plasma.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 29. Part 1: Extended Abstracts, International Symposium on Solar Activity Forcing of the Middle Atmosphere. Part 2: MASH Workshop, Williamsburg, 1986; p 196-202
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