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  • GEOPHYSICS  (594)
  • 1980-1984  (594)
  • 1925-1929
  • 1983  (594)
  • 1
    Publication Date: 2011-08-18
    Description: NASA is proposing to launch a new geopotential fields exploration system called the Geopotential Research Mission (GRM). Two spacecraft will be placed in a circular polar orbit at 160 km altitude. Distances between these satellites will vary from 100 to 600 km. Both scalar and vector magnetic fields will be measured by magnetometers mounted on a boom positioned in the forward direction on the lead satellite. Gravity data will be computed from the measured change in distance between the two spacecraft. This quantity, called the range-rate, will be determined from the varying frequency (Doppler shift) between transmitter and receiver on each satellite. Expected accuracies (at the one-sigma level) are: gravity field, 1.0 milliGal, 5 cm geoid height; magnetics, scalar field 2 nT, vector to 20 arcsec, both resolved to less than 100 km. With these more accurate and higher resolution data, it will be possible to investigate the earth's structure from the crust (with the shorter wavelength gravity and magnetic anomalies) through the mantle (from the intermediate wavelength gravity field) and into the core (using the longer wavelength gravity and magnetic fields).
    Keywords: GEOPHYSICS
    Type: EOS (ISSN 0096-3941); 64; 609-611
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  • 2
    Publication Date: 2011-08-18
    Description: Samples of stratospheric trace gases were obtained on eight flights of NASA high-altitude aircraft from April 16 through December 13, 1982. The sampling occurred at altitudes from 15 to 22 km, latitudes from 23 to 52 deg N, and longitudes from 108 to 130 deg W. The cryogenically concentrated samples were analyzed by gas chromatography for SO2, a primary precursor of the gas-to-particle conversion process. The measured mixing ratio of SO2 varied between 8 and 132 pptv. Evidence from aerosol measurements indicates that a few of our early samples may have been collected in the fringes of the volcanic cloud from El Chichon. Samples obtained on some later flights may have been from the eruption cloud but were taken at times when most of the volcanically injected SO2 should have been converted to H2SO4.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; 1045-104
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  • 3
    Publication Date: 2011-08-18
    Description: Dominant effects of the El Chichon eruption on stratospheric aerosols at 19.8 to 20.7 km are: (1) vapor depositional growth of the small-aerosol (background) mode; (2) development of a large-particle mode by sedimentation from the highest altitudes in the cloud; (3) a change in the large-particle mode from sulfate-coated silicates to sulfate aerosols, some with silicate cores; (4) a 100-fold increase in sulfate mass in the large particle mode. Terminal velocities of large silicate particles, maximum r = 2.3 micron, sampled 1 month after eruption, and calibrated with the aid of lidar data, indicate initial injection to 26 to 27 km. Smaller velocities of sulfate aerosols, median r = 0.5 micron, are compatible with major growth in 2 to 3 months at 27 to 28 km. Aerosol settling accounts for the descent of the main lidar return to 26.5 km in August and to 20 to 21 km in December.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; 1021-102
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  • 4
    Publication Date: 2011-08-18
    Description: A series of calculations with a one-dimensional, time-marching, radiative-convective model are performed to assess the impact of the El Chichon volcanic cloud on the radiation budget of the northern tropics during the 6-month period following the injection of volcanic material into the stratosphere. Extensive measurement of the cloud obtained from airborne, spacecraft, and ground platforms were used to define the model parameters and to test the predictions of the model. The El Chichon cloud is predicted to have caused an increase in planetary albedo of 10 percent, a decrease in total solar radiation of 2-3 percent at the ground on cloudless days, and an increase in temperature of 3.5 K at the 24-km (30-mb) level. These predictions are compatible with relevant observations, within their respective error bars.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; 1057-106
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  • 5
    Publication Date: 2011-08-18
    Description: It is noted that the model presented here extends the previous description of neutral parameters to the base of the thermosphere in a continuous manner while maintaining the basic structure of the MSIS model at higher altitudes. As the altitude decreases, the composition approaches lower atmosphere values, whereas yearly, and to a lesser extent daily, variations in temperature and density are in reasonable agreement with earlier results for the lower thermosphere. An alternate description is given of magnetic storm variations on the basis of the three hour ap indices and an 8- to 10-hour exponential decay in thermospheric density and temperature response after a heating event. Additional coefficients are included for the time independent and magnetic activity terms, among them a longitudinally dependent seasonal magnetic activity effect. The description of molecular oxygen derives from mass spectrometer and EUV absorption measurements rather than ion chemistry.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 10170-10
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  • 6
    Publication Date: 2011-08-18
    Description: The response of Mobile VLBI design to error sources is addressed. The sensitivity of the hydrogen maser to variations in ambient temperature is discussed, with an example of drifts in the frequency system causing excursions in the time-delay observable exceeding + or - 200 cm. It is shown that baselines determined only from S-band data can contain errors in excess of 30 cm during periods of high ionospheric activity. The effect of the troposphere on baseline solutions is examined by comparing calibrations from the Water Vapor Radiometer (WVR) to those from a surface model. The apparent ability of the WVR to track relatively short-period fluctuations in water vapor is noted. Finally, consideration is given to the effects of source structure and the technique of monitoring closure of the time-delay observable around a closed figure of baselines.
    Keywords: GEOPHYSICS
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  • 7
    Publication Date: 2011-08-18
    Description: Balloon-borne measurements of condensation nuclei and H2SO4 molecules in large negative ion clusters have been made in the stratosphere at around 30 km altitude. The nuclei observed were in the 0.01-0.1 micron diameter range. Consideration was given to sunspot activity as a triggering event for ionization of upper atmospheric H2SO4 species and subsequent formation of the nuclei. A numerical model was defined for a steady state between the H2SO4 association and ion recombination in order to determine a critical nucleation rate. It is concluded that condensation nuclei are produced in ion nucleation in an H2SO4 supersaturated polar cloud chamber, with the process being initiated by solar flare particle ionization.
    Keywords: GEOPHYSICS
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  • 8
    Publication Date: 2011-08-18
    Description: The total O3 and the O3 mixing ratio at various pressure levels in the stratosphere measured from the Nimbus-4 BUV experiment over a 7-yr period (1970 to 1977) comprises a comprehensive data base available to study the possible effects of solar variability on stratospheric O3. It is shown that with the decrease in solar activity from 1970 to 1976, the globally averaged O3 inferred from Nimbus-4 data decreases from about 10 to 12 percent in the upper stratosphere to about 1 to 3 percent in the lower stratosphere. The systematic decrease in O3 seems to be correlated with the conventional indices of solar activity; however, it is difficult to account for the observed changes at various pressure levels with the current understanding of the photochemical models and the solar UV flux variations over a solar cycle.
    Keywords: GEOPHYSICS
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  • 9
    Publication Date: 2011-08-18
    Description: Excitation of the earth's ionosphere by delta function current sheets is considered, and the temporal and spatial evolution of wave packets is analyzed for a two-component collisional F2 layer. Approximations of an inverse Fourier-Laplace transform via saddle point methods provide plots of typical wave packets. These illustrate cold plasma wave theory and may be used as a diagnostic tool since it is possible to relate specific features, e.g., the frequency of a modulation envelope, to plasma parameters such as the electron cyclotron frequency. It is also possible to deduce the propagation path length and orientation of a remote radio beacon.
    Keywords: GEOPHYSICS
    Type: Radio Science (ISSN 0048-6604); 18; 1337-135
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  • 10
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    Publication Date: 2011-08-18
    Description: In this paper it is shown that the earth's rigid body (rb) motions can be represented by an analytical set of eigensolutions to the equation of motion for elastic-gravitational free oscillations. Thus each degree of freedom in the rb motion is associated with a rb normal mode. Cases of both nonrotating and rotating earth models are studied, and it is shown that the rb modes do incorporate neatly into the earth's system of normal modes of free oscillation. The excitation formula for the rb modes are also obtained, based on normal mode theory. Physical implications of the results are summarized and the fundamental differences between rb modes and seismic modes are emphasized. In particular, it is ascertained that the Chandler wobble, being one of the rb modes belonging to the rotating earth, can be studied using the established theory of normal modes.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 9437-944
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  • 11
    Publication Date: 2011-08-18
    Description: A bump-on-tail unstable reduced velocity distribution, constructed from data obtained at the upstream boundary of the electron foreshock by the GSFC electron spectrometer experiment on the ISEE-1 satellite, is used as the initial plasma state for a numerical integration of the 1D-Vlasov-Maxwell system of equations. The integration is carried through the growth of the instability, beyond its saturation, and well into the stabilized plasma regime. A power spectrum computed for the electric field of the stabilized plasma is dominated by a narrow peak at the Bohm-Gross frequency of the unstable field mode but also contains significant power at the harmonics of the Bohm-Gross frequency. The harmonic power is in sharp peaks which are split into closely spaced doublets. The fundamental peak at the Bohm-Gross frequency is split into a closely spaced triplet. The mechanism for excitation of the second harmonic is shown to be second order wave-wave coupling. Previously announced in STAR as N83-17315
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 9081-909
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  • 12
    Publication Date: 2011-08-18
    Description: Distinct medium scale disturbances in Southern Hemisphere total ozone were observed by the Nimbus 7 Total Ozone Mapping Spectrometer during the 1979 FGGE observing period. These disturbances are shown to be a result of advection by the zonal harmonic wave five which is centered near the tropopause (Salby, 1982). The contribution to the total ozone field by vertical advection due to this wave is shown to be nearly equal to that due to horizontal advection.
    Keywords: GEOPHYSICS
    Type: American Meteorological Society, Bulletin (ISSN 0003-0007); 64; 1358-136
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  • 13
    Publication Date: 2011-08-18
    Description: The Nd and Sr isotopic compositions presently reported for anorthosites and related rocks from the Grenville and Nain Provinces of the eastern Canadian shield indicate that the massifs were delivered from at least two distinct mantle source regions which were established before 1650 Myr ago. These regions were episodically involved in magmatism over about 500 Myr. One reservoir was isotopically similar to the depleted, modern midocean ridge basalt source. The other reservoir was chondritic-to-moderately-enriched, and is most easily identified in the Nain Province, but may have occurred scattered throughout Superior Province, as well.
    Keywords: GEOPHYSICS
    Type: Nature (ISSN 0028-0836); 306; 679
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  • 14
    Publication Date: 2011-08-18
    Description: The study of the distribution and isotopic composition of low molecular weight hydrocarbon gases at the Big Soda Lake, Nevada, has shown that while neither ethylene nor propylene were found in the lake, ethane, propane, isobutane and n-butane concentrations all increased with water column depth. It is concluded that methane has a biogenic origin in both the sediments and the anoxic water column, and that C2-C4 alkanes have biogenic origins in the monimolimnion water and shallow sediments. The changes observed in delta C-13/CH4/ and CH4/(C2H6 + C3H8) with depth in the water column and sedimeents are probably due to bacterial processes, which may include anaerobic methane oxidation and different rates of methanogenesis, and C2-to-C4 alkane production by microorganisms.
    Keywords: GEOPHYSICS
    Type: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 47; 2107-211
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  • 15
    Publication Date: 2011-08-18
    Description: The homogeneous set of 80-year-long (1900-1979) International Latitude Service (ILS) polar motion data is analyzed using the autoregressive method (Chao and Gilbert, 1980), which resolves and produces estimates for the complex frequency (or frequency and Q) and complex amplitude (or amplitude and phase) of each harmonic component in the data. The ILS data support the multiple-component hypothesis of the Chandler wobble. It is found that the Chandler wobble can be adequately modeled as a linear combination of four (coherent) harmonic components, each of which represents a steady, nearly circular, prograde motion. The four-component Chandler wobble model 'explains' the apparent phase reversal during 1920-1940 and the pre-1950 empirical period-amplitude relation. The annual wobble is shown to be rather stationary over the years both in amplitude and in phase, and no evidence is found to support the large variations reported by earlier investigations. The Markowitz wobble is found to be marginally retrograde and appears to have a complicated behavior which cannot be resolved because of the shortness of the data set.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 10299-10
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  • 16
    Publication Date: 2011-08-18
    Description: New interior samples of four Yamato polymict eucrites (Y74159, Y74450, Y75011, and Y75015) have been studied by electron microprobe, transmission electron microscope, and X-ray diffraction techniques, and compared with several samples of the Victoria Land polymict eucrites. These same samples have been analysed using Rb-Sr and Nd-Sm isotopic systematics. Several grains of inverted pigeonite, with blebby augite similar to those in Binda and Moama, have been identified in all four Yamato eucrites. Coarse-grained meso-stasis-rich subophitic basalts, which contain Mg-rich pigeonite (with Fe-rich olivine veinlets) zoned outward to a subcalcic ferroaugite rims, have also been found. These unique clasts were not found in ALH76005, 77302, 78040, 7858, and 78165 and EET eucrites. The tight grouping of Rb/Sr and Sm/Nd ratos, and similar modal compositions of the Yamato group indicate that they are most likely to be pieces from a single fall, and distinct from the ALH and EET groups. However, the Yamato, Allan Hills, and Elephant Moraine groups may sample a few distinct magmas or similar but different source regions on the same parent body.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research, Supplement (ISSN 0148-0227); 88; B245-B25
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  • 17
    Publication Date: 2011-08-18
    Description: The Satellite Emission Range Inferred Earth Surveying (SERIES) concept is based on the utilization of NAVSTAR Global Positioning System (GPS) radio transmissions without any satellite modifications and in a totally passive mode. The SERIES stations are equipped with lightweight 1.5 m diameter dish antennas mounted on trailers. A series baseline measurement accuracy demonstration is considered, taking into account a 100 meter baseline estimation from approximately one hour of differential Doppler data. It is planned to conduct the next phase of experiments on a 150 m baseline. Attention is given to details regarding future baseline measurement accuracy demonstrations, aspects of ionospheric calibration in connection with subdecimeter baseline accuracy requirements of geodesy, and advantages related to the use of the differential Doppler or pseudoranging mode.
    Keywords: GEOPHYSICS
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  • 18
    Publication Date: 2011-08-18
    Description: Model calculations describing stormtime variations in the earth's dayside plasmasphere are used to examine variations in ion composition. The model storm is initiated by high-latitude thermospheric heating that generates meridional winds that carry neutral species, momentum, and energy equatorward. The thermosphere acts on the plasmasphere through collisional transfer of momentum and through chemical reactions between neutral species and ions. Over latitudes near the region of thermospheric heating, the thermosphere-plasmasphere coupling processes cause enhancement in the density of oxygen ions while protons are being lost. Meanwhile, densities of oxygen ions and protons near the equator are increasing together, almost in phase. The largest enhancements in ion density develop at latitudes near 45 deg invariant for both oxygen and hydrogen.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 10233-10
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  • 19
    Publication Date: 2011-08-18
    Description: A time-dependent box model of the lower troposphere which includes a description of photochemical and physical processes has been developed. This model has been applied to the calculation of nitric acid and NO(x)(NO + NO2) concentrations over a diurnal cycle which includes precipitation. Nitric acid concentrations and the HNO3/NO(x) ratio are found to be highly variable under the assumptions regarding the frequency, duration, and intensity of precipitation employed in this model. The chemistry of odd nitrogen compounds during the night is potentially important in establishing the level of nitric acid in the lower troposphere. These calculations also indicate that relatively large errors may occur when the continuity equation describing nitric acid variations is averaged over a diurnal cycle which includes precipitation. Interpretation of simultaneous measurements of HNO3 and NO(x) will require some knowledge of the history of the observed air mass and may require an improved understanding of nighttime odd nitrogen chemistry.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 10697-10
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  • 20
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    Publication Date: 2011-08-18
    Description: Data from the LIMS instrument for January 1979 are used to provide further evidence for the often observed vacillation between the amplitudes of waves 1 and 2 in the stratosphere. The vacillation is shown to result primarily from nonlinear wave-wave interactions within the stratosphere. Two ways of interpreting nonlinearity are discussed. In the first, the basic state is defined to include large amplitude waves as well as the mean zonal wind. A forced wave propagates with respect to this asymmetric basic state, which can lead to changes in the conventional zonal wavenumber measured at one latitude. The other view of nonlinearity, interaction of wave with the zonal flow and with other wavenumbers are considered separately. Wave-wave interactions among waves 1, 2 and 3 are calculated. The derivation and computation of wave-wave interaction terms in the potential enstrophy balance are given. The observations indicate that enstrophy transfer among waves can be substantial even when the amplitude of one of the contributing waves is small. The computed enstrophy balance also demonstrates that wave-wave interactions can have a large effect on the interaction of waves with the mean flow.
    Keywords: GEOPHYSICS
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; 2484-249
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  • 21
    Publication Date: 2011-08-18
    Description: The technique of nonlinear least squares spectral curve fitting has been used to derive the stratospheric vertical temperature profile from balloon-borne measurements of the 10.4 micron band of CO2. The spectral data were obtained at sunset with the approximately 0.02 per cm resolution University of Denver interferometer system from a float altitude of 33.5 km near Alamogordo, New Mexico, on 23 March 1981. The r.m.s. deviation between the retrieved temperature profile and correlative radiosonde measurements is 2.2 K.
    Keywords: GEOPHYSICS
    Type: Journal of Quantitative Spectroscopy and Radiative Transfer (ISSN 0022-4073); 30; 327-334
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  • 22
    Publication Date: 2011-08-18
    Description: Large convective electric fields of the order of 10 mV/m (sometimes as high as 22 mV/m) are observed at rotational magnetopause discontinuities. These observations were made with the long cylindrical (179-m base line) probes carried on the ISEE 1 satellite. These electric field observations yield convective velocity magnitudes (equal to the cross product of the vector E and the vector B, the latter divided by the square of the magnitude of B) of the order of 150 km/s. In this format for the convective velocity magnitudes, some of these observations are similar to the high speed plasma velocity observations that were made at the magnetopause with the plasma experiment carried on the ISEE 1 satellite. It is shown that, for many of these magnetopause crossings, there exists a special moving coordinate system where the observed electric fields vanish. Such a unique reference system is often used in theoretical studies of magnetic discontinuities. This special coordinate system does not move at the local plasma velocity but moves instead at a velocity intermediate between the convective velocity and the local Alfven velocity. It is used here as a diagnostic tool for the experimental investigation of rotational discontinuities at the magnetopause.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 10000-10
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  • 23
    Publication Date: 2011-08-19
    Description: Various lines of evidence point to the lower crust as the source of the long-wavelength magnetic anomaly field measured by the POGO and Magsat satellites. Using seismically determined lower crust thicknesses and equivalent source inversion of the satellite anomaly data, magnetization for the lower crust for much of the United States has been calculated. The average magnetization for two hundred sixty-six 150 x 150 km areas is 3.5 A/m with a standard deviation of 1.1 A/m. These values are consistent with laboratory measurements of mafic-ultramafic rocks expected in the lower crust, and in agreement with previous estimates of lower crust magnetization based on long-wavelength aeromagnetic data. Average lower crust thickness for the same areas is 18.2 km (sigma = 6.4). Thus, over large regions, it appears that variation in magnetization and variation in magnetic layer thickness contribute almost equally in causing the anomaly field variation at satellite altitude.
    Keywords: GEOPHYSICS
    Type: Tectonophysics (ISSN 0040-1951); 93; 33-45
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  • 24
    Publication Date: 2011-08-19
    Description: Great advances with respect to the study of the earth's magnetosphere could be achieved in connection with the launch of the Dynamics Explorer (DE) 1 and 2 spacecraft. These advances were made possible partly because of the unique combination of coplanar orbits which simultaneously sample the low altitude ionospheric and atmospheric signature (DE-2) and the high altitude phenomena of the inner magnetosphere (DE-1). It was, thus, feasible to obtain new measurements of the coupling of plasmas and fields between these fundamentally important regions. One basic element of the coupling involves the interchange of low energy plasma between the ionosphere and magnetosphere. The flow characteristics of the low energy plasma are indicators of the magnetospheric and ionospheric electric fields which drive the current system. The Retarding Ion Mass Spectrometer (RIMS) instrument has been designed for conducting measurements regarding this plasma population. Attention is given to details regarding RIMS, an example RIMS orbit, plasma trough characteristics, and polar cap phenomena.
    Keywords: GEOPHYSICS
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  • 25
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    Publication Date: 2011-08-18
    Description: The NASA Crustal Dynamics Project has developed very-long baseline interferometer (VLBI) systems and satellite laser ranging (SLR) systems for geodynamics measurements. In VLBI, a radio noise signal from a distant quasar is received by two or more radio antennas and coherently recorded. These recordings are cross-correlated to determine the relative signal delays between stations which are used to derive the vector baselines between the stations. The SLR systems accurately determine the range to a retroreflector satellite as a function of time with short laser pulses. These range measurements from several stations to the same satellite are used in orbit analysis programs to determine the position of the stations and the vector baselines between the stations. Measurements with these systems have achieved precisions of a few centimeters in length for distances of several thousand km. These systems are now operating in a global network for measuring the relative motion of the N. American, Pacific, S. American, Nazca, Eurasian and Australian tectonic plates. Highly mobile VLBI and SLR systems are being operated at many sites in the active earthquake areas in western N. America in order to determine the crustal deformation and strain accumulation.
    Keywords: GEOPHYSICS
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  • 26
    Publication Date: 2011-08-18
    Description: A theoretical model of the opening of the Cayman Trough is developed on the basis of geological evidence from a wide area. It is proposed that strike slip motion began about 30 Myr ago and proceeded at a rate of 37 + or - 6 mm/yr for a total of 1100 km of relative plate displacement, and that Central America Underwent an anticlockwise rotation with internal plate deformation. Maps of the reconstructed motion are provided.
    Keywords: GEOPHYSICS
    Type: Tectonics (ISSN 0278-7407); 2; 633-643
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  • 27
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    Publication Date: 2011-08-18
    Description: After outlining the constituent parts of the magnetospheric system, a historical review is presented of studies of the earth's magnetic field. It is noted that a connection between the aurora and variations in the magnetic field was first suggested by Halley in 1716. In discussing the magnetosphere, it is pointed out that the geomagnetic field can be thought of as being produced by a huge bar magnet embedded in the earth, with the axis of the magnet tilted away slightly from the earth's rotational axis. Attention is also given to the interplanetary magnetic field, to the relationship between the interplanetary magnetic field and the geomagnetic field, to convective flow, to field-aligned currents, and to Birkeland currents and auroral emissions. Various questions concerning the Birkeland currents are summarized.
    Keywords: GEOPHYSICS
    Type: Johns Hopkins APL Technical Digest (ISSN 0270-5214); 4; 276-284
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  • 28
    Publication Date: 2011-08-18
    Description: Electron beam experiments using rocket-borne instrumentation confirmed earlier observations of fast magnetospheric echoes of artificially injected energetic electrons. A total of 234 echoes were observed in a pitch angle range from 9 to 110 deg at energies of 1.87 and 3.90 keV. Of these, 102 echoes could unambiguously be identified with known accelerator operations at 2, 4 or 8 keV energy and highest current levels resulting in the determination of transit times of typically 300 to 400 ms. In most cases, when echoes were present in both energy channels, the higher energy electrons led the lower energy ones by 50 to 70 ms. Adiabatic theory applied to these observations yields a reflection height of 3000 to 4000 km. The injection process is discussed as the strong beam-plasma interaction that occurred near the electron accelerator appears to be instrumental in generating the source of heated electrons required for successful echo detection.
    Keywords: GEOPHYSICS
    Type: ESA Active Expts. in Space; p 113-120
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  • 29
    Publication Date: 2011-08-18
    Description: The calibration standards used in the Atmospheric Lifetime Experiment (ALE) for CFCl3, CF2Cl2, CH3CCl3, and CCl4 are described. This includes the preparation of the primary standards by static dilution and their propagation and stability for the period 1977-1982. Two independent assessments of the absolute concentrations of the primary standards used to initiate the ALE measurements in 1977-1978 are reported. For consistency in the ALE program the values assigned to the primary standards and subsequent working standards used in the field were not altered during the experiment when results of better estimates of the original concentration values were obtained. Rather, the appropriate factors by which the ALE mixing ratios for a given species should be multiplied to obtain the best estimate of the current concentration of a given species, are provided.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Oct. 20
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  • 30
    Publication Date: 2011-08-18
    Description: Computer simulations have been performed to determine the geographical and temporal coverage of various satellite orbits and scanning and nonscanning radiometers for earth radiation budget measurements. These results were used to simulate the sampling of a diurnally varying cloud and radiation field for several different satellite systems to estimate errors in regional monthly mean reflected radiation. The combined results indicate that coincient observations with a minimum of one sun-synchronous satellite and a midinclined orbit satellite are needed to obtain the required regional, zonal, and global coverage with sufficient temporal sampling for obtaining accurate estimates of monthly mean reflected solar radiation. Overall, the best sampling capability and lowest errors were obtained with a three-satellite system, i.e., two sun-synchronous satellites with different equatorial crossing times combined with either a 46 or 57-deg orbit satellite. The results from these analyses have been used in defining a joint NASA-NOAA multisatellite mission for an earth radiation budget experiment.
    Keywords: GEOPHYSICS
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4560); 20; Sept
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  • 31
    Publication Date: 2011-08-18
    Description: Initial results of studies of low-energy plasma using the light ion mass spectrometer (LIMS) on the SCATHA satellite are presented. Results are discussed primarily for plasma flux in the noon to midnight local time sector, examining the behavior of the plasma with geomagnetic activity and local time. Measurements of the ion mass composition in this region for the energy ranges of the LIMS instrument are presented. Results of temperature measurements are given and a possible explanation for the difference between the whistler and OGO 5 plasmapause positions is suggested. The observed pitch angle distributions are presented, limited to a broad characterization of the plasma population. The effects of the spacecraft potential on the low-energy plasma measurements are considered.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Oct. 1
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  • 32
    Publication Date: 2011-08-18
    Description: Sun photometer and lidar backscatter measurements of the El Chichon volcanic cloud were obtained during an airborne latitude survey. The observations were collected between 46 deg N and 46 deg S from Oct. 19-Nov. 7, 1982. Comparisons between these data sets have been performed. An aerosol optical model was developed for the conversion of the lidar measurements to optical thickness values using numerical aerosol size distribution data and index of refraction information collected with coordinated dustsonde balloon flights. The derived lidar optical thickness values were found to agree with the sun photometer optical thickness values within measurement uncertainties. The lidar derived values ranged from 0.16 at the equator to 0.03 at 30 deg S latitude. Peak values were concentrated between 35 deg N and 10 deg S.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; Sept
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  • 33
    Publication Date: 2011-08-18
    Description: Sun photometer measurements of the spectral optical thickness of the El Chichon eruption cloud were obtained during an airborne latitudinal survey. The measured optical thicknesses were greatly enhanced over background levels for the stratosphere. The observations covered 44 deg N to 36 deg S, and increased optical thickness was found at all latitudes where measurements were made. Significant variations in the magnitude and spectral dependence of the optical thickness were found within the latitude range covered by the observations. The maximum optical thickness was found at 20 deg N and the minimum was found at 30 deg S. The optical thickness values ranged between 0.13 and 0.017 at 870 nm and between 0.15 and 0.044 at 440 nm.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; Sept
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  • 34
    Publication Date: 2011-08-18
    Description: The eruptions of El Chicon in Mexico during March and April, 1982, produced the largest enhancements in stratospheric aerosols, which were experienced in at least the last 20 years. An experimental survey flight was conducted in October-November 1982 to underfly El Chichon's eruption cloud and to map out its latitudinal distribution. A NASA aircraft was flown between 46 deg N latitude and 46 deg S latitude in a coordinated field campaign. The present investigation is concerned with the results of lidar stratospheric measurements taken over the entire mission. The employed airborne lidar system consists of a ruby laser, nominally emitting 1 joule/pulse at 0.5 pulse/sec during flight, and a 35.6-cm receiving Cassegrainian-configured telescope. The lidar data presented are described in two forms, taking into account the lidar backscattering ratio and the integrated aerosol backscattering function.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; Sept
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  • 35
    Publication Date: 2011-08-18
    Description: A quasi-continuous record of atmospheric attenuation is obtained. The data were gathered during a 24-day period in September and October 1982 and a 10-day period in December of that year. The opacity is arrived at by measuring the thermal emission of the atmosphere over a bandwidth of approximately 300 MHz. Using an experimental relationship established by Zammit and Ade (1981), opacity measurements at 1.1 mm are converted to the precipitable water vapor column overhead. With the precipitable water vapor, estimates of opacity due to water vapor can be made for other mm and FIR wavelengths. These estimates require model absorption curves for the atmosphere.
    Keywords: GEOPHYSICS
    Type: International Journal of Infrared and Millimeter Waves (ISSN 0195-9271); 4; Sept
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  • 36
    Publication Date: 2011-08-18
    Description: Lead isotope data on whole-rock samples and two feldspar separates for a variety of Pan-African (late Precambrian) igneous rocks for the Egyptian Shield are presented. It is pointed out that the eastern desert of Egypt is a Late Precambrian shield characterized by the widespread occurrence of granitic plutons. The lead isotope ratios may be used to delineate boundaries between Late Precambrian oceanic and continental environments in northeastern Africa. The samples belong to three groups. These groups are related to a younger plutonic sequence of granites and adamellites, a plutonic group consisting of older tonalites to granodiorites, and the Dokhan volcanic suite.
    Keywords: GEOPHYSICS
    Type: Precambrian Research (ISSN 0301-9268); 20; 1983
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  • 37
    Publication Date: 2011-08-18
    Description: The precise amount of O2 and O3 in the earth's prebiological paleoatmosphere has been a topic of considerable discussion in the past. Since the photolysis of H2O and CO2, the prebiological mechanisms to produce O2, depends on the ultraviolet flux from the Sun, a reliable quantification of the problem requires detailed knowledge of such flux. Using the most recent astronomical observation of young stars from the International Ultraviolet Explorer, as well as a detailed photochemical model of the paleoatmosphere, it is found that the amount of O2 in the prebiological paleoatmosphere may have been as much as a million times greater than previously estimated. Some of the implications of this new value are discussed.
    Keywords: GEOPHYSICS
    Type: Precambrian Research (ISSN 0301-9268); 20; 1983
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  • 38
    Publication Date: 2011-08-18
    Description: The optical properties of suspended dust particles from the eruption of Mt. St. Helens on July 23, 1980 are investigated using photoelectric observations of standard stars obtained on the 0.76-m telescope at the University of Washington 48 hours after the eruption. Measurements were made with five broad-band filters centered at 3910, 5085, 5480, 6330, and 8050 A on stars of varying color and over a wide range of air masses. Anomalous extinction effects due to the volcanic ash were detected, and a significant change in the wavelength-dependent extinction parameter during the course of the observations was established by statistical analysis. Mean particle size (a) and column density (N) are estimated using the Mie theory, assuming a log-normal particle-size distribution: a = 0.18 micron throughout; N = 1.02 x 10 to the 9th/sq cm before 7:00 UT and 2.33 x 10 to the 9th/sq cm after 8:30 UT on July 25, 1980. The extinction is attributed to low-level, slowly migrating ash, possibly combined with products of gas-to-particle conversion and coagulation.
    Keywords: GEOPHYSICS
    Type: Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 95; July 198
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  • 39
    Publication Date: 2011-08-18
    Description: Data on species of interest in the photochemistry of the ozone layer obtained from balloon flights are presented. The flights made use of remote-sensing instruments that took measurements in the wavelength region from the ultraviolet to millimeter wavelengths. Most of the data were obtained with instruments whose readings were in the midinfrared wavelengths. Descriptions are given of the two techniques generally used in this type of research, namely solar absorption and atmospheric emission. The promise that these techniques hold for providing data on the photochemistry of the ozone layer is discussed.
    Keywords: GEOPHYSICS
    Type: Applied Optics (ISSN 0003-6935); 22; Sept. 1
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  • 40
    Publication Date: 2011-08-18
    Description: A method is developed for directly measuring atmospheric winds in the 20-120 km altitude interval from a spacecraft. The wind sensor measures the Doppler shift between the spectral absorption lines of a gas in a cell within the instrument and the thermal emission lines of the same gas in the atmosphere. The wind measurements are performed using a spacecraft-borne gas correlation spectrometer viewing the limb of the atmosphere. The wind-induced Doppler shift between the two spectra, and thus the magnitude of the wind itself, is obtained by phase modulating the incoming thermal radiation (equivalent to frequency modulation) by means of an electrooptically active crystal to determine the frequency shift required to reestablish exact correlation between the lines in the cell and the lines from the atmosphere. Results of numerical simulations of the wind-sensor performance indicate that the noise-equivalent-wind is between 1-5 m/s over most of the stratosphere and mesosphere.
    Keywords: GEOPHYSICS
    Type: Applied Optics (ISSN 0003-6935); 22; Sept. 1
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  • 41
    Publication Date: 2011-08-18
    Description: The temperature variations of the neutral gas in the thermosphere are considered as a function of local time and season, taking into account the latitude range from -17.5 deg to +17.5 deg and the altitude range from about 250 km to about 400 km. The temperature measurements were conducted in situ with the Neutral Atmospheric Temperature Experiment (NATE) on the Atmospheric Explorer E (AE-E) spacecraft during the time between December 1976 and January 1979. The altitude of the circular orbit of the spacecraft was gradually increased during this period from 250 to 400 km. A significant result of the reported analysis is the latitudinal (seasonal) variation observed in the semidiurnal and terdiurnal tides during solstice. It is found that this variation is responsible for the seasonal behavior of the midnight temperature maximum.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Sept. 1
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  • 42
    Publication Date: 2011-08-18
    Description: Attention is given to isotropic distribution, bidirectional field alignment distribution, unidirectional field alignment distribution, and low flux, in a statistical examination of low energy ion data from the ISEE 1 plasma composition experiment whose aim was the study of pitch angle distributions in all local times of the magnetosphere. The isotropic distribution consisting of less than 10 eV ions is a persistent inner region feature, while the bidirectional field-aligned distribution consisting of warm ions is a persistent feature of the outer dayside and is seen just outside the isotropic distribution region of the nightside. On the outer nightside, the unidirectional field-aligned distribution consisting of warm ions is the dominant signature. The 'sources' of ions in various regions are discussed in view of the present and other results.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Sept. 1
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  • 43
    Publication Date: 2011-08-18
    Description: Using the recently completed JTLA absolute gravity meter, we made a survey of twelve sites in the United States. Over a period of eight weeks, the instrument was driven a total distance of nearly 20,000 km to sites in California, New Mexico, Colorado, Wyoming, Maryland and Massachusetts. The time spent in carrying out a measurement at a single location was typically one day. We report the results of the measurements in this survey along with earlier measurements made with the instrument, discuss the measurement accuracy and compare our results with other measurements. Previously announced in STAR as N83-20480
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Sept. 10
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  • 44
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    Publication Date: 2011-08-18
    Description: Previously reported measurements of stratospheric ClO using a balloon-borne laser heterodyne radiometer, launched from Palestine, Texas, are re-evaluated as a result of recent spectroscopic data. A spectral feature which was observed during September, 1978 and November, 1979 flights was incorrectly identified as a ClO absorption line, while a second feature observed during the latter flight with somewhat limited sensitivity is now believed to be due to ClO. This new interpretation results in a measured ClO profile which falls off more rapidly with decreasing altitude than the previous results indicated.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; Aug. 198
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  • 45
    Publication Date: 2011-08-18
    Description: An analysis is undertaken of the properties of a one-level seasonal energy balance climate model having explicit, two-dimensional land-sea geography, where land and sea surfaces are strictly distinguished by the local thermal inertia employed and transport is governed by a smooth, latitude-dependent diffusion mechanism. Solutions of the seasonal cycle for the cases of both ice feedback exclusion and inclusion yield good agreements with real data, using minimal turning of the adjustable parameters. Discontinuous icecap growth is noted for both a solar constant that is lower by a few percent and a change of orbital elements to favor cool Northern Hemisphere summers. This discontinuous sensitivity is discussed in the context of the Milankovitch theory of the ice ages, and the associated branch structure is shown to be analogous to the 'small ice cap' instability of simpler models.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Aug. 20
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  • 46
    Publication Date: 2011-08-18
    Keywords: GEOPHYSICS
    Type: Geological Society of America Bulletin (ISSN 0016-7606); 94; Feb. 198
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  • 47
    Publication Date: 2011-08-18
    Description: The goal of the study is to calculate numerically the deceleration and heating caused by breaking gravity waves. The effect of the radiative dissipation of the wave is included as vertical-wavelength-dependent Newtonian cooling. The parameterization for zonal deceleration is extended by breaking gravity waves (Lindzen, 1981) to include the turbulent diffusion of heat and momentum. After describing the numerical model, the numerical results are presented and compared with the parameterizations in a noninteractive model of the mean zonal wind. Attention is then given to the transport of constituents by gravity waves and the attendant turbulent zone. It is noted that if gravity wave breaking were not an intermittent process, gravity wave stresses would produce an adiabatic mesosphere with a zonal mean velocity close to the phase speed of the breaking wave.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; June 20
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  • 48
    Publication Date: 2011-08-18
    Description: The present examination of the linear Vlasov stability of a class of electron velocity distributions modeling those observed within the earth's bow shock is restricted to electrostatic waves propagating parallel to the ambient magnetic field B. Two instabilities are identified as driven by free energy in the direction parallel to B: an ion acoustic wave with real frequency below the ion plasma frequency, and an electron acoustic wave whose real frequency is several times the ion plasma frequency. Unstable wave characteristics are in accord with the trend of the observed electrostatic waves toward polarization parallel to the magnetic field. The instabilities identified may contribute to electron dissipation in collisionless shocks.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 88; Apr. 1
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  • 49
    Publication Date: 2011-08-18
    Description: (Previously cited in issue 08, p. 1248, Accession no. A82-22043)
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  • 50
    Publication Date: 2011-08-18
    Description: Analytical solutions to the refraction integrals appropriate for ray trajectories along slant paths through the atmosphere are derived in this paper. This type of geometry is commonly encountered in remote-sensing applications utilizing an occultation technique. The solutions are obtained by evaluating higher-order terms from expansion of the refraction integral and are dependent on the vertical temperature distributions. Refraction parameters such as total refraction angles, air masses, and path lengths can be accurately computed. It is also shown that the method can be used for computing refraction parameters in astronomical refraction geometry for large zenith angles.
    Keywords: GEOPHYSICS
    Type: Applied Optics; 22; Mar. 1
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  • 51
    Publication Date: 2011-08-18
    Description: The possible contribution by natural hydrocarbon emissions to the total ozone budget recorded in the Tidewater region of southeastern Virginia during the height of the summer period was examined. Natural sources investigated were limited to the primary HC emitters and most prevalent natural vegetation, the forests. Three types and their areal coverage were determined for Region VI of the Virginia State Air Pollution Control Board using remotely sensed data from Landsat, a NASA experimental earth resources satellite. Emission factors appropriate to the specific types (coniferous 0.24 x 10 to the 13th, mixed 0.63 x 10 to the 13th, deciduous 1.92 x 10 to the 13th, microgram/h), derived from contemporary procedures, were applied to produce an overall regional emission rate of 2.79 x 10 to the 13th microgram/h for natural non-methane hydrocarbons (NMHC). This rate was used with estimates of the anthropogenic NO(x) and NMHC loading, as input into a photochemical box model. Additional HC loading on the order of that estimated to be produced by the natural forest communities was required in order to reach certain measured summer peak ozone levels as the computer simulation was unable to account for the measured episodic levels on the basis of the anthropogenic inventory alone.
    Keywords: GEOPHYSICS
    Type: Air Pollution Control Association; vol. 33
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  • 52
    Publication Date: 2011-08-18
    Description: Magnetic field measurements from the first two passes of the ISEE-3 GEOTAIL Mission have been used to study the structure of the trans-lunar tail. Good agreement was found between the ISEE-3 magnetopause crossings and the Explorer 33, 35 model of Howe and Binsack (1972). Neutral sheet location was well ordered by the hinged current sheet models based upon near earth measurements. Between X = -20 and -120 earth radii the radius of the tail increases by about 30 percent while the lobe field strength decreases by approximately 60 percent. Beyond X = -100 to -1200 earth radii the tail diameter and lobe field magnitude become nearly constant at terminal values of approximately 60 earth radii and 9 nT, respectively. The distance at which the tail was observed to cease flaring, 100-120 earth radii, is in close agreement with the predictions of the analytic tail model of Coroniti and Kennel (1972). Overall, the findings of this study suggest that the magnetotail retains much of its near earth structure out to X = -220 earth radii.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; Oct. 198
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  • 53
    Publication Date: 2011-08-18
    Description: Nimbus 7 LIMS data and a photochemical model are used to show that the observed sharp latitudinal gradients in stratospheric wintertime NO2 are consistent with the conversion of NO2 to N2O5 at high latitudes. This conversion, and the sharp gradients, are brought about by the interaction between transport and photochemistry. Calculated variations show good agreement with observations.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; Oct. 198
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  • 54
    Publication Date: 2011-08-18
    Description: Measurements of atmospheric ozone and water vapor profiles obtained using a differential absorption lidar (DIAL) technique at Haute Provence Observatory are reported. The DIAL technique is based on the comparison of differences in attenuation in backscattered signals at wavelengths centered on strong absorptions or absorption lines of the species in question, and wavelengths corresponding to weaker or no absorption. The system in use is based on three lasers - a Nd:YAG Q-switched laser frequency doubled to emit at 532 nm, and two tunable narrowline dye lasers used to convert this emission into the IR or UV spectral regions. Ozone concentration profiles have been recorded up to a height of 30 km, and reveal large day-to-day variations in number density which were correlated with a decrease in tropopause height. Measurements of water vapor concentrations show a variability of the mixing ratio at heights up to 2.5 km representative of dynamic processes, and a variability above 2.5 km that is within the measurement error. Day-to-day variations in tropospheric mixing ratio were also observed.
    Keywords: GEOPHYSICS
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  • 55
    Publication Date: 2011-08-18
    Description: In connection with the eccentricity of the earth's orbit, conditions of solar radiation are not strictly symmetrical for the two hemispheres. The intensity of solar irradiation is approximately 6.6 percent higher near perihelion than near aphelion. As the ozone densities in the upper stratosphere and mesosphere are mainly controlled by photochemical processes, the asymmetry of irradiation conditions for both hemispheres could result in corresponding asymmetries regarding the ozone content. The present investigation is concerned with this possibility. The investigation takes into account Nimbus-7 and Nimbus-4 satellite data. It is found that the hemispheric asymmetries of the ozone distribution in the summer mesosphere and upper stratosphere are fully ascribable to the hemispheric temperature differences due to the combined effects of the earth's orbital ellipticity and its tilted spin axis from the ecliptic plane. The wintertime hemispheric asymmetries imply the presence of additional effects.
    Keywords: GEOPHYSICS
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; May 1983
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  • 56
    Publication Date: 2011-08-18
    Description: Ozone transport is calculated for steady, dissipative planetary waves using the Eulerian, Lagrangian mean, and residual circulation. A Lagrangian model of parcel dynamics is used to interpret planetary wave-photochemistry interaction. In chemically active regions the mean field ozone changes are found to be significant only where there are large gradients in chemical sources and sinks along parcel trajectories. The largest changes in the mean field are found in the lower stratosphere and are due to the Lagrangian mean advection. When the Lagrangian mean advection is approximated by the residual circulation, errors in the transport velocities as large as 30 pct may occur.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; June 20
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  • 57
    Publication Date: 2011-08-18
    Description: The eruptions of El Chichon volcano on March 28 and April 3 and 4, 1982 were observed by the Nimbus 7 total ozone mapping spectrometer due to strong absorption by volcanic gases at the shortest wavelengths of the spectrometer (312.5 and 317.5 nm). These ultraviolet pictures permit a measurement of the volume, dispersion, and drift of volcanic gas clouds. The tropospheric clouds were rapidly dispersed in westerly winds while persistent stratospheric clouds drifted in easterly winds at speeds up to 13 m/sec. The spectral reflectance is consistent with sulfur dioxide absorption and rules out carbon disulfide as a major constituent. A preliminary estimate of the mass of sulfur dioxide deposited in the stratosphere by the large eruptions on April 3 and 4 is 3.3 million tons. Prior estimates of volcanic cloud volume were based on extrapolation of locally measured sulfur dioxide concentrations.
    Keywords: GEOPHYSICS
    Type: Science (ISSN 0036-8075); 220; June 24
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  • 58
    Publication Date: 2011-08-18
    Description: Ionospheric and field-aligned sheet current density distributions are presently inferred by means of MAGSAT vector magnetometer data, together with an accurate magnetic field model. By comparing Hall current densities inferred from the MAGSAT data and those inferred from simultaneously recorded ground based data acquired by the Scandinavian magnetometer array, it is determined that the former have previously been underestimated due to high damping of magnetic variations with high spatial wave numbers between the ionosphere and the MAGSAT orbit. Among important results of this study is noted the fact that the Birkeland and electrojet current systems are colocated. The analyses have shown a tendency for triangular rather than constant electrojet current distributions as a function of latitude, consistent with the statistical, uniform regions 1 and 2 Birkeland current patterns.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; June 1
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  • 59
    Publication Date: 2011-08-18
    Description: Magnetospheric electrons precipitated by ground-based coded very low frequency radio transmissions have been detected by rocket measurement of bremsstrahlung X-rays, caused by impact of the electrons with the upper atmosphere. The direct correlations obtained between the very low frequency signals and the X-rays demonstrate the limits of sensitivity required and indicate that this remote sensing technique would be useful for future study of very low frequency effects induced by single lightning strokes.
    Keywords: GEOPHYSICS
    Type: Science; 219; Mar. 18
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  • 60
    Publication Date: 2011-08-18
    Description: A new algorithm has been developed which permits, for the first time, real time data reduction of nadir measurements taken with a gas filter correlation radiometer to determine tropospheric carbon monoxide concentrations. The algorithm significantly reduces the complexity of the equations to be solved while providing accuracy comparable to line-by-line calculations. The method is based on a regression analysis technique using a truncated power series representation of the primary instrument output signals to infer directly a weighted average of trace gas concentration. The results produced by a microcomputer-based implementation of this technique are compared with those produced by the more rigorous line-by-line methods. This algorithm has been used in the reduction of Measurement of Air Pollution from Satellites, Shuttle, and aircraft data.
    Keywords: GEOPHYSICS
    Type: Applied Optics; 22; Mar. 1
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  • 61
    Publication Date: 2016-06-07
    Description: A plausible scenario for the existence of a persistent back-ground of turbulence in the free atmosphere is described. The MST radar technique is the only existing technique that can be used to describe the morphology of occurrence of turbulence as a function of altitude, wind speed, shear, weather conditions, geographical location, etc. This technique was used also to assess the degree of universality of shape and amplitude of the buoyancy wave spectrum and the relation between the buoyancy wave spectrum and turbulence.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions Middle Atmosphere Program, Vol.
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  • 62
    Publication Date: 2016-06-07
    Description: Gravity waves and their associated breaking into turbulence are very important in producing the overall picture of middle atmosphere global dynamics and associated transport. It is shown in this research that MST radars represent a most powerful technique for obtaining the needed parameters for gravity-wave-induced drag and diffusion effects as well as measuring wave accelerations and diffusion directly. A mathematical solution to this problem is that of radiative equilibrium with a balanced thermal wind.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions Middle Atmosphere Program, Vol. 9; p 241-246
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  • 63
    Publication Date: 2016-06-07
    Description: Winter mesospheric echoes are observed between about 55 and 80 km when auroral absorption is present during daylight hours. Relatively steady auroral absorption during sunrise and sunset periods causes a distinct onset and decay signature in mesospheric echo occurrence. The echo onset and disappearance time are shown versus height by the inclined lines for four different dates. The more vertical lines give the visible sunlight height/time curves for both sunrise (SR) and sunset (SS). The data is combined and replotted to give the morning onset height and the afternoon disappearance height as a function of solar zenith angle. Echoes are not observed at the lowest heights in the morning until the solar zenith angle is less than 90 deg. The afternoon echoes at the lowest heights also start to disappear as soon as the solar zenith angle exceeds 90 deg, implying that the solar component which sustains the mesospheric echo is screened by a layer extending up to about 60 km. The morning echo at 73 km onsets near the time of visible sunrise, but in the afternoon the 73 km echo lasts well past visible sunset.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions Middle Atmosphere Program, Vol. 9; p 145-146
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  • 64
    Publication Date: 2016-06-07
    Description: Abnormal refractivity gradients may cause radio waves to be trapped within tropospheric layers, thus producing regions through which the waves do not pass called radio holes. For some locations and for many applications, refractive corrections based on the surface refractivity are adequate for elevation angles above a few degrees. However, new systems which operate at elevation angles near the horizon often require improved accuracies. Techniques for obtaining these improved corrections are reviewed.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center Proc. of the 16th Ann. Precise Time and Time Interval (PTTI) Appl. and Planning Meeting; p 247-248
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  • 65
    Publication Date: 2016-06-07
    Description: The Wawa greenstone belt is located in the District of Algoma and extends east-northeast from Lake Superior to the western part of the Sudbury District in Ontario, Canada. Recent mapping by Attoh has shown that an unconformity at the base of the Dore' Formation and equivalent sedimentary rocks marks a significant stratigraphic break which can be traced throughout the volcanic belt. This break has been used to subdivide the volcanic-sedimentary into pre- and post-Dore' sequences. The pre-Dore' sequence includes at least two cycles of mafic-to-felsic volcanism, each capped by an iron-formation unit. The post-Dore' sequence includes an older mafic-to-felsic unit, which directly overlies sedimentary rocks correlated with the Dore' Formation, and a younger felsic breccia unit interpreted to have formed as debris flows from a felsic volcanic center. In the present study, samples of both the pre-and post-Dore' volcanic sequences were analyzed for major and trace elements, incuding rare earths (REE). This preliminary study is part of an ongoing program to assess the petrogenesis of the volcanic rocks of the Wawa greenstone belt.
    Keywords: GEOPHYSICS
    Type: Lunar and Planetary Inst. Workshop on a Cross Section of Archean Crust; p 81-82
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  • 66
    Publication Date: 2016-06-07
    Description: Meta-sediments from Isua, West Greenland were analyzed by instrumental thermal neutron activation analysis (ITNAA). These sediments are chemical precipitates having some layers of remarkably high Cr content. The latter were compared to Cr poor layers. It turned out that the Cr enriched layers had higher Ir and Ni contents than the samples from the Cr poor layers. Compared to phanerozoic samples the highest Ir contents are not extraordinarily higher than in a modern sediment, and the Cr poor layers, representing more or less phanerozoic shale. From the cratering record of the Moon one can assume a similar cratering of the Earth at about the time when the Isua rocks were formed.
    Keywords: GEOPHYSICS
    Type: Lunar and Planetary Inst. Workshop on a Cross Section of Archean Crust; p 71-75
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  • 67
    Publication Date: 2016-06-07
    Description: Geophysical properties of continental crust depend on the nature of crustal evolution. This is well illustrated by examination of two crustal cross-sections (1), the combined Ivrea-Verbano zone (IVZ) and Strona-Ceneri zone (SCZ) of northern Italy and the Pikwitonei granulite belt (PGB) and Cross Lake subprovince (CLS) of Manitoba. These two cross-sections are of particular interest because the IVZ and SCZ developed during Phanerozoic time whereas the PGB-CLS is an example of Archean crustal evolution. Consequently, each cross-section is geologically distinctive and, thus, exhibits very different geophysical properties such as density, seismic velocity, heat production, and magnetism. Results of geological investigations of each area are given.
    Keywords: GEOPHYSICS
    Type: Lunar and Planetary Inst. Workshop on a Cross Section of Archean Crust; p 47-50
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  • 68
    Publication Date: 2016-06-07
    Description: In southern India, it is possible to study the transition from an Archean granite-greenstone terrain (the Karnataka province) into high grade charnockites. The transition occurs over an outcrop width of 20-35 km and appears to represent burial depths ranging from 15 to 20 km. Field and geochemical studies indicate that the charnockites developed at the expense of tonalites, granites, and greenstones. South of the transition zone, geobarometer studies indicate burial depths of 7-9 kb.
    Keywords: GEOPHYSICS
    Type: Lunar and Planetary Inst. Workshop on a Cross Section of Archean Crust; p 34-37
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  • 69
    Publication Date: 2016-06-07
    Description: The demonstration that the Kapuskasing structure involves substantial thrusting of deep continental crustal rocks over shallower continental rocks calls into question an earlier suggestion (by Wilson) that the Circum-Ungaua suture zone continued through the Kapuskasing to join the Penokean fold belt (implying that the Kapuskasing marked the site of what has since come to be called a cryptic suture). Problems are discussed which arose in attempting to reconcile Wilson's idea with data from more recent studies: whether the Kapuskasing and the Thompson belt both mark sutures of about 1700 Ma age; why there is no age difference across the Kapuskasing if it does mark the site of continental collision, and why there is no offset of Superior subprovinces across the Kapuskasing.
    Keywords: GEOPHYSICS
    Type: Lunar and Planetary Inst. Workshop on a Cross Section of Archean Crust; p 20-23
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  • 70
    Publication Date: 2016-06-07
    Description: The circumstances leading to the formation and exposure at the Earth's surface of supracrustal granulites are examined. These are defined as sediments, volcanics, and other rock units which originally formed at the surface of the Earth, were metamorphosed to high-pressure granulite facies (T = 700-900 C, P = 5-10 kbar), and reexposed at the Earth's surface, in many cases underlain by normal thicknesses of continental crust (30-40 km). Five possible heating mechanisms to account for granulite metamorphism of supracrustal rocks are discussed: magnetic heating, thermal relaxation of perturbed temperature profiles following underthrusting of the continental crust, thermal relaxation after underthrusting of thin slivers of supracrustal rocks below continental crust of normal thickness, major preheating of the upper plate, and shear heating caused by frictional stress along the thrust plane.
    Keywords: GEOPHYSICS
    Type: Workshop on a Cross Section of Archean Crust; p 13-19
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  • 71
    Publication Date: 2016-06-07
    Description: A joint France/U.S. experiment was conducted near the mouth of the Rhone river in southern France as part of the ALPEX program. This experiment used 3 vertically directed 50 MHz radars separated by 4 to 6 km. The main purpose of this experiment was to study the spatial characteristics of gravity waves. The good height resolution (750 meters) and time resolution (1 minute) and the continuous operation over many weeks have yielded high resolution vertical wind speed power spectra under a variety of synoptic conditions. Vertical spectra obtained during very quiet (low wind) conditions in the troposphere and lower stratosphere from a single site are presented.
    Keywords: GEOPHYSICS
    Type: International Council of Scientific Unions Middle Atmosphere Program, Vol. 9; p 269
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  • 72
    Publication Date: 2011-08-18
    Description: High-energy tail distributions (k distributions) are used as an alternative to a bi-Lorentzian distribution to study the influence of energetic protons on the right- and left-hand cyclotron modes in a hot two-temperature plasma. Although the parameters are chosen to be in a range appropriate to solar wind or magnetospheric configurations, the results apply not only to specific space plasmas. The presence of energetic particles significantly alters the behavior of the electromagnetic ion cyclotron modes, leading to a wide range of unstable frequencies and increased growth rates. From the strongly enhanced growth rates it can be concluded that high-energy tail distributions should not show major temperature anisotropies, which is consistent with observations.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 88; Jan. 1
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  • 73
    Publication Date: 2011-08-18
    Description: Aerosol evaluation was found to be necessary to explain the 30 mb temperature increases observed in July-Oct. 1982 in comparison with averages for the period 1964-1981. An average difference of 1-1.5 C was determined at 30 mb, coinciding with 1 C deviations at the 50 mb level, for the first half of 1982. The 30 mb differences increased to 4.5-5 C, compared to the 18 yr average, during the July-Oct. period. GOES satellite imagery indicated that material from the El Chichon volcano eruptions had entered the stratosphere. Lidar backscattering ratios indicated the preponderance of the material resided in the 22-28 km interval. Airborne lidar measurements on two occasions confirmed the anomalies' presence south of 30 deg N latitude. Further monitoring of the aerosol evolution is indicated.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 10; Jan. 198
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  • 74
    Publication Date: 2011-08-18
    Description: Ion velocity-space distributions resulting from barium injections from orbiting spacecraft and shaped charges are discussed. Active experiments confirm that anomalous ionization processes may operate, but photoionization accounts for the production of the bulk of the barium ions. Pitch-angle diffusion and/or velocity-space diffusion may occur, but observations of barium ions moving upwards against gravity suggests that the ions retain a significant enough fraction of their initial perpendicular velocity to provide a mirror force. The barium ion plasmas should have a range of Alfven Mach numbers and plasma betas. Because the initial conditions can be predicted these active experiments should permit testing plasma instability hypotheses.
    Keywords: GEOPHYSICS
    Type: ESA Active Expts. in Space; p 305-310
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  • 75
    Publication Date: 2011-08-18
    Description: A beta plane model is used to study the transport of ozone and a tracer distributed like ozone. In the first experiment, ozone is transported with a time dependent diabatic circulation in a beta channel. Increase in the ozone column density occurs principally through downward advection from the high altitude source region into the lower stratosphere. Compared with observations, the maximum in the total ozone field occurs too late and is too large. Transient planetary waves produce large temporary increases in total ozone near the pole during sudden warming events, but permanent increases are much smaller. Warmings which penetrate below the chemical transition region (major warmings) are most effective in changing the zonal mean ozone distribution. Combining the sudden warming and diabatic circulations simulates many of the observed features of the seasonal changes in total ozone at high latitudes. The diabatic circulation provides the major enhancement of the ozone column density while the transient planetary waves move ozone to high latitudes. This result suggests sudden warmings can play an important role in our understanding of the fluctuations in total ozone, and the final warming may be the key event which determines the date and magnitude of the spring maximum.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Oct. 20
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  • 76
    Publication Date: 2011-08-18
    Description: Observations of the chlorofluorocarbon CFCl3 obtained several times daily over the period July 1978 to June 1981 at Adrigole, Ireland; Ragged Point, Barbados; Point Matatula, American Samoa; and Cape Grim, Tasmania are reported. In addition, observations at Cape Meares, Oregon are given for the period January 1980 to June 1981. On January 1, 1980, the average mixing ratio of CFCl3 in the lower troposphere is esimated to have been 168 pptv, and this is calculated to have been increasing 5.7 percent annually. Assuming that the only destruction of CFCl3 occurs in the stratosphere, the lifetime, on January 1, 1980, estimated by a trend technique is 83 + 73, or -27 years; the lifetime estimated from the global inventory of CFCl3 is to + 89 or -25 years. The maximum likelihood current lifetime estimate obtained by combining the estimates from both analysis techniques is 78 years.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Oct. 20
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  • 77
    Publication Date: 2011-08-18
    Description: The Atmospheric Lifetime Experiment is designed to determine accurately the atmospheric concentrations of the four halocarbons CFCl3, CF2Cl2, CCl4, and CH3CCl3, and also of N2O with emphasis on measurement of their long-term trends in the atmosphere. Comparison of these concentrations and trends for the four halocarbons with estimates of their industrial emission rates then enables calculations of their global circulation rates and globally averaged atmospheric lifetimes. The experiment utilizes automated dual-column electron-capture gas chromatographs which sample the background air about 4 times daily at the following globally distributed sites: Adrigole, Ireland, Cape Meares, Oregon; Ragged Point, Barbados; Point Matatula, American Samoa, and Cape Grim, Tasmania. The climatology of these 'clean air' sites and their ability to describe the global air mass are reviewed. The instrumentation and methods for data acquisition and processing are then described. An overview of the data obtained and the trends derived during the 3-year period from July 1978 through June 1981 for each of the five species being measured is presented.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Oct. 20
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  • 78
    Publication Date: 2011-08-18
    Description: The direct computation of atmospheric transmittance and clear column radiances for the channels of HIRS2 and MSU as a function of atmospheric and surface conditions is described in detail. A comparison is made between the observations and the calculated radiances derived from colocated oceanic radiosondes. It is found that under clear conditions, calculated brightness temperatures for the HIRS2 have a standard deviation of the order of 0.7 C compared with observations, whereas MSU channels have a standard deviation of approximately 1 C. In some channels, small biases are found that can be removed by an empirical 'tuning' with coefficients that can be successfully transferred from one season to another. Less satisfactory agreement is obtained from a comparison of calculations with 'reconstructed' clear radiances, which are used in analyzing sounding data under partially cloudy conditions.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Oct. 20
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  • 79
    Publication Date: 2011-08-18
    Description: By allowing for the effect of wave electric fields on electron orbits, a nonlinear dispersion relation for type I irregularities is obtained. This relation predicts (1) isotropy of the Doppler shift with elevation, (2) a limiting phase velocity equal to the ion acoustic speed, and (3) a saturation amplitude which is maximum for horizontally propagating waves and decreases with elevation. With the theory presented here, the in situ electric field measurements of Pfaff et al. (1980) in the electrojet environment could provide a quantitative check for the theory of orbit diffusion by stochastic electric fields.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; Oct. 198
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  • 80
    Publication Date: 2011-08-18
    Description: In late January and early February 1983, observations made by the Stratospheric Aerosol Measurement (SAM II) satellite system showed that aerosol extinction profiles measured within the northern polar vortex differed significantly above 18 km from those measured outside the vortex. Values of the calculated optical depths above 18 km for February 1, 1983, are lower by approximately one order of magnitude within the polar vortex than those outside. Similar differences were found in the aerosol back-scattering profiles obtained using an airborne lidar system when crossing the polar vortex. Since potential vorticity at a constant altitude is not conserved across the polar vortex, horizontal adiabatic transport does not occur.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 10; Oct. 198
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  • 81
    Publication Date: 2011-08-18
    Description: A balloon-borne laser radar (LIDAR) system for determining the stratospheric hydroxyl radical concentration constructed and flown by the Goddard Space Flight Center is discussed. The system measured hydroxyl in the altitude range of 34-37 km during an afternoon and early evening, producing the first post-sunset hydroxyl determination ever obtained. Daytime values (approximately 5 x 10 to the 6th/cu cm) are somewhat lower than previous measurements using in situ resonance fluorescence. Nighttime values (approximately 7 x 10 to the 5th/cu cm at 2100 CDT) are found to be higher than predicted by current one-dimensional models. Possible sources of these discrepancies, together with improvements possible in future systems, are outlined.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; June 20
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  • 82
    Publication Date: 2011-08-18
    Description: A laser operating at 266 nm is used to photolyze the product of the ClO + NO2 + M reaction, and the yield of Cl atoms, measured by resonance fluorescence, is found to be identical with that from equivalent concentrations of ClONO2. This is interpreted as a strong indication that no other isomers are formed in the recombination reaction. Evidence for isomers is surveyed, and the apparent forward-and-reverse-rate constant discrepancy is explained as a probable uncertainty in the thermochemistry.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; June 20
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  • 83
    facet.materialart.
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    Publication Date: 2011-08-18
    Description: A numerical filter inversion technique that reduces wide-angle satellite measurements to top-of-the-atmosphere radiant exitances has been proposed for the Earth Radiation Budget Experiment (ERBE). The matrix formulation of this technique is presented, and the design of the numerical filter is discussed. The filter is smoothed with a singular value decomposition. The inversion process is simulated by generating synthetic measurements from a 24 degree spherical harmonic radiation field derived from Nimbus 6 ERB data. The numerical filter is applied to these measurements after they are corrupted with instrument error. The results are curves of expected error versus resolution area.
    Keywords: GEOPHYSICS
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; April 19
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  • 84
    facet.materialart.
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    Publication Date: 2011-08-18
    Description: Pressure-broadening coefficients were determined for 156 O3 absorption lines made with the Fourier-transform spectrometer at the McMath Solar Telescope of the Kitt Peak National Observatory in the 9-micron region, with a resolution of 0.005/cm. O3 prepared from O2 by silent arc discharge and collected on cold silica gel was held at stable concentrations over 50 percent in a glass or stainless-steel cell with a rock-salt window, and broadened with dry N2. Interferograms were made in several scans of the interferometer during 30 min. The pressure-broadening coefficients were calculated by an iterative least-squares approach, a synthetic spectrum was constructed and compared to the actual spectrum, and the parameters were varied to achieve the best fit. It is shown that the estimated precision of the values reported is about 7 percent, and that the deviation from the theoretical calculations of Tejwani and Yeung (1975) averaged 7.6 percent (a small number of large discrepancies having been excluded).
    Keywords: GEOPHYSICS
    Type: Journal of Quantitative Spectroscopy and Radiative Transfer (ISSN 0022-4073); 29; June 198
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  • 85
    Publication Date: 2011-08-18
    Description: A series of measurements of enhanced levels of atmospheric N2O associated with thunderstorm lightning are reported. The data were gathered by instrumentation on-board an aircraft operated as part of the NASA Storm Hazards Project. Air samples were taken both during storms and in clear conditions to have a basis for comparisons; sample bottles were filled at altitudes from 11,000-40,000 ft. Gas chromatography was employed for sample composition analyses, revealing clear air N2O concentrations of about 310 ppbv, while storm concentrations reached, for example, 490, 729, and 393 ppbv. Although the measurements did not precisely characterize the actual lightning contributions, the enhancements being present during electrically active storms did confirm that trace gases are produced by lightning. Calculations are presented to demonstrate that the 3 to greater than 12 keV X rays detected in storm clouds are of sufficient energy to drive the production of N2O from the reaction of metastable nitrogen with molecular oxygen.
    Keywords: GEOPHYSICS
    Type: Nature (ISSN 0028-0836); 303; May 26
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  • 86
    Publication Date: 2011-08-18
    Description: Upwelling-IR observations of the North Pacific by polar orbiters NOAA 3, 4, 5, and 6 and TIROS-N from 1974 to 1981 are analyzed statistically in terms of interannual variability (IAV) in monthly averages and climatic noise due to short-term weather fluctuations. It is found that although the daily variance in the observations is the same in summer and winter months, and although IAV in winter is smaller than that in summer, the climatic noise in winter is so much smaller that a greater fraction of winter anomalies are statistically significant. The smaller winter climatic noise level is shown to be due to shorter autocorrelation times. It is demonstrated that increasing averaging area does not reduce the climatic noise level, suggesting that continuing collection of high-resolution satellite IR data on a global basis is necessary if better models of short-term variability are to be constructed.
    Keywords: GEOPHYSICS
    Type: Monthly Weather Review (ISSN 0027-0644); 111; March 19
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  • 87
    Publication Date: 2011-08-18
    Description: Methane loss to the atmosphere from flooded wetlands is influenced by the degree of supersaturation and wind stress at the water surface. Measurements in freshwater ponds in the St. Marks Wildlife Refuge, Florida, demonstrated that for the combined variability of CH4 concentrations in surface water and air velocity over the water surface, CH4 flux varied from 0.01 to 1.22 g/sq m/day. The liquid exchange coefficient for a two-layer model of the gas-liquid interface was calculated as 1.7 cm/h for CH4 at air velocity of zero and as 1.1 + 1.2 v to the 1.96th power cm/h for air velocities from 1.4 to 3.5 m/s and water temperatures of 20 C.
    Keywords: GEOPHYSICS
    Type: Tellus; vol. 35B
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  • 88
    facet.materialart.
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    Publication Date: 2011-08-18
    Description: An assessment is presented of the current state of knowledge concerning Birkeland currents and the parallel electric field, with discussions focusing on the Birkeland primary region 1 sheets, the region 2 sheets which parallel them and appear to close in the partial ring current, the cusp currents (which may be correlated with the interplanetary B(y) component), and the Harang filament. The energy required by the parallel electric field and the associated particle acceleration processes appears to be derived from the Birkeland currents, for which evidence is adduced from particles, inverted V spectra, rising ion beams and expanded loss cones. Conics may on the other hand signify acceleration by electrostatic ion cyclotron waves associated with beams accelerated by the parallel electric field.
    Keywords: GEOPHYSICS
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  • 89
    Publication Date: 2011-08-18
    Description: Experimental and theoretical investigations of high-latitude circulation in the upper thermosphere are reported. Vector-wind plots constructed by combining remotely sensed meridional-wind and in situ zonal-wind data obtained during four south-polar and three north-polar passes of the NASA Dynamics Explorer satellite in October and December, 1981, are presented and analyzed, taking the geomagnetic activity level and local solar time into account. The results are then compared with the predictions of 3D time-dependent global models of thermospheric neutral winds (Fuller-Rowell and Rees, 1980, 1981, 1983) adjusted to account for both solar-UV/EUV heating and ionization effects and quiet (Kp from 1 to 2) or moderately disturbed (Kp from 3 to 4) geomagnetic conditions (models Q and MD). An MD model incorporating a self-consistent description of the high-latitude ionosphere and a Q model excluding high-latitude effects are found to give the most accurate predictions for the respective geomagnetic conditions.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science (ISSN 0032-0633); 31; 1299-131
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  • 90
    Publication Date: 2011-08-18
    Description: Results are presented from a laboratory study of the kinetics of the S(IV)-O3 reaction in aqueous solution, including measurements of the effects of UV radiation, dissolved transition metals, and an antioxidant (hydroquinone) on the rate. On the basis of the results, relative rates of S(IV) conversion by O3 in tropospheric cloud water are compared with those predicted for H2O2 and for O2. The reaction mechanism is discussed, with an outline given of the elements of a possible reaction scheme. Application of the rate constants obtained to SO2 conversion in cloud water predicts conversion rates by ozone to be competitive with those by H2O2 at pH above about 4.5 and to dominate at pH above about 5.5. It is pointed out that since these pH's are typical for nonurban tropospheric cloud water, ozone is a potentially important contributor to the overall oxidative conversion of SO2 to sulfate in the nonurban troposphere.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 10721-10
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  • 91
    Publication Date: 2011-08-18
    Description: The total energy balance for two events with the objective of obtaining check on the interpretation in terms of reconnection is examined. To within experimental uncertainties, the plasma and magnetic field data are consistent with reconnection. An enthalpy increase comparable to the kinetic energy increase occurs in the magnetopause. Thus substantial dissipation is present in the rotational discontinuity. An ion heat flow associated with a beam of reflected magnetosheath particles carried away some 20% of the total converted electromagnetic energy.
    Keywords: GEOPHYSICS
    Type: Magnetopause Studies Using Data from the ISEE Mission; 25 p
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  • 92
    Publication Date: 2011-08-18
    Description: The basic qualitative and quantitative aspects of reconnection in its magnetopause setting are summarized. First, the basic morphological and dynamic features of asymmetric reconnection are examined with emphasis on the important role played by the rotational discontinuity in these geometries. Second, the structure and other properties of rotational discontinuities are discussed. Third, the manner in which individual particles are energized or de-energized during their interaction with current layers in general, and rotational discontinuities in particular, is examined. Finally, the question of nonsteady, localized reconnection and its relation to flux transfer events is discussed and a qualitative model is proposed to describe these phenomena.
    Keywords: GEOPHYSICS
    Type: Magnetopause Studies Using Data from the ISEE Mission; 31 p
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  • 93
    Publication Date: 2011-08-18
    Description: NCAR thermospheric-general-circulation-model (TGCM) computations of solar-maximum thermospheric neutral-gas temperature and circulation around the December solstice are presented and discussed. The TGCM uses a 5 x 5-deg grid and 24 constant-pressure layers, corresponding to altitudes of about 97-500 km. The results are mapped as electron-density contours, polar plots, cylindrical equidistant projections, meridional cross sections, and F-region polar plots comparing the TGCM predictions with DE-2 satellite observations. The significant differences between summer and winter high-latitude F-region winds are attributed to the ion drag momentum associated with magnetospheric convection. The TGCM wind predictions follow the same pattern as the satellite measurements but are too small; possible model corrections are considered.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science (ISSN 0032-0633); 31; 1479-149
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  • 94
    Publication Date: 2011-08-18
    Description: Observations of dichlorodifluoromethane obtained several times daily over the period July 1978 to June 1981 at Adrigole, Ireland (52 deg N, 10 deg W), Ragged Point, Barbados (13 deg N, 59 deg W), Point Matatula, American Samoa (14 deg S, 171 deg W), and Cape Grim, Tasmania (41 deg S, 145 deg E), are reported. Observations at Cape Meares, Oregon (45 deg N, 124 deg W), are also given for the period November 1980 to June 1981. On January 1, 1980, the average mixing ratio of dichlorodifluoromethane in the lower troposphere is estimated to have been 285 pptv and to have been increasing at 6.0 percent/year. The atmospheric lifetime of this compound is estimated from this data by adjusting its destruction rate in a two-dimensional model of the atmosphere so as to provide the best fit to the observations. Assuming destruction of CF2Cl2 in the stratosphere only, the lifetime estimate for January 1, 1980, by the inventory technique is 69 + 36 or - 18 years. The trend technique principally provides a lower limit to the lifetime of 81 years. The results suggest a need for further assessment of dichlorodifluoromethane release estimates, particularly those from the USSR and eastern Europe.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Oct. 20
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  • 95
    Publication Date: 2011-08-18
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; Aug. 10
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  • 96
    Publication Date: 2011-08-18
    Description: The International Ozone Rocket Sonde Intercomparison (IORI) conducted at Wallops Island during October 1979 provided a unique opportunity to observe ozone variations in great detail from several observing systems. The measurement period lasted 15 days during which time ozone observations were taken by ground-based, balloon, rocket, and satellite instruments. These data provided a unique opportunity for diagnosing regional stratospheric variability over a 2 week period. Examination of NMC analyses indicated that during this period the stratospheric polar vortex moved southeastward bringing air form high latitudes to Wallops Island above 10 mb. A concurrent change was observed in the upper stratosphere ozone fields observed by Nimbus-7 SBUV and in the ozone vertical distribution measured by the rocket soundings. In this study the satellite and rocket measurements are compared. The agreement is good, certainly within the errors of the measurements.
    Keywords: GEOPHYSICS
    Type: (ISSN 0273-1177)
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  • 97
    Publication Date: 2011-08-18
    Description: The Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) data over Europe have been processed for 2 days of the ozone sensor intercomparison balloon campaign in June 1981 at Gap, France. The June 19 TOMS map shows an elongated ozone maximum (about 400 D.U) extending in a NW-SE direction across central Europe and an ozone minimum (300 D.U.) in the central Atlantic. This pattern produces a 12 D.U. decrease along the balloon trajectory from the fist ascent to the second descent. On June 26 a much smaller ozone maximum (400 D.U.) is centered in northern France with its main axis running in a SW-NE direction. The total ozone contours tend to lie parallel to the balloon trajectory so that the total ozone during the flight is nearly constant.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science (ISSN 0032-0633); 31; July 198
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  • 98
    Publication Date: 2011-08-18
    Description: O3 soundings made with balloon-borne optical sensors during the French Intercomparison Ozone Campaign in June, 1981, are reported. The GSFC four-channel UV-filter-photometer ozonesonde designed for the Super Loki rocket was attached to the gondola roof for redundant O3-density measurements at altitudes of 22-32 km, using the 300 and 303-nm filters. Sensor calibration, data processing, input constants, and vertical O3-distribution calculations are discussed. The density profiles for three legs of the flight, calculated using Bass or Vigroux cross sections, agreed within a standard error of 1.4 percent for each channel, but showed a consistent 4-5 percent (significant) difference between channels. Total average O3-column amounts determined by combining the GSFC data with ECC measurements for altitudes below 21 km were in good agreement with bias-corrected TOMS data from Nimbus-VII and with ground-based data from the Observatoire de Haute-Provence at Mt. Chiran, when the latter were computed using the pre-campaign calibration. A 9-percent discrepancy arose when the Chiran data were corrected for a post-campaign recalibration of the Dobson spectrophotometer.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science (ISSN 0032-0633); 31; July 198
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  • 99
    Publication Date: 2011-08-18
    Description: Measurements made by the NASA-JSC ozone instrument during the ozone intercomparison campaign from Gap, France during June 1981 are reported. Two flights were made on board the large balloon platform with other instruments using different techniques. The NASA-JSC instrument employs UV absorption photometry to obtain in situ results. Concentration and mixing ratio profiles are given for altitudes from 16 km to float altitudes of 32 and 39 km, respectively, for the two flights. A measure of the total column content of ozone was obtained by integrating the NASA-JSC results from 16 km to float altitude and combining them with results from other techniques below 16 km and above float altitudes.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science (ISSN 0032-0633); 31; July 198
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  • 100
    Publication Date: 2011-08-18
    Description: An empirical method to measure the spectral surface albedo of surfaces from Landsat imagery is presented and analyzed. The empiricism in the method is due only to the fact that three parameters of the solution must be determined for each spectral photograph of an image on the basis of independently known albedos at three points. The approach is otherwise based on exact solutions of the radiative transfer equation for upwelling intensity. Application of the method allows the routine construction of spectral albedo maps from satelite imagery, without requiring detailed knowledge of the atmospheric aerosol content, as long as the optical depth is less than 0.75, and of the calibration of the satellite sensor.
    Keywords: GEOPHYSICS
    Type: Journal of Climate and Applied Meteorology (ISSN 0733-3021); 22; April 19
    Format: text
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