bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for a primordial magnetic field during the meteorite parent body era
Authors: Sonett C. P.
Published: February 2008

A total of 247 measurements of natural magnetic remanence (NRM) and effective susceptibility of meteorites tabulated by Herndon et al. (1972) from Russian data is investigated. A log‐log plot of
, magnetic moment/gm, versus
, susceptibility/gm, shows a straight line relation with a slope of unity over a range of meteorite types extending from the achondrites at the low Fe‐Ni end to the stony‐irons, and over a span in
and
of between four and five orders. In view of the wide variability of the different classes of meteorite and the effects of unstable soft magnetization, this relation is unexpected. One suggestion is a common background field; this supports the hypothesis of an ancient magnetic field at the time of meteorite formation. An estimate of the primordial field strength cannot be made with certainty because the field strength H = 1.8/ρ ²N, where ρ is density and N is the average carrier demagnetization factor; N can vary from zero to 4 π. Thus an extreme lower limit for H is 0.02 oersted for N = 4 π, in agreement with Brecher and Ranganayaki (1975). For the mean field of 0.27 oersted determined from critical study of individual meteorites (Stacey and Banerjee, 1974), the average N = 0.74, corresponding to elongated grains.
Nitrous oxide in Michigan waters and in U.S. municipal waters
Authors: Cicerone Ralph J. , Shetter James D. , Liu Shaw Chen
Published: February 2008

We have measured dissolved nitrous oxide (N2O) concentrations in Michigan surface waters by equilibration of the water samples with ambient air followed by gas chromatographic analysis of the air. Two rivers and one lake show significant N2O supersaturations (factors of five or more) directly traceable to sewage treatment plant effluents. Municipal tap water samples from 19 U.S. cities also show supersaturations. Our data indicate that chlorination of river water and of wastes might be a key step in N2O production. To measure N2O fluxes from water to air we employ a gas collection device; two initial flux measurements from supersaturated waters are reported.
Theory of coherent parametric instabilities excited by two or more pump waves
Authors: Cragin B. L. , Fejer J. A. , Showen R. L.
Published: February 2008

A method based on energy balance is used to obtain the thresholds of parametric instabilities of the ‘purely growing’ and ‘arithmetic mean’ varieties which can exist in a plasma irradiated by two or more electromagnetic pump waves. These instabilities produce growing standing electron plasma waves at frequencies satisfying either ω = ωi, where ωi is the frequency of the ith pump wave, or ω = (ωi+ωj)/2, where i and j correspond to two different pump waves. Additionally growing ion standing waves of zero frequency or of frequency (ωi−ωj)/2 are produced. These coherent instabilities are found to be coupled in a sense with the usual ‘decay’ instability and, in the case of three or more pump waves, with each other. The results of this investigation are applied to a recent ionospheric heating experiment described in a companion paper.
Mathematical expression for the O (¹D) quantum yields from the O3 photolysis as a function of temperature (230‐320 K) and wavelength (295‐320 nm)
Authors: Moortgat Geert Karel , Kudszus Eberhard
Published: February 2008

The exact quantum yield of the O (¹D) formation from the ozone photolysis in the UV range 295‐320 nm is important for aeronomic calculations, since O (¹D) is the primary source for OH radicals in the troposphere. Recent O (¹D) quantum yield determinations at 230, 268, 298 and 320 K are summarized and an analytical expression is derived which relates the quantum yield of O (¹D) formation as a function of wavelength and temperature.
Diode laser spectra of CCl2F2 near 10.8µm; air‐broadening effects
Authors: Jennings D. E.
Published: February 2008

Laboratory spectra of CCl2F2 in the 10.8μm region have been recorded using a tuneable diode laser spectrometer at 10−4 cm−1 resolution. Effects of air‐broadening at pressures up to 48 Torr show that spectral structure should be exhibited under high resolution at altitudes as low as 19 Km. The single‐line pressure‐broadening coefficient for CCl2F2 is estimated to be 8 ± 2 MHz/Torr FWHM.
A balloon borne instrument to induce corona currents as a measure of electric fields in thunderclouds
Authors: Weber M. E. , Few A. A.
Published: February 2008

A device for measuring the point discharge emitted from a 2m length of copper wire, using a radiosonde as carrier platform, has been developed in order to measure the distribution of charged regions inside thunderclouds with respect to temperature and altitude. No modifications to the radiosonde or in its standard receiving equipment are required.

In four penetrations of electrified clouds over central New Mexico, corona currents were induced in the conducting wire. The measurements were characterized by reversals in the polarity of the current which can be interpreted as a result of the balloon's rising past the level at which charge of one sign is concentrated.
The altitude dependence of the local time variation of thermospheric density
Authors: Sharp L. R. , Hickman D. R. , Rice C. J. , Straus J. M.
Published: February 2008

Analysis of density measurements from the AE‐E satellite have demonstrated that the local time variation in the thermosphere at low latitudes (<20°) changes from predominantly diurnal at high altitudes (∼300 km) to predominantly semidiurnal at low altitudes (∼140 km). This behavior is significant because it both affects the accuracy of density predictions at low satellite altitudes and confirms that the mesospheric semidiurnal tide is important to the dynamics of the lower thermosphere. Comparison of the results with the local time dependence found in the thermospheric model of Jacchia (1971) and the MSIS model of Hedin et al. (1977a and b) indicate that only the latter correctly models the transition to dominantly semidiurnal behavior at lower thermospheric altitudes near the equator.
Inter‐arc basins: A kinematic model
Authors: Poehls Kenneth A.
Published: February 2008

It is observed that active inter‐arc basins are found only where the subducted plate can interact with the plate behind the trench. This condition exists where trenches are terminated or offset by transform faults or where large variations in subduction rates occur. Shear coupling between the two juxtaposed plates across a transform or strike‐slip fault creates a tensional regime behind the island arc. Differential subduction velocities will couple the plate motions across both the more slowly subducting trench and across the intervening fracture zone. If the trench axis is assumed to move more slowly than a plate, inter‐arc basin spreading may be initiated to conserve area.
Spectrometric measurement of atomic oxygen 63µm emission in the thermosphere
Authors: Offermann D. , Grossmann K. U.
Published: February 2008

Thermospheric far infrared emission was measured by a rocket borne, helium cooled grating spectrometer in the wavelength region 45µm to 125µm. The rocket was launched on March 16, 1977 at 2304 CET from Andoya, Norway, during a moderate geomagnetic disturbance. First spectral measurements of 63µm atomic oxygen fine structure transition were obtained in the altitude regime 90 ‐ 180 km. No other emissions were found in the spectral range covered at altitudes above 130 km. The minimum detectable radiance was below 2 · 10−11W/cm²sr. Radiometric measurements of CO2 15µm band emission were made by the same instrument in the altitude range 102 ‐ 140 km.
Possible scavenging reactions of C2H2 and C2H4 for phosphorus‐containing radicals in the Jovian atmosphere
Authors: Vera Ruiz Hernan G. , Rowland F. S.
Published: February 2008

The ultraviolet photolysis of PH3 in the laboratory leads to the formation of elemental red phosphorus, and the occurrence of the same reactions in the atmosphere of Jupiter has been suggested as the source of the chromophore of the Great Red Spot. The inclusion of either C2H2 or C2H4 as scavenger molecule in the laboratory photolysis at 295°K completely suppresses the formation of red phosphorus. Experiments are needed on the activation energies for the reactions of PH2, PH and P2 with C2H2 and C2H4 to determine whether the scavenging processes are also effective at Jovian Atmospheric temperatures. If the scavenging reactions are effective there, the formation of red phosphorus should occur only in regions with low concentrations of C2H2 and C2H2.
Balloon observations of a particle layer injected by a stratospheric aircraft at 23 km
Authors: Hofmann D. J. , Rosen J. M.
Published: February 2008

An extensive layer of small particles (r ≳ 0.01 µm) was observed in association with the passage of a jet aircraft at 23 km altitude. The data are used to estimate the small particle emission index and the source strength of such aircraft at stratospheric altitudes. The impact of such flights on the stratospheric particle population is probably negligible; however, when the results are applied to the currently projected Concorde SST fleet in the stratosphere and the commercial jet fleet in the upper troposphere both are estimated to contribute non‐negligible equilibrium concentrations of such particles to their respective altitude regimes.
Magnetotellurics using lock‐in signal detection
Authors: Goubau Wolfgang M. , Gamble Thomas D. , Clarke John
Published: February 2008

Magnetotelluric measurements were performed simultaneously at two sites 4.8 km apart near Hollister, California. The data obtained at each site were analyzed using the two magnetic field measurements at the other site as a remote reference. Even for data for which the E‐E predicted coherencies were as low as 0.1, the apparent resistivities obtained using this technique were consistent with resistivities calculated from high coherency data at adjacent periods. Apparent resistivities calculated by a conventional analysis of the same data were biased downward by magnetic noise, sometimes by as much as two orders of magnitude.
Evolution of the East Pacific Rise between 3°S and 13°S since the Middle Miocene
Authors: Rea David K.
Published: February 2008

Since Middle Miocene time seafloor spreading activity in the southeast Pacific has shifted westward from the Galapagos Rise, then the last active segment of the Farallon Ridge system in the South Pacific, to the East Pacific Rise. This shift was accomplished by three large jumps of fracture‐zone‐bound axial sections which progressed from south to north. The jumps spanned an average distance of 750 km and occurred 8.2, 6.4 and 5.7 m.y. ago respectively. Positioning of the newly‐formed axes along the EPR trend apparently was controlled by asthenospheric rather than lithospheric phenomena.
Correction to “Recirculation of energetic particles in Jupiter's magnetosphere”
Authors: Sentman D. D. , Van Allen J. A. , Goertz C. K.
Published: February 2008

During a recent comprehensive analysis of the pitch angle distributions of energetic particles in Jupiter's magnetosphere we found an intermittent error in our Pioneer 11 data reduction software. When present, this error caused a phase shift of 180° in the assignment of spacecraft roll angles. The corrected analysis reveals significant proton anisotropies directed toward the planet in the southern hemisphere, contrary to our previous report. In the northern hemisphere both proton and electron anisotropies are directed away from the planet, as reported previously. Hence, our earlier claim of direct evidence for the hypothesis of recirculation of energetic particles in the Jovian magnetosphere is invalidated. Nonetheless, we consider that the hypothesis continues to have merit on the basis of indirect evidence, though the recirculation process must be weaker than envisioned originally and obscured by other processes.
Symmetrical equator—pole anisotropy during an unusual cosmic ray storm
Authors: Duggal S. P. , Pomerantz M. A.
Published: February 2008

The third remarkable cosmic ray storm in more than two decades of continuous observations commenced on February 14, 1978. In contrast with its two predecessors (July 11, 1959 and August 4, 1972), the magnitude of the decrease at equatorial‐viewing stations significantly exceeded (∼ a factor of 2) that at stations in both polar regions. Thus, in contrast with the usual situation characterized by some degree of north‐south asymmetry, this unique event manifested an equator‐pole bidirectional anisotropy indicating a symmetrical cosmic ray density gradient rising from the equatorial plane. The nucleonic intensity data suggest that the solar plasma regime responsible for the modulation on this occasion engulfed the earth in a symmetrical configuration with respect to the equator. As is the case for the basic diurnal variation, the modulation varies as cos λ*, where λ* is the weighted mean latitude of the viewing direction.
A simple model of upwelling in the Gulf of Guinea
Authors: O'Brien James J. , Adamec David , Moore Dennis W.
Published: February 2008

A simple linear baroclinic numerical model of an equatorial beta‐plane ocean is integrated for the Atlantic Ocean. The seasonal increase of westward trade winds in the western Atlantic generates a trapped equatorial disturbance which propagates westward at internal gravity wave speeds and produces strong upwelling along the coast of the Gulf, of Guinea. A windstress perturbation of 0.025 Newtons m−2 produces over 20 m of upwelling for over 90 days in the Gulf of Guinea.
Sulfate behavior in eastern U.S. precipitation
Authors: Pack Dee William
Published: February 2008

Analyses of H+, SO4=, and NO3− concentrations in precipitation from five Eastern U.S. sites between Virginia and upstate New York indicate that monthly weighted concentrations of SO4= are highly correlated between sites out to the farthest site separation distance (750 km). NO3− concentrations, however, are significantly correlated between sites out to only 150 km. The H+ ion is significantly correlated between sites out to 600 km site separation, a value intermediate between SO4= and NO3−, as would be expected. These results suggest that SO2 and/or SO4= (factors producing SO4= concentrations in precipitation) are well mixed over the Eastern U.S. A sulfur reservoir that fluctuates uniformly within this region can be inferred. NO3− does not show the same tendency for consistent fluctuation over large separation distances.
Observation of atmospheric NO3
Authors: Noxon J. F. , Norton R. B. , Henderson W. R.
Published: February 2008

Absorption by atmospheric NO3 at 6620Å has been detected at night using the moon as the light source. The absorption exhibits a <30% increase during the night which implies the NO3 observed to be in the stratosphere. The column abundance is 1 ± 0.2 × 1014cm−2, close to that predicted to exist in the stratosphere.
Fe+ ions in the high latitude F‐region
Authors: Grebowsky J. M. , Brinton H. C.
Published: February 2008

Ion mass spectrometer measurements on Atmosphere Explorer C orbits from December 1974 to December 1976 were surveyed poleward of ±30°Λ for instances in which the Fe+ number density exceeded the spectrometer threshold sensitivity of 30/cm³. The occurrences of Fe+ within the altitude range covered by the orbit, 220 to 320km, revealed a distinct pattern apparently associated with regions of upward plasma transport. At night a band of such events occurred between 50° and 60°Λ which typically corresponded to the location of the main ionospheric trough. In this region large upward ion drifts due to the drag of an equatorward blowing neutral wind are expected. The Fe+ band extends past 06 MLT to ∼11MLT during the summer, but is not observed in the afternoon. The dayside distributions possibly result from the upward drifts of F‐region ions detected by back‐scatter techniques after dawn during summer. At higher latitudes patches of Fe+ were detected in regions where strong plasma drifts often prevail and hence where poleward
motions and atmospheric expansion through Joule heating can lift the ions upwards.
Search for26 Al effects in the Allende Fun Inclusion Cl
Authors: Esat Tezer M. , Lee Typhoon , Papanastassiou D. A. , Wasserburg G. J.
Published: February 2008

The Mg isotopic composition in plagioclase from the Allende inclusion Cl has been measured to correlate excess 26Mg* with isotopic anomalies for elements of higher atomic number. No large 26Mg* excesses were observed in samples with 27Al/24Mg up to 165. The inferred initial 26Al/27Al is 5 × 10−6 which is a factor of ten less than previously observed in other Allende inclusions. The low 26Al abundance may be the result of late formation of Cl (by 2.5 m.y.) or due to the non‐uniform addition of 26Al to the solar system. The major mineral phases in Cl which are Mg rich and the bulk alteration products all have a uniform Mg isotopic composition with 30‰ per mass unit fractionation and δ26Mg≈ −1.6‰. The plagioclase data show variable Mg isotopic fractionation which ranges from 0 to 30‰ per mass unit. Isotopic homogeneity was demonstrated for the major mineral phases rich in Mg both in macroscopic samples and in microscopic individual crystals. The detailed correlation of 26Al with the more general isotopic anomalies and its use as a chronometer marking the production and introduction of isotopically anomalous material into the solar system remains an open question.
Relationship between midlatitude thermospheric winds and the time rate of change of DSt
Authors: Hernandez G. , Roble R. G.
Published: February 2008

Nighttime thermospheric winds and temperatures over Fritz Peak Observatory (39.9°N, 105.5°W) have been determined from the Doppler shifts and line profiles of the (OI) 15876‐K (6300 Å) line emission. The peak winds measured during several geomagnetic storms are shown to be linearly related to the time rate of change of the equatorial ring current parameter (d(DSt)/dt). During these geomagnetic storm periods the time variation of the measured meridional winds are also strongly correlated with the time rate of change of DSt although the observed winds at midlatitudes may lag variations in this parameter by several hours. The energy input derived from d(DSt)/dt is consistent with the high latitude energy input that is necessary in a thermospheric dynamic model to bring the calculated meridional winds into agreement with the observations. These results suggest that d(DSt)/dt is a useful index for determining the magnitude and time history of the high latitude energy input during both quiet and disturbed geomagnetic conditions for use in global thermospheric dynamic models.
Reply to “Solar wind effects on the surface chemistry of lunar grains” by E. Bilson
Authors: Zinner Ernst
Published: February 2008

Bilson (1978) has criticized our interpretation of ion probe measurements on lunar plagioclase grains by contending that the sputter action of solar wind H and He can account for observed surface enhancements of Mg and Fe. We think that an inappropriate analogy between lunar bulk soils and plagioclase grains led Bilson to this conclusion. While it is true that ion implantation is unlikely to have a dominant effect on the major element composition of the surface of lunar grains of average bulk soil composition, we show that chemical alteration by solar wind sputtering cannot explain our ion probe result on plagioclase grains. Glass splashes on shielded grains and solar wind implanted ions on some selected exposed crystals are the most likely source of Mg and Fe enhancements.
Possible strengths of dynamo magnetic fields of the Galilean satellites and of Titan
Authors: Neubauer Fritz M.
Published: February 2008

Simple models for the interiors of the Galilean satellites and Titan involving metallic cores have been constructed. Then using a similarity law due to Busse possible surface equatorial dynamo magnetic fields of 2200, 800, 200, 60 and 100 nT have been estimated for Io through Titan, respectively.
The reaction of N(²D) with O2 as a source of O (¹D) atoms in aurorae
Authors: Rusch D. W. , Gérard J ‐C. , Sharp W. E.
Published: February 2008

We have investigated the source of O(¹D) atoms in the auroral ionosphere using sounding rocket data. Previously, it has been shown that the conventional sources of O(¹D) atoms in the aurora, dissociative recombination of O2+ and electron impact excitation of atomic oxygen, fail to explain the measured 6300Å volume emission rate profile. We suggest that the atom‐atom interchange reaction of N(²D) with O2 can be the major source of auroral 6300Å emission if O(¹D) is created with high efficiency.
The phase function of Venus cloud particles from Mariner 10 data
Authors: Hapke Bruce
Published: February 2008

Mariner 10 images of Venus taken at several phase angles were photometrically reduced. The analysis shows that the phase function of the cloud particles is not isotropic, as had been deduced earlier from the brightness distribution on spacecraft images taken at a single phase angle, but has a broad minimum near 60° and is forward‐scattering. The scattering properties are in quantitative agreement with previous deductions from earth‐based polarization measurements by Hansen and his associates.
Fluorescent accessory phases in the carbonaceous matrix of ureilites
Authors: Berkley John L. , Taylor G. Jeffrey , Keil Klaus , Healey John T.
Published: February 2008

The carbonaceous matrix of ureilite meteorites (C‐bearing olivine‐pigeonite achondrites) contain abundant minute phases that emit a multicolored fluorescence under electron bombardment. These phases include NaCl and KCl, found in all seven ureilites studied, high‐Si glass with pyroxene and chlorapatite quench crystals in North Haig, an unidentified high‐Ca‐Al‐Cl phase in Novo Urei, and possibly free SiO2 in Novo Urei and Dingo Pup Donga. The origin of these phases is uncertain but some, especially chlorides and glass, may represent residual postcumulus materials precipitated from a late‐stage interstitial liquid during the igneous phase of ureilite history.
Effect of CO2 on the buoyancy of geothermal fluids
Authors: Straus Joe M. , Schubert Gerald
Published: February 2008

The presence of large amounts of CO2 in geothermal fluids is shown to generally enhance convective instability. The buoyancy of water‐CO2 solutions can be dominated by the large volume changes that occur when CO2 enters or leaves solution. The transfer of water between the liquid and vapor phases which accompanies the movement of CO2 into or out of solution also contributes to changes in the fluid volume and resultant buoyancy. The effective thermal expansivity αeff in the CO2 rich fluid of the Broadlands geothermal region of New Zealand exceeds the coefficient of thermal expansion of ordinary water αell for depths are large as a 2 km; αeff is more than an order of magnitude larger than αell at depths less than 500 m.
Chemistry and thermodynamics of sulfur on Venus
Authors: Young A. T.
Published: February 2008

While photochemical reactions convert SO2 to H2SO4 and remove O2 from the Venus stratosphere, thermochemical reactions near the surface probably make the SO2, regenerate CO2 from photolytic CO, and produce free sulfur. Venera data suggest a light drizzle of liquid sulfur above 18 km, and several per cent of sulfur vapor below.
Detection of SO2 in the UV spectrum of Venus
Authors: Barker Edwin S.
Published: February 2008

The broad absorption feature below 3300Å in the Venus uv spectrum previously reported by Barker is identified as primarily due to SO2 absorption based on new higher resolution spectra of the 3000‐3400Å region showing broad (10Å), unresolved absorptions in the regions at all SO2 band origins between 3000 and 3300Å. SO2 mixing ratios vary from 5 × 10−7 down to an upper limit of 2 × 10−8 at a phase angle of 138°. Previous observational determinations of the SO2 mixing ratio were biased toward large phase angles, and consequently did not detect any SO2 absorption at the 10−8 level. The upper limit derived from the CS2 band head at 3206Å is ≤ 5 × 10−8. The observed range of SO2 mixing ratios (<2 × 10−8 to 5 × 10−7) is consistent with model predictions based on the sulfur photo‐chemistry at the cloud tops. Ground‐based observations of SO2 mixing ratio will provide constraints on models and check on the Venera and Pioneer Venus measurements of the mixing ratios of SO2 and other sulfur‐bearing gases with altitude.
A linear relationship between Earth models and seismic body wave data
Authors: Dorman LeRoy M.
Published: February 2008

When the velocity distribution in a laterally homogeneous earth is described by dz/du, the derivative of depth with slowness, the earth model thus derived is shown to be linearly related to the delay time function τ(p), the travel time, T(p) and distance X(p), thus allowing the direct application of linear inverse theory to the body wave observations through joint inversion of, τ(p), X(p) and T(p) observations. This joint inversion is advantageous in restricting the set of earth models consistent with the data.
Neutral atmospheric waves determined from Atmospheric Explorer measurements
Authors: Hoegy W. R. , Dyson P. L. , Wharton L. E. , Spencer N. W.
Published: February 2008

Atmosphere Explorer measurements of neutral wind, temperature, and composition are used to determine the characteristics of atmospheric gravity waves. Wind (horizontal or vertical component) and temperature data for N2 and composition data for O, N2 and He are filtered to separate the wave information from the gross features. A spectral analysis of the wave data is performed using the Maximum Entropy Method (MEM) to calculate wave amplitude, phase, and coherence at different Doppler shifted frequencies. An atmospheric wave is identified when a strong peak is observed in the auto‐power and cross‐power spectra at the same Doppler shifted frequency for all of the wave quantities (wind, temperature, and composition). We derived the dispersion relation and polarization relations for two specie gravity waves in an isothermal, horizontally stratified atmosphere (without dissipation) which are fit to the amplitudes and phases from the spectral analysis to determine the wave parameters ω and
. There is sufficient information in the amplitudes and phases of wind, temperature, and composition to completely specify the period, wavelength and direction of propagation. It is found that the theoretical wave amplitudes and phases are not significantly modified with the neglect of heat conduction, viscosity and ion drag.
New paleomagnetic results from the Rio Dell Formation, California
Authors: Kodama Kenneth P.
Published: February 2008

A new paleomagnetic study of the Plio‐Pleistocene siltstones and mudstones of the northern California Rio Dell Formation confirms its Matuyama age but locates the Jaramillo and Olduvai normal events more accurately than does a previous paleomagnetic study. In addition, it records one of the short Réunion events not reported in the previous study. Detailed alternating field and thermal demagnetization studies, an average stratigraphic distance of 32 m between sites, two to ten samples per site, and careful consideration of the data allow the derivation of a magnetostratigraphy in a reversed polarity section plagued by normal polarity magnetic overprinting. Our magnetostratigraphy suggests that the stratigraphic location of the microfaunally determined Plio‐Pleistocene boundary is approximately 1.6 m.y.b.p. in age. The rate of sedimentation between the upper boundaries of the Jaramillo and Olduvai events is 0.7 m/1000 yrs. This agrees with the average sedimentation rates determined by microfaunal studies of the section and by the previous paleomagnetic study.
On divergences of thermospheric meridional winds at midlatitudes
Authors: Hernandez G. , Roble R. G.
Published: February 2008

The existence of large scale (300 m/s) divergences, or convergences, of the meridional wind field is shown to be a common feature of the thermosphere at night during geomagnetic quiet times. This finding weakens the arguments used to invoke energetic neutral‐atom precipitation at low and midlatitudes to explain the divergence in the meridional wind during the geomagnetic storm of April 1, 1976. For this storm it is also shown that the maximum time rate of change of Dst is accompanied by a maximum value of the AE index, thus indicating that energy is flowing into the high latitude thermosphere as well as into the magnetospheric ring current.
Measurements of H2O2 and HNO3in rural air
Authors: Kelly Thomas J. , Stedman Donald H. , Kok Gregory L.
Published: February 2008

In a preliminary study of two new analytical techniques, we have measured hydrogen peroxide (H2O2) and nitric acid (HNO3) near ground level at a rural site near Boulder, Colorado during February, 1978. H2O2 was measured with a liquid‐phase chemiluminescence technique. HNO3 in a sample air stream was converted to NO2 in a packed quartz tube at 350°C, and detected with a fast response NOx monitor. O3, CO, NO, and NO2 were also measured simultaneously. H2O2 was found between 0.3 and 3 ppb. HNO3 concentrations as high as 5 ppb were found with NOx always greater than HNO3 by at least a factor of 5.
Secular variation of gravity in Mexico?
Authors: Singh S. K. , Mena M. , Monges J.
Published: February 2008

Based on data obtained during the period 1949‐1967, Woollard and others reported large secular variation of gravity in Mexico. Data obtained since 1971, using LaCoste‐Romberg gravimeters, indicate that no significant variation is occurring between Mexico City and Acapulco and Monterrey and Mexico City at present. Local secular variation of gravity reported for Mexico City is continuing and is well correlated with the sinking (due to water withdrawal) of the city.

This article contains supplementary material.
Ionospheric bubbles observed by the Faraday Rotation Method at Natal, Brazil
Authors: Yeh K. C. , Soicher H. , Liu C. H. , Bonelli E.
Published: February 2008

By a sample record we show that the radio beacon experiments which utilize the Faraday rotation technique and the scintillation observations can be used to observe equatorial ionization bubbles. In a two‐hour period 5 isolated bubbles have been identified. The depleted total electron content for one such bubble is 2.2×1016 electrons/m² and the east‐west dimension is about 72 km. This translates to a total depletion of 1.6×1021 electron per meter in the north‐south direction.
Pioneer 10 studies of interplanetary shocks at large heliocentric distances
Authors: Mihalov J. D. , Wolfe J. H.
Published: February 2008

Pioneer 10 Ames plasma analyzer data collected in the 6.1 to 12.6 AU range of heliocentric distances (November 1974 to April 1977) have been examined for interplanetary shock waves. Eighteen shock signatures have been identified, with four of these being of the reverse type and the remainder the forward type. Sonic Mach numbers in the range from 3 to 10 are estimated for these events.
Plasma in the Jovian current sheet
Authors: Goertz C. K. , Schardt A. W. , Van Allen J. A. , Parish J. L.
Published: February 2008

In a recent study of the Pioneer 10 observational data in the outer magnetospheric current sheet of Jupiter, Walker, Kivelson, and Schardt conclude that high energy (> 60 keV) ions frequently are dominant contributors to the plasma pressure and suggest that low energy (≤ 5 keV) plasma is of much less importance. These results are dependent in a crucial way on their adopted extrapolation of observed energy spectra of protons to energies considerably lower than the low end of the observed range. We reach essentially opposite conclusions on the basis of (a) a more thorough study of a larger body of proton spectral data and (b) a simple magnetohydrodynamic theory of the current sheet using the observed magnetic field structure. Our specific conclusion is that the dominant contribution to the plasma pressure in the radial range 25 to 62 RJ is by thus‐far unobserved protons (ions) having energies of the order of 0.1 ‐ 10 keV.
Double photoionization and doubly charged ions in the thermosphere
Authors: Victor G. A. , Constantinides E. R.
Published: February 2008

We show that a plausible cross section for double photoionization of atomic oxygen,

urn:x-wiley:00948276:media:grl1063:grl1063-math-0001
yields the dominant source mechanism for O++ in the thermosphere. With this large source, harmony is obtained between the measured O++ concentrations and the large (k ∼ 10−9 cm³ s−1) measured sink (by charge exchange with molecular species) at altitudes above about 250 km.
A note on the identification of a Gulf Stream spin‐off eddy from Eulerian data
Authors: Pietrafesa Leonard J. , Janowitz Gerald S.
Published: February 2008

The variability of currents and hydrography along the outer continental shelf of the South Atlantic Bight is occasionally dominated by Gulf Stream frontal spin‐off eddies. These eddy events have been recognized as an important mechanism for water mass, nutrient and larvae exchange on the outer shelf. Recent efforts to characterize the dynamics of these events from moored recording current meter data have considered a detection scheme based on a Lagrangian viewpoint, i.e., that the eddy events are cold core with the velocity vector at a fixed point rotating counterclockwise with time in the horizontal plane. However, as we show in this paper, the horizontal velocity vector at a fixed point can rotate either clockwise or counterclockwise depending on whether the mooring is located to the right or to the left of the center of the eddy as it is advected past the mooring and is independent of sense of rotation of the eddy as viewed by an observer moving with it. Further, depending on the shelf hydrographic season, the eddy event could either warm or cool the shelf locally. Therefore, conventional eddy detection schemes using moored instrument data are lacking in perspective.
Tropospheric and lower stratospheric vertical profiles of ethane and acetylene
Authors: Cronn Dagmar , Robinson Elmer
Published: February 2008

The first known vertical distributions of ethane and acetylene which extend into the lower stratosphere are reported. The average upper tropospheric concentrations, between 20,000 ft (6 km) and 35,000 ft (11 km), near 37°N ‐ 123°W were 1.2 µg/m³ (1.0 ppb) for ethane and 0.24 µg/m³ (0.23 ppb) for acetylene while the values near 9°N ‐ 80°W were 0.95 µg/m³ (0.77 ppb) and 0.09 µg/m³ (0.09 ppb), respectively. Detectable quantities of both ethane and acetylene are present in the lower stratosphere. There is a sharp decrease in the levels of these two compounds as one crosses the tropopause and ascends into the lower stratosphere. The observed levels of ethane and acetylene may allow some impact on the background chemistry of the troposphere and stratosphere.
Excitation of Alfvén waves by bouncing electron beams ‐ An origin of nightside magnetic pulsations
Authors: Hasegawa Akira
Published: February 2008

Electron beams produced in the night to dusk‐side magnetosphere at geomagnetic substorm times are shown to be able to excite the kinetic Alfvén wave, the Alfvén wave with a perpendicular wavelength comparable to the ion gyroradius. This process can be an origin of dusk‐side magnetic pulsations which are often observed by synchronous satellites.
Upper limits on argon isotope abundances in the Venus thermosphere
Authors: Mauersberger K. , von Zahn U. , Krankowsky D.
Published: February 2008

On December 9, 1978 the neutral gas mass spectrometer aboard the NASA Pioneer Venus multiprobe bus has measured density, composition, and temperature of the Venus dayside thermosphere. There was no positive identification of argon down to the lowest measuring altitude of 130 km. For the altitude level of 135 km the following upper limits for the number densities of argon isotopes were derived: n(36Ar) < 1.3 × 106 cm−3 and n(40Ar) < 2.8 × 106 cm−3. From our upper atmosphere observations we infer for the troposphere of Venus the following upper limits for the mixing ratios: n(36Ar)/total number density < 9 × 10−6 and n(40Ar)/total number density < 20 × 10−6.
Dissociative recombination of N2+ in the ionosphere
Authors: Torr Marsha R. , Torr D. G.
Published: February 2008

Earlier attempts to determine the rate coefficient for the process from the Atmosphere Explorer satellite data were based on measurements made near the minimum of the solar cycle. This phase of solar activity is not optimum for such a determinationas the N2+ chemistry is dominated by the minor ion speciesO+(²D). In a study of the N2+ ion using measurements made during 1978a significantly higher phase of solar activitywe find the major source of N2+ is photoionizationrather than charge exchange with O+(²D)and the major loss process above 300 km is dissociative recombination with electrons. Under such conditions α can be unambiguously determined. Using a data sample for which the electron temperature covered the range 1000 to 3400°Kwe evaluate αand find the results to be in good agreement with the laboratory measurements given by the expression
Artificial stimulation of auroral electron acceleration by intense field aligned currents
Authors: Holmgren G. , Boström R. , Kelley M. C. , Kintner P. M. , Lundin R. , Fahleson U. V. , Bering E. A. , Sheldon W. R.
Published: February 2008

A cesium doped high explosion was detonated at 165 km altitude in the auroral ionosphere during quiet conditions. An Alfvén wave pulse with a 200 mV/m electric field was observed with the peak occurring 135 ms after the explosion at a distance of about 1 km. The count rate of fixed energy 2 keV electron detectors abruptly increased at 140 mspeaked at 415 ms and indicated a downward field aligned beam of accelerated electrons. An anomalously high field aligned beam of backscattered electrons was also detected. We interpret the acceleration as due to a production of an electrostatic shock or double layer between 300 and 800 km altitude. The structure was probably formed by an instability of the intense field aligned currents in the Alfvén wave launched by the charge separation electric field due to the explosion.
Spectroscopic measurement of carbonyl sulfide (OCS) in the stratosphere
Authors: Mankin William G. , Coffey Michael T. , Griffith David W. T. , Drayson S. Roland
Published: February 2008

A Fourier transform spectrometer aboard an aircraft at 12 km has been used to measure the stratospheric overburden of carbonyl sulfide (OCS). Line parameters derived from laboratory measurements of OCS absorption spectra made with the same instrument were used to interpret the results. Column abundances were determined for winter and summer at latitudes from the equator to 48°N. The mean vertical column abundance above 12 km is 1.9 × 1015 molecules‐cm−2corresponding to an average volume mixing ratio of 4.6 × 10−10. We observe little variation with latitude or season.
The OI(¹S) state: Its quenching by O2 and formation by the dissociative recombination of vibrationally excited O2+ ions
Authors: Zipf Edward C.
Published: February 2008

The rate coefficient for the quenching of metastable O(¹S) atoms by O2 has been measured as a function of temperature from 250°K to 550°K. The resulting Arrhenius expressionk1 = 4.9 × 10−12 exp[‐(885 ± 35)/T]is in good agreement with previous laboratory work. It is suggested that the much larger value for k1 inferred from an analysis of the artificial auroral experimentPrecedeis due to overestimating the contribution to O(¹S) production from O2+ dissociative recombination. The possibility that O(¹S) atoms are produced only by the dissociative recombination of vibrationally excited O2+ ions is discussed; such excited ions would not exist at the altitude of the Precede experiment because of the rapid cooling of these ions by resonant charge transfer processes.
Prediction of the occurrence and intensity of magnetospheric substorms
Authors: Akasofu S.‐I. , Chao J. K.
Published: February 2008

The solar wind and IMF data obtained by the Venus probe Mariner 5 (at a distance of 460 earth radii) and by the earthbound Explorer 34 satelliteon June 2425and 261967 were examined. It is demonstrated that the occurrence and intensity of magnetospheric substorms can be predicted about 1‐3 hours prior to their onsets by monitoring the energy coupling function at a distance of a few hundred earth radii upstream of the solar wind. It appears that the ‘ ∈ signal ’ propagates with different speedsperhaps depending on the propagation time of disturbances which increase ∈
Whistler propagation in the Jovian magnetosphere
Authors: Menietti J. D. , Gurnett D. A.
Published: February 2008

Computer ray tracing results are presented for lightning generated whistlers propagating in the Jovian Magnetosphere. The waves are launched from a point on the Jovian surface at 66° latitude and propagate approximately along L = 6 out to near the equatorial plane and into the Io plasma torus. The magnetospheric model includes the Io torus centered at the magnetic equator. The torus model is an empirical fit of the density contours presented by Warwick et al. [1979], and the electron density outside of the torus is an adaptation from Sentman and Goertz [1977]. The results clearly indicate that the whistlers propagate through the magnetosphere with very little dispersion until reaching the torus, at which time the dispersion starts to increase very rapidly. We find that the computed dispersions using the assumed electron density model are in excellent agreement with the observed whistler dispersions, thereby confirming the validity of the model.

In addition to the ray path studies, the effect of Landau damping on whistler waves has been investigated as a function of the electron temperature within the torus. For a constant electron temperature of 105°K only the lowest frequencies, ≲1.0 kHz, show appreciable attenuation after passing through the torus. But an increase in the electron temperature of only a factor of three results in a very large attenuation over the entire frequency range observed. This result suggests an upper limit for the electron temperature in the torus of a few times 105°K.
Spectral scattering properties of turbid waters
Authors: Whitlock Charles H. , Poole Lamont R. , Houghton William M.
Published: February 2008

River water samples have been examined for optical scattering properties at wavelengths between 400 and 800 nm. Scattering coefficients were calculated from measurements of beam attenuation and absorption coefficients and are observed to vary with wavelength. At a fixed wavelength, the scattering coefficient is influenced by both phytoplankton concentration (as indicated by chlorophyll a) and suspended solids concentration. Measurements of small angle volume‐scattering function indicate that the phase function at an angle of 1.5° is not constant for turbid waters and varies with both wavelength and beam attenuation coefficient. These data differ from previously published results for relatively clear oceanic and coastal waters. Caution is required when attempting to estimate scattering coefficient values from single‐angle measurements of volume‐scattering function.
Sudden stratospheric warmings forced by mountains
Authors: Schoeberl Mark R. , Strobel Darrell F.
Published: February 2008

A global, quasigeostrophic model of planetary wave interaction with the mean zonal flow has been used to simulate sudden stratospheric warmings forced by mean tropospheric zonal winds interacting with orography. Planetary waves m = 1 and 2 are simultaneously computed and interact with each other only through the mean zonal flow. Orographic forcing is determined by the tropospheric wind field. An increase in the jet stream maximum from 36 ms−1 to 48 ms−1 is sufficient to initiate repeated major warmings with an ∼80 day cycle. These results are in good agreement with the observed anti‐correlation of the annual variation of the winter monthly averaged jet stream strength and polar night jet strength, which is interpreted to be a direct consequence of the increased planetary wave stresses on the mean flow in the stratosphere.
The secondary circulation associated with a vertically aligned planetary wave critical line
Authors: Schoeberl Mark R.
Published: February 2008

An analytic model of the secondary circulation associated with a vertically aligned, energy absorbing, planetary wave critical line shows that strong zonal mean vertical motions and heating (or cooling) can develop even though no eddy transport of heat occurs. The type of secondary circulation which develops around a vertically aligned critical line may provide a mechanism for stratosphere‐troposphere exchange of air. The model predictions are discussed with reference to the 76/77 sudden warming.
A linear formulation of the plate motion problem
Authors: Simpson Robert W.
Published: February 2008

The problem of finding the angular velocity vectors which describe the relative motions of tectonic plates can be posed as a linear least‐squares problem. A simple geometric interpretation of the fitting process is given for the case of two plates.
Simultaneous measurement of the volume mixing ratios of HCl and HF in the stratosphere
Authors: Buijs H. L. , Vail G. L. , Tremblay G. , Kendall D. J. W.
Published: February 2008

The simultaneous measurement of the 1‐0 bands of HCl and HF has been achieved from near‐infrared solar absorption spectra obtained during a balloon flight near Fairbanks, Alaska (65°N, 148°W) in the evening of May 22, 1976. Several lines from each band have been measured to provide volume mixing ratio profiles for both constituents from 15 to 30 km. The HCl profile is consistent with the results of other workers, however the HF profile shows a substantially larger concentration than a recent determination.
A variational approach to model the depth dependence of radiogenic heat in the crust
Authors: Singh Rishi N. , Negi Janardan G.
Published: February 2008

A quadratic functional criterion for the mathematical modelling of crustal radiogenic heat and heat flux is utilised. Following the classical variational analysis it is inferred that the exponential law of the depth dependence of radiogenic heat is the optimal model.
Simultaneous observations of lightning radiations from above and below clouds
Authors: Brook Marx , Tennis Richard , Rhodes Charley , Krehbiel Paul , Vonnegut Bernard , Vaughan Otha H.
Published: February 2008

Daytime optical measurements of a lightning flash made simultaneously from above and below a thundercloud show nearly identical signals. The optical pulses are clearly related to electric field changes detected by an E change meter and to the signals detected by a 2200 MHz receiver. Source power levels ranging from 107 to 1010 W optical were detected at 20 km altitude from three lightning flashes.
E.P.R. study of the reactivity of ClO with H2CO at 298 K
Authors: Poulet Gilles , Le Bras Georges , Combourieu Jean
Published: February 2008

The reaction of ClO with H2CO has been studied by the discharge flow EPR technique. An upper limit of 10−15 cm³ molecule−1 s−1 has been found for the rate constant at 298 K. Then this reaction cannot be a sink for ClO radicals in the stratosphere. Besides, evidence has been shown for a noticeable reactivity between ClO and HCO at 298 K.
Double‐layer criterion on the altitude of the auroral acceleration region
Authors: Kan J. R. , Lee L. C.
Published: February 2008

The double‐layer criterion, consisting of necessary conditions for the existence of double‐layer solutions, is derived for both extended and localized parallel electric fields along converging geomagnetic field lines in the presence of backscattered and trapped electrons. According to the criterion, the parallel electric field is either distributed from ∼0.5 RE to less than ∼1.5 RE altitudes in the case of an extended double‐layer or concentrated in a few Debye lengths at an altitude above ∼0.5 RE but below a few RE in the case of a localized double‐layer. The lower limit on the altitude is determined by the supersonic transition altitude of the polar wind. The upper limit is controlled by the number density of the backscattered primary electrons and the electric potential profile near the upper boundary.