bluuebunny/crossref_metadata_2025 huggingface dataset:
Extensive areas of reduced waves leeward of the Lesser Antilles
Authors: Strong Alan E. , DeRycke Richard J. , Stumpf Harry G.
Published: February 2008

A Very High Resolution Radiometer on the NOAA‐2 satellite has provided some imagery of the Lesser Antilles showing large areas of relatively calmer water (about 200 km) downwind from the islands. The relatively calm seas are caused by the disruption of air flow over the islands.
Theory of Ulf modulation of VLF emissions
Authors: Chen Liu
Published: February 2008

A theory of quasi‐periodic VLF emissions associated with ULF geomagnetic pulsations is presented. The theory is based on an approach of treating as adiabatic the interactions between the VLF emissions and the externally‐excited ULF waves. The obtained theoretical results are consistent with available observations.
On wind profiles over sea ice
Authors: Langleben M. P.
Published: February 2008

Values of friction velocity calculated from wind speeds at two levels, 4 m and 1 m above the surface, during periods of neutral stratification are compared to those obtained from least‐squares fit of the wind data measured at 5 levels for about 150 wind profiles which exhibited very nearly logarithmic variation of wind speed with height. It is shown that the friction velocity determined from the difference in wind speed at two levels is subject to large uncertainty, typically about ±15% for even small errors in wind speed measurement. Profile sets for a number of cases when the wind profiles were irregularly shaped with kinks, bends and, occasionally, wind speed maxima are shown to argue that their existence would not have been revealed if wind speeds had been measured at only two levels.
Ion gauge measurements of latitudinal density variations at night
Authors: Ching B. K. , Carter V. L.
Published: February 2008

Atmospheric densities have been obtained from a cold cathode ion gauge flown on the satellite 1972‐32A in April‐May 1972. The satellite orbit was inclined at 81.5° in a noon‐midnight configuration. Data obtained at heights between 200 and 275 km during a geomagnetically quiet period have been examined for latitudinal effects. Transformed to a constant altitude of 230 km, the data show a variation on the dark side by as much as a factor of 2, the highest density being at high northern latitudes and the lowest at middle to high southern latitudes. General agreement was obtained between the data and both the Jacchia‐1971 and OGO‐6 models. An equatorial maximum was sometimes observed that closely resembled the pure N2‐distribution as described by the OGO‐6 model.
Excitation of infrared auroral emissions in collisions of H+ and H with N2
Authors: Birley John H. , Johnson Peter A.
Published: February 2008

Cross sections for emission of the N2+(A²Πu − X²Σg+) Meinel (2, 0) and the N2 (B³Πg − A³Σu+) first positive (1P) (3, 1) bands in 0.5–25 ke V H+ and H impact on N2 are reported. It is shown that, in a hydrogen aurora, H+ and H impact make comparable contributions to the Meinel band intensity but that neutral hydrogen impact is the predominant source of 1P emission. The vibrational distribution of N2+ A²Πu formed in 25 ke V H+ and H impact with v′ = 2–5 is shown to be in good agreement with the prediction of a simple Franck‐Condon model.
Possible acceleration of charged particles through the reconnection of magnetic field lines in interplanetary space
Authors: Levy E. H. , Ipavich F. M. , Gloeckler G.
Published: February 2008

Prominent intensity spikes in the flux of protons and alphas with less than 0.5 MeV per charge have been observed in the region several hours behind an interplanetary shock front. The small spatial scale of these events and the high anisotropy of the particle flux suggest local acceleration. The spectra of the particles, which are cut off at equal energy per charge, suggest acceleration through an electric field. We examine the possibility that these events have their origin in active magnetic neutral sheets in the shocked solar wind.
Periodic escape of relativistic electrons from the Jovian magnetosphere
Authors: Hill T. W. , Carbary J. F. , Dessler A. J.
Published: February 2008

We adopt a model in which the Jovian magnetospheric tail is forced open by plasma that is accelerated out of the ionosphere by the centrifugal force of corotation. Any longitudinal asymmetry that exists in the ionospheric plasma source and/or the planetary magnetic field will cause a diurnal variation in the radial extent of the trapping region for energetic electrons. This diurnal variation in the extent of the particle trapping region can result in a time‐dependent loss of relativistic electrons from the Jovian magnetosphere, modulated at the planetary rotation period. The diurnal trapping process may be relevant to the observation of electron pulses in interplanetary space during the Pioneer 10 approach to Jupiter.
Heliocentric distribution of cosmic dust intercepted by Pioneer 8 and 9
Authors: Rhee John W. , Berg Otto E. , Richardson F. Frank
Published: February 2008

More than seven years of impact data from the Pioneer 8 and 9 cosmic dust experiments indicate that the distribution of cosmic dust particles of mass 10−16 Kg and larger is nearly independent of heliocentric distance between 0.75 AU and 1.09 AU. In this heliocentric distance range the particle concentration is ∼10−8 per m³ and the corresponding mass density is ∼10−24 Kg per m³. No particle flux enhancement is found at 1 AU.
Electron spectroscopic studies related to solar‐wind darkening of the lunar surface
Authors: Yin Lo I , Tsang Tung , Adler Isidore
Published: February 2008

Improved instrumentation in the x‐ray photoelectron spectrometer allowed the first direct observation of the change of valence state of iron in the silicate Fayalite under helium‐ion bombardment. From the observed ion dosage necessary to reduce the iron in the topmost atomic layers to the metallic state it is estimated that similar reduction on the lunar surface under solar‐wind proton bombardment would occur between 700 to 1000 years. Within such a time scale, it seems likely that all surface iron in the iron‐containing lunar fines should have been reduced to the metallic state. Implications of these experimental observations in terms of various proposed darkening mechanisms are discussed.
The ionosphere and atmosphere of Io
Authors: Whitten R. C. , Reynolds R. T. , Michelson P. F.
Published: February 2008

In order to explain the ionosphere of Io as observed by Pioneer 10, we propose a tenuous atmosphere of neon, which is ionized by solar radiation. Predicted plasma number densities and temperatures are presented and discussed.
Source mechanism for terrestrial kilometric radiation
Authors: Benson Robert F.
Published: February 2008

The intense electromagnetic radiation of near earth origin, observed by the OGO, IMP, and Hawkeye satellites, can be explained in terms of plasma oscillations near the upper hybrid frequency which are stimulated in the high latitude regions at distances within 5 earth radii (5RE). The wave energy is converted from the longitudinal electrostatic mode to the transverse electromagnetic mode as it travels in the slightly inhomogeneous magnetosphere, and it is reflected at the point where the wave frequency equals the local electron plasma frequency. This emission region is confined to radial distances less than about 4RE; the peak emission region occurs near 2RE. The original plasma oscillations are generated in the turbulent plasma produced by precipitating electrons associated with discrete auroral arcs. The mechanism has possible applications to studies of the irregular structure of the magnetospheric thermal plasma and to models for the decametric radiation from Jupiter.
Propagation prediction model selection using VLF atmospherics
Authors: Hughes H. G. , Pappert R. A.
Published: February 2008

Measurements of very low‐frequency (VLF) atmospherics were made simultaneously at California and the Island of Hawaii. A third station in the source area in Oklahoma aided in locating each individual lightning event. From the differences in measured field strengths at the two remote stations the transmission loss as a function of frequency was determined for 37 waveform pairs. The average measured transmission loss was then compared to that predicted numerically using several exponential ionospheric conductivity models described by an inverse scale height β and reference height h′ [in the notation of Wait and Spies (1965)]. Based on a weighted least‐squares analysis of the calculated and measured data an appropriate ionospheric conductivity model (β = 0.35 km−1, h′ = 72 km) was chosen which best predicts the measured daytime east‐west transmission loss for a selected frequency band 7 kHz–18 kHz.
The September 5, 1970 Sea of Okhotsk Earthquake: A multiple event with evidence of triggering
Authors: Strelitz Richard
Published: February 2008

The September 5, 1970 Sea of Okhotsk earthquake consisted of two possibly causally related but dissimilar events: a small (Mag 4.5) event at the hypocenter given by the International Seismologic Centre (52.28 N, 151.49 E, 560 km) followed 5.16±.06 seconds later by a larger (Mag 5.7) event almost at the same epicenter but 23.0±1 km deeper. The fault planes and the principal stress axes of the two events are significantly different; furthermore, the second event does not lie on either of the nodal planes of the first event. We interpret this as a possible triggering of the second event by the smaller first event and not as a change in direction of rupture propagation during a single continuous faulting episode.
Numerical investigation of dilatancy biasing of hypocenter locations
Authors: Wu Chee , Crosson Robert S.
Published: February 2008

We assume that a dilatant zone which develops as a precursor to an earthquake may be modeled by a zone of low‐velocity rock having the shape of a triaxial ellipsoid. For varying ellipsoid dimensions, velocity contrasts, and hypocenter distributions, we generate a synthetic data set of arrival times at surface stations. The artificial events are relocated using a constant‐velocity model to test for systematic hypocenter biasing. For all cases tested, the depth change for the distribution as a whole was not significant although individual events may move substantially. A downward migration of the ensemble of hypocenters was produced by a long, narrow ellipsoidal zone, however, the magnitude of migration for this case was only two percent.
Latitudinal profiles of stratospheric water vapor
Authors: Kuhn P. M. , Stearns L. P. , Lojko M. S.
Published: February 2008

Water vapor burden and in situ mixing ratios above and at high altitude flight levels were inferred from observations in the rotational water vapor spectral band (19.0–35.0 µm). Flight levels ranged from 15.3 to 20.0 km during 12 meridional traverses of a W‐B57‐F jet. The method of radiance observation, while radiometric, involved emission observations rather than absorption spectra analyses employed by McKinnon and Morewood [1971]. The flights made during September, October, November 1973 and January 1974 provide profiles of lower stratospheric water vapor by overlapping tracks from 50°S latitude to 75°N latitude.

The objective of the research is to describe the method of recovery of the water vapor burden and in situ mixing ratio by inference from infrared emission observations and to present the results as a latitudinal profile.
Auroral N2 vibrational excitation and the electron density trough
Authors: Schunk R. W. , Banks P. M.
Published: February 2008

Through various processes molecular nitrogen within the nocturnal auroral oval is vibrationally excited, substantially increasing the rate at which O+ is lost via the reaction O+ + N*2 → NO+ + N. Owing to the action of thermospheric winds and diffusion, N*2 does not remain at its point of origin but is transported to regions outside the auroral oval where it can act to substantially reduce the F‐region electron density. For an equatorward transport speed of 100 m sec−1, N*2 can travel 3° to 4° of latitude before quenching with atomic oxygen substantially reduces the N*2 density. This process may contribute significantly to the formation of the mid‐latitude F‐region electron density trough.
Solar radiation induced rotational bursting of interplanetary particles
Authors: Sparrow J. G.
Published: February 2008

It is suggested that the magnitudes of the two radiation induced rotational bursting mechanisms have been overestimated and that they do not work significantly faster than the Poynting‐Robertson effect in removal of interplanetary particles.
An analytical model of the Jovian magnetosphere
Authors: Barish Franklin D. , Smith Robert A.
Published: February 2008

Using Euler potentials, we construct a class of axisymmetric magnetic field models that exhibit the general features of the dayside Jovian field as observed by Pioneers 10 and 11. The particular model used for illustration contains a distended, disk‐like field along the equator, a blunt, Earth‐like magnetosphere boundary, and the possibility of multiple traping regions along a field line. The self‐consistent ring current is calculated, together with representative drift periods for energetic particles.
Proton precipitation by a whistler‐mode wave from a VLF transmitter
Authors: Koons H. C.
Published: February 2008

Protons with 50 keV < E < 530 keV were detected by sensors aboard satellite 1972‐76B at an altitude of 700 km in the region conjugate to the transportable very‐low‐frequency (TVLF) transmitter which was being operated near Anchorage, Alaska (L ∼ 4). Temporal maxima in the proton count rates can be identified on a one‐to‐one basis with short pulsed transmissions by the VLF transmitter. The observed time delay between the center of a transmitted pulse and the detection of the next maximum in the proton count rate at the sensor agrees well with the delay predicted from a simple plasmaspheric model.
Two barium plasma injections into the northern magnetospheric cleft
Authors: Jeffries R. A. , Roach W. H. , Hones E. W. , Wescott E. M. , Stenbaek‐Nielsen H. C. , Davis T. N. , Winningham J. D.
Published: February 2008

Barium plasma was injected into the northern magnetospheric cleft twice during January, 1975. Lofted by rockets launched after local magnetic noon from Cape Parry, NWT, Canada, high‐explosive shaped charges compressed hollow barium cones to generate vapor jets moving upward with initial velocities near 13 km/s parallel to the geomagnetic field. Barium plasma streaks created by solar photoionization of the vapor were convected through the polar magnetosphere and were observed optically from airborne and ground‐based sites until about 40 min after injection. Numerous indicators were monitored to determine the degree of magnetospheric disturbance; ionosondes at Cape Parry and Sachs Harbour, NWT, monitored latitudinal cleft motions preceding rocket launch. Spectrometers in the payloads recorded charged‐particle fluxes during both flights. The first injection occurred poleward in the cleft with subsequent plasma convection antisunward across the polar cap; the second occurred centrally with plasma convection duskward at constant magnetic latitude.
Cretaceous K‐Ar ages of volcanic rocks from the Musicians Seamounts and the Hawaiian Ridge
Authors: Clague David A. , Dalrymple G. Brent
Published: February 2008

K‐Ar conventional and 40Ar/39Ar ages on plagioclase from altered basalt samples show that Khatchaturian and Rachmaninoff Seamounts in the Musicians Seamounts, north‐central Pacific, are 65.2 ± 2.6 and 86.6 ± 5.2 m.y. old, respectively. The minimum age of Wentworth Seamount, located on the Hawaiian Ridge near Midway, is 71 ± 5 m.y. Wentworth appears to be a Cretaceous volcano that was incorporated into the Hawaiian volcanic chain. A single boulder of rhyolite dredged from the northern slope of the seamount underlying Necker Island has an age of 77.6 ± 1.7 m.y. Apparently Necker is a composite seamount constructed of both Cretaceous and late Tertiary volcanoes. With one possible exception, the ages of these and other Cretaceous seamounts in the north‐central Pacific are less than or equal to the age of the adjacent sea floor indicating that the seamounts formed at or near the crest of the East Pacific Rise.
Rocks 60618 and 65785: Evidence for admixture of kreep in lunar impact melts
Authors: Keil K. , Warner R. D. , Prinz M. , Dowty E.
Published: February 2008

We present evidence to support the hypothesis that the fine‐grained, basaltic‐textured portions of rocks 60618 and 65785 were produced by impact melting of the coarse‐grained spinel‐olivine anorthosite (60618) and spinel troctolite (65785) portions, coupled with admixture of approximately 33% and 63%, respectively, material of alkalic high‐alumina basalt (KREEP) composition. The abundance of impact‐modified rocks at the Apollo 16 site with compositional similarities to the impact melts reported here, suggests that the relations observed in these rocks are indicative of widespread impact mixing with KREEP rocks of the lunar highlands.
Steady state finite amplitude Rayleigh Taylor modes in spread F
Authors: Chaturvedi P. K. , Kaw P. K.
Published: February 2008

We present some special steady state solutions of the nonlinear one‐dimensional set of equations describing the Rayleigh‐Taylor instability. This instability is believed to be one of the possible mechanisms responsible for equatorial spread F and we discuss the relevance of our results to some recent experimental observations.
Effects of atomic nitrogen on the nocturnal ionosphere
Authors: Torr M. R. , Torr D. G. , Walker J. C. G. , Hays P. B. , Hanson W. B. , Hoffman J. H. , Kayser D. C.
Published: February 2008

Recently, atomic nitrogen densities of ∼5 × 107 to 108cm−3 were inferred in the daytime thermosphere from studies of the NI(²D−4S) 5200Å emission and from the photochemistry of various ion species using data measured by the Atmosphere Explorer‐C satellite. In this paper we use the photochemistry of NO+ and O2+ at night to determine nocturnal N(4S) densities in the thermosphere. We present evidence for a missing source of NO+ and a missing sink for O2+ at night and show that this can be adequately supplied by the reaction O2+ + N → NO+ + O if the N density at 200 km is ∼7 × 106cm−3. The atomic nitrogen has an important effect on studies of the 6300Å airglow. The omission of N in calculations of O(¹D) using ground‐based data results in an overestimate of the rate coefficient for quenching of O(¹D) by N2.
Fluorine photochemistry in the stratosphere
Authors: Stolarski R. S. , Rundel R. D.
Published: February 2008

The photochemistry of fluorine in the stratosphere is surveyed in order to estimate the effect on ozone of fluorine atoms released by the breakdown of chlorofluoromethanes. The catalytic efficiency for ozone destruction by fluorine is found to be less than 10−4 that of chlorine in the altitude range from 25 to 50 km.
Latitudinal measurements of NO and O3 in the lower stratosphere from 5° to 82° north
Authors: Loewenstein Max , Savage Howard
Published: February 2008

Latitudinal measurements of NO and O3 concentrations were carried out in June and October of 1974 and June and July of 1975 at altitudes between 18.3 and 21.3 km using in situ measuring techniques. The observed NO number densities range from 5 × 108 to 3 × 109 cm−3 and are generally consistent with other recent in situ and remote observations of NO concentrations in the lower stratosphere. The NO concentration increases steadily toward the north at 21.3 km while at 18.3 km the NO concentration exhibits a broad minimum at about 45° north latitude. Ozone measurements show the expected increase of ozone toward the pole.
Unsteadiness in longshore currents
Authors: Wood William L. , Meadows Guy A.
Published: February 2008

Classically, field and laboratory investigations have relied on averaged results from Lagrangian measurements to establish longshore current velocities. Likewise, conservation equations have been time averaged in the formulation of longshore current theories. Recent experimental measurements by the authors indicate that at a fixed point in the surf zone variations in excess of 150 percent of the mean current velocity occur over time periods from three to eighty seconds. These unsteady motions in longshore currents persist horizontally across the surf zone and vertically from the surface to the bottom. This persistence and magnitude of the observed velocity fluctuations from this investigation imply that time dependent analytic treatments of conservation equations are necessary in order to properly determine longshore current velocity.
Vp/Vs and b‐Values: A test of the dilatancy model for earthquake precursors
Authors: VanWormer J. D. , Gedney L. D. , Davies J. N. , Condal N.
Published: February 2008

Three days prior to a magnitude 3.0 earthquake near Fairbanks, Alaska, the b‐value began to decrease, reaching a statistically significant minimum one day before the event. This decrease in b‐value is in accord with the dilatancy model for earthquake occurrence. Changes in Vp/Vs would have been only marginally detectable with the data available.
Paleomagnetism of the oldest red beds and the direction of the Late Aphebian Polar Wander relative to Laurentia
Authors: Roy J. L. , Lapointe P. L. , Anderson P.
Published: February 2008

The direction of the apparent polar motion relative to Laurentia for the interval 2.2 to 1.9 b.y. ago is the subject of a controversy owing to difficulties in determining the age relationships and age of the complex magnetization of those very old rocks. Three cleaning treatments (thermal, chemical and alternating field) were used to study the fossil magnetization of 104 specimens (8 sites) of 2.3 b.y. old red argillites of the Huronian Supergroup. The results indicate that the magnetization was acquired during the initial process of magnetization. The mean direction 337°, +52° (N=8; α95=8°) yields a pole at 158°E, 67°N (δp=8°; δm=11°). This and other recently published results indicate that the apparent polar motion relative to Laurentia for the 2.3 to 1.9 b.y. ago was mainly latitudinal and from north to south.
Influence of surface recombination in satellite atomic oxygen measurements inferred from the AEROS‐A mass spectrometer
Authors: Lake L. R. , Krankowsky D.
Published: February 2008

Although the assumption of complete and immediate recombination of atmospheric atomic oxygen at the surfaces of the open ion source of the AEROS‐A mass spectrometer is reasonable below 300 km, application of this assumption at higher altitudes results in a substantial underestimation of the ambient density of atomic oxygen. A two layer surface model seems necessary to explain the observations. Parameters for several surface reaction processes are estimated.
Observations of Jovian electron events in the vicinity of Earth
Authors: Krimigis S. M. , Sarris E. T. , Armstrong Thomas P.
Published: February 2008

A number of quiet‐time enhancements in the intensity of interplanetary electrons over the range 0.22 ≲ E ≲ 2.5 MeV have been observed with the JHU/APL experiment on the earth orbiting near‐circular (∼ 32 by 38 Re) Explorer 47 (IMP‐7) spacecraft during 1973 and 1974. These quiet‐time increases last from ∼ 3 to ∼ 20 days and are observed both in the interplanetary medium and inside the magnetotail. The main features of the observations are as follows: (a) The increases occur during the first 200 days of 1973 and from day ∼ 20 to ∼ 230 in 1974. (b) The intensity onset is relatively slow (1 to 2 days) when compared to either solar electron events or magnetospheric electron bursts, (c) The electron energy spectrum is quite distinct from that of solar or magnetospheric electrons and is consistent with γ = 1.3±0.3 in a differential power law spectrum. (d) Significant anisotropies are present, several days after the onset of the increase. (e) Some distinct fluctuations appear in some of the intensity profiles, suggesting the presence of a modulated source. The appearance of these enhancements occurs during times when the earth could be magnetically connected to the magnetosphere of Jupiter, assuming typical solar wind velocities. Further, the energy spectrum is not unlike that observed by instrumentation on Pioneer 10 in the vicinity of Jupiter. On the basis of the above it is reasonable to suggest that the observed electrons may be of Jovian origin. The implications of these results are discussed, and it is suggested that interconnection between the interplanetary and Jovian magnetic field takes place. Using this concept, a length of the Jovian magnetotail of ∼4.6 AU is computed.
The lower ionosphere of Mars
Authors: Whitten R. C. , Poppoff I. G.
Published: February 2008

It is suggested that a recent observation of an apparent lower ionosphere on Mars may be due to ionization by galactic cosmic rays.
High‐order magnetic multipoles as a source of gross asymmetry in the distant Jovian magnetosphere
Authors: Dessler A. J. , Hill T. W.
Published: February 2008

The longitudinal asymmetry of the surface magnetic‐field strength at Jupiter causes a longitudinal asymmetry in the equatorial plasma mass density within the Jovian magnetosphere. The rotation of these density variations with the planet causes a diurnal variation of the radial distance on the night side at which the centrifugal stress of the magnetospheric plasma exceeds the local magnetic‐field tension. This is approximately the distance at which the magnetic field opens to interplanetary space; we estimate that the opening distance can vary by as much as 14% as a result of the observed surface field asymmetry. Such a diurnal variation of the boundary of the particle trapping region can account for the observed ten‐hour modulation of relativistic electrons emitted from Jupiter into interplanetary space.
On the triggering of an isolated magnetic substorm: A theory
Authors: Sinha M. , Sundaram A. K.
Published: February 2008

We propose a high frequency electromagnetic instability of non resonant type, driven by cross current as a source for the onset of substorm expansion phase and the field line reconnection beyond 15RE. By including a normal component of the tail field, BZ, we find that the instability can be quenched provided BZ exceeds certain threshold value ‐ 1.8 × 106√Te/λ gauss (0.06 γ, for typical values in the neutral sheet).
Filamentation of large amplitude whistler waves
Authors: Stenzel R. L.
Published: February 2008

A filamentation instability of large amplitude whistler waves is observed in a laboratory experiment. The radiation pressure of the wave creates a field‐aligned density trough (δne/ne ≃ 40%) in which the wave is ducted. It is predicted that similar nonlinear effects may arise in the ionosphere in connection with the planned high power whistler wave experiments of the AMPS mission.
The magnetic moment of Venus: Venera‐4 measurements reinterpreted
Authors: Russell Christopher T.
Published: February 2008

Re‐examination of the Venera‐4 magnetic field measurements at Venus encounter suggests that Venus may have an intrinsic magnetic dipole moment of about 6.5×1022 Gauss‐cm³ which corresponds to a surface field of 30 gammas (1γ=10−9 Tesla).
Limitation of fertilizer induced ozone reduction by the long lifetime of the reservoir of fixed nitrogen
Authors: Liu S. C. , Cicerone R. J. , Donahue T. M. , Chameides W. L.
Published: February 2008

Stratospheric ozone is destroyed catalytically by nitrogen oxides originating from N2O produced by denitrifying bacteria at the surface of the earth. Concern has been expressed that major perturbations in N2O production will result by the beginning of the 21st century because of increased use of industrially produced fertilizers. It is pointed out here that the reservoir of fixed nitrogen is so large that the time required to produce a significant increase in N2O production from denitrification is probably many hundreds of years.
On the half‐life of 228Ra and the errors in oceanographic data due to use of the 6.7 year (wrong) value
Authors: Reid David F.
Published: February 2008

Through 1975 published measurements of 228Ra in most geochemical samples have been calculated using a 6.7 year half‐life for 228Ra. The currently accepted half‐life is 5.75 years and was established in 1962. Measurements as early as 1908 indicated a value of about 5.5 years, but a 1918 measurement giving a 6.7 year half‐life was adopted and remained unchallenged until 1960. Seawater 228Ra activities calculated using a 6.7 year half‐life are probably no more than 4% low, and approximately 2% low on the average. Therefore, data that have appeared in the literature are not significantly altered by the new value. Diffusion coefficients derived from the distribution of 228Ra in seawater are generally 8% to 20% low due to possible errors in the calculated activities and use of the wrong decay constant. Coral growth rates derived from the distribution of 228Ra in modern corals are about 14% low.
Microwave radiometric detection of atmospheric internal waves
Authors: Martin L. U. , Beard C. I.
Published: February 2008

Microwave radiometers have recently demonstrated a new capability by detecting internal waves in the atmospheric boundary layer and localizing their altitude. Varying the intersection height of a narrow antenna beam with that of a wide vertically pointing antenna beam allowed determination of the wave altitudes. The ground‐based radiometers were located at San Diego where, in an experiment in May‐June 1975, the Naval Electronics Laboratory Center provided "atmospheric‐truth" for comparison to the radiometer data obtained by the Naval Research Laboratory. Preliminary results showed cases of correspondence between the signals of the passive radiometers and the active FM‐CW radar and acoustic sounder systems. Examples included internal wave trains up to an hour in length.
Ground level detection and feasibility for monitoring of several trace atmospheric constituents by high resolution infrared spectroscopy
Authors: Bradford C. M. , Murcray F. H. , VanAllen J. W. , Brooks J. N. , Murcray D. G. , Goldman A.
Published: February 2008

Ground‐based infrared solar spectra at an unapodized resolution of 0.06 cm−1 are presented showing the detection of HNO3, CF2Cl2 and CFCl3 in the atmosphere and demonstrating the feasibility of ground monitoring of these species. Similar data indicate that higher resolution and/or a high altitude site are required for detection and monitoring of NO and HCl from the ground. Calculations show that it may be possible to monitor NO2 from a high mountain station using this method.
Comparison of neutral temperatures inferred from instruments on the AE‐C satellite
Authors: Hedin A. E. , Spencer N. W. , Hanson W. B. , Bauer P.
Published: February 2008

Four determinations of neutral thermospheric temperature from data taken with instruments aboard the AE‐C spacecraft have been compared during the circular orbit phase in late December 1974 and January 1975 when the satellite altitude was near 260 km. These temperatures are found to be in overall agreement to within about 10% during periods of low magnetic activity (Ap < 12). The methods are based on: (1) analysis of the satellite spin modulation of N2 density; (2) analysis of the ion temperature; (3) and (4) the calculation of the temperature needed to match measured N2 and Ar densities assuming fixed boundary conditions at 120 km. Systematic differences are observed such that the ‘argon temperature’ increases the most from winter to summer and ion temperature the least.
Comparison of stratospheric ozone destruction by fluorocarbons 11, 12, 21, and 22
Authors: Robbins Donald E. , Stolarski Richard S.
Published: February 2008

Measured photoabsorption cross sections for fluorocarbons (FC) 11, 12, 21, and 22 are presented for the wavelength region from 1740Å to about 2200Å. Solar radiation in this region dissociates these molecules in the stratosphere releasing atomic chlorine which participates in catalytic reactions that destroy ozone. Photolysis by solar UV is the only known loss mechanism for FC11 and FC12. However, FC21, and FC22 also react with OH in the troposphere reducing the amount of ground level releases which reach the stratosphere. Calculations comparing the steady state stratospheric ClX due to equal release rates of fluorocarbons 11, 12, 21, and 22 are presented using a range of OH profiles and eddy diffusion coefficients. These calculations indicate approximately a factor of 20 to 450 less ClX in the stratosphere for FC21 and a factor of 40 to 130 for FC22, compared to an equal release rate of FC11 and FC12.
Near bottom velocity and temperature profiles observed by cyclesonde
Authors: Mercado A. , Van Leer J.
Published: February 2008

Three days of twice hourly temperature and velocity profile data were obtained on the southwest Florida Continental Shelf. Measurements in the bottom boundary layer were made with a Cyclesonde to within 5m of the bottom in a depth of 200m with an average vertical resolution ∼ 5m. In the lowest 30m, temperature was nearly constant and the current vectors rotated clockwise from the bottom upward as in an Ekman spiral (total angle of veering ∼ 13°‐18°), while in the 20m immediately above, the velocity was nearly constant. The bottom stress, τ o =0.22 to 0.48 dynes/cm ² was estimated by determining the non‐geostrophic mass transport within the friction layer. The similarity constant relating the total veering angle and the geostrophic drag coefficient was about 2 to 3. The ratio of the boundary layer thickness to u * /f was about 0.3 to 0.4.
Halocarbon decomposition by natural ionization
Authors: Campbell Malcolm J.
Published: February 2008

A significant natural sink for halocarbons may exist in ion‐molecule reactions in the troposphere. Laboratory measurements, under conditions approximating the real atmosphere in all respects except ion age, show large rate constants for removal of CCl4 and CFCl3, apparently by atmospheric ions. The rate constant for CF2Cl2 is much smaller. If the same rate constants hold for older ions, the lifetimes against removal by this mechanism in the atmosphere are about 41 yr for CCl4 and 70 yr for CFCl3. Under steady state conditions a sink of this magnitude may decrease the global concentration of CFCl3 by a factor two.
Calculations of equatorial scintillations at VHF and gigahertz frequencies based on a new model of the disturbed equatorial ionosphere
Authors: Costa Emanoel , Kelley M. C.
Published: February 2008

The weak scattering, thin screen theory of scintillation of radio stars and satellites has been applied, in a mathematically rigorous way, to the observations of the plasma density structure deduced from rocket and radar measurements during equatorial spread F conditions. It is shown that bottomside spread F is capable of producing moderate scintillation at VHF, but not at gigahertz frequencies. Upwelling regions of depleted plasma density however, such as those described in several recent publications, are shown to have properties that could cause intense VHF scintillations as well as scintillations in the gigahertz range.
Solar wind and extreme ultraviolet modulation of the lunar ionosphere/exosphere
Authors: Freeman John W.
Published: February 2008

The ALSEP/SIDE detectors routinely monitor the dayside lunar ionosphere. Variations in the ionosphere are found to correlate with both the 2800 MHz radio index which can be related to solar EUV and with the solar wind proton flux. For the solar wind, the ionospheric variation is proportionately greater than that of the solar wind. This suggests an amplification effect on the lunar atmosphere due perhaps to sputtering of the surface or, less probably, an inordinate enhancement of noble gases in the solar wind. The surface neutral number density is calculated under the assumption of neon gas. During a quiet solar wind this number agrees with or is slightly above that expected for neon accreted from the solar wind. During an enhanced solar wind the neutral number density is much higher.
The densities and bulk compositions of Ceres and Vesta
Authors: Morrison David
Published: February 2008

Present radiometric and polarimetric measurements of the sizes and albedos of asteroids 1 Ceres and 4 Vesta, although uncertain in absolute calibration, determine the ratio of diameters with sufficient precision (Ceres/Vesta = 1.87 ± 0.03) to permit meaningful discussion of their relative densities. These measurements combined with the known masses yield a ratio of densities Vesta/Ceres = 1.33 ± 0.17, thus demonstrating that: (1) the bulk compositions are likely different, and (2) the difference is consistent with indications from remotely‐determined surface composition that Vesta is differentiated while Ceres may be of undifferentiated carbonaceous chondritic composition.
VLF hiss generated by supra‐thermal electrons
Authors: Boswell R. W.
Published: February 2008

Experiment results are presented which show that electrostatic cyclotron harmonic (Bernstein) waves generated by supra‐thermal electrons can decay parametrically into whistler mode waves with very high efficiency. The spectral intensity of the whistler mode waves so produced has a maximum at twice the lower hybrid frequency. It is proposed that this is the dominant process responsible for the generation of VLF hiss and the so‐called VLF saucers.
Tornado‐parent storm relationship deduced from a dual‐Doppler radar analysis
Authors: Ray Peter S. , Hane Carl E. , Davies‐Jones Robert P. , Alberty Ronnie L.
Published: February 2008

Two Doppler radars at the National Severe Storms Laboratory were used to measure a tornadic storm wind field. The derived wind fields suggest dynamical contributions to storm organization and development. Location of the vortex with respect to the parent circulation is consonant with the veering of the damage path to the right of storm motion. Wind fields derived from the radar observations indicate vorticity production processes important to tornado maintenance.
Potential of soil as a sink for atmospheric nitrous oxide
Authors: Blackmer A. M. , Bremner J. M.
Published: February 2008

Recent articles concerning the potential effect of nitrous oxide (N2O) on stratospheric ozone have emphasized the need for research to identify sources and sinks of atmospheric N2O. Work reported shows that soils have a significant capacity for uptake of N2O and may represent an important natural sink for atmospheric N2O. Uptake of N2O by soils is a microbial process involving reduction of N2O to N2. It is promoted by anaerobic conditions and by organic substances that promote growth of soil microorganisms, and it is retarded by nitrate. Studies with nine Iowa surface soils showed that their capacity for uptake of N2O under conditions favorable for denitrification of nitrate was much greater than their capacity for release of this gas.
Mass spectrometric observation of SO2 in the stratosphere
Authors: Sagawa E. , Itoh T.
Published: February 2008

A newly developed mass spectrometer which employs a sputter ion pump was flown on a balloon in May, 1975, and obtained mass spectra for neutral constituents in the stratosphere. The measured mass spectra show an abnormally high concentration at the mass number of 64, to be about 30 ppm. This particular component has a similar altitude profile to that of the aerosols, and could be assigned to sulfur dioxide. Such a high concentration of SO2 that was measured in this flight may be partly associated with the eruption of Mt. Fuego.
The extreme ultraviolet (750‐1230 A) spectrum of an aurora
Authors: Park H. , Feldman P. D. , Fastie W. G.
Published: February 2008

Extreme ultraviolet auroral spectra have been obtained in the wavelength range of 750‐1230 A resolution with a rocket‐borne grating spectrometer. Atomic emissions of NI, NII, OI and OII are the dominant features along with geocoronal HI Lyman α. N2 emission bands, which appear strongly in laboratory electron impact spectra, appear only as a modest background continuum between 900 to 1100 A. The observed intensities are consistent with electron impact excitation of O and N2. For optically thick emissions, such as NI λ1200, radiation transport along the arc results in an intensity enhancement when viewed through the arc towards the zenith.
Q of shear waves estimated from S – SS spectral ratios
Authors: Brune James N.
Published: February 2008

Q for S waves has been estimated by amplitude correlation of S and SS waves. The Q corresponding to the average Q−1 value is 131 ± 8. There is an indication that the Q values increase with distance, from about 100 at 30° to about 250 at 70° (correlation coefficient .56). The value of 250 at 70° is compatible with the value of 156 found by Jordan and Sipkin (1977) for ScS in the western Pacific Ocean.
Satellite observation of internal wave refraction in the South China Sea
Authors: Fett Robert , Rabe Kevin
Published: February 2008

A visible image for 21 May 1973 obtained from the DMSP satellite suggests the occurrence of internal waves refracting around the Pratas Islands in the South China Sea. Arguments are presented suggesting that the waves are tidally forced along the density interface prevalent for that area during the spring season.
A quiet band produced by VLF transmitter signals in the magnetosphere
Authors: Raghuram R. , Bell T. F. , Helliwell R. A. , Katsufrakis J. P.
Published: February 2008

Signals from a VLF transmitter suppress magnetospheric mid‐latitude hiss in a band up to 200 Hz wide located just below the transmitter frequency. These quiet bands take 5 to 25 s to develop and last more than 30 s after the end of transmissions. The modification of the electron velocity distribution function by the transmitter signals is a possible explanation for this new phenomenon.
Comment on low energy electron measurements in the Jovian magnetosphere
Authors: Grard R. J. L. , DeForest S. E. , Whipple E. C.
Published: February 2008

We suggest that the low energy electrons reported by Intriligator and Wolfe (1974) in the outer magnetosphere of Jupiter may actually be photoelectrons and/or secondary electrons from the Pioneer spacecraft surfaces. The electron spectrum is similar to the observed photoelectron spectrum on earth‐orbiting satellites where differentially charged surfaces have deflected the electrons into particle detectors.
Twilight ozone measurement by solar occultation from AE 5
Authors: Guenther B. , Dasgupta Ranjit , Heath Donald
Published: February 2008

The BUV on AE 5 was used for a solar occultation measurement of atmospheric ozone. An observation was carried out during the morning twilight near 5°N, December 17, 1976, at a fixed wavelength of 255.5 nm, and a profile between 49 and 82 km was obtained. The number densities determined by this measurement were 3.7 × 1010 cm−3 at 50 km, 5.1 × 109 at 60 km, 3.9 × 108 at 70 km and 3.0 × 107 at 80 km. No evidence of a high altitude secondary maximum was found. These concentrations are between a factor of 4 and 20 smaller than those midnight results reported from a Copernicus measurement, and similar to the values from the Krueger‐Minzner Mid‐Latitude Model above 55 km. These values may be as much as a factor of 2 less than the Krueger‐Minzner Model below 50 km.
Monitoring surface albedo change with Landsat
Authors: Otterman J.
Published: February 2008

A pronounced decrease of the surface albedo (reflectivity) has been observed in an area in the Northern Sinai, fenced‐in in the summer of 1974. Analysis of the LANDSAT Multispectral Scanner System digital data from an April 1977 pass indicates a reduction in the albedo in the exclosure by Δa = 0.06, or 13%, as compared to the outside, which continues to be subjected to overgrazing and anthropogenic pressures. The reduction of reflectivity is approximately the same in all the spectral bands, and is therefore attributable to accumulation of dead plants and plant debris, and not directly to live vegetation.
Ferrobasalts from Mare Crisium: Luna 24
Authors: Vaniman D. T. , Papike J. J.
Published: February 2008

Soils from the Soviet Luna 24 mission to Mare Crisium contain fragments of ferrobasalt and ferrogabbro. The ferrobasalt is very low in Ti content (∼ 1.0 wt.% TiO2), similar to very low Ti “VLT” basalts from Apollo 17. It is characterized by Mg/(Mg + Fe) ∼ 0.3‐0.4, Al2O3 ∼ 13%, CaO ∼ 13%, and Cr2O3 ∼ 0.2‐0.3%. Brown glasses and micropoikilitic fragments similar to the ferrobasalt occur in the Crisium soils, and green glasses similar to the Apollo 17 VLT basalt have been found. There is growing evidence that very low Ti basalts may be an abundant mare basalt type; there is a possibility that this suite may be derived by crystal fractionation from magma similar to green glass in composition.
The mechanism for ultraviolet photolysis of gaseous chlorine nitrate at 302.5 nm
Authors: Smith W. S. , Chou C. C. , Rowland F. S.
Published: February 2008

The laboratory photolysis of chlorine nitrate (ClONO2) with 302.5 nm ultraviolet light leads to the destruction per quantum of 4 molecules of ClONO2 and the formation of 1 molecule of O2, 2 of Cl2 and 2 of N2O5. These quantum yields are not consistent with the current assumption that the primary photolysis step for ClONO2 in the stratosphere leads to the formation of ClO plus NO2. A consistent mechanism exists in which the photolytic step involves the decomposition of ClONO2 to ClONO + O(³P). The onset of observed absorption of radiation by ClONO2 corresponds approximately to the thermodynamic accessibility of this simple splitting away of an O atom.

The photolysis of ClONO occurs very rapidly in the stratosphere, either to Cl + NO2 or ClO + NO. The substitution of either Cl + NO2 + O or ClO + NO + O for ClO + NO2 as the eventual photolysis products from ClONO2 is not expected to cause appreciable alteration in predictions from stratospheric modeling.
Microseismicity near the Indian Ocean triple junction
Authors: Solomon Sean C. , Mattaboni Paul J. , Hester Richard L.
Published: February 2008

During March 1976 a three‐component ocean bottom seismometer was dropped for two weeks near the RRR triple junction near 25°S, 70°E in the central Indian Ocean to monitor microseismicity. The seismometer, using a digital event recorder scheme, recorded 38 earthquakes, about half of which were local events within 5 to 40 km epicentral distance. These near events had nominal local magnitudes of 0 to 1.5, seismic moments of 1017 to almost 1019 dyne‐cm, and S wave corner frequencies of 15 to 25 Hz. The moment versus fault dimension relation for these earthquakes scales as for larger events on other spreading centers, suggesting similar stress drops. Thus any thermal or mechanical differences between the triple junction and other ridge crest and transform systems is not reflected in the character of locally generated earthquakes.
Stratospheric nitric oxide and ozone measurements using photoionization mass spectrometry and UV absorption
Authors: Maier E. J. , Aikin A. C. , Ainsworth J. E.
Published: February 2008

Nitric oxide has been measured in situ between 38.4 and 29.8 km by a new technique, photoionization mass spectrometry. Data indicate a peak mixing ratio of 5.7 ± 0.35 ppbv at 37.5 km and only 0.2 ± 0.2 ppbv at 32.8 km with a sharp gradient in concentration between 33 and 34 km. Simultaneous in‐situ measurements of the ozone concentration show no significant feature at that altitude. The rapid decrease in mixing ratio is not predicted by current theory.
Electrostatic shocks, double layers, and anomalous resistivity in the magnetosphere
Authors: Hudson M. K. , Mozer F. S.
Published: February 2008

Electrostatic shocks and double layers are defined, discussed and compared with anomalous resistivity. It is suggested that turbulence and anomalous resistivity may provide local modification of particle distribution functions essential to the production of electrostatic shocks and double layers in space plasmas.