bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of polar cap boundary and daytime cusp structure using the characteristics of precipitating ions
Authors: Troshichev O. A. , Shishkina E. M.
Published: February 2008

Particle data obtained from the Defense Meteorological Satellite Program spacecraft for periods of northward interplanetary magnetic field show that ion spectra above the polar cap arcs usually display the same character as those in the midnight auroral oval. Evidently, this means that polar cap arcs and the midnight oval arcs have the same source. At the same time ion spectra in spikes of particle precipitation in the discrete oval vary with MLT in a regular manner, such that the flux of ions in the energy range 0.1 < Ei < 1 keV increases from midnight toward noon. This feature of ion spectra makes it possible to identify the boundary of the polar cap from the precipitation patterns when the interplanetary magnetic field is northward. The structural zones such as the cusp proper and the poleward and equatorward edges of the cusp can be separated from the daytime oval region using specific features of the ion spectra. The ion population in all these zones is composed of three parts, namely, the mantle, the cusp, and the low‐latitude boundary layer plasmas. Densities of all plasma fractions are maximal in the cusp proper and decrease when moving toward the cusp periphery.
Paleomagnetic constraints on the initiation of uplift on the Santa Susana Fault, Western Transverse Ranges, California
Authors: Levi Shaul , Yeats Robert S.
Published: February 2008

The Plio‐Pleistocene nonmarine Saugus Formation is widely exposed in the east Ventura basin and the northern San Fernando Valley, north and south of the Santa Susana fault. In the east Ventura basin, the Saugus is overlain by the Pacoima Formation. Magnetostratigraphy of the fine‐grained Saugus and Pacoima strata and the presence of the 0.76 Ma Bishop ash are used to calculate their average sedimentation rates: 0.9 km/m.y. in the east Ventura basin and 1.1 km/m.y. in the northern San Fernando Valley. Extrapolation of the Saugus and Pacoima sedimentation rates shows that they were deposited from about 2.3 to 0.5 Ma both north and south of the Santa Susana fault. The shift from remote to locally derived clasts marks the initiation of uplift of the Santa Susana Mountains. The extrapolated age of this boundary is about 0.7–0.6 Ma.
Chlorine activation and ozone depletion in the Arctic vortex: Observations by the Halogen Occultation Experiment on the Upper Atmosphere Research Satellite
Authors: Müller Rolf , Crutzen Paul J. , Grooß Jens‐Uwe , Brühl Christoph , Russell James M. , Tuck Adrian F.
Published: February 2008

Chlorine‐catalyzed ozone destruction is clearly observed during austral spring in the Antarctic lower stratosphere. While high concentrations of ozone‐destroying ClO radicals have likewise been measured during winter in the Arctic stratosphere, the chemical ozone depletion there is more difficult to quantify. Here we present observations of the Halogen Occultation Experiment on the Upper Atmosphere Research Satellite in the vortex region of the Arctic lower stratosphere during the winter and spring months of 1991/1992, 1992/1993, 1993/1994, and 1994/1995. All February measurements indicate an almost complete conversion of the otherwise main chlorine reservoir species HCl to chemically more reactive forms. Using CH4 as a chemically conserved tracer, we show that significant chemical ozone loss occurred in the Arctic vortex region during all four winters. The deficit in column ozone was about 60 and 50 Dobson units (DU) in the winters 1991/1992 and 1993/1994, respectively. During the two winters of 1992/1993 and 1994/1995 a severe chemical loss in lower‐stratospheric ozone took place, with local reductions of the mixing ratios by over 50% and a loss in the column ozone of the order of 100 DU.
Analysis of the interference due to differential rain attenuation induced by an adjacent path on a dual‐site diversity Earth‐space system
Authors: Kanellopoulos J. D. , Ventouras S.
Published: February 2008

Knowledge of interference effects are of the utmost importance to the reliable design of satellite communication systems. In this paper interference caused by differential rain attenuation from an adjacent Earth‐space system operating at the same frequency is considered as dominant. In particular, a method to predict rain differential attenuation statistics used for single‐site Earth‐space systems is extended to include dual‐site diversity systems. Just as with the original method the modified one is again based on a model of convective rain cells and on the lognormal model for point rainfall rate statistics. The effects of various parameters on the diversity gain, corresponding to the carrier‐to‐interference ratio, are calculated numerically, leading to some very useful conclusions.
In Situ Measurement of the Solute Adsorption Isotherm Using a Disc Permeameter
Authors: Clothier Brent E. , Magesan G. N. , Heng Lee , Vogeler Iris
Published: February 2008

In situ observations of the resident concentration and penetration of reactive chemical underneath a disc permeameter are used to infer the adsorption isotherm that characterizes soil‐solution exchange in two structured soils. In permeameters set to the unsaturated head of −40 mm, the use of the dual tracers of inert bromide and reactive 35S, in two contrasting soils, enabled resolution of their sulfate adsorption isotherms. In Manawatu fine sandy loam, a mobile‐immobile water soil, measurements of the resident concentration of 35S and Br− under the disc showed sulfate to be only weakly adsorbed. However, an analytical solution for the one‐dimensional dispersive entry of reactive chemical into soil indicated that for any degree of adsorption,substantial depths of infiltration (≫200–300 mm) would be required for the adsorbed concentration (S, mol kg−1) to reach equilibrium with the concentration of the influent solution (c, mol L−1). But this same equation showed that under the disc, the retardation of the reactive chemical (35S) behind the inert tracer (Br−) could be used to infer the strength of the adsorption exchange. When carried out at two different concentrations, this retardation procedure can be used to infer the nonlinear Freundlich isotherm of exchange. In the Ramiha silt loam, a fully mobile water soil, different retardations were observed during concurrent unsaturated infiltration of Br− and labeled sulfate at 20 μmol L−1 and at 2 mmol L−1 SO42−. The isotherm was found to be S=2.3c0.7. This is less than the S=3.0c0.53 measured by the standard batch procedure on saturated 1∶5 soil solution samples.
Aerosol black carbon measurements over the western Atlantic Ocean
Authors: Hansen A. D. A. , Novakov T.
Published: February 2008

During the aircraft operations phase of the Western Atlantic Ocean Experiment (WATOX) program conducted in January 1986 off the eastern seaboard of the United States, we performed measurements of the optically absorbing carbonaceous component of the ambient aerosol. We collected the aerosol on filters that were exposed for several hours; we also operated the aethalo meter to measure the concentration of aerosol black carbon in real time. The filter analyses represent averages over the altitude range and time span during which the filter was collecting. The real‐time results were sorted by altitude to calculate vertical profiles of black carbon concentration. Values typically ranged from 200 to 500 ng/m3 in the boundary layer, decreasing to 50 to 100 ng/m3 at higher altitudes. By multiplying the mean concentration profile by the offshore air flux, we may estimate the export of aerosol black carbon from the coast to be of the order of 5 × 1010 g/yr.
Potential methane production and methane oxidation rates in peatland ecosystems of the Appalachian Mountains, United States
Authors: Yavitt Joseph B. , Lang Gerald E. , Downey Daniel M.
Published: February 2008

Potential rates of methane production and carbon dioxide production were measured on 11 dates in 1986 in peat from six plant communities typical of moss‐dominated peatlands in the Appalachian Mountains. Annual methane production ranged from 2.7 to 17.5 mol m−2, and annual carbon dioxide production ranged from 30.6 to 79.0 mol m−2. The wide range in methane production values among the communities found within a single peatland indicates that obtaining one production value for a peatland may not be appropriate. Low temperature constrained the potential for methane production in winter, while the chemical quality of the peat substrate appears to control methane production in the summer. Methane oxidation was measured throughout the peat profile to a depth of 30 cm. Values for methane oxidation ranged from 0.08 to 18.7 uM h−1 among the six plant communities. Aerobic methane‐oxidizing bacteria probably mediated most of the activity. On a daily basis during the summer, between 11 and 100% of the methane produced is susceptible to oxidation within the peat column. Pools of dissolved methane and dissolved carbon dioxide in pore waters were less than 0.2 and less than 1.0 mol m−2, respectively, indicating that methane does not accumulate in the pore waters. Peatlands have been considered as an important source of biologically produced methane. Despite the high rates of methane production, the high rates of methane oxidation dampen the potential emission of methane to the atmosphere.
Seasonal variations in ebullitive flux and carbon isotopic composition of methane in a tidal freshwater estuary
Authors: Chanton Jeffrey P. , Martens Christopher S.
Published: February 2008

Methane carbon isotopic composition ranged from −76.9 to −62.6‰ in a tidal freshwater estuary (the White Oak River, North Carolina, United States) with site specific seasonal variations ranging from 6 to 10‰. During warmer months, tidally induced bubble ebullition actively transported this methane to the atmosphere. At two sites, these seasonally varying fluxes ranged from 1.2 ± 0.3 to 1.3 ± 0.3 mol CH4 m−2yr−1 (19.2 to 20.8 g CH4m−2yr−1), with flux‐weighted average isotopic compositions at two sites of −66.3 ± 0.4 and −69.5 ± 0.6‰. The carbon isotopic composition of naturally released bubbles was shown to be indistinguishable from the sedimentary methane bubble reservoir at three sites, leading to the conclusion that isotopic fractionation did not occur during the ebullition of methane. The hypothesis was developed that ebullitive methane fluxes are depleted in 13CH4 relative to fluxes transported via molecular diffusion or through plants, as zones of 13C enriching microbial methane oxidation are bypassed.
Using ecosystem models to predict regional CO2 exchange between the atmosphere and the terrestrial biosphere
Authors: King Anthony W. , O'Neill Robert V. , DeAngelis Donald L.
Published: February 2008

Ecologically sound models of the terrestrial biosphere are needed in the investigation of the Earth system and global change. Traditional ecosystem models simulate many processes and dynamics relevant to the functioning of the Earth system, but their application is limited by their local, small‐scale, often site‐specific nature. We address this limitation by deriving a method for predicting regional biosphere dynamics by extrapolation from smaller‐scale ecosystem models. We use models of local ecosystem carbon dynamics to predict the seasonal exchange of CO2 between the atmosphere and terrestrial ecosystems of 64°N to 90°N latitude. Monte Carlo simulation is used to integrate solutions of a tundra model and a coniferous forest model across within‐biome heterogeneity in the models' climatic driving variables. The product of the expected value of each model's output and the area of the region occupied by that biome or ecosystem type is an estimate of biome‐scale CO2 exchange. Regional CO2 exchange is the sum of the biome exchanges. Comparisons of the extrapolation's results with independent estimates of seasonal CO2 exchange and annual net primary production support the proposition that extrapolation of ecosystem models can be used to simulate regional biosphere dynamics.
Overview of the 1988 GCE/CASE/WATOX Studies of biogeochemical cycles in the North Atlantic region
Authors: Pszenny Alexander A. P. , Galloway James N. , Artz Richard S. , Boatman Joseph F.
Published: February 2008

The 1988 Global Change Expedition/Coordinated Air‐Sea Experiment/Western Atlantic Ocean Experiment (GCE/CASE/WATOX) was a multifaceted research program designed to study atmospheric and oceanic processes affecting the biogeochemical cycles of carbon, nitrogen, sulfur, and trace metals in the North Atlantic Ocean region. Field work included (1) a 49‐day research cruise aboard NOAA ship Mt. Mitchell (Global Change Expedition) from Norfolk, Virginia, to Bermuda, Iceland, the Azores, and Barbados, (2) eight flights of the NOAA King Air research aircraft, four off the Virginia Capes and four near Bermuda (CASE/WATOX), and (3) a research cruise aboard the yacht Fleurtie near Bermuda (WATOX). Objectives of GCE/CASE/WATOX were (1) to examine processes controlling the mesoscale distributions of productivity, chlorophyll, and phytoplankton growth rates in Atlantic surface waters, (2) to identify factors controlling the distribution of ozone in the North Atlantic marine boundary layer, and (3) to estimate the contributions of sources on surrounding continents to the biogeochemical cycles of sulfur, nitrogen, and trace metals over the North Atlantic region during the boreal summer season. The individual papers in this and the next two issues of Global Biogeochemical Cycles provide details on the results and analyses of the individual measurement efforts. This paper provides a brief overview of GCE/CASE/WATOX.
A technique using high‐flow, dichotomous filter packs for measuring major atmospheric chemical constituents
Authors: Bardwell C. A. , Maben J. R. , Hurt J. A. , Keene W. C. , Galloway J. N. , Boatman J. F. , Wellman D. L.
Published: February 2008

We developed a high‐resolution technique to measure major reactive trace gases and the chemical composition of size‐segregated aerosols in the troposphere as part of the 1988 Global Change Expedition/Coordinated Air‐Sea Experiment/Western Atlantic Ocean Experiment. We sampled air over the western North Atlantic Ocean from the NOAA King Air research aircraft and NOAA ship Mt. Mitchell during July. Our system used filter packs containing an upstream, 90‐mm quartz filter to collect particles followed by two 90‐mm rayon filters impregnated with 10% K2C03‐10% glycerol to collect alkaline reactive gases. Paired filter packs were exposed when the aircraft sampled the boundary layer. An upstream cyclone with a 50% aerodynamic cut radius of approximately 0.4 μm removed large particles from one of the filter‐pack inlets. Air was sampled at an average rate of 0.12 m3 STP min−1 for the fine filter packs and 0.26 m3 STP min−1 for the total over intervals of 45 min to 90 min. Particulate‐phase concentrations of major anions (SO42−, CH3SO3−, NO3−, Cl−) and organic species (HCOOt [HCOO− and HCOOH] and CH3COOt [CH3COO− and CH3COOH]) were measured by gradient elution ion chromatography; base cations (Ca2+, Mg2+, Na+, K+) by atomic‐absorption spectroscopy; NH4+ by automated colorimetry; and H+ by glass electrode. We quantified SO2, HNO3, and HCl using two isocratic ion chromatography methods. This technique provided higher signal‐to‐noise ratios allowing increased temporal and spatial resolution, pH determination of particulate‐phase filter extracts, and measurement of HCl on gas‐phase filters.
Horizontal diffusion and new production in the Sargasso Sea
Authors: Hitchcock Gary L. , Olson Donald B. , Knauer George A. , Pszenny Alexander A. P. , Galloway James N.
Published: February 2008

Estimates of vertical particulate carbon flux and inorganic nitrogen input from rain events were evaluated in relation to horizontal diffusion during a short‐term (4 days) study in the Sargasso Sea. Productivity (∼300 mg C m−2 d−1) and particulate organic C flux (l‐ratio of 0.17) from sediment trap arrays were similar to those recently documented in this region. The drifters traversed the periphery of a small anticyclonic eddy, and an estimate of horizontal diffusivity (∼3 to 10 × 104 cm2 s−1) was derived from relative drifter separation. The corresponding length scale (a few kilometers) and time scale (a day) is related to the effective collection area from which drifting sediment traps can sample the surrounding environment. Measurements of inorganic nitrogen from two rain events were similar to those in a more extensive series of observations from Bermuda. The summer Bermuda data are used to evaluate the inorganic nitrogen input to the oligotrophic surface waters with respect to phytoplankton uptake rates and horizontal diffusion. For small, convective rain events, diffusion may be as important as phyloplankton uptake in reducing nitrogen concentrations to ambient nanomolar levels.
K‐Ar dating: Addition of atmospheric argon on rock surfaces from crushing
Authors: Keeling David L. , Naughton John J.
Published: February 2008

The amount of atmospheric argon uptake from crushing rock samples in air was measured for an alkalic and tholeiitic basalt, basaltic glass, and a gabbro, to evaluate its importance as a limitation in K‐Ar dating. A small decrease in air argon was sometimes observed as a result of initial crushing and/or mild acid treatments. Argon was acquired in significant quantities only in the sizes smaller than 250 mesh (63µ), and the amount was related to the surface area but it apparently was not held by simple adsorption. The use of crushed samples as opposed to large chunks or blocks for dating young rocks is suggested.
Whistler‐like pulsation events in the frequency range 20 to 200 Hz
Authors: Heacock R. R.
Published: February 2008

A class of events, sweeping down in frequency, occurring between 20 and 200 Hz, were observed for the first time. The observing site is at Poker Flat, Alaska, 65°N. Characteristics include a daytime diurnal maximum, an apparent seasonal minimum in winter, a tendency for maximum occurrences on magnetically quiet days, and a typical event duration of ∼1 minute. The events occur at the same frequencies as a type of hiss observed on OGO‐5 (Kivelson and Russell, 1973) and a class of events observed on Injun 5 called ‘lion's roar’ (Gurnett and Frank, 1972), but the spectral form of the events observed on the ground is quite different from either of those types.
Atmospheric HT and HTO: Major HT injections into the atmosphere 1973
Authors: Mason A. S. , Östlund H. G.
Published: February 2008

Two major injections of tritium gas into the atmosphere occurred in late 1973. They appeared to originate from underground nuclear detonations, and were detected by our sampling stations at Fairbanks, Alaska; at Miami, Florida; and at Mauna Loa Observatory, Hawaii. Total injected amount is estimated at 80 g of tritium.
A random medium analysis of crust and upper mantle structure under Norsar
Authors: Capon J. , Berteussen K. A.
Published: February 2008

A random medium analysis based on Chernov's (1960) theory has been performed for the crust and upper mantle under NORSAR (Norwegian Seismic Array). It is found that the Chernov theory may not be applicable to the problem of scattering of the P‐waves under the array.
Evidence for chemiexcitation as the source of the sodium nightglow
Authors: Sipler D. P. , Biondi Manfred A.
Published: February 2008

Spectral line profiles of the D1 and D2 sodium line emission from the twilight and the nightglow have been obtained by means of a 150 mm aperture Fabry‐Perot interferometer. The observed doppler broadening of the twilight profiles yields a temperature for the emitting atoms of (210 ± 15) K, in good agreement with the expected temperature of the sodium layer at ∼ 90 km. By way of contrast, the nightglow line profiles are found to be much broader, their width yielding an apparent temperature of (600 ± 50) K. It is shown that chemiexcitation is the most likely process which imparts kinetic energies in excess of ambient thermal values to the emitting atoms.
Detection of fluorocarbons in the stratosphere
Authors: Murcray D. G. , Bonomo F. S. , Brooks J. N. , Goldman A. , Murcray F. H. , Williams W. J.
Published: February 2008

Infrared laboratory absorption spectral measurements of CF2Cl2 and CFCl3 are applied to balloon flight data of August 12, 1968. A volume mixing ratio of 5 × 10−11 is derived for CF2Cl2 and a probable volume mixing ratio of 2 × 10−11 is estimated for CFCl3. These values are compared with calculations by Crutzen and by Cicerone et al. for 21 km. In addition, an upper limit for HF in the lower stratosphere up to 30 km is set at 3 × 10−10 v/v for September 30, 1965.
Inductive electric field of a time‐dependent magnetotail current
Authors: Murphy C. H. , Wang C. S. , Kim J. S.
Published: February 2008

The inductive electric field produced by a time‐dependent magnetotail current system is investigated using a simple model. The model current system used in these calculations is a ‘theta’ representation consisting of a flat sheet of current flowing westward to represent the neutral sheet and return currents flowing eastward on the boundary of the tail. Assuming realistic parameters for the dimensions and strength of the current system and a linear variation of the current during times of magnetic activity, it is found that the inductive electric field is predominantly in the east‐west direction, and is fairly uniform over a large range of east‐west and antisolar directions. An east‐west inductive electric field of as much as 0.70 mv/m is produced during substorms by a time variation of the tail current which corresponds to a rate of change of the total magnetic field near the inner edge of the neutral sheet of about 10−2γ/sec.
Surface ozone in the South East Atlantic between Dakar and Walvis Bay
Authors: Stallard R. F. , Edmond J. M. , Newell R. E.
Published: February 2008

A continuous section of surface ozone concentration in the eastern equatorial and southern tropical Atlantic shows maximum values (30–48 ppbV) in the ITCZ with low uniform values (13–15 ppbV) in the southeast trades. The high values are associated with mesoscale downdrafts in the convergence region. The southerly data show diurnal variations with night‐time maxima the amplitude of which increases landwards. These are probably caused by atmospheric cooling over the warm ocean.
Reawakening of Mauna Loa Volcano, Hawaii: A preliminary evaluation of seismic evidence
Authors: Koyanagi Robert Y. , Endo Elliot T. , Ebisu Jennifer S.
Published: February 2008

Following many years of few earthquakes, the seismicity of Mauna Loa increased markedly in 1974. Well determined foci of 171 earthquakes with magnitudes between 1.5 and 4.6 in 1974, as well as the locations of other earthquakes from 1962 to 1973, outline a broad seismic zone around the summit. Most earthquakes are at depths less than 15 km; some are as deep as 50 km. The significant increase in seismicity, combined with expansion measured at the summit, suggest that Mauna Loa may be reawakening after nearly 25 years of quiescence.
Cratering and cosmogenic nuclides
Authors: Blake Michael L. , Wasserburg G. J.
Published: February 2008

A simple probabilistic model was constructed for the average value of a cosmogenic nuclide as a function of depth in a regolith. An arbitrary function was chosen for the size distribution of craters. The resulting integro‐differential equation was found to reduce in limiting cases to: 1) the marching equation with a characteristic residence time, and 2) to the diffusion equation. The regolith diffusion constant is shown to be a simple integral of the cratering rate weighted by geometrical terms. This formal treatment provides a direct and general connection between cosmogenic nuclides and cratering rates and crater population in a simple analytical form. The validity of this model remains to be tested.
On the generation of magnetohydrodynamic waves at the onset of a substorm
Authors: Chang R. P. H. , Lanzerotti L. J.
Published: February 2008

Theoretical analysis of magnetoacoustic waves driven unstable by a neutral charged‐particle beam suggests that such waves can be generated in the plasma sheet at the onset of a substorm. It is further suggested that the magnetohydro‐dynamic waves observed to occur at the onset of substorms (often called Pi2 pulsations) may be attributed to the coupling of the magnetoacoustic waves to shear Alfvén waves on locally‐resonant field lines on the nightside of the earth. Experimental determinations of the distribution of resonant field lines for various frequency components of the waves, together with the theoretical concepts, can ultimately yield information on the inward velocity of hot plasma particles at substorm onsets.
Rocket and ground‐based measurements of the dayside magnetospheric cleft from Cape Parry, N.W.T.
Authors: Shepherd G. G. , Pieau J. F. , Creutzberg F. , McNamara A. G. , Gerard J. C. , McEwem D. J. , Delana B. , Whitteker J. H.
Published: February 2008

On Dec. 6, 1974, a Black Brant VB rocket was launched from Cape Parry, N.W.T. into the dayside magnetospheric cleft. The prime launch criterion was the detection of 6300 Å emission by two ground based scanning photometers, but support was provided by two ionosondes. The payload passed through a narrow region of several ergs cm−2 sr−1 sec−1 of soft electron precipitation, a broader region of enhanced electron densities, and a similarly broad region of 0I5577 and 6300 Å emission. At apogee of 236 km the payload had not penetrated into the 5200 Å emission, which had a very sharp equatorward boundary, and extended far into the polar cap, presumably as a result of anti‐sunward convection.
Measurements of atmospheric ozone made from a Gasp‐equipped 747 airliner: Mid‐March, 1975
Authors: Falconer Phillip D. , Holdeman James D.
Published: February 2008

Atmospheric trace constituents in the upper troposphere and lower stratosphere are now being measured as part of the NASA Global Atmospheric Sampling Program (GASP), using fully automated air sampling systems on board commercial 747 aircraft in routine airline service. Measurements of ozone mixing ratio and related meteorological information obtained during several GASP flights in March, 1975 are reported. The height of the tropopause during these flights was obtained from National Meteorological Center (NMC) gridded data. Good agreement is observed between the tropopause heights and the GASP ozone, wind, and static air temperature data. The data presented show examples of upper tropospheric and lower stratospheric ozone mixing ratio variations, both as a function of geographical location and aircraft altitude.
Crater populations in the early history of Mercury
Authors: Guest John E. , Gault Donald E.
Published: February 2008

Crater populations on two major geologic units of Mercury have been classified into three morphologic types which characterize their state of degradation. The results indicate that one or more processes either prior to or contemporary with the formation of the 1300 km diameter Caloris Planitia reduced the population of fresh craters smaller than 70‐80 km diameter and totally erased the population of fresh craters smaller than 20‐30 km.
The structure of stationary planetary waves in winter in relation to the polar night jet intensity
Authors: Schoeberl Mark R. , Geller Marvin A.
Published: February 2008

The structure of stationary planetary waves in winter and the dependence of this structure on the intensity of the polar night jet is studied by means of calculations using a quasi‐geostrophic model on a sphere. Results indicate that planetary wave structure is strongly dependent on the magnitude of the polar night jet. There appears to be reasonable agreement between these computations and observed planetary waves. The reason for the apparent discrepancy between the planetary wave models of Matsuno (1970) and Simmons (1974) is found to be due to their use of different wind models.
Microwave FM‐CW Doppler radar for boundary layer probing
Authors: Strauch R. G. , Campbell W. C. , Chadwick R. B. , Moran K. P.
Published: February 2008

A microwave FM‐CW radar can obtain the complete spectrum of radial velocities of both precipitation particles and refractive‐index fluctuations in the optically clear air. Heretofore the extraction of the Doppler spectrum from this type of radar was believed to be a formidable, if not impossible, task. We have implemented a Doppler processing technique that uses a data acquisition system developed for pulsed Doppler radar. We present Doppler spectra obtained with a zenith‐pointing FM‐CW radar that demonstrate this new capability. In addition to the strong refractive‐index layers observed by the FM‐CW radar in the optically clear air, there is evidence that scattering from a background continuum of Cn² can be detected when a Doppler operating mode is employed.
A rocket measurement of the extreme ultraviolet dayglow
Authors: Christensen Andrew B.
Published: February 2008

Extreme ultraviolet spectra of the mid‐latitude dayglow in the wavelength range of 550 to 1250A have been obtained with a rocket borne grating spectrometer at a resolution of 20A. Spectra were obtained in the altitude range of 140 to 280 km. The spectra are dominated by emissions from atomic multiplets and no molecular bands have been identified with certainty. The strongest emissions other than H Lyman‐alpha are OI(989) and OII(834). Other prominent emissions include HeI(584), NII(916) and NII(1085). An unexpected feature near 612A has an intensity comparable to HeI(584).
Comment on “FMR Thermomagnetic studies” by Morris et. al.
Authors: Griscom D. L.
Published: February 2008

Morris et al. [1975] have reported ferromagnetic resonance (FMR) thermomagnetic studies of lunar soils and potential lunar analogue materials up to 900°C. They were thereby able to demonstrate that glasses containing magnetitelike phases as the sole ferromagnetic constituent are not lunar soil analogues. Although they did not explicitly take note of the fact, their data also show that glasses containing metallic iron as their sole magnetic constituent are not lunar soil analogues either. Irreversible FMR intensity losses observed for the lunar soils upon heating above 650°C, but not for similarly handled glasses containing only iron particles ∼ 100Å, can be explained by the co‐presence of both fine‐grained iron and fine‐grained magnetitelike phases in the lunar soils. This explanation is supported by previous thermomagnetic studies concerned with the integrated area under the FMR absorption curve.
Reply to “Comments on ‘FMR Thermomagnetic…’” by D. L. Griscom
Authors: Morris Richard V.
Published: February 2008

The arguments presented by Griscom (1975) in response to our paper (Morris et al., 1975) require a magnetite‐like phase and an equivalent or larger amount of metallic iron to be the components that are observed in the ferromagnetic resonance (FMR) spectra of lunar soils. In addition Griscom et al. (1975) concluded from FMR studies up to ∼300°C that mature lunar soils contain 0.1 to 0.5 wt. % of a magnetite‐like phase. It seems highly unlikely that a Curie point for such a large amount of a magnetite‐like phase would not be observed in the FMR thermomagnetic studies (ie, both (ΔH)²A and ΔH versus T) up to 900°C of Morris et al. (1975). That is, the only Curie point observed in both the (ΔH)²A and ΔH data of Morris et al. (1975) was at 770°C, which was attributed to pure or nearly pure metallic iron. The irreversible loss of intensity is thus best attributed to oxidation of metallic iron to FeO.
Global characteristics of 0.2 to 26 keV charged particles at F region altitudes
Authors: Torr D. G. , Torr M. R. , Hoffman R. A. , Walker J. C. G.
Published: February 2008

Measurements have been made by the low energy electron experiment (LEE) on the Atmosphere Explorer‐C satellite (AE‐C) of electrons and protons in the energy range 0.2 to 26 keV. We analyze data taken in the altitude range 250 to 300 km during the period 15 December 1973 to 25 May 1975. Measurements were made over a range of magnetic latitudes extending from the equator to 80°. The average electron flux at midlatitudes at night (19 to 05 local solar time) is found to be ∼(1‐5) × 10−4 ergs cm−2sec−1, and increases by about an order of magnitude during the day. The upper limit for the nighttime and daytime proton energy flux is about 1 × 10‐4 ergs cm−2sec−1. The total nighttime energy flux will result in a production rate of ˜.3 to ˜10 ions cm−3sec−1 at the base of the F region and in the D region respectively and should constitute an important source of ionization in the nocturnal ionosphere. The average daytime (05 ‐ 09 LT) total energy flux is insignificant in comparison with other sources of energy in the thermosphere. The average mid‐auroral zone nocturnal electron energy flux is ˜2 ergs cm−2sec−1, and appears to decrease during the day (average ˜1.5 ergs cm−2sec−1. The average for protons is 0.04 ergs cm−2sec−1 for both day and night.
Terrestrial OH abundance measurement by spectroscopic observation of resonance absorption of sunlight
Authors: Burnett Clyde R.
Published: February 2008

Spectroscopic observations have been made of the resonance absorption of sunlight by terrestrial OH. Changes in the daytime OH slant column absorption were observed, from which lower limits on the vertical abundances were calculated. These atmospheric vertical abundances were on the order 1014/cm² with apparent large daytime variations. The tropospheric contribution is expected to be not more than 1013/cm². The abundances reported here are thus predominately due to stratospheric OH.
The 650 km mantle discontinuity
Authors: Anderson Don L.
Published: February 2008

The bulk moduli of silicate and oxide solid solutions depend very little on iron content, but are diagnostic of crystal structure. Comparison of laboratory with seismic data suggests that the upper mantle mineral assemblages as a function of depth are: I. olivine + pyroxene + garnet (200‐400 km), II. β‐spinel + pyroxene‐garnet solid solution (400‐500 km), III. (β + γ) − spinel + pyx‐ga s.s.(500‐600) km, IV. γ‐spinel + SiO2 (stishovite) or mixed oxides (650‐800 km) and V. mixed oxides or perovskite + MgO(>800 km). The 650 km discontinuity is primarily due to phase changes in the pyroxene‐garnet, rather than the olivine, portion of the mantle.
Location of the source of magnetospheric energetic particle bursts by multispacecraft observations
Authors: Sarris E. T. , Krigmigis S. M. , Iijima T. , Bostrom C. O. , Armstrong T. P.
Published: February 2008

During a magnetic substorm on October 16, 1973 a number of magnetospheric bursts of energetic particles were observed simultaneously by IMP‐6 and IMP‐7 in the magnetotail (at XSM ≃ −32 Re, YSM ≃ 1.2 Re and ZSM ≃ −4.7 Re) while the two spacecraft were separated by only ∼ 1 Re along the XSM axis (ΔXSM ≃ 1 Re, ΔYSM = ΔZSM ≃ 0 Re). Detailed anisotropy measurements of 210 and 290 keV protons by the JHU/APL instruments on both spacecraft provide for the first time an indication of the location of the "source" of the energetic magnetospheric particles as well as evidence for its movement with speeds from ∼ 30 to more than 80 km/sec in association with the intensification of the westward auroral electrojet during a magnetic bay at the station closest to the local time of the spacecraft (also local midnight). The size of the source was estimated to be ΔX ≃ 500 km. The observations indicate that in this case energetic particles are accelerated to > 1.85 MeV in a moving and localized region in the geomagnetotail.
Auroral zone winds detected near the tropopause with the Chatanika UHF Doppler radar
Authors: Balsley Ben B. , Farley Donald T.
Published: February 2008

Neutral wind velocities in the lower atmosphere can be measured with powerful radars operating at a wide range of frequencies. We report the first such Doppler measurement in the auroral zone, using the Chatanika Radar Facility near Fairbanks, Alaska. A sample result from near the tropopause is in good agreement with nearly concurrent Fairbanks radiosonde data.
Comparison between Pc‐1 pulsation propagation paths and the whistler determined plasmapause
Authors: Cahill L. J. , Johnson J. C.
Published: February 2008

Observations of structured Pc‐1 pulsations at Siple Station, Antarctica allow comparison of the propagation paths of these signals with previously reported whistler observations. The whistler data have provided a detailed history of the plasmapause location during a six day interval of magnetic disturbance and recovery. Determination of the equatorial distances to the propagation paths of the Pc‐1 signals by dispersion analysis indicates that the hydromagnetic whistlers propagate 1 to 4 R e above the plasmapause. We find, however, that structured Pc‐1 signals are observed only when the plasmapause is near or above the Siple field lines. This suggests that the Pc‐1 signals are propagating in or below the plasmapause and that some of the assumptions of the dispersion analysis may be in error.
Rocket‐borne wave, field, and plasma observations in unstable polar cap E‐region
Authors: Olesen J. K. , Primdahl F. , Spangslev F. , Ungstrup E. , Bahnsen A. , Fahleson U. , Fälthamner C.‐G. , Pedersen A.
Published: February 2008

This paper presents initial results from the first comprehensively instrumented rocket flown through a Farley‐unstable polar cap E‐region. Groundbased ionosondes and magnetometers at two locations and HF radar backscatter at the launch site were used to determine the presence of a geographically widespread ionospheric plasma instability. The observed wave direction, electric field, and current density fit the predictions of the linear theory of the Farley instability, whereas the gradient‐drift instability seems to be excluded by the geometry of the observations.
Production of atmospheric nitrous oxide by combustion
Authors: Weiss R. F. , Craig H.
Published: February 2008

Measurements of N2O in the effluent gases from the burning of coal and fuel oil show that these are significant anthropogenic sources of atmospheric N2O. We estimate that the present global production of N2O from these sources is 1.6 Mtons N2O(N) per year and is increasing at a rate of ∼ 3.5% per year. Catalytic converters for the reduction of NO emissions also represent a major potential source of atmospheric N2O.
Steady‐state seismic slip – A precise recurrence model
Authors: Bufe Charles G. , Harsh Philip W. , Burford Robert O.
Published: February 2008

Regularity of seismic slip along a 9 km segment of the Calaveras fault zone is believed to result from steady‐state loading of a creeping fault to generate stresses on an isolated stuck patch which moves in a stick‐slip event in the magnitude range 3 to 4 whenever a critical threshold is reached. The patch behavior can be described by a simple model similar to the spring‐driven frictional models used in laboratory simulations of stick‐slip. The (M ≥ 3) recurrence time for this model is directly proportional to the seismic slip (computed from magnitudes) since the last time the threshold was reached. If the model is correct, an (3 ≤ M ≤ 4) earthquake should occur at 37° 17′ ± 2′ N, 121° 39′ ± 2′ W within 48 days of January 1, 1977.
Atmospheric halocarbons: Evidence in favor of reduced average hydroxyl radical concentration in the troposphere
Authors: Singh Hanwant B.
Published: February 2008

Data are provided on the May 1976 northern hemispheric background concentrations of 13 halocarbons, SF6, and N2O. A model is developed that permits an easy comparison of atmospheric lifetimes, emissions, and ambient concentrations. Our measurements indicate that atmospheric levels of CCl2F2(F12) and CCl3F(F11) are consistent with an average residence time of 50 (±33) and 36 (±8) years respectively. The tropospheric lifetimes of reactive species such as CH3CCl3, CHCl3, and C2Cl4 are found to be 7.2 (±1.2), 1.7 (±0.4), and 0.4 (±0.1) years respectively. These longer lifetimes of tropospherically reactive species are inconsistent with the existing knowledge of atmospheric chemistry. Our conservative analysis of atmospheric halocarbon data shows that average HO concentrations must be 2 to 6 × 105 HO/ml instead of the accepted range of 10 to 30 × 105 HO/ml. These lower HO values tend to resolve the apparent discrepancies in the biospheric budgets and distribution of chlorinated hydrocarbons and CO. The tropospheric and stratospheric implications of reduced HO levels are discussed.
Statistical analysis of Tokyo winter temperature approximations, 1443–1970
Authors: Landsberg H. E. , Kaylor R. E.
Published: February 2008

Spectral analysis of winter temperatures in Tokyo from 1443‐1970, based to 1870 on Lake Suwa freezing dates and since then on observations, shows significant contributions to variance in the 2.1, 3.0, 10.9 and 21.7 years bands. Consecutive thirty year means show very little variation. The coldest period was between 1489 and 1528. There is no notable variation during the so‐called Maunder sunspot minimum.
Confirming the presence of hydrofluoric acid in the upper stratosphere
Authors: Zander R. , Roland G. , Delbouille L.
Published: February 2008

Infrared solar observations made by balloon at 27.9 km altitude in April 1976, and from the ground station of the Jungfraujoch, Switzerland, in October 1976, have confirmed the presence of hydrofluoric acid in the upper stratosphere. An average value of (3.6 ± .7) × 10−10 ppv has been deduced for the concentration of HF above 27.9 km. The comparison between the ground‐and the balloon observations tends to indicate that over 50% of the total atmospheric HF is located above 25 km altitude.
The tropospheric‐stratospheric polar vortex breakdown of January 1977
Authors: Quiroz Roderick S.
Published: February 2008

An extraordinary warming of the stratosphere in December‐January 1976‐77 was followed by tropospheric warming in the polar region and cooling in middle latitudes. During January 10‐20, the associated polar anticyclone extended from the surface to 10 mb. Antecedents of the polar vortex breakdown are reviewed with the aid of results of zonal‐harmonic analyses of planetary waves, for heights of the pressure surfaces (700‐10 mb), temperature, and mean stratospheric temperature (the latter determined from satellite radiation measurements). Wave 1 in height and temperature played a dominant role in the stratosphere, attaining amplitudes of 1600 gpm and 25°C, respectively, at 10 mb. On the other hand, superposition of retrogressing wave 1 and quasi‐stationary wave 2 in the height of the 300‐mb surface, with individual amplitudes exceeding 300 gpm, is judged to have been an important factor in the overall development.
Estimation of the attenuation operator for multiple ScS waves
Authors: Jordan Thomas H. , Sipkin Stuart A.
Published: February 2008

A procedure for retrieving the attenuation operator for SH‐polarized multiple ScS waves by spectral stacking is outlined. Application of the procedure to 17 multiple ScS phase pairs from 5 western Pacific deep‐focus events digitally recorded at Kipapa, Hawaii, and Matsushiro, Japan, yields the following results: (1) Stable estimates of the phase and amplitude response of the attenuation operator are obtained in the frequency interval 6 mHz ‐ 60 mHz; (2) Within this band the apparent Q for ScS waves multiply reflected beneath the western Pacific is 156 ± 13. No significant variation of Q as a function of frequency is observed; (3) Within this band no significant dispersion of multiple ScS waves is observed. However, given the uncertainties in the estimates of the phase response, the existence of the dispersion predicted by linear, causal, constant‐Q models is compatible with the observations.
Possible origins of time variability in Jupiter's outer magnetosphere, 1. Variations in solar wind dynamic pressure
Authors: Coroniti F. V. , Kennel C. F.
Published: February 2008

We qualitatively examine the effects of changes in the solar wind dynamic pressure on the structure of a centrifugally driven planetary wind from Jupiter. We suggest that dynamic pressure variations can induce a transition between a super‐Alfvenic wind and sub‐Alfvenic breeze on Jupiter's dayside, which could possibly account for the observed large scale changes in the structure of Jupiter's outer magnetosphere.
The odd nitrogen mixing ratio in the stratosphere
Authors: Evans W. F. J. , Kerr J. B. , McElroy C. T. , O'Brien R. S. , Ridley B. A. , Wardle D. I.
Published: February 2008

The total odd nitrogen mixing ratio experiment has been conducted successfully for a second time on a balloon flight of PROJECT STRATOPROBE launched on August 17, 1975 from 51°N. The measured NOy profile was found to be similar to the first profile measurement from 58°N on July 22, 1974 with a maximum mixing ratio of 13 ppbv at 32 km decreasing at lower altitudes to less than 2 ppbv at 16 km. This result was not unexpected, since the ozone mixing ratio profile was similar on both flight dates. Both measurement sets were carried out at mid latitudes during late summer, an excellent time for measurements of ozone layer photochemistry since the ozone layer is very stable during this season.
Accumulation rates of manganese nodules and sediments: An Alpha Track Method
Authors: Andersen M. E. , Macdougall J. D.
Published: February 2008

Autoradiographs of the total alpha activity distribution in slices through manganese nodules can be used to determine growth rates and to investigate the mode of incorporation of alpha emitters into nodules. Total alpha vs. depth profiles, measured with high resolution by counting alpha tracks in cellulose nitrate detectors, are almost always exponential and apparently record nodule growth. Accumulation rates determined by 230Thex measurements are in approximate agreement with the alpha track measurements. Sediment accumulation rates may also be measured by this technique.
Lead 210 or climatic changes at South Pole?
Authors: Sanak J. , Lambert G.
Published: February 2008

The 210Pb concentration has been measured in 92 adjacent firn samples collected at the South Pole along a 18 m depth profile. The decay analysis shows that significant changes happened around 1920 and 1954 either in the accumulation rate or in the 210Pb content of the new fallen snow.
Correlated errors in satellite altimetry geoids
Authors: Anderle R. J. , Hoskin Rose L.
Published: February 2008

The vertical component of position of the GEOS‐3 satellite has been computed to an accuracy of 2 m by analysis of Doppler observations. Comparison of altimetry data from the satellite at the intersections of ground traces of the orbital path yielded corrections to the satellite position such that the contribution of the orbit error to the error in the geoid computed from the altimetry data would be as low as 20 to 30 cm if the original orbit errors were uncorrelated. However, simulations of the effects of uncertainties in the gravity field have shown that the orbit errors are correlated over a distance of about 500 km normal to the direction of the satellite track. As a consequence, the geoid based on the GEOS‐3 altimetry will have correlated errors which are estimated to be 50 cm with a wave length of 2500 km. The results imply that the geoid based on SEASAT‐A altimetry data will have correlated errors over similar distance.
The vertical distribution of HCl in the stratosphere
Authors: Raper O. F. , Farmer C. B. , Toth R. A. , Robbins B. D.
Published: February 2008

The vertical distribution of HCℓ in the stratosphere has been measured from infrared solar absorption spectra recorded with a balloon‐borne interferometer. The flights were made in September, 1975, and May, 1976 at float altitudes of 40 km and 37 km, respectively, near Palestine, Texas. Concentration profiles derived from the data show an increase from 0.6 ppbv at 20 km to 1.7 ± .5 ppbv in the region of 37 km. Above 37 km, the data permit only the total abundance to be determined; this value is found to be equivalent to 1.6 ± .6 ppbv if the gas were uniformly mixed. The results from the two flights are closely similar, and no significant seasonal variation in the HCℓ concentrations can be discerned. The balloon data are consistent with the profile in the 14‐21 km altitude region of the stratosphere reported earlier from U‐2 observations.