bluuebunny/crossref_metadata_2025_split huggingface dataset:
Paleosecular variations from lake sediments
Authors: Lund S. P. , Banerjee S. K. 
Published: February 2008

We have known since at least the 16th century that the Earth's magnetic field varies with time as well as geographic position. This secular variation (SV), which has been monitored instrumentally at various locations since that time, is fundamentally important to a complete understanding of the geomagnetic field and its origin. Unfortunately, the instrument record for SV is very short in duration and if we wish to extend this record backward through time we must use a very different recording process.Paleomagnetists have considered this problem for well over 100 years, and have discovered two processes by which the SV may be commonly recorded. The first, thermoremanent magnetization (TRM), essentially causes a rock, which has been heated above a characteristic temperature, to acquire a remanent magnetization parallel to the field present when the rock cools. In this manner, lava flows and fired pottery or bricks record an instantaneous picture of the field during their cooling process.
The electric field and global electrodynamics of the magnetosphere: Review and Quadrennial Report to the IUGG
Authors: Stern David P. 
Published: February 2008

When the radiation belt was discovered some 20 years ago, its very existence posed a fundamental problem. The way the geomagentic field managed to trap and to hold particles was readily explained—but what processes energized them in the first place, and how were they brought into their trapped orbits?As our knowledge about the Earth's environment increased it became evident that similar questions also applied to other plasma populations such as those of the ring current and of the plasma sheet. In most cases, it turned out, both the particles' energization and their transport were provided by a large‐scale electric field
, permeating the magnetosphere. The “main” part of
, oriented roughly from dawn to dusk (near the equatorial plane), is the one responsible for a large‐scale sunward plasma flow (“convection”) found throughout most of the magnetosphere. In addition, the various sources of
accelerate charged particles in several distinct ways, maintain a global system of electric currents linking the magnetosphere with the ionosphere [Potemra, 1979] and transfer energy from the solar wind to the magnetosphere. For more complete details the reader is referred to a recent review by Stern [1977].
Progress in the design of hydrologic‐data networks
Authors: Moss M. E. , Tasker G. D. 
Published: February 2008

The design of hydrologic‐data networks is a topic that previously has not been raised to the status of a separate article in the U.S. National Reports to the International Union of Geodesy and Geophysics. However, three articles (Matalas, 1975; Peck, 1975; Schwarz, 1975) in the 1970–1974 Report considered it significant enough to be included as specific sections. Thus, because of the novelty of this article, some references will be made to work performed prior to the report period of 1975–1978 for the sake of completeness.The collection of hydrologie data has been perceived as a design problem only within the past few decades. Although some earlier work had been done in the area of precipitation gaging networks, Langbein (1954) presented the first comprehensive description of what needed to be done to manage objectively a hydrologic‐data program.
Paleoceanographic events—Recognition, resolution, and reconsideration
Authors: Arthur Michael A. 
Published: February 2008

Studies of the last 125 million years of oceanographic and climatic history have benefited greatly from the impetus provided by the Deep Sea Drilling Project. Knowledge of the sedimentary and paleontologic record of the major ocean basins, in conjunction with study of pelagic marine sections exposed on land, has permitted both the testing of old and the development of new hypotheses to explain local and global ocean chemical, sedimentologic and biotic events. Some of the more striking and topical problems in paleoceanography are the oceanic “anoxic events” of early to middle Cretaceous age, the biotic crisis at the Cretaceous/Tertiary boundary, the Eocene/Oligocene extinctions and climatic and circulation events, the Messinian “salinity crisis” (late Miocene) and its effects on the world ocean, and Pleistocene glacial cycles and paleoceanography. Possible explanations of these events, which have been proposed over the last five years, are reviewed in this paper.Application of new concepts and techniques, especially in micropaleontology and geochemistry, has led to refinements in stratigraphic resolution and in recognition of paleoenvironmental signals. Among the most powerful tools now in use is stable isotope geochemistry. Paleomagnetic studies and statistical techniques for processing micropaleontological data have contributed greatly to stratigraphic resolution.Although we are beginning to unravel the complex interactions of global sea level changes, climate and ocean chemistry and their influence on life, there are innumerable challenging problems still remaining. As stratigraphic resolution and coverage improve so does our perception of the ocean system.
Planetary basalts: Chemistry and petrology
Authors: Papike J. J. , Bence A. E. 
Published: February 2008

Basaltic rocks have continued to receive considerable attention in the period 1975‐1978. This is largely due to the recognition of their effectiveness as probes of planetary interiors. Basalts that have formed by partial melting in planetary interiors and have been delivered to the planetary surface without gain or loss of material carry clues to: (1) the formation and earliest differentiation history of the terrestrial planetary bodies, (2) residual mineralogy and phase chemistry of the source region, (3) temporal evolution of the source region, (4) depth of the source region, (5) the thermal history of the planetary body, and (6) the intensive thermodynamic values that obtained during basalt petrogenesis.Because basalts are key indicators of planetary evolution, an experimental project, entitled “Basaltic Volcanism on the Terrestrial Planets Studies Project,” was organized by the Lunar and Planetary Institute, Houston, Texas. The project, funded in part by NASA, is a pilot project in comparative planetology involving approximately 80 scientists representing a variety of disciplines including observational astronomy, cosmochemistry, geochemistry, geology, geophysics, mineralogy, petrology and volcanology. The project was initiated in 1977 and will culminate in 1980 with a book entitled “Basaltic Volcanism on the Terrestrial Planets,” which will summarize the results of the project. The major advances in our understanding of terrestrial basalt petrogenesis that have occurred in the past four years are to a large extent a consequence of the Deep Sea Drilling Project's crustal drilling program. Deeper penetration and improved recovery on Legs 34, 37, 45‐46, 49, 51‐53, and 55 have provided spatial and temporal controls on sampling of the oceanic crust with a much greater areal coverage than can be achieved by submersibles.
Planetary atmospheres
Authors: Beebe Reta 
Published: February 2008

The period from 1979 to 1982 has been characterized by extensive exploration of the Solar System. Pioneer and Voyager missions to Venus, Jupiter, and Saturn combined with ongoing analysis and data collection from the Viking‐Mars mission have contributed greatly to our understanding of planetary atmospheres.The Pioneer orbiter and the Pioneer multiprobe missions that arrived at Venus in December 1978, yielded results [Donahue, 1979] which have been combined with those from Venera 11 and 12 in December 1979, and Venera 13 and 14 in March 1982, [Moroz, 1981] to provide atmospheric data of significantly higher resolution and precision that has been available previously.
Cosmic‐ray modulation and the anomalous component
Authors: Jones Frank C. 
Published: February 2008

This review is concerned with advances in Cosmic‐Ray Modulation observation and theory and in the study of the anomalous component of the cosmic radiation. It concentrates primarily on advances made in American research and reported in the open literature during the years 1979–1982. This rule is, of course, not rigidly adhered to; certain works that are intimately related to the subject under discussion are cited even though they may lie outside of the above mentioned bounds.Since the last report in this series there have been two International Cosmic Ray Conferences, in Kyoto in 1979, and in Paris in 1981. A great number of papers that are relevant to our subject were presented at both of these conferences. I have, therefore, cited freely from the proceedings of these conferences with one exception; If I found that a conference paper was subsequently published, by the same authors, in unchanged or expanded form in the open literature, I considered the conference paper to be a “preliminary report” and have cited the final paper instead.
Magnetospheric and interplanetary physics 1979–1982
Authors: Stern David P. 
Published: February 2008

The quadrennium 1979–1982 witnessed notable advances in magnetospheric and interplanetary physics, and demonstrated some major trends. Examples of both will be listed below, followed by an evaluation of the state of the discipline and of its future.Standing out among the advances is the enormous volume of data about the magnetospheres of the giant planets, collected by Voyagers 1–2 and by Pioneer 11. At the start of 1979 the very existence of Saturn's magnetic field was uncertain, and the role of the satellite Io in Jupiter's magnetosphere was only dimly guessed: 4 years later we have extensive information on both magnetospheres, on their underlying planetary fields, ring currents, radio emissions, plasma composition and nightside configuration, and about such matters as Io's plasma torus and the current filament linking Io to Jupiter, Saturn's inner radiation belt (from neutron albedo) and Titan's wake.
Plasma waves in planetary magnetospheres
Authors: Anderson Roger R. 
Published: February 2008

The studies of magnetospheric plasma waves in the 1979–1982 quadrennium have included not only intensive studies of plasma waves in the Earth's magnetosphere but also, for the first time, in situ observations and detailed analyses of plasma waves in the magnetospheres of Jupiter and Saturn. While much of the research has involved the continuing identification and classification of plasma wave phenomena in the magnetospheres, increasingly greater emphasis has been placed on understanding the sources of the plasma waves and the interactions of plasma waves with the particles. Many studies have also shown that plasma wave measurements may be used to discern numerous geophysical boundaries and parameters.At the earth, significant progress in plasma wave research has been made that has increased our understanding of wave‐particle interactions and their effects, throughout the magnetosphere from the auroral ionosphere out to the bow shock and back into the tail. Observations of auroral kilometric radiation both in the source region and far from it have provided much new information about this intense emission. Details of the fine structure of the radiation and its polarization and propagation characteristics along with particle distribution and other plasma wave measurements in the source region have provided valuable inputs to various generation theories. Similar progress has also been made in understanding electron cyclotron harmonic emissions and nonthermal continuum radiation. Detailed characterizations of plasma wave phenomena reported during this quadrennium in the plasmasphere, outer magnetosphere, magnetopause, magnetosheath and tail regions have been important in assessing the impact of the waves on the particle distributions and vise versa.
Satellite altimetry
Authors: Marsh James G. 
Published: February 2008

During the past four years satellite altimetry activities have been primarily concerned with analyses of the GEOS‐3 and Seasat data sets, and the justification and design of next generation altimetric missions and associated instrumentation.Since the last IUGG Quadrennial review of satellite altimetry [Stanley, 1979a], considerable documentation of altimetric engineering and scientific results has occurred. There has been a special issue of the Journal of Geophysical Research [JGR Vol. 84, B8, 1979] dedicated to scientific results from GEOS‐3. A special issue of Marine Geodesy [Vol. 3, 1980] contains numerous papers on the analysis of altimeter data presented at an International Symposium on Interaction of Marine Geodesy and Ocean Dynamics. A special issue of the IEEE Journal of Oceanic Engineering [OE‐5(2), April 1980] contains a discussion of Seasat sensors and attendant processing algorithms. A special issue of the Journal of the Astronautical Sciences [28(4), Oct‐Dec 1980] was devoted to the problem of orbit determination for Seasat; a subject of importance to users of satellite altimeter data. A special issue of the JGR [Vol. 87, C5, 1982] was dedicated to Seasat geophysical processing algorithms and evaluation. A second Seasat JGR special issue dedicated to scientific results will be published in early 1983, and a special issue of Marine Geodesy devoted to satellite altimetry also will be published in 1983.This review presents a summary of the geodetic applications of altimeter data, precision orbit determination analyses, the status of the instrumentation and the plans for future altimeter missions. A review of the applications of altimetry to oceanography, including mesoscale current detection and variability, wind and waves, ocean tides and ice is presented in a separate paper by Brown and Cheney [1983].
Main field and recent secular variation
Authors: Alldredge Leroy R. 
Published: February 2008

As Cain (1979) indicated might happen in the last IUGG quadrennial report, added resources were made available during the past few years and a real impulse was added to the geomagnetic work in the United States by the launching of the MAGSAT Satellite. This new effort paid off in terms of new charts, additional long wavelength studies, and external source studies. As before, however, the future funding for new starts in geomagnetism does not look bright at the present time.A single MAGSAT in orbit a little more than seven months did wonders for main field (M.F.) charting, but did little or nothing for secular variation (S.V.) charting. It would take a number of repeated MAGSATS to help the S.V. picture. Meanwhile, the world magnetic observatory net and surface repeat stations remain as the main source of S.V. data.
Small‐scale physics of the ocean
Authors: Caldwell Douglas R. 
Published: February 2008

Four years ago, we noted that, although there was a widespread belief that the key to many ocean processes must be the communication of energy by internal waves, there had been little progress in definitely relating small‐scale processes to internal waves (Caldwell, 1983a). For example, although it seemed plausible that the energy that supplies spots of turbulence in the thermocline is delivered to those spots by internal waves, the process had neither been directly observed nor shown theoretically in a verifiable calculation. In the past four years there has been some progress; observations have been made which render such connections more plausible and some theoretical ideas have been advanced, but we've seen no breakthrough in this direction.Instead, progress has come on other fronts. Our picture of turbulent processes in the upper ocean, especially in the equatorial ocean, is becoming more clear (and more complicated). Strong downdrafts in the mixed layer have been discovered. Dissipation in the convective mixed layer has been found to scale very much as it does in similar layers in the atmosphere. The dynamics of intrusions have drawn attention because they may contribute a good deal of the mixing of the oceans. Although significant laboratory experiments are now available, controversy remains concerning the application of laboratory turbulence concepts to the ocean. Bottom‐layer flows have now been carefully defined. One notable development is the increased interest in the effect of mixing conditions on biological activity. Our instrumentation is becoming more routinely deployable, an important step toward obtaining the large amount of sampling required to form a reasonably accurate picture of small‐scale processes in the ocean.
Planetary atmospheres
Authors: Leovy Conway 
Published: February 2008

Rapid advances in our understanding of planetary atmospheres have occurred since the previous quadrennial review (Beebe, 1983), based to a large extent on analyses of planetary spacecraft data from earlier periods. The VEGA mission at Venus and Voyager 2 at Uranus provided new data, as did an active program of remote sensing from Earth and its vicinity.A number of valuable books and review articles appeared focusing on the origin and evolution of atmospheres as well as their present states (e.g., Lewis and Prinn, 1984; Hunt, 1983; Pollack and Consolmagno, 1984). Clearly, research on atmospheres in the solar system is no longer just exploratory; it has reached the stage of in‐depth study.
Solar particle acceleration and propagation
Authors: Lin R. P. 
Published: February 2008

Large solar flares are the most energetic natural particle accelerators in the solar system, occasionally accelerating ions to many GeV and electrons to ≳102 MeV energies. The accelerated particles can be studied indirectly, via observations of the electromagnetic emissions produced by the particles in their interactions with the solar atmosphere, or directly by spacecraft and ground‐based observations of the particles which escape into the interplanetary medium. The electromagnetic emissions (X‐ray, gamma‐ray, and radio emission) depend critically on ambient conditions in the solar atmosphere where the accelerated particles reside (the density, magnetic field, and temperature), while the interpretation of the particle fluxes observed in the interplanetary medium depends on the characteristics of the escape and interplanetary propagation processes.Radio, X‐ray and gamma‐ray, and energetic particle observations obtained before the 1980 solar maximum suggest that there are at least two acceleration processes associated with solar flares. During the impulsive or flash phase, electrons are often accelerated to ∼10–100 keV energies, even in small flares or subflares. For some flares, the energy contained in these electrons may be a substantial fraction of the total flare energy. Thus the primary energy release mechanism for flares may initially convert stored magnetic energy into energetic electrons. These electrons can produce most of the observed impulsive phase flare phenomena through their interactions with the solar atmosphere. In large flares a second acceleration sometimes occurs which accelerates both ions and electrons to MeV energies and above. This second acceleration appears to have a close association with shock waves in the solar atmosphere as observed by type II radio bursts. Based on observations of escaping particles and hard X‐ray and gamma ray bursts, the impulsive phase acceleration events occur on the order of ∼102 times a month near solar maximum while large solar energetic particle (LSEP) events where >10 MeV ions and relativistic electrons are accelerated to observable levels occur a few times a month.
Boundary Between Laminar and Turbulent Flow
Authors: Thorpe S. A. , Strohbehn J. , Birkemeier W. P. , Plate E. J. , Scorer R. S. 
Published: February 2008

This group was asked to consider the characteristic structure of the boundary between laminar and turbulent flows (the L‐T boundary) and to answer the following specific questions. If we consider the boundaries at the top and bottom of a patch of intense turbulence in a stratified medium,a. Can we predict the two‐dimensional spectrum of the height deviations of the boundary?Answer: no.b. Will there be density fluctuations induced in the laminar layers where the stratification still remains?Answer: yes.c. If so, what spectrum can we predict for these fluctuations?Answer: refer to Townsend [1964].d. How intense will the fluctuations of a passive scalar quantity be at the boundary relative to a point in the middle of the thoroughly mixed zone (patch)?Answer: it is not known.
Characteristics of the Sporadic E Layer at Waltair Using the Phase Path Technique
Authors: Reddi C. Raghava , Rao B. Ramachandra 
Published: February 2008

The Es‐echo phase path records on 5.6 MHz have shown that the bottom surface of the Es was sometimes very sharply bounded. Some evidence showing that the formation of Es is a highly localized phenomenon has been obtained. The phase path variations of ‘O’ and ‘X’ components in the F2‐region echo during the formation of Es showed that the increase in the ionization in the Es is not totally from a vertical redistribution of the ionization along the ray paths.From spaced phase path records of Es echoes taken during the daylight hours, apparent drift speeds in the range 40–130 m/sec with an eastward sense of the east‐west components of Es apparent drifts were observed. This is opposite to the sense of the east‐west components of E‐region drifts during the daylight hours but is the same as that during the nighttime hours. An attempt is made to interpret these observations.
Attention and Two‐Stream Instability: Summary Report
Authors: Larenz R. W. 
Published: February 2008

The last session with invited papers and contributions dealt with two topics: (a) attenuation and (b) two‐stream instability. It also gave an occasion to include a few other contributions, which could not be presented during the preceding sessions.K. Suchy presented an invited paper on topic a dealing with collisional damping for linear wave coupling. Questions concerned with the physical meaning of this coupling mechanism and with some difficulties concerning the notations for describing the polarization of waves in a magnetoplasma have been answered in the printed version of this paper which is found in this issue.
A Practical Evaluation of Earth‐Backscatter Simulation and an Estimate of the HF Ground‐Scatter Coefficient
Authors: Althouse Edwin L. , Davis John R. 
Published: February 2008

An attempt has been made in this work to perform an appraisal of the degree to which fixed‐frequency amplitude versus time‐delay simulations can be made to agree in detail with actual HF‐radar ground‐back‐scatter observations taken with azimuthally broad beam antennas. The physical constraints and effects of propagation phenomena such as the spatial distribution of the ionospheric electron density, D‐layer absorption, the antenna pattern, rough‐surface scattering of the surface of the earth, and cross‐polarization losses are discussed.A composite backscatter‐simulation method, based upon a weighted sum of individual simulations (separate raytraces and backscatter simulations) from different electron density distributions, is used to account for downrange geographical variation in electron density profiles, and the multiplicity of propagation modes which may occur during conditions of nonblanketing sporadic‐E or spread‐F ionization. Tabular descriptions of electron density versus height, from actual ionospheric soundings, are used instead of ionospheric models. Both isotropic and anisotropic scattering models are used. Order of magnitude estimates are given for the radar cross section per unit area (σ0) of land illuminated by one‐hop 16‐MHz radiation westward from Washington, D.C.