bluuebunny/crossref_metadata_2025_split huggingface dataset:
Introduction to the Report on Geodesy
Authors: Mueller Ivan I. 
Published: February 2008

The following articles summarize the achievements of the U.S. geodetic community during the years 1971–1974, between the General Assemblies of the IUGG. During this quadrennium, American geodesy made the first transition from meeting the traditional needs of surveying and mapping to catering to the geophysical and oceanographic communities, trying to satisfy their ever‐increasing appetite for ultraprecise surveys.Major achievements included the completion of the National Geodetic Satellite Program, probably the largest single effort to establish a global network of satellite tracking stations and the determination of the earth's gravity field to an accuracy heretofore not available; the proliferation of Doppler satellite observations for control surveys and polar motion determination; the affirmation of lunar and satellite laser ranging and very long base line interferometry (VLBI) as the best available geodetic tools for global geophysical investigations, such as plate tectonics, polar motion, and the earth's rotation; the development of the satellite‐borne altimeter and the establishment of its feasibility for a better definition of the surface of the oceans; major improvements in the knowledge of the dynamics, size, shape, gravity field, and topography of the moon and some of the major planets; the extension of the high‐precision transcontinental traverse to a total of 9000 km, only 10% of the network remaining for completion in 1975; the start of the readjustment of the North American Datum, in collaboration with Canada, Mexico, and Denmark; and an unprecedented cross‐fertilization between geodesy, solid earth geophysics, oceanography, and dynamical astronomy.
Minor constituents in the stratosphere and mesosphere
Authors: Hudson R. D. 
Published: February 2008

This paper is a brief survey of the research on the role of the trace constituents in the stratosphere and mesosphere that was published between 1975 and 1979. During this period of time the emphasis shifted away from the role of the nitrogen oxides in the stratosphere to the role of the chlorine oxides and the hydrogen oxides. A great deal of progress was reported in the understanding of the natural stratosphere and its response to anthropogenic perturbations.This is but a brief review of that portion of the research carried out in the stratosphere and mesosphere which dealt with the role of the trace constituents. The years between 1971 and 1974 were reviewed by Cicerone (1975). This review is limited to the years 1975 to 1978. The increase in interest in research in the stratosphere noted by Cicerone has continued, spurred by the public concern on the effects of the chlorofluoromethanes on stratospheric ozone. Changes in reaction rates have tended to alleviate concerns over increases in the nitrogen oxides, but not, it should be noted, removed them completely.
Crustal movements and earthquake‐related deformation
Authors: Thatcher Wayne 
Published: February 2008

The past four years have seen significant advances in delineating the current movement pattern at and near major plate boundaries, modeling the earthquake‐related deformation occurring there, and developing new high‐precision measurement techniques. At the same time, interpretation of both historic geodetic survey data and new precise measurements in the western U.S. has uncovered some unexpected results, emphasizing that despite notable progress in modeling observed movements, a number of significant features of plate boundary deformation are not yet well understood.The Southern California UpliftUndoubtedly the most notable development since 1975 has been the discovery by R. O. Castle and his colleagues (Castle et al., 1976) of a remarkable episode of ground uplift in southern California. Analysis of a very large collection of repeated leveling measurements has shown that between 1959 and 1974 approximately 90,000 km2 of southern California was uplifted by 200 mm or more. In contrast to these rapid movements, earlier measurements indicate negligible aseismic vertical deformation between at least 1926 and 1959. A very similar though not precisely identical episode of uplift occurring sometime between 1897 and 1914 is also documented by the leveling observations (Castle et al., 1976). This earlier uplift episode included much of the region that sustained rapid upwarping after 1959, but also encompassed most of the Peninsular Ranges, an area not significantly elevated in the most recent phase of uplift (Wood and Elliott, 1979). In the case of both deformation events, uplift of as much as 400 mm was followed by a regional partial collapse that averaged near 50% of the initial upwarping. Some observations of contemporaneous horizontal deformation are available for the 1959–74 uplift and its subsequent partial collapse; triangulation data indicate some anomalous changes in the rate and orientation of shear strains during the uplift (Thatcher, 1976), and recent geodimeter measurements (1974–78) show a very uniform pattern of nearly uniaxial north‐south compression of ∼0.2 microstrain/yr (Savage et al., 1978) that coincided with the subsequent downwarping. Because of uncertainties concerning the precise pattern of interseismic horizontal deformation related to the San Andreas fault system (and possible temporal fluctuations in this strain field), it is not yet possible to unambiguously distinguish these interseismic strains from those which may be related to the uplift or its collapse, and as a result the proper interpretation of both the triangulation and geodimeter data is correspondingly uncertain. Similarly, although several interpretations have been proposed concerning the origin and geophysical significance of the southern California uplifts (Thatcher, 1976; Wyss, 1977; Rundle, 1978a), no one explanation has yet been universally accepted.
Planetary radar astronomy
Authors: Ostro Steven J. 
Published: February 2008

Planetary radar research reported during 1979–1982 was highlighted by radar observations of Venus by the Pioneer Venus spacecraft, Earth‐based high‐resolution imaging of Venus and the Moon, construction of accurate topographic profiles for Martian tropical regions, observational and theoretical advances in relating the radar signatures of Mars and the Moon to surface characteristics, and the initial radar detections of echoes from a comet and a mainbelt asteroid.This review begins with a brief synopsis of radar definitions and technical terminology, and then summarizes recent results for individual targets. Readers interested in radar astronomy prior to the current quadrennium are directed to excellent reviews by Jurgens (1982a), Pettengill (1978), Evans (1969), Muhleman (1966), and Pettengill and Shapiro (1965). Detailed descriptions of planetary radar techniques include Pettengill (1970) and Evans and Hagfors (1968).
U.S. contributions to auroral aeronomy, 1979‐1982
Authors: Rees M. H. 
Published: February 2008

Auroral aeronomy is the scientific discipline devoted to the study of the interaction of energetic particles and electric fields with the atmosphere of planets that have an appreciable intrinsic magnetic field. Specific topics that describe this interaction include: transport and energy degradation of energetic electrons and ions in a collision dominated medium, the excitation of atoms and molecules by collisions and by chemical reactions, the auroral spectrum, its production and interpretation, perturbations upon the ionospheric plasma in terms of enhanced ionization, composition, dynamics and heating, and perturbations upon the neutral atmosphere in terms of composition, dynamics and heating.It is not possible, however, to identify aeronomic processes as being uniquely relevant to the aurora because solar EUV photons and photoelectrons are subject to similar physical and chemical reactions leading to spectral emissions that also result from auroral electron bombardment of the atmosphere. Thus, a large segment of aeronomic research carried out during the quadrennium is reviewed in companion articles of this report to the I.U.G.G. An overview of Polar and Auroral Phenomena is presented by Reiff [1983, this issue]. She reviews auroral morphology, including pulsating aurora, emphasizing the relationship to magnetospheric phenomenology. Local and global characteristics of energetic particle precipitation are presented, and a summary of recent observations of energetic ions of ionospheric origin is given. Observations and theories on auroral electrodynamics are also reviewed by Reiff [1983], The effects of heating and ionization on Thermospheric Dynamics are reviewed by Roble [1983, this issue]. Progress in our understanding of the Neutral and Ion Composition of the Thermosphere is reported by Torr [1983, this issue]. This review focuses on reaction rate coefficients that are inferred from rockets and satellite observations of ion and neutral densities and optical emission rates, a technique that is particularly useful for studying metastable states of atmospheric gases. The chemical–ionic reactions pertinent to the dayglow are also relevant to the aurora so that progress in auroral aeronomy leans heavily on our understanding of the aeronomy at middle and low latitudes . Dynamical effects of auroral electric fields upon the high latitude ionosphere are discussed in the review by Richmond [1983, this issue]. The aurora and, in particular, the energetic solar proton events (SPE) significantly perturb the middle atmosphere, i.e. the mesosphere and upper stratosphere. Effects upon the chemistry and ionization are reviewed by Solomon [1983, this issue] while the dynamic and electrodynamic consequences are discussed, respectively, by Hartmann [1983, this issue] and by Kelly [1983, this issue].
The Jovian magnetosphere
Authors: Birmingham Thomas J. 
Published: February 2008

The 1979–82 quadrennium was a time of unprecedented excitement and achievement in Jovian magnetospheric physics, highlighted by the traversais by Voyager‐1 and ‐2 (V‐1, ‐2) in March and July 1979. Our knowledge has been expanded immensely by Voyager observations and their interpretations, and this review is devoted largely to them. Not to be overlooked, however, is activity in the areas of continuing Pioneer‐10 and ‐11 (P‐10, ‐11) data analysis and ground based observations, both of which complement the Voyager results spatially and temporally.This report focuses on Jovian fields and plasmas (and under plasmas we include charged particles of all energies). Not included is the considerable body of observations of waves in Jupiter's magnetosphere, which are involved in plasma dynamics but which are covered in the companion report “Plasma Waves in Planetary Magnetospheres” by R. Anderson.
Introduction to Geomagnetism and Paleomagnetism Section of IUGG Report, 1979–1982
Authors: Fuller M. 
Published: February 2008

My function, in writing these notes, is to bring you up to date in Geomagnetism and Paleomagnetism, in as painless a manner as possible—without tears as the French language texts for tourists used to promise. In writing this account of progress in the past quadrennium, I must first acknowledge that it is a personal and subjective viewpoint; another reporter would surely emphasize other developments. Yet, there is some virtue in writing of things, about which one knows something, so I leave to future reporters the task of redressing the balance in matters covered.At the outset, one very sad event must be recorded. On April 3rd, 1981, Sir Edward Bullard died. His published work alone marks him as one of the leaders of geomagnetism in our times. Yet his contribution was much greater; many an American geophysicist, as well as a whole generation of British colleagues have felt the benefit of his perceptive advice on their research. To those who saw him in the last few months of his life, his courage in the face of his illness was a remarkable example of fortitude. It is by now well known that the definitive paper, which he wrote with Malin, on secular variation at London, was only completed immediately before his death. The transmittal letter had been typed, but death prevented him from signing it. Bullard returned in this final paper to a topic to which he had contributed much. In it, he notes the role of Halley, who first described the phenomenon of westward drift, to which Bullard gave a new numerical precision, two and a half centuries later. I seem to remember Bullard saying in a lecture years ago that, while the Newtons of this world seem other than mortal, Halley was a scientist whose life and achievements could encourage one's own efforts. Bullard, like Halley, inspires and encourages us.
Atmospheric boundary layers
Authors: Mahrt L. 
Published: February 2008

Since more than a dozen papers relating to atmospheric boundary layers are published every month, it is necessary to restrict the scope of this review. Here we address only fundamental aspects of the physics of the boundary layer and exclude research related to instrumentation, specific applied areas of boundary layer research, and interactions with larger‐scale circulations.Some aspects of the boundary layer will be treated very briefly or included only in the reference lists while other topics, which have been omitted in past reviews, will be covered in more depth. Wyngaard (1978, 1979), Paegle (1979), Zeman (1981) and Nieuwstadt (1982) recently surveyed many aspects of atmospheric boundary layer research.
Paleo‐oceanography: Global ocean evolution
Authors: Kennett James P. 
Published: February 2008

Paleoceanography, one of the youngest branches of earth sciences, is concerned with the development of oceanic circulation through geologic time. This is a multifaceted and integrated endeavor since none of the subdisciplines is easily separated from the others. The field is holistic in character, and includes the history and effects of bottom, intermediate and surface circulation patterns, planktonic and benthonic biogeographic development and rates of organic evolution, the history of biogenic productivity and dissolution and their effect on sediment distribution and the consequences of sea level change.Paleoceanography was largely born of the Deep Sea Drilling Project (DSDP) and continues to be nourished by it. Because problems are of global scope, the appetite for new sediment core material is large, and is being supplied by numerous expeditions of DSDP. This article is a brief overview of a number of advances that have occurred in paleoceanography and related fields during the period from 1979 to 1982. Because of page limitations, all publications cannot be cited which is not meant to indicate any lack of importance.
Seismology in the U.S. 1979–82
Authors: Chinnery Michael A. 
Published: February 2008

The years 1979 to 1982 have been marked by a continuing expansion and development of seismology in the United States. In this introduction, we summarize some of the highlights of this period, as a prelude to the more detailed papers that follow. These papers cover both improvements in our understanding of earth processes together with improvements in the various geophysical techniques available to study them.Perhaps the most traditional area of seismology is the study of the structure of the earth's interior, though recent developments are following most untraditional directions. Highlights of this area include significant new information on lateral heterogeneity, anisotropy and the mechanisms of scattering and attenuation. Using a variety of techniques, we are beginning to identify the regions of the earth that are the most heterogeneous, and to characterize the heterogeneity in those regions. The upper mantle has long been known to contain lateral variations, particularly in the uppermost part. New data are beginning to suggest substantial heterogeneity in the transition region between 400 and 670 km depth. In addition, more evidence is confirming lateral variations in the lower 200 km of the mantle. Attempts to relate these various heterogeneities to tectonic processes at the earth's surface and motions in the earth's core are continuing.
Rock‐forming silicates
Authors: Hazen Robert M. 
Published: February 2008

Rock‐forming silicates are the focus of an active and diverse research effort. In the past quadrennium many researchers have examined these complex phases to gain an understanding of unifying principles of crystal chemistry and physics, while other mineralogists and petrologists have looked to natural silicates as a key to deducing the thermal and barometric history of their host rocks.The framework for the research described in this review is built on two fundamental questions. The first question is posed implicitly by many of the experimentalists who study silicates:
Tectonophysics – 1979–1982
Authors: Scholz C. H. 
Published: February 2008

Studies in tectonophysics are becoming increasingly interdisciplinary: hence there was an attempt in this report to concentrate on subjects which have attracted particularly broad interest during this quadrinium, rather than on concentrating on the activities of the individual diciplines.One of the strongest debates during this period has been on the state of stress in the lithosphere, reported on by M. Zoback. This debate has centered on the conflict between the low heat flow over the San Andreas fault, which suggests very low stresses, and the experimentally determined laws of rock friction, which suggest the opposite. Other lines of evidence, such as that of shear heating in ductile shear zones, in‐situ stress measurements, and strengths necessary to support flexure of the lithosphere, and paleopeizometry have also been brought into the debate, all of which seem to support the latter point of view.
Mineral and melt physics a summary of research in the United States, 1979–1982
Authors: Jeanloz Raymond 
Published: February 2008

Mineral physics and the related fields concerned with the properties of molten minerals are currently thriving due to major advances both in theory and in experimentation. In particular, there is a healthy trend of increasing cross‐fertilization between many disciplines, including physics, chemistry, materials science, and the corresponding fields of geophysics and geochemistry. A sense of this can be had by referring to the proceedings of recent conferences, that range from international meetings on high‐pressure research [Timmerhaus and Barber, 1979; Vodar and Marteau, 1980; Schilling and Shelton, 1981], to more topical gatherings on structure and bonding in minerals [M. O'Keeffe and Navrotsky, 1981], shock‐wave research [Nellis, et al., 1982] and the application of high‐pressure studies to geophysical problems [Akimoto and Manghnani, 1982].Several important review articles and books related to mineral physics have appeared in the last few years. For example, Bassett [1979], Liebermann [1979], Ahrens [1980] and O.L. Anderson [1981] have recently summarized many of the geophysical applications of research on mineral properties. In this report, Bell [1983] discusses static high‐pressure experiments, and the present summary of melt properties is abbreviated in light of G.E. Brown's [1983] companion paper [see also Hargraves, 1980, and Mysen, et al., 1982]. Among the most important reviews of the last few years have been S.W. Kieffer's papers [1979a, b, c; 1980, 1982] that summarize the thermodynamic properties of minerals. Her analysis is in terms of a simple physical model that results in rernaf kably good predictions of phase equilibria. Detailed presentations of current static techniques for high‐pressure experimentation are provided by Jamieson [1981], and Hazen and Finger [1982]. Similarly, shock‐wave studies are reviewed by Davison and Graham [1979], and an important new summary of data is that of Marsh [198O]. Finally, it is worth noting that W.A. Harrison's [1980] text is a useful introduction to some of the most successful quantum mechanical approaches that are now being applied to the properties of condensed matter.
The Spectral Gap
Authors: Bretherton F. P. , Bull G. , Lindzen R. S. , Pao Yih‐Ho , Reiter E. R. , Wilhelmsson H. 
Published: February 2008

The primary problem we discussed is how to distinguish by means of spectral analysis the different types of dynamics believed to be dominant on different scales in the atmosphere; in particular, synoptic scales (dominated by rotation), mesoscale (waves or buoyancy), and microscale (‘turbulence’). The group rapidly concluded that they did not know how to do this, even in principle, and this report describes their observations on the subject.For this purpose, spectra should be plotted (Figure 1) such that the area under a given portion of the graph is directly proportional to the contribution to the mean‐square fluctuation. All spectra are based on an average over an ensemble of realizations of the relevant field: 1. by combining records taken on separate occasions, or 2. by subdividing a continuous record into separate parts, or 3. by taking a Fourier series for a single record and smoothing the result, (which is ultimately equivalent to no. 2 above).
Fossil Turbulence
Authors: Woods J. D. , Högström V. , Misme P. , Ottersten H. , Phillips O. M. 
Published: February 2008

Fossil turbulence is the name given to the three‐dimensional microstructure of temperature, humidity, or some other scalar property that is advected by the mean flow. (The first use of the expression seems to be attributable to Woods, but the physical phenomenon that it represents has been recognized for some time by fluid dynamicists.) The fossil turbulence was produced by a turbulent field that has since decayed; its scalar fluctuations occur at an intensity and on a scale that cannot be accounted for by the existing velocity field.The relevance to this colloquium of fossil turbulence in the atmosphere is that it may produce appreciable radar backscattering, provided that it contains significant three‐dimensional refractive‐index structure on a scale equal to half the radar wavelength (typically 5–50 cm). Similarly, fossil turbulence may be of importance in radio forward‐scattering, although the relevant scale sizes here are larger (typically 3 meters or more) and depend on radio wavelength and scattering angle. Fossil turbulence, if it exists in the atmosphere, will also affect line‐of‐sight radio propagation and the propagation of optical and acoustical waves, its effects depending on the propagation geometry and the frequency of the propagating waves.
Determining deviatoric stress tensors from calcite twins: Applications to monophased synthetic and natural polycrystals
Authors: Laurent Philippe , Tourneret Christophe , Laborde Olivier 
Published: February 2008

Theoretically, calcite twins analysis makes possible the full determination of the deviatoric stress tensor responsible for the formation of the twin lamellae, that is, the orientations of the principal stress axes and the three differential stress values (σi–σj) may be calculated, assuming conditions of constant resolved shear stress for twinning. Inverse method using nonlinear regression and robust estimation is proposed.Applications to monophased synthetic polycrystals that are generated numerically by solving the direct problem and to a natural sample from the Quercy (southwest of France) have given good results. Comparison with the first method proposed by Turner (1953), modified by Nissen (1964) for principal stress orientations and by Jamison and Spang (1976) for differential stress values, clearly emphasizes the considerable interest of this new method.