bluuebunny/crossref_metadata_2025 huggingface dataset:
The Smithsonian Astrophysical Observatory Solar Constant Program
Authors: Hoyt Douglas V.
Published: February 2008

The Astrophysical Observatory of the Smithsonian Institution (APO) made measurements of the solar constant at many locations on the earth's surface from 1902 to 1962. These measurements have been interpreted by various authors to show that the sun has both a long‐term secular change in brightness and cyclic variations. The same data set has been used by other authors to show that the sun is constant in output. The APO solar constant data are reexamined in this review in order to clarify what the APO staff did and what their results say about the behavior of the sun. There are serious problems with the internal consistency of the APO solar constant measurements indicated by the general lack of a common signal between stations or between different measurement methods. If the overall data set is considered, there is no evidence for cyclic variations or any long‐term trend in the solar constant greater than a few tenths of a percent. Overall the solar constant appears to be constant to within about 0.1% over the period 1923–1954. Most of the observed variations are explained by errors in the data reduction scheme which failed to remove all the effects of atmospheric extinction or by improper changes in the radiation scale. The solar constant values are independent of solar activity. Although this null conclusion based on the examination of this data set is not encouraging as an easy explanation for climatic change during the twentieth century, the conclusion is valuable in that it sets constraints on the required long‐term accuracy and reproducibility needed in the upcoming satellite observations of the solar constant.
Interplanetary particle acceleration, modulation and drift
Authors: Jokipii J. R.
Published: February 2008

This report is concerned mainly with the contribution of U. S. scientists, during the period 1975–1978, to the general area of particle acceleration and transport in the solar wind, excluding particles of solar origin. Other work is cited only when it bears directly on the subject being discussed. Progress in this area is currently very rapid, and I will discuss those aspects which appear to be affecting the current mainstream. Excellent reviews concerning this area have been published by Volk (1975) and Fisk (1977).
Kimberlites and the mantle
Authors: Meyer Henry O. A.
Published: February 2008

During the quadriennal period 1975 to 1978 a considerable number of investigations, often closely related, have been undertaken on kimberlites, mantle xenoliths and diamonds. Much progress was made into our knowledge of specific occurrences of kimberlite and diamond in the United States. However, these works are few when compared with the large number of studies carried out on Southern African kimberlites and xenoliths, many by scientists in U.S. institutions. Since the mecca of kimberlite, xenoliths and diamonds in South Africa, particularly Kimberley, it is difficult and unwarranted to separate out the various investigations by nationality.
Experimental metamorphic petrology
Authors: Chernosky Joseph V.
Published: February 2008

Since Bowen and Tuttle's pioneering study of the system MgO‐SiO2‐H2O in 1949, advances in experimental metamorphic petrology have occurred steadily rather than in “leaps and bounds”. The number and quality of papers published during the past quadrennium, 1975–1978, attests to the health of the science. Although the purpose of this report is to focus international attention on the U.S. effort in experimental metamorphic petrology, some papers published by foreign experimentalists have been included, especially where their contributions complement those made in the U.S. To keep the review current, abstracts of papers read at national meetings of the Geological Society of America and the American Geophysical Union in 1978 are included.
Volcanology
Authors: Simkin Tom
Published: February 2008

Volcanology in the 1970s has expanded greatly in both size and scope. Comparison of the references listed here with those of the U.S. National Report to IUGG for 1963–6 (by R. W. Decker) and 1967–70 (by T. L. Wright)* illustrates many of these changes. The number of references has doubled, reflecting increased interest in active volcanoes as well as the overall increase in scientific literature. Kilauea has been at least twice as active as any other oceanic volcano during the last decade, and its references (48) continue to dominate work on individual U.S. volcanoes.
Review of plate tectonics
Authors: Burke Kevin , Şengör A. M. C.
Published: February 2008

It is now more than a decade since geophysicists became generally aware of Wilson's (1965) recognition of the plate structure of the lithosphere. The implications of this recognition for the solid‐earth sciences have been so wide that a short review of achievements in the field can only be highly selective and must reflect strongly the prejudices of the reviewers—two field geologists. Major advances in plate tectonics since Dewey's review four years ago (Dewey, 1975a) have largely involved better understanding of the complexities of plate boundary phenomena although understanding of present plate motions continues to improve (Minster and Jordan, 1978). Revision of the basic principles of plate tectonics has not yet proved necessary, but intensive studies have revealed subtleties that may not have been clearly appreciated in the earliest research.
Geodetic instrumentation
Authors: Decker B. Louis
Published: February 2008

Although significant advances have occurred in geodetic instrumentation during the past 20 years, especially with respect to converted inertial navigation systems and satellite related instrumentation, they did not result from systematically following some well organized development plan. Instead, these advances have originated for a variety of reasons—the availability of new technologies either directly or indirectly relatable to instrumentation, accuracy requirements stated in support of particular tasks, and improvements or developments accomplished or initiated by individual scientists, commercial instrument concerns, or field users. Developments or advances occurring during 1975–1978 are recorded herein.
Polar oceanography I: Arctic Ocean
Authors: Aagaard Knut
Published: February 2008

Oceanographic work in the Arctic seas the past four years has concentrated on the dynamics of the planetary boundary layer, meso‐scale events, regional problems (particularly on the shelves), and the connection with the North Atlantic (including the formation and outflow of deep water).

A major U.S. effort in the Arctic during the present reporting period was the Arctic Ice Dynamics Joint Experiment (AIDJEX). While the main thrust of the work was in ice dynamics, a good deal of oceanography was accomplished, particularly in boundary layer flow. During the 1972 pilot study, the first simultaneous measurements were made of mean and turbulent velocity at several levels through a fully developed planetary boundary layer (McPhee and Smith, 1976). The turbulent structure corresponded closely to recent atmospheric planetary boundary layer models when scaled by U*, U*2, and U*/f for velocity, stress, and depth, where U* is the surface layer friction velocity and f is the Coriolis parameter. The general conceptual framework developed was used to interpret results of the year‐long 1975–76 AIDJEX main experiment. In particular, McPhee (1977) used a bulk transport model and measured winds to predict ice drift during the melt season, when stress gradients in the ice were small. The simulations reproduced the observed velocity and velocity gradient fields remarkably well, underscoring the idea that U*/f scaling is appropriate, rather than, say, a mixed‐layer slab approach. In a second paper, McPhee (1978b) refined the statistics of the ice drift/water stress couple to show that a model adapted from the atmospheric planetary boundary layer theory of Businger and Arya (1974) gave statistics that were indistinguishable from the AIDJEX observations. The model was consistent with a Rossby‐number similarity law for the ice drag. The observations preclude the type of drag one would obtain by assuming constant eddy viscosity for a mixed‐layer slab. Other studies of the stress field beneath the ice include that of Hunkins (1975), as well as a large number published in the AIDJEX Bulletin by a variety of investigators.
Planetary magnetospheres
Authors: Siscoe George L. , Slavin James A.
Published: February 2008

Although the Jupiter encounters of Pioneers 10 and 11 occurred in the previous quadrennium, the flood of new information that they released launched a wave of publications that crested in the present quadrennium. For completeness all of the magnetospheric literature relating to the two encounters is included in the bibliography. The present quadrennium also recorded one Venus encounter and three Mercury encounters by Mariner 10, as well as Soviet missions to both Venus and Mars. Earth based optical and radio exploration of the magnetospheres of Jupiter, Saturn and (possibly) Uranus occurred and provided a number of important new results.
Boundary layer physics and turbulence—Observational aspects
Authors: Wyngaard J. C.
Published: February 2008

Since the range of applications of boundary‐layer meteorology is broad, and my space limited, I thought it best to direct this review toward structural and dynamical fundamentals of the planetary boundary layer (PBL) rather than toward particular applications. In doing so, I have made slight reference to the particular needs of users in large‐scale circulation, air‐pollution meteorology, agricultural meteorology, and environmental engineering. Certainly, however, much PBL research owes its justification and support to those communities.

This review is organized, therefore, along lines that would be generally appropriate for a discussion of any turbulent flow. Section 2 deals with the structure of the PBL, and the effects of stratification; Section 3 covers the interactions of the PBL with the surface below and the flow above; and Section 4 covers advances in measurement and (as they bear on observations) modeling.
Impact of man upon local and regional weather
Authors: Changnon Stanley A. , Semonin Richard G.
Published: February 2008

The 1975–1978 period has brought new realization that considerable atmospheric modification exists in the United States as a result of man's land use change [Weather Modification Advisory Board, 1978]. Cities, power plants, and certain agricultural activities modify the weather, often dramatically, on local and regional scales. Concern over these unintentional changes has grown nationally, making study of their nature and magnitude essential in many design and policy areas. Awareness of inadvertent weather modification has only recently become a part of wise planning for hydrologic, agricultural, transportation systems, and human activities.
Activities of the World Data Center‐A
Authors: Lander James F.
Published: February 2008

Much of the research in geophysics requires data from world‐wide sources. The global and extra terrestrial interests of the research in meteorology, oceanography, seismology and solar terrestrial physics make exchanges almost an absolute necessity. Many of the research problems in geophysics involve large geographical areas and costly surveys and monitoring to develop the data bases needed to solve problems involving time and space varying phenomena. Practicality suggests sharing of the effort through international cooperation.
Magnetic and chemical changes in marine sediments
Authors: Henshaw P. C. , Merrill R. T.
Published: February 2008

A considerable amount of chemical knowledge of marine sediments has been acquired in recent years but has not yet been utilized by paleomagnetists. On the other hand, geochemists are often unaware of the usefulness of numerous magnetic techniques. In this review we try to bridge this gap, and in particular, we outline many of the chemical and magnetic principles that should allow paleomagnetists to better identify and understand chemical changes that affect the magnetic properties of marine sediments. The chemical principles include those for distinguishing the four major sources of sediments (continental, biological, authigenic/hydrogenous, volcanic/hydrothermal) from one another by determining elemental abundance distributions, as well as for investigating the stabilities of mineral phases relative to changes in pE and pH. The magnetic principles include the effects of authigenesis and diagenesis on magnetic properties, particularly on the direction and intensity of natural remanent magnetization (NRM). These principles are then applied to several sedimentary cores obtained from the Pacific Ocean. It is shown that although low‐temperature oxidation of titanomagnetites occurs in some of these cores, such oxidation has had only a minor effect on altering the NRM in most cases. On the other hand, some ferromanganese phases are magnetic and form authigenically in the marine environment. At least one of these phases, probably todorokite, sometimes carries a remanence sufficiently large to mask the depositional remanence carried by the titanomagnetite grains.
Highlights of theoretical progress related to the International Magnetospheric Study
Authors: Hill T. W.
Published: February 2008

The goals of the International Magnetospheric Study (IMS) have been addressed by a variety of U.S. theoretical research efforts within three broad areas: (1) the solar wind/magnetosphere interaction, (2) the substorm dynamics of the magnetospheric tail, and (3) the electrodynamic magnetosphere/ionosphere interaction. In area 1, an important development is the suggestion that magnetic merging may occur predominantly near the polar cusps rather than near the subsolar point; this hypothesis has several interesting consequences, including the possibility that a large area of the dayside magnetopause may be magnetically closed even in the presence of a significant level of magnetic merging at the cusps. Several potential mechanisms have been identified to account for noncollisional diffusion of solar wind plasma across such a closed magnetopause. In area 2, the importance to magnetotail dynamics of a continuous source of solar wind plasma and of sporadic plasma loss associated with an unsteady convection cycle has been stressed, although self‐consistent models incorporating these effects have yet to be developed. In area 3, basic understanding of the relevant physics appears to be relatively advanced, both with respect to magnetosphere/ionosphere coupling in the subauroral region and with respect to the large‐scale structure of auroral zone electric fields parallel and perpendicular to the magnetic field. Significant progress has been made in quantitative global modeling of the magnetosphere/ionosphere interaction in sufficiently realistic detail to interact directly and productively with the IMS observational program.
Planetary science: 1979–1982
Authors: Squyres Steven W.
Published: February 2008

It is not an exaggeration to say that the past four years have brought a growth in our knowledge of the solar system unprecedented in all of history. Prior to this quadrennium, our closeup exploration of the planets had been limited to the atmosphere and a few surface sites on Venus, the surfaces of Mercury, the Moon, Mars, Phobos, and Deimos, and an intriguing but limited glimpse at Jupiter. To this list have been added the global topography of Venus, and a wide variety of data on Jupiter, Amalthea, Io, Europa, Ganymede, Callisto, Saturn, Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Hyperion, Iapetus, and Phoebe. Among the recent discoveries are continent‐sized landforms on Venus, a ring encircling Jupiter, the most volcanically active surface in the solar system on Io, hitherto unknown forms of global tectonism on icy Europa, Ganymede, and Enceladus, and intricate structure within Saturn's rings.
Outer planets satellites
Authors: Morrison David
Published: February 2008

During the four years 1979–1982, studies of the satellites of the outer planets matured into a major branch of planetology, largely in consequence of seven spacecraft encounters with the Jovian and Saturnian systems. Previously these objects had been investigated only by a small group of planetary astronomers, and few planetologists recognized their potential contribution to the study of planetary origins and evolution. A good perspective on the accomplishments of these largely astronomical studies can be found in reviews by Morrison and Cruikshank (1974), Morrison and Burns (1976), Morrison et al. (1977), Johnson (1978), and Cruikshank (1979).

The first direct studies of the outer solar system were accomplished by the Pioneer spacecraft, which flew through the Jovian system in 1973 and 1974 and achieved a first encounter with Saturn in September 1979. These appropriately‐named craft were the pathfinders for the much more sophisticated and intensive explorations of Voyager 1 and 2, which encountered the Jovian system in 1979 (March and June) and the Saturnian system in 1980 (November) and 1981 (August). More than a dozen objects, heretofore only faint points of light visible in the telescope, were revealed as complex worlds amenable to geological and geophysical investigation. As a result, a planetologist in 1982 can consider the comparative study of about triple the number of solid‐surface planets under investigation four years ago. This sudden and dramatic expansion in our data base promises to support a revolution in perspective comparable to that achieved earlier when the first geological information was returned by spacecraft from the Moon, Mars, and Mercury.
The geology of the terrestrial planets
Authors: Carr Michael H.
Published: February 2008

During the last four years our knowledge of the geology of the terrestrial planets has advanced rapidly. The advances are particularly noticeable for Venus and Mars. Improved understanding of Venus has come largely from the Pioneer Venus mission (Colin, 1980), which has given us our first global view of the planet, albeit at fairly low resolution. The period was also one of almost continuous data gathering for Mars as the Viking orbiters and landers, emplaced at the planet in 1976, continued to function.
U. S. Report to the IUGG, 1979–1982: Solar‐planetary relationships—Aeronomy
Authors: Stolarski R. S.
Published: February 2008

Aeronomy is the study of the physics and chemistry of the upper atmosphere. The upper atmosphere is usually defined as the region of the atmosphere above the tropopause extending upward to the point where electric and magnetic fields dominate the phenomena rather than the atmospheric atoms and molecules. The lower part of this region, from about 10 to 90 kilometers altitude, has become known as the middle atmosphere. An international program called MAP (Middle Atmosphere Program) is now underway to intensively study this region.
Neutral and ion composition of the thermosphere
Authors: Torr Douglas G.
Published: February 2008

This report reviews developments over the past four years in thermospheric chemistry and composition, thermal structure, energy sources and energy budget. The discussion is limited to middle and low latitudes.
Aeronomy of the inner planets
Authors: Cravens T. E. , Nagy A. F.
Published: February 2008

Recent progress concerning the thermospheres of Venus and Mars is reviewed in this report. A dramatic advance in our understanding of the upper atmosphere and ionosphere of Venus has occurred during the 1979–82 quadrennium, and was primarily due to the large amount of data generated by the Pioneer Venus mission. Progress on Mars has been rather modest and has stemmed from theoretical modeling efforts related to the 1976 Viking observations. This report covers the following topics: the thermosphere and ionosphere of Mars, the thermosphere of Venus, some aspects of the solar wind‐ionosphere interaction of Venus, the dayside ionosphere of Venus including both composition and energetics, and the nightside ionosphere of Venus.
Middle atmospheric electrodynamics
Authors: Kelley Michael C.
Published: February 2008

In the last four years considerable interest has been evidenced in the physics and chemistry of the earth's middle atmosphere in general and in middle atmosphere electrodynamics in particular. In this review we discuss a variety of new techniques which have been developed to study this region and several exciting and controversial results accruing from this effort.
Solar activity
Authors: Rust David M.
Published: February 2008

During the past four years, the emphasis in much of the solar research in the United States gradually shifted from the structure of active regions to the nature of the impulsive phase of flares. The first two years of the review interval were dominated by completion of the Skylab data analyses, and especially by the Skylab Workshops on Solar Active Regions (Orrall, 1981) and on Solar Flares (Sturrock 1981). In the second half of the review interval, results from the Solar Maxmum Year began to appear, with especially strong contributions from the Solar Maximum Mission (Bohlin et al., 1980; Chipman, 1981) and the P78‐1 satellite experiment teams (Sheeley et al., 1980b; Landecker and McKenzie, 1982). Both satellites carry instruments that are better suited for studying flare phenomena than the Skylab instruments.
Crustal movement
Authors: Brown Larry , Reilinger Robert
Published: February 2008

The past four years have been a paradoxical watershed for the geodetic measurement of contemporary crustal motion in the U.S. More than ever before, the role of systematic errors in the techniques used to monitor crustal movement has been a major issue. Yet while concern was growing over such errors in some studies, other measurements were reaffirming the unique and effective contribution of geodetic techniques to geodynamic investigation by confirming previously mapped patterns of crustal deformation as well as providing exciting evidence of movement in previously unstudied areas. With new efforts to understand and minimize the influence of errors, to resurvey substantial portions of the U.S. geodetic network, to computerize historical geodetic measurements, and to bring online new space‐based geodetic systems well underway, geodesy is certain to play an increasingly important role in the investigation of contemporary tectonics.
Satellite positioning
Authors: Hill R. W.
Published: February 2008

In the previous Quadrennial Report, Brown (1979) reviewed the developments in positioning by satellites. During the current period, the exponential increase in numbers of satellite Doppler receivers has continued. According to Hoskins (1982), the total of 4000 units has grown to over 16,000 units (of which 1000 are of the two frequency geodetic type). Positional accuracy obtained from this geodetic equipment is frequently being reported at the one‐meter level and better.
Archaeo‐ and paleosecular variation, and long‐term asymmetries of the geomagnetic field
Authors: Barton Charles E. , Merrill Robert T.
Published: February 2008

This report summarizes progress made during the last four years in (i) obtaining records of the geomagnetic secular variation using paleomagnetic techniques, (ii) analysis and modelling of the secular variation, and (iii) the study of asymmetries in the time‐averaged field: seen both as departures from the geocentric axial dipole model, and as statistical differences between polarity states.
Magnetic anomalies
Authors: Harrison C. G. A.
Published: February 2008

Without a doubt, the main event concerning the study of magnetic anomalies to have happened during this quadrennium was the successful deployment of a low elevation satellite which measured the scalar and vector magnetic field of the Earth. This satellite, called MAGSAT, was launched from Vandenberg Air Force Base on October 30, 1979 into a twilight, sun‐synchronous orbit of apogee 561 km above the Earth's surface, perigee 352 km and inclination 96.76°. It remained in orbit until June 11, 1980, well exceeding its designed lifetime. Many preliminary results have been presented at various meetings (AGU, IAGA in Edinburgh, SEG) and a significant number of results have been published, mostly in a special issue of Geophysical Research Letters (volume 9 number 4, April 1982). But it should be emphasized that these are preliminary results, and there will be much more analysis done during the next quadrennium on the extensive data sets gathered by the satellite. With the acquisition of more surface data further steps were made in describing the tectonic history of the oceanic basins, but several problems remain. In particular, there seems to be considerable disagreement on the timing of the break up of Gondwanaland, and on the history of the various plates of the Pacific ocean basin. Major events in the study of continental magnetic anomalies have been the publication of magnetic anomaly maps of the conterminous United States, and of Alaska and the Hawaiian Islands. Further work has been done using continental magnetic anomalies to constrain models of various geological and geophysical features. Some useful advances have been made in modelling sea surface magnetic anomaly data. Problems in separating core and crustal field signals have been discussed by several authors.
Rock magnetism
Authors: Shive Peter N.
Published: February 2008

I have the responsibility of reviewing the advances made in rock magnetism (and paleomagnetic data analysis) over the last four years. My charge includes the specific invitation to comment on the use of rock magnetism in the service of paleomagnetism. This is, of course, a distinction that is often difficult to draw. It could be argued that there are no rock magnetic studies that do not, at least ultimately, serve paleomagnetism.
Unsaturated soil water flow
Authors: Smith Roger E.
Published: February 2008

The following summary covers research by United States's scientists published in journals during the nominal period 1979 to 1982, inclusive. Much excellent work published in the same journals by scientists from other countries has been passed over. The last half year 1982 could not be covered due to publication deadlines. For the same reason, research published in late 1978 has been included which was not discussed in the previous quadrennial report. The summary and bibliography are not exhaustive insofar as local institutional reports and journals not ordinarily dealing with the subject have not been searched through.
Ground water: A review
Authors: Bredehoeft J. D.
Published: February 2008

There is growing documentation that a significant portion of the Nation's fresh ground water in the densely populated areas of the country is contaminated. Because of the slow rates of ground‐water movement, ground water once contaminated will remain so for decades, often longer. Cleanup of contaminated ground water is almost always expensive and often technically unfeasible; the expense is often prohibitive.

While questions remain about the fundamental nature of dispersion, engineering estimates of the movement of contaminants in a porous medium are within the current state of the art. Chemical reactions commonly take place as the contaminants are transported by ground water. Estimates of contaminant movement in situations where chemical reactions play an important role are possible in those instances in which the reactions are understood. The biological control of many of the organic reactions taking place with organic contaminants in ground water is presently poorly understood.

The fractured media remain as the major area in ground‐water physics for which no consensus about the appropriate flow and/or transport theory exists. Flow and transport in fractured media remain as unsolved theoretical problems in ground‐water hydrology.

The methods for solving the mathematical problems posed by flow and transport a in porous medium have to a large extent been solved during the last decade. However, the methods for obtaining the parameters in the field which characterize real systems are largely those developed in the 1940's and 1950's. The problem of obtaining field data remains cumbersome and expensive; new and improved methods are needed.
Progress in cloud physics 1979–1982
Authors: Hallett John
Published: February 2008

Cloud Physics is concerned with the initiation, growth and loss of particles in the earth's atmosphere. Information is therefore required of the behavior of particles as individuals over a wide range of dimensions, from 1/100 ym aerosol to 10 cm hailstones. In addition, the length of time a particle grows in a given environment depends on its motion in the atmosphere, so that the vertical air motion in the neighborhood of a particle is of equal importance in predicting its growth history. Applied problems abound.
An overview of the physical oceanography report
Authors: Leetmaa Ants
Published: February 2008

To a great extent, this U.S. physical oceanographic report to IUGG (1978–1982) focuses on advances made in large‐scale oceanography. Reviews are presented for the areas of equatorial oceanography, subtropical gyre studies, polar oceanography, mid‐latitude variability and oceanic heat flux. The last topic is a common thread that runs through all of the reviews since there is the realization that the ocean is an essential element in determining the climate of the earth. With increased concern over the coastal zone as a region where recreational, commercial, energy, and fisheries interests overlap, a great deal of effort has also gone into investigating the oceanography of the continental margins.
Poleward heat transport by the ocean
Authors: Bryan Kirk
Published: February 2008

Poleward heat transport and its relation to the thermohaline circulation of the World Ocean have long been neglected subjects, but a perceived need for a better understanding of the Earth's climate have given an impetus to studies of the ocean's role in the global heat balance. Oceanographers have a new appreciation of the existing hydrographie and geochemical data base, and ambitious plans are being made to measure new sections in all the major oceans. It is best to consider ocean heat transport in the context of fresh water, oxygen, silica and other geochemical transports. From the standpoint of climate, however, heat transport is of primary interest.
Equatorial oceanography
Authors: Cane Mark A. , Sarachik E. S.
Published: February 2008

Interest and activity in the equatorial oceans (defined arbitrarily as that part of the oceans within ten degrees of the equator) have undergone a remarkable expansion in the last four years. The previous IUGG report (O'Brien, 1979) listed about one hundred references – the present one lists over two hundred and fifty. Among the many reasons for this growth, a primary one is the realization of the rapid nature of equatorial responses. The vanishing of the Coriolis parameter in the presence of density stratification means that the ocean can respond strongly to basinwide winds on the climatically important, and observationalIy accessible, annual and interannual time scales. This realization has taken hold as the result of an interplay among theory, modelling and observation.
Seismicity, focal mechanisms, and tectonics
Authors: Forsyth Donald W.
Published: February 2008

In the last four years, there has been a tremendous increase in the detail of tectonic processes reported in the typical seismotectonic study. New data from many local and regional networks of seismographs established during the previous four‐year period, plus the now routine application of improved hypocentral location procedures, long‐period body wave modelling, and moment‐tensor inversion using digitally recorded data, have increased resolution of both the hypocentral location and the nature of the faulting process. Consequently, research emphasis has been on local tectonics, or those aspects of regional and global tectonics requiring high resolution. I briefly describe below some of the highlights of these studies.
Seismic studies of crustal structure
Authors: Phinney Robert A. , Odom Robert I.
Published: February 2008

During the past four years, seismology has continued its role as the key technique for determination of the structure of the continental and oceanic crust. By and large, however, the field and analysis methods used bear little resemblance to those of ten years ago. A continued push to increase the number of recording channels has led to the routine use of ocean bottom seismometers, sonobuoys, and multichannel streamers in oceanic studies, and to the use of large sets of portable instruments and multichannel seismic reflection strings on land. In studies using earthquakes as sources, local and regional arrays provide a capability for obtaining geologically useful two‐ and three‐dimensional information about the crust.
New developments in magmatic processes
Authors: Walker David
Published: February 2008

There has recently been a renewal of interest in a broad spectrum of long‐neglected magmatic processes. Mixing of magmas, Soret differentiation, metasomatism, and assimilation have been rediscovered. Double‐diffusive convection and crystallization boundary layers have been newly recognized as agents in magmatic differentiation. Some of this awareness derives from attention to the requirements of physical plausibility as well as chemical plausibility of magmatic differentiaton models. These new processes are supplementary to the well established crystal fractionation processes: partial melting and partial crystallization. They do not replace them.
Ridge crest volcanism
Authors: Edmond John M.
Published: February 2008

Developments in this area have preceeded very rapidly. Much of this progress has resulted from sophisticated multi‐channel seismic surveys of the ridge axes and especially from the detailed investigation or mapping of small areas using multibeam arrays, towed cameras and submersibles.

The Magma Chamber

The depth‐lateral dimensions of the magma chamber remain unconstrained. Multi‐channel seismic reflections from the mantle and from the top of the magma chamber under the crest of the East Pacific Rise at 9°N have been reported by Stoffa et al. [1980] and Herron et al. [1980]. These have been re‐interpreted by Hale et al. [1982] as showing an assymetric chamber caused perhaps by assymetric spreading or by the intersections of the profile with an unmapped fracture zone. Herron [1982] using the same data has resolved the transition from the pillow basalt layer to the sheeted dyke complex at a depth of about 400 m. All interpretations are consistent with the top of the magma chamber being at a depth of between 1.5 and 2 km below the sea floor in this area.
Metamorphic petrology
Authors: Loomis Timothy P.
Published: February 2008

Continued advances in thermodynamic models of mineral and fluid equilibrium and in the kinetics of mineral reactions have made metamorphic petrology a quantitative science. Thermometers and barometers for many rocks are accurate enough to locate the origin of the rocks in the crust and mantle, and the development of kinetic models promises to enable tracing the P‐T path through time of individual specimens of some rocks. Data on the flow of fluids through metamorphic rocks and their interaction with minerals contributes toward an understanding of the processes responsible for the formation of some ore deposits and the geochemical evolution of the oceans. Models of partial melting should prove to be useful for predicting igneous contamination.
State of stress in the lithosphere
Authors: Zoback Mark D.
Published: February 2008

Recent estimates of the magnitude and orientation of lithospheric stresses are reviewed. Data come from a variety of sources including earthquake focal mechanisms, fault slip data, young volcanic dikes and feeders, in‐situ stress measurements at depth, lithospheric flexure models, microstructure paleopiezometry, and consideration of constraints on maximum stress differences from laboratory‐determined friction and flow laws.
Passive continental margins: A review
Authors: Pitman Walter C.
Published: February 2008

This appears to be the first U.S. I.U.G.G. quadrennial report on passive continental margins. For this reason alone a systematic review of all of the noteworthy literature would be voluminous. In addition very significant advances have been made during the past several years toward understanding the major stages of evolution of these margins. For these reasons this review will focus on these advances, the various analyses that led up to them and their consequences.
Polar oceans
Authors: Gordon Arnold L. , Owens W. Brechner
Published: February 2008

We survey progress in studies of ocean circulation, water mass formation, and ocean‐ice interaction in both the Southern Ocean and the Arctic region during the period 1983–86. This review places emphasis on U.S. publications, but other significant work is included. It is not meant to be a complete synthesis of polar oceanography of the last four years, but rather to provide an overview of progress. There are articles included in the reference list not cited in the text.
Planetary science: 1983–1986
Authors: Clifford Stephen M.
Published: February 2008

It would be fair to say that planetary science in the U.S. has seen better times. In the 1960's the United States launched, or attempted to launch, twenty‐five spacecraft to the Moon (including four manned Apollo flights), four spacecraft to Mars, and three to Venus. The 1970's saw five Apollo flights to the Moon, four spacecraft launched to the outer planets, four to Mars, two to Venus, and a Venus‐Mercury flyby. To date, in the 1980's, not a single U.S. planetary spacecraft has left the launch pad.
Experimentation in planetary geology
Authors: Cintala Mark J.
Published: February 2008

The reasons for conducting experimentation are as varied as the topics that are studied. Whether a specific parameter must be quantified or an attempt is being made to duplicate a peculiar process, all experiments are unified by a common, ultimate objective: to provide a tangible link between theory and observation, although a suitable theory is often nonexistent at the time of the experiment. Experimentation in planetary geology assumes particular importance because of the factors inherent in the field of study itself—often enormous spatial scales, timescales rivaled only by those of cosmology, and the remoteness of the objects of study. In addition, any geoscientist who has entertained thoughts of developing a realistic mathematical model of even the simplest of processes rapidly becomes acquainted with the intimidating complexity of geological phenomena; experimentation is still, in many cases, the only effective means of learning more about some natural mechanisms.
Mesoscale and severe storm meteorology
Authors: Maddox Robert A.
Published: February 2008

The past four years have witnessed substantial research on mesoscale and severe thunderstorm phenomena. The reasons for rapidly expanding activities in both areas are quite clear. Severe thunderstorms and intense mesoscale weather phenomena account for much of the dangerous and economically disruptive weather that occurs in the United States each year [for example, recent severe, tornadic, and damaging weather events are documented in Ferguson et al., 1983, 1985, and 1986; Rogers et al., 1983 and 1985]. Further, rapid advancements in technology indicate that increasing amounts of information on mesoscale phenomena will steadily become available for study.
Review of atmospheric boundary layer research, 1983–1986
Authors: Friehe Carl A.
Published: February 2008

The atmospheric boundary layer comprises the lower portion of the atmosphere that is dynamically or thermodynamically affected by the presence of and interactions with the underlying surface. The momentum, heat, water vapor and species exchanges at the surface have important effects on the boundary layer and a large portion of man's activities. The height of the boundary layer can range from only several tens of meters in extreme inversion situations, to many kilometers. Boundary‐layer sub‐specialties are often divided along the lines of the nature of the underlying surface: ocean (air‐sea interaction), ice, smooth terrain, urban, vegetation of significant height (canopies) and large‐scale features such as hills and valleys.
Advances in meteorological instrumentation
Authors: Serafin Robert J. , Dabberdt Walter F. , Cooper William A.
Published: February 2008

Current work on meteorological instrumentation and observing systems is summarized. In situ sensing, aircraft instrumentation, remote sensing systems, and tropospheric sounding techniques are discussed specifically. The primary focus is on the state of the art in the United States, but some attention is also given to work in other countries.
Natural and anthropogenic perturbations to the stratosphere
Authors: Wuebbles Donald J.
Published: February 2008

This review describes the research progress made during the last four years concerning natural and anthropogenic perturbations to the stratosphere. Observed trends in ozone and temperature, along with other available atmospheric measurements, are discussed and compared with theoretical model calculated analyses of perturbation effects.
Trace gas measurements in the stratosphere using balloon‐borne instruments
Authors: Murcray David G.
Published: February 2008

The large balloon has played a significant role in obtaining information on the concentration of trace species in the stratosphere. During the last few years the failure rate of these balloons has been high, in fact it is considered excessive. As a result the number of flights attempted as well as the number of successful flights has been reduced. Consequently the number of measurements made using balloons during the past four years is down significantly from previous reporting periods. The emphasis of the measurements being made during this period is also different. A significant portion of the flights have been made as part of intercomparison campaigns rather than as single measurements. The majority of the individual measurements reported during this period were descriptions of new techniques for obtaining data on constituents which had been previously measured with other techniques.
Radiative heating‐cooling and the energetics of the stratosphere and mesosphere
Authors: Strobel Darrell F.
Published: February 2008

One of the principal activities during the past four years for which this brief report is written was further efforts to parameterize IR radiation in the middle atmosphere. The ultimate goal is a computationally efficient, accurate algorithm which can be used in middle atmosphere dynamics models. The need for this is obvious when one considers the CO2 15μ bands. Schwartzkopf and FeIs [1985] In a detailed line‐by‐line calculation of cooling rates treated over 12,500 of the approximately 20,000 tabulated lines in these bands to obtain an accurate benchmark for their parameterization scheme.
Dynamics of the middle atmosphere
Authors: Schoeberl Mark R.
Published: February 2008

This review summarizes middle atmosphere (stratosphere and mesosphere) research in the United States over a period from October 1982 to May 1986. Some important relevant works by foreign investigators are also included. Previous work is summarized in the IUGG report by Hartmann (1983). The reference list encompasses the relevant work although each individual paper may not be discussed in the text.

The research topics discussed here cover all scales of motion in the stratosphere and mesosphere except for acoustic phenomena. The categories are: extratropical wave motions and instabilities (e.g., planetary to medium scale waves), gravity waves, tropical motions, the general circulation of the middle atmosphere and constituent transport where dynamically significant. These categories are not definitive. Nonetheless, this division of motion fields roughly follows historical precedence and the scaling approximations used in dynamical meteorology.
Progress in magnetospheric physics: 1983–86
Authors: Schulz Michael
Published: February 2008

It has been a distinct pleasure, as well as an educational experience, to have served as associate editor for magnetospheric physics on this quadrennial report to IUGG. Fourteen authors and eighteen referees have done their utmost, despite the pressure of firm deadlines and the constraint of severe page limits, to make the magnetospheric report (consisting of the ten papers that follow) a valuable resource for the international space‐research community. Users of this report are encouraged to cite not only the original references found pertinent to their research but also the IUGG review article(s) in which those original references were compiled.

Authors of the ten review articles that follow were asked to compile fairly complete lists of relevant papers based on work performed at institutions in the United States and published between late 1982 and late 1986. Additional papers could be cited in the interest of providing context or perspective. Review authors were not required to mention in text every article included in their reference lists. The reader should attach no stigma, however, to the omission of any paper from either the text or the reference list of an IUGG review article. Any omission may have been an oversight, or it may have been necessary for the flow or balance of a particular review.
Modeling of the magnetosphere
Authors: Stern David P.
Published: February 2008

Magnetospheric modeling is the art of deriving the configuration of the magnetosphere and representing its behavior. Two main levels exist: descriptive modeling which tries to represent the observed magnetic field B and perhaps the electric field E, and physical modeling which also includes plasma effects. Descriptive modeling must only satisfy Maxwell's equations, in particular ∇ · B = 0; physical modeling adds density ρ, pressure p etc. and must also satisfy conservation laws of magneto‐hydrodynamics (MHD).

Discussed below are descriptive models and simple physical ones, up to the level of the magneto‐hydrostatic (MHS) approximation; full MHD simulations are covered in a companion report. In the MHS approximation the MHD momentum balance condition reduces to

∇p =j×B
Coronal mass ejections
Authors: Kahler S.
Published: February 2008

While the first coronal mass ejections (CMEs) were observed with the OSO‐7 white light coronagraph (Tousey, 1973), it was the Skylab coronagraph observations that clearly established CMEs as an important component of solar coronal physics. CMEs have been defined by Hundhausen et al. (1984a) as observable changes in coronal structures occurring on time scales of minutes to hours and involving new, discrete bright features in the field of view. Although only a fraction of all observed coronal activity, CMEs are of interest because they involve discrete additions of mass and magnetic fields to the solar wind. These large coherent structures, observed to expand to many times the diameter of the sun as they moved outward into interplanetary space, not only provided a fascinating new phenomenon for study, but were also perceived as the “missing link” between solar flares and geomagnetic storms (Hundhausen et al., 1984b).
Earth tides
Authors: Kuo John T.
Published: February 2008

Since the last report on “Earth Tides” by Goad [1983] as the U.S. National Report to IUGG, this serves as a continuation concerning the activities in the area of earth tides, and some aspects of ocean tides, which are inseparable from earth tides. (See also Kuo [1983].) It is evident that the study of “earth tides” moves rapidly from the phase of observations to that of applications, although observations are still needed. It is further evident that the basic phenomenon of the tidal deformation has been understood; however, the perturbation of the load deformation of the Earth due to ocean tides still requires the accurate information of the ocean tides on a global scale and particularly on the continental shelves, slopes and various transition regions of the continents and oceans.