bluuebunny/crossref_metadata_2025 huggingface dataset:
Brittle phenomena
Authors: Logan John M.
Published: February 2008

The term “brittle phenomena” includes a number of processes that are dominated by fracture as a mechanism or are controlled by the presence of preexisting fractures. Brittle phenomena in rocks are the most pervasive processes in the shallow crust of the Earth influencing natural deformation and controlling man's attempt to utilize natural resources. In particular, brittle phenomena affect: (1) the production of hydrocarbons, which requires a knowledge of the properties of fractured rocks in reservoirs and boreholes and an understanding of hydrofracturing; (2) mining techniques which involve rock removal, underground stability, water flow, and safety; (3) earthquake prediction, which depends upon a knowledge of the mechanical properties in and adjacent to natural fault zones; (4) engineering site evaluation and utilization; (5) waste disposal of radioactive materials, which is contingent not only upon the brittle response of the rock, but upon fluid transport through the material. It is clear that it is not just the brittle response of the rocks, but how fractures influence fluid flow, geophysical measurements, and associated phenomena that makes this an important area of scientific research today.
Evaporation and transpiration
Authors: Ziemer Robert R.
Published: February 2008

For years, the principal objective of evapotranspiration research has been to calculate the loss of water under varying conditions of climate, soil, and vegetation. The early simple empirical methods have generally been replaced by more detailed models which more closely represent the physical and biological processes involved. Monteith's modification of the original Penman evapotranspiration equation to include a term for canopy resistance signaled a shift in emphasis in evapotranspiration research from a physically controlled process to one which can be physiologically controlled. This change in direction was acknowledged by Federer [1975] in his earlier review and has continued for the past four years.
Urban hydrology
Authors: McPherson M. B.
Published: February 2008

Because the complex interactions of human activity in concentrated settlements with air, water and land must be taken into account, urban hydrology is a distinctive branch of the broad field of hydrology. As opposed to conventional hydrology, because urban development everywhere has been in continuous states of expansion and flux, urban hydrology contends with the dimension of dynamic change. Also, urban water management utilizes the social and biological sciences as well as the physical sciences. The fact that the term urban hydrology gained currency less than two decades ago reflects the lag in the recognition that America became an urban nation over half a century ago.
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 Uplift

Undoubtedly 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.
New developments in satellite oceanography and current measurements
Authors: Huang Norden E.
Published: February 2008

The study of the ocean from satellites has many obvious advantages. The potential of remote sensing techniques has caused increasing numbers of investigators from the oceanographic research community to turn toward satellite sensors as viable alternatives for data collection. Some of the achievements and the problems of applying these techniques to oceanography have been summarized by Apel (1976), Szekielda (1976), Huh and Nobel (1976), Schanda (1976) and AGARD (1977), but real data used in these discussions are from visible and infrared sensors primarily. Applications of the active microwave sensors to oceanographic studies started only recently.
Ionospheric irregularities
Authors: Fejer B. G , Kelley M. C.
Published: February 2008

Extensive experimental and theoretical research has been performed in the last decade to study ionospheric irregularities. These studies have shown that plasma instabilities play a major role in the generation of the irregularities. In this work we describe in detail the recent experimental studies of the E and F region irregularities and also the extensive work on plasma instability theories developed to explain them. We also describe both radio wave and spacecraft‐borne experimental techniques to allow a common ground for the understanding of the data from ground‐based and in situ experiments. To date, theoretical work has been mostly concentrated on the low‐latitude irregularities and, together with computer simulations, has been able to explain many aspects of the experimental data. These theoretical efforts are also discussed in some detail. The role of neutral winds in the creation of large‐scale ionospheric structures such as mid‐latitude sporadic E is beyond the scope of this review.
A comparison of volcanic with other fluxes of atmospheric trace gas constituents
Authors: Cadle Richard D.
Published: February 2008

Estimates of the average annual rates of emissions of various trace atmospheric constituents to the atmosphere by volcanoes are made and compared with estimates of the fluxes from other sources. On a global scale, volcanic fluxes are for the most part minor in comparison with those of other sources. The substances considered are SO2, H2S, COS, CS2, HCl, HF, HBr, H2, CO, CO2, Hg vapor, and organic compounds. During and following a volcanic eruption the concentrations locally and regionally may greatly exceed those usually found in the atmosphere and have disastrous effects on the biosphere. A surprising finding is that estimated values of global annual volcanic SO2 fluxes have increased and estimates of biogenic fluxes have decreased until similar values are being obtained for the two sources.
Marine magnetic anomaly timescales for the Cenozoic and Late Cretaceous: A précis, critique, and synthesis
Authors: Ness Gordon , Levi Shaul , Couch Richard
Published: February 2008

Anomaly timescales for the last 90 million years, derived from marine magnetic profiles and published prior to mid‐1979, are summarized, illustrated for comparison, and critically reviewed. A revised timescale is constructed using calibration points which fix the ages of anomalies 2.3′, 5.5, 24, and 29. An equation is presented for converting K‐Ar dates that is consistent with the recent adoption of new decay and abundance constants. The calibration points used in the revised timescale are so converted, as are the boundary ages of geologic epochs within the range of the timescale.
Chemistry within aqueous atmospheric aerosols and raindrops
Authors: Graedel T. E. , Weschler C. J.
Published: February 2008

Hundreds of chemical compounds have been identified as constituents of atmospheric aerosols and raindrops, and there is substantial evidence for chemical transformations occurring among them. Since tropospheric aerosols have a water content of 30–50 wt % at typical relative humidities, aerosols and raindrops may be regarded (at least to a first approximation) as aqueous solutions. In this review, atmospheric measurements and solution chemistry data are combined to examine reactions and physical parameters of potential importance in aerosol and raindrop systems; much of the information is potentially applicable as well to lake and ocean surface waters. Among the conclusions are the following: (1) Solar radiation penetrates aqueous aerosols and raindrops, photodissociating several molecules and ions. H2O2, formed in the gas phase and dissolved in the aerosol, photodissociates to produce OH ·, which is thus a common constituent of aqueous atmospheric systems and appears to play a role in many chemical processes. (2) The decomposition of atmospheric ozone dissolved in aqueous aerosols or raindrops is a second prolific source of HOx· radicals. (3) An analysis of the transition metal chemistry appropriate to these systems indicates that copper, manganese, and vanadium are potentially the most important homogeneous catalysts and that the concentrations of transition metals in aerosols are significant. (4) The oxidations of alkanes to alcohols, of alcohols to aldehydes, and of aldehydes to carboxylic acids result from chemical chains initiated by hydroxyl radicals or perhaps by organic photochemistry. (5) Rate parameters are available for many of the reactions of interest, particularly for the inorganic processes. Tabulations of relevant rate parameters, absorption coefficients, equilibrium constants, and aqueous solubilities are presented. (6) The tropospheric aerosol can be viewed schematically as an aqueous solution surrounding an insoluble core and covered by an organic surface film of varying integrity, thickness, and composition.
Generalized nonlinear inverse problems solved using the least squares criterion
Authors: Tarantola Albert , Valette Bernard
Published: February 2008

We attempt to give a general definition of the nonlinear least squares inverse problem. First, we examine the discrete problem (finite number of data and unknowns), setting the problem in its fully nonlinear form. Second, we examine the general case where some data and/or unknowns may be functions of a continuous variable and where the form of the theoretical relationship between data and unknowns may be general (in particular, nonlinear integrodifferential equations). As particular cases of our nonlinear algorithm we find linear solutions well known in geophysics, like Jackson's (1979) solution for discrete problems or Backus and Gilbert's (1970) solution for continuous problems.
Atmospheric gravity waves generated in the high‐latitude ionosphere: A review
Authors: Hunsucker Robert D.
Published: February 2008

A review of theoretical and observational results describing atmospheric gravity wave (AGW)/traveling ionospheric disturbance (TID) phenomena at high latitudes is presented. Some recent experimental studies of AGW's using the Chatanika incoherent scatter radar and other geophysical sensors are reported. Specifically, the following features are described in detail: (1) cause/effect relations between aurorally generated AGW's and TID's detected at mid‐latitudes, including probable ‘source signature’ identification, (2) AGW source phenomenology, particularly a semiquantitative assessment of the relative importance of Joule heating, Lorentz forces, intense particle precipitation, and other mechanisms in generating AGW's, and (3) detection of TID's in the auroral ionosphere. Several instances of F region electron density, temperature, and plasma periodicities accompanied by horizontal plasma velocities which were consistent with theoretical AGW/TID models are documented.
The IMSAS scientific reviews: An introduction
Authors: Southwood D. J. , Russell C. T.
Published: February 2008

The following eight papers are based on review papers presented at the International Magnetospheric Study Assessment Symposium (IMSAS) held at Goddard Space Flight Center, Maryland, in May 1981. The IMS was an international program set up under the auspices of the International Council of Scientific Unions Special Committee on Solar Terrestrial Physics, and our job as organizers of IMSAS was to use the meeting (1) to identify what data were obtained during the IMS for coordinated studies, (2) to assess the various, often innovative workshops which were convened to facilitate coordinated studies at an international or national level, and (3) to examine the status of the problems the IMS was to attack. The reader can assess our success in prosecuting aims 1 and by 2 by reading the AGU publication containing the relevant IMSAS proceedings (The IMS Source Book: Guide to the International Magnetospheric Study Data Analysis, edited by C. T. Russell and D. J. Southwood, 1982). The papers presented here are those we invited to pursue aim 3, the scientific progress due to the IMS.
origin and emplacement of ophiolites
Authors: Moores E. M.
Published: February 2008

Ever since their recognition, ophiolites have been a source of controversy, although all workers have agreed upon their importance. A number of conflicting schools of thought have become unified in the interpretation of ophiolite complexes as fragments of oceanic crust and mantle formed at spreading centers. An expanded version of the Penrose ophiolite definition is proposed, herein called the ophiolite association, taking into account rocks which bear upon the origin and significance of ophiolite complexes. An ideal ophiolite association includes the following units from bottom to top: (1) a crystalline basement and shallow water sedimentary sequence, (2) a tectonic unit of thrust slices of continental margin and rise and abyssal sediments and/or melange, (3) a metamorphic unit, as much as a few hundred meters thick, generally with higher‐grade rocks over lower‐grade ones, (4) ultramafic tectonite unit composed dominantly of multiply deformed peridotite, dunite, and minor chromitite, (5) a cumulate complex, ultramafic at the base grading to mafic or intermediate at the top, (6) a noncumulus unit of varitextured gabbro and minor trondhjemite (7) a sheeted dike complex, (8) an extrusive section of massive and pillowed flows and intercalated sediments, (9) an abyssal or bathyal sediment sequence which may include radiolarian chert, red pelagic limestone, metalliferous sediments, breccias, and/or pyroclastic deposits, and (10) postemplacement deposits of laterite, reef limestone, or shallow marine or subaerial sediments. This expanded ophiolite association allows greater precision in inferring original origin and emplacement. Some ophiolite complexes, particularly in the Tethys (herein designated Tethyan type), exhibit units 1, 2, 3, and 4, whereas others, particularly in the Cordilleran belt (herein termed Cordilleran type), lack units 1, 2, 3, and, in places, 4. The emplacement of the former probably occurred during collision of a passive margin with a subduction zone or incipient subduction zone. Emplacement of the Cordilleran type generally is not clear‐cut. The nature of the spreading center which produced a given ophiolite is indicated more clearly by the presence or absence of units 5–9 than by chemistry or mineralogy. Some ophiolite complexes lack complete sections and may have formed along transform faults. Others contain volcanic pyroclastic deposits instead of pelagic sedimentary sequence and probably formed within or near an arc. Several ophiolite complexes may have originated by conversion of a transform fault into a subduction zone. Such conversion may result from normal plate evolution or from major plate reorganization. Major times of ophiolite emplacements appear to correspond with global plate reorganizations.
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.
Polar and auroral phenomena: A review of U.S. progress during 1979–1982
Authors: Reiff Patricia H.
Published: February 2008

The quadrennium 1979–1982 has been a highly active time in the field of polar and auroral research, with nearly 400 research papers and thirty general or topical review papers written by U.S. authors. This paper highlights progress in understanding auroral morphology, precipitating particle fluxes, the spectra and sources of upward‐flowing particles, large‐scale Birkeland currents, and theoretical and experimental advances in auroral‐scale electrodynamics. Global electrodynamics, active experiments, plasma waves, and auroral aeronomy, although certainly ‘polar and auroral phenomena,’ are discussed in other papers in this issue.
Energy transfer in the quiet and disturbed magnetosphere
Authors: Burch J. L.
Published: February 2008

Progress on magnetospheric energy transfer reported during the 1979–1982 quadrennium is reviewed. A discussion of the macroscopic control of magnetospheric phenomena by solar‐wind electric and magnetic fields and kinetic pressure is followed by sections on energy transfer processes at the dayside magnetopause, in the magnetotail, near geosynchronous orbit, and at altitudes of ≈ 1RE above the auroral oval. Rapid progress in these areas has been stimulated primarily by ISEE and S3‐3 observations and by the development of techniques for the large‐scale computer simulation of plasma phenomena.
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.
Tectonomagnetism
Authors: Davis Paul M.
Published: February 2008

The magnetization of crustal rock is influenced by stress by virtue of piezomagnetic effects in crystals of magnetic minerals. Crustal stress changes in tectonic zones are therefore expected to generate changes in the crustal component of the geomagnetic field and so provide a mechanism for monitoring stress. During the last quadrennium, rock magnetic studies further quantified our understanding of the stress sensitivity, but showed that while the standard rotation models explain observations in SD and PSD magnetic grains, a new model is required to describe MD effects. Observations of several tectonomagnetic effects were reported and the method of observation improved using predictive filtering techniques to remove the disturbing influence of ionospheric and magnetospheric activity. The possibility that fluid flow in the crust might generate magnetic fields comparable to those due to stress changes was evaluated. However supporting experimental evidence is lacking. Long term monitoring of the geomagnetic field has been continued at 29 stations (of the U.S. Geological Survey) on the San Andreas fault between San Francisco and the Mexican border. None of the fields has changed by more than 5nT since the study was initiated (which for five of the stations was 1974). Two earthquakes of moderate size (ML = 5.2, 5.9) have occurred within the array during this time. Although changes of several nT have been observed, apparently spatially and temporally related to these events, no clear pattern emerges as yet.
Surface water hydrology: On‐line estimation
Authors: Sorooshian Soroosh
Published: February 2008

In recent years a large number of mathematical models of different types have been developed to represent various aspects of the rainfall‐runoff (R‐R) process. This proliferation of models has led some investigators to voice concerns about the difficulties that the practicing engineer faces in the selection of an appropriate model for his/her specific application. Given the amount of effort (in terms of money and time) that has been devoted to the development and improvement of R‐R models, it is perhaps disconcerting that the most widely applied technique for short‐interval (24 hours or less) on‐line flow forecasting is still the unit hydrograph. Clearly there seems to be some reluctance on the part of practicing hydrologiste to employ the newer models.
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.
Mid‐latitude mesoscale variability
Authors: Schmitz William J. , Holland William R. , Price James F.
Published: February 2008

Neither homogeneous quasi‐geostrophic turbulence nor the effect of eddies on the interior ocean circulation remains the major focus of mesoscale research as was the case for much of the preceding 20 years following identification of the phenomena. Concentration on basin‐wide geographical exploration of eddy properties was rather well established by 1978. Over the last few years, a promising zero‐order description and rationalization of the mesoscale field has become available. That is, eddy energy is largest near strong flows (intensification not only in western boundary currents, but along their mid‐latitude open‐ocean extension), roughly as indicated by gyre‐scale numerical models where eddies develop as a result of instability processes in the mid‐latitude jet and recirculation regimes, and then propagate into the ocean interior. Our point of view is that mesoscale eddies drive recirculations but do not play a crucial role in the dynamics of the mean flow in the ocean interior [in the North Atlantic, for example, the idea is that the downstream increase in transport of the Gulf Stream is eddy‐driven but not the flow through the Florida Straits]. In addition, the fluctuating response to forcing by variable winds may now be widely perceived as forming the horizontally homogeneous background signal in subtropical gyres. The time‐dependent field associated with thermohaline flows at abyssal depths also has a special character.
Polar oceanography
Authors: Gordon Arnold L.
Published: February 2008

Oceanographie progress pertaining to polar waters for the 1979–1982 period is briefly presented within three research areas: Southern Ocean; Arctic; and ocean‐ice interaction, after a discussion of general review articles and atlases. A conclusion is added which presents the author's view of future research direction in a general sense. Emphasis is placed on published U.S. work, though key non U.S. publications are included. The bibliography contains articles not cited in the text.
Advances in marine chemistry 1979–1982
Authors: Jenkins W. J. , Edmond J. M.
Published: February 2008

These four years saw advances in many areas. Further developments in sampling and analytical techniques have opened new avenues of exploration for trace elements and particulate matter. The impact of the GEOSECS expedition was further felt in the field of marine chemistry as the results were still being published. A major field effort occurred as a follow‐on to the GEOSECS work (TTO), and intensive sampling was performed in the newly discovered submarine hydrothermal vent fields. An important and unresolved controversy has arisen regarding the ability to measure “preformed” CO2 in the seawater system. In many respects the field of marine chemistry appears to be gaining a momentum spurred by both improvements in analytic techniques and an increasing social and economic relevance.
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.
Volcanology, geochemistry, and petrology 1979–1982
Authors: James David E.
Published: February 2008

This introduction to the Volcanology, Geochemistry and Petrology (VGP) section of the 1979–1982 IUGG Quadrennial Report is intended to serve as a thumbnail sketch of some major research developments and trends in VGP over the past four years. These notes are drawn from, and limited to, the nine review articles which follow in this section. While I have made an effort to give mention to all areas covered by the reviews, the subjects about which I know most have inevitably received the greater play. A full reading of the reviews will provide a more balanced summary.
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:
Volcanology
Authors: Swanson D. A. , Casadevall T. J.
Published: February 2008

Volcanoes erupt and are constructed of materials that were subjected to complex physical and chemical processes during ascent and emplacement on the earth's surface. To understand these processes is the most fundamental reason for studying volcanoes. We take a broad approach in this review, which concentrates on American efforts in volcanology during 1979–82, and emphasize those investigations concerned with processes of magma rise, eruption, and emplacement on the surface. Volcanology draws on many diverse disciplines, including petrology, geochemistry, geophysics, geodetics, mechanics, and classical geology.
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.
World Data Center‐A activities, 1978–1982
Authors: Lander James F.
Published: February 2008

The year 1982 marks the 25‐year anniversary of the International Geophysical Year (IGY) as well as the birth of the World Data Center (WDC) system. The WDC's were created to provide access to the data generated by the IGY global program. Two “universal” WDC's with activities in all covered fields were created—WDC‐A in the United States and WDC‐B in the USSR. Other WDC's for individual disciplines were established in Europe and Japan as WDC‐C's where special centers of expertise existed.
Accreted terranes
Authors: Nur Amos
Published: February 2008

Geologists have known for years that many allochthonous bodies in the form of accreted blocks and microcontinents are present in the Alpine‐Himilaya Mountain belt. In the past a few allochthonous bodies have also been identified in the Circum Pacific Mountain belts. More recently, however, the extent of these bodies and their large numbers around the Pacific (Figure 1) have been appreciated. Moreover, it is only in the last few years that the significance of these accreted bodies has emerged.
Planetary energy balance for tidal dissipation
Authors: Platzman George W.
Published: February 2008

Dissipation of tidal energy is expressed here as an integral on the surface of a sphere that encloses the mass of the planet. When developed in constituent form, this surface integral depends linearly on the secondary potential that arises from the tidal disturbance; it can therefore be expressed as the sum of one part due to the body tide and another due to the fluid tides. The body tide part depends only on the anelastic response of the solid earth to the primary potential. The fluid tide part depends mainly on the elastic solid earth response to tidal loading and on the sum of the ocean tide and atmospheric tide mass disturbances. The atmosphere's contribution can be evaluated reliably from published analyses of the observed barometric tide. Tide gage data, on the other hand, do not suffice for a comparably reliable analysis of the observed ocean tide and must therefore be supplemented by dynamical interpolation through numerical integration of Laplace's tidal equations. Dissipation obtained from ocean tide models published during the past 5 years has a range of at least ±15% from the average value. The main cause of this uncertainty is the difficulty of modeling dissipation, but there are other uncertain aspects of existing models, notably the lack of provision for absorption of energy into baroclinic motions and for the anelastic response of the solid earth to tidal loading.
A review of homomorphic deconvolution
Authors: Jin D. J. , Eisner E.
Published: February 2008

The purpose of this paper is to review the definition, to outline advantages and disadvantages, and to present both solved and unsolved problems of homomorphic deconvolution. The advantages of homomorphic deconvolution are that it does not require the assumptions of a minimum‐phase wavelet and of a white random reflection coefficient series. Recognized disadvantages of the method have been difficulties in unwrapping the phase, in dealing with band‐limited signals, and in handling mixed‐phase reflection coefficient series. These difficulties may be overcome by using an “adaptive numerical integration algorithm,” frequency transformations, and exponential weighting of the signal, respectively. Two unresolved problems in homomorphic deconvolution are deciding the cutoff quefrencies in liftering convolutional components and eliminating the effect of additive noise. No theoretical means of recovering one convolutional component of an arbitrary real seismogram which is not contaminated by the other component has been discovered. Additive noise plays an important role in homomorphic deconvolution, so that it is unreliable when the spectral amplitudes of the signal are very small over certain frequency bands in signals of relatively small signal‐to‐noise ratios.
Gravity wave saturation in the middle atmosphere: A review of theory and observations
Authors: Fritts David C.
Published: February 2008

This paper provides a review of recent advances in our understanding of gravity wave saturation in the middle atmosphere. A brief discussion of those studies leading to the identification of gravity wave effects and their role in middle atmosphere dynamics is presented first. This is followed by a simple development of the linear saturation theory to illustrate the principal effects. Recent extensions to the linear saturation theory, including quasi‐linear, nonlinear, and transient effects, are then described. Those studies addressing the role of gravity wave saturation in the mean circulation of the middle atmosphere are also discussed. Finally, observations of gravity wave motions, distribution, and variability and those measurements specifically addressing gravity wave saturation are reviewed.
Selective factors in Sun‐weather research
Authors: Taylor Harry A.
Published: February 2008

The extensive body of investigations of apparent correlations between solar wind/IMF disturbances and subsequent changes in the vorticity of the winter troposphere, which we designate as SV, is reviewed as representative of the search for sun‐weather relationships. Research on aspects of SV has for more than a decade been a dominant and controversial thrust in the search for links between short‐term solar variations and associated changes in the lower atmosphere. In particular, correlations identified between IMF sector boundary passages and subsequent decreases in the tropospheric vorticity, while not ubiquitous, continue to be perceived as one of the more credible sets of evidence for possible sun‐weather responses. We identify uncertainties in this research, which appear to have contributed inappropriate biases on both sides of the issue of the credibility of the SV response. Analyses leading to either positive or negative conclusions have generally concentrated upon the statistical procedures and have typically not addressed either the choice of parameters or the selective factors involved in the physical relationships existing between parameters. Thus we find that investigations of SV have characteristically lacked sufficient rigor for substantial conclusions to be drawn. Nonetheless, throughout the investigations on the subject a thread of observational evidence persists, suggestive of the possible associations between external forcing and atmospheric change. The obvious significance of such a possibility in our view clearly encourages further investigation. However, we strongly recommend that the research be conducted in a more interdisciplinary manner, emphasizing the variable physical relationships and the secular change in these relationships, selective factors which are known to exist between the variables believed critical to the problem.
Cloud and precipitation physics research 1983–1986
Authors: Beard Kenneth V.
Published: February 2008

Research in cloud and precipitation physics has traditionally emphasized microphysical scales of particle growth and interactions as is evident by the first modern treatises on the subject [Mason, 1957; Fletcher, 1962; Borovikov et al., 1963; Byers, 1965]. Our understanding of cloud microphysics has steadily progressed, although, as pointed out in the most recent text, “many microphysical mechanisms are not understood in quantitative detail” [Pruppacher and Klett, 1980]. It is now evident that the solution to many of the outstanding problems in atmospheric science will require an understanding of processes within the scope of cloud and precipitation physics. These include the traditional subjects of precipitation forecasting and weather modification, and the more recent problems of acid rain, nuclear “winter” and cloud‐radiative processes important to climate change.
Meteorological radar
Authors: Jameson A. R.
Published: February 2008

The field of radar meteorology continues to mature and blossom. Keeping it alive and well, however, will require a vigorous commitment to new technology and to the nurturing of new talent.
Aeronomy 1983–1987: An overview
Authors: Frederick John E.
Published: February 2008

Aeronomy focuses on the thermosphere, mesosphere, and stratosphere of Earth as well as on the atmospheres of other planets. The fundamental scientific disciplines from which aeronomy draws are atomic and molecular physics, photochemistry, radiative transfer, electromagnetic theory, and plasma physics. This introduction provides a brief overview of aeronomic research over the past four years as background for the more detailed reviews that follow.