bluuebunny/crossref_metadata_2025_split huggingface dataset:
Miocene deepwater oceanography
Authors: Woodruff Fay , Savin Samuel M. 
Published: February 2008

A global synthesis of Miocene benthic foraminiferal carbon and oxygen isotopic and faunal abundance data indicates that Miocene thermohaline circulation evolved through three regimes corresponding approximately to early, middle, and late Miocene times. There is evidence for major qualitative differences between the circulation of the modern ocean and the Miocene ocean prior to 11 Ma. The 13C/12C ratios of the benthic foraminifera Cibicidoides are interpreted in terms of water mass aging, i.e., the progressive depletion of dissolved O2 and lowering of δ13C values as the result of oxidation of organic matter as water flows further from its sources at the surface of the oceans. Both isotopic and faunal data indicate that the early Miocene regime, from 22 to 15 Ma, was the most different from today's. During that interval intermediate and deep waters of both the Atlantic and the Pacific oceans aged in a northward direction, and the intermediate waters of the Indian, the South Atlantic and the South Pacific oceans were consistently the youngest in the global ocean. We speculate that early Miocene global thermohaline circulation may have been strongly influenced by the influx of warm saline water, Tethyan Indian Saline Water, from the Tethys into the northern Indian Ocean. The isotopic and faunal data suggest that flow from the Tethyan region into the Indian Ocean diminished or terminated at about 14 Ma. Isotopic and faunal data give no evidence for North Atlantic Deep Water (NADW) formation prior to about 14.5 Ma (with the exception of a brief episode in the early Miocene). From 14.5 to 11 Ma NADW formation was weak, and circumpolar and Antarctic water flooded the deep South Atlantic and South Pacific as the Antarctic ice cap grew. From about 10 Ma to the end of the Miocene, thermohaline circulation resembled the modern circulation in many ways. In latest Miocene time (6 to 5 Ma) circulation patterns were very similar to today's except that NADW formation was greatly diminished. The distribution pattern of siliceous oozes in Miocene sediments is consistent with our proposed reconstruction of thermohaline circulation. Major changes which occurred in circulation during the middle Miocene were probably related to the closing of the Tethys and may have contributed to rapid middle Miocene growth of the Antarctic ice cap.Appendices 1, 4, 6, and 7 are available withentire article on microfiche. Order fromAmerican Geophysical Union, 2000 FloridaAvenue, N.W., Washington, DC 20009.Document 88P‐002; $5.00. Payment mustaccompany order.
Physical mechanisms of seismic‐wave attenuation
Authors: Jackson David D. , Anderson Don L. 
Published: February 2008

The theoretical and experimental evidence concerning mechanisms likely to be responsible for the attenuation of seismic waves are reviewed. Intergranular thermoelastic relaxation, atomic diffusion, and dislocation mechanisms cannot be ruled out as significant causes of seismic attenuation, but the most effective mechanisms seem to be associated with partial melting, grain‐boundary relaxation, and a poorly understood mechanism called ‘high‐temperature, internal‐friction background’ which obeys an equation of the formQ‐1 = (A/ƒ) exp (—H*/RT)Here Q−1 is a dimensionless measure of anelasticity, f is the frequency, T is the absolute temperature, and A, H*, and A, H*,and RR are constants for a material of uniform composition and grain size. Many of the mechanisms considered here have a strongly frequency‐dependent Q−1. However, in a material as complex as a rock, there is unlikely to be a single discrete relaxation time or activation energy, or a single ‘typical’ grain size. The observed Q−1 is likely to result from a superposition of several mechanisms and involve a spectrum of parameters leading to weaker frequency dependence than is predicted from a single simple mechanism. The seismic data cannot at present resolve the question of whether or not Q−1 has an intrinsic frequency dependence. The extent and the limitations of the available seismic data are discussed. Experimental data on the attenuation of oxides are summarized, the measurements at high temperature and low frequency being emphasized.
The tectonics of the eastern Mediterranean: A geophysical review
Authors: Lort J. M. 
Published: February 2008

A summary is given of present geophysical data available for the eastern Mediterranean, and the structural and tectonic history of the area is interpreted. The western Mediterranean is described in sufficient detail only for comparison.The region is delineated into plates on the basis of seismic activity at their margins. The African plate is moving northward relative to Europe with crustal destruction and underthrusting occurring along the Crete and Calabrian island arc systems. The intervening Aegean, Apulian, and Turkish plates are small and rapidly moving; they show intense seismicity at the boundaries. All observations (sediment deformation, gravity, magnetics and heat flow) suggest the existence of a zone of compression in the eastern Mediterranean.Anticlockwise rotation relative to Eurasia of parts of southern Europe occurred during an extensional phase in the west, permitting the development of new oceanic crust and accompanied by compression in the east. What little evidence there is suggests that the crust in the eastern Mediterranean is oceanic, but there are no magnetic stripes to indicate the orientation of the mid‐oceanic ridge from which it developed.
Oceanic volcanism: A review
Authors: McBirney A. R. 
Published: February 2008

Recognition of the magnitude and tectonic significance of oceanic volcanism has recently stimulated intensive investigation of the volcanic rocks and structures of the sea floor. An adequate interpretation of these features depends on a thorough understanding of submarine volcanic mechanisms. The pressure of deep water restricts the amount of vesiculation of eruptive magmas so that explosive activity is suppressed. Pillow lavas are probably shorter but thicker than subaerial flows of the same composition. Fragmental hyaloclastites are also important, but seem to be most common at relatively shallow depths. Most lavas and hyaloclastites are basaltic, but more siliceous pyroclastic deposits may be common in shallow seas of the continental shelves.Circumstantial evidence indicates that most abyssal basalts of the ocean floor were erupted at spreading centers and have been transported laterally. The rate of eruption of lavas is probably related to the mechanism of dike intrusion into a spreading center. Slow spreading rates result in less vertical transfer of heat, so that only relatively thick dikes reach the surface. Thinner dikes are chilled before erupting and cause a differential dilation of the crust that is reflected in shallow normal faulting. With increasing spreading rates, wall rocks are maintained at higher temperatures, and almost all dikes reach the surface to produce lava flows and smoother topography.Seamounts may begin to grow at ridge crests and continue as the volcano moves outward, but many must begin their activity far from the spreading center. Most of the submarine structure of seamounts must consist of pillow lavas with increasing amounts of hyaloclastites in the upper portion. Injection of dikes and sills adds substantially to the volume of the structure.Most abyssal basalts erupted at ridge crests are tholeiites, commonly with relatively high alumina contents. Silica‐deficient alkaline basalts become more common outward, especially at the crests of seamounts. The ultramafic rocks dredged from the mid‐Atlantic ridge fall into two classes. Some are clearly cumulate rocks related to associated gabbro and differentiated basalt. Others are strongly depleted in low‐melting components and appear to have been emplaced along fault zones; they may be derived from a residual layer from which basalt was extracted during an earlier episode of partial melting. It is difficult to find conclusive evidence that oceanic volcanism was as intense in pre‐Mesozoic time as it is postulated to be today.
Ionospheric irregularities
Authors: Perkins F. W. 
Published: February 2008

Ionospheric irregularities are small‐scale structures in the ionospheric plasma density generally oriented so that the plasma density variations occur rapidly across the geomagnetic field but slowly (or not at all) along the geomagnetic field. On the practical side, they play an important role in satellite communication systems [Utlaut, 1974].The scale length of ionospheric irregularities can range from a few meters to several kilometers across the magnetic field. A vast literature of radio wave studies has produced a fairly complete morphological picture of their occurrence pattern [Herman, 1966; Aarons and Allen, 1971]. Briefly, they occur in the auroral and polar cap F region almost all the time [Aarons, 1973], in the auroral E region in times of geomagnetic activity [Greenwald et al., 1973], in the equatorial E region [Balsley and Farley, 1973], and in the equatorial F region at night [Farley et al., 1970]. Ionospheric irregularities occur at temperate latitudes only in the nighttime F region during times of geomagnetic activity [Herman, 1966]. Often the occurrence of F region irregularities is called ‘spread F,’ a term derived from the appearance of ionograms under conditions when irregularities occur. Ionospheric irregularities have also been generated artificially by barium plasma releases [Rosenburg, 1971] and radio wave heating experiments [Utlaut and Cohen, 1971].
Parameterization of the planetary boundary layer in atmospheric general circulation models
Authors: Bhumralkar Chandrakant M. 
Published: February 2008

The interaction between the atmosphere and the underlying surface occurs through the planetary boundary layer. The basic information required for describing the large‐scale processes in terms of the boundary layer processes relates to the turbulent fluxes of momentum, heat, and moisture, the height of the boundary layer, and surface parameters such as soil moisture content and topography.The numerical models of the atmospheric general circulation incorporate the (statistical) effects of the boundary layer processes in terms of the large‐scale parameters computed by the model through parameterization techniques. This paper reviews various parameterization techniques used in current general circulation models and suggests the need for a sensitivity test to find the best one.
Compositions of energetic particle populations in interplanetary space
Authors: Gloeckler George 
Published: February 2008

Although the study of the composition of low‐energy particles in the interplanetary medium is a relatively new subject, our knowledge in this field has been advancing rapidly. Discoveries of pronounced anomalies in the compositions of solar flare particles and low‐energy “cosmic‐rays”, and of large‐scale interplanetary acceleration regions beyond several AU have been followed by more systematic investigations aimed at characterizing each of the components of the interplanetary energetic particle population.The discoveries may be attributed to a combination of three favorable circumstances: (a) availability of sophisticated instruments capable of performing composition measurements at low energies, (b) properly instrumented deep space probes exploring the outer and inner heliosphere, and (c) a favorable time period in the solar activity cycle during which the discovered phenomena were especially prominent. Composition measurements not only have played a key role in the initial discoveries, but have also contributed significantly to our understanding of the acceleration processes responsible for the production of energetic particles which populate interplanetary space.
Seismic wave attenuation in rocks
Authors: Mavko Gerald , Kjartansson Einar , Winkler Kenneth 
Published: February 2008

A fundamental feature associated with the propagation of stress waves in all solids is absorption of energy, which usually results in a change of the shape of transient waveforms. Despite its importance, the processes by which mechanical wave energy is converted into heat, and its effect on seismic observations, have been poorly understood. Although considerable progress has been made during the past few years, seismic attenuation remains a controversial subject as there is still considerable disagreement between different authors about some of its most fundamental aspects.In the first section of this paper the progress in arriving at a general phenomenological description of wave propagation and related effects such as the frequency dependence of the elastic moduli and transient creep will be covered. It turns out that for most attenuation mechanisms that are significant in rocks, this can be treated relatively independent of the details of the particular physical mechanisms responsible for the energy dissipation, which are treated in the second section. The third section gives a review of experimental results.
Observing, analyzing, and modeling mesoscale weather phenomena
Authors: Kreitzberg Carl W. 
Published: February 2008

Recent progress and current research in this field are placed in perspective, along with key problems to be addressed in the coming years. Modeling has progressed further than analysis because mesoscale analysis requires assimilation of information from diverse observing systems. Physical equations are essential tools in data analysis; four‐dimensional dynamic assimilation is a powerful but complex tool. Dynamic model predictions permit observations at different times to be interpreted in a consistent manner.Key observing systems and field programs are discussed briefly. Analysis techniques are discussed in relation to dynamic models with which they interact. Different classes of dynamic models are discussed, including prediction models, simulation models, and parameterization schemes. The relation of research on different classes of models is described. The emphasis throughout is on systems of models that use real data and can be verified against real data. Subsections are included dealing with communications among researchers and analysis of precipitation.The conclusion is that even more rapid progress is likely in the coming years, but the key problem will be four‐dimensional data assimilation. The challenge is to efficiently combine diverse types of data and provide for effective collaboration of diverse scientific specialties. When the challenge is met, this field will have advanced to the point that operational applications will be feasible and productive.An extended bibliography is included and sources of important technical reports are identified.
Urban hydrology
Authors: Delleur J. W. 
Published: February 2008

The period of 1967–1974, in Urban Hydrology, was called the period of “tool making” by McPherson (1980) and was followed by the 1975–1978 period of “tool wielding”. The four years of 1979–1982 are characterized primarily by a greater attention to the problems associated with the runoff quality, by the extension and improvement of computer models for a better simulation of pollutant washoff and pollutant effects on receiving streams, by a better understanding of the limitations of detention basins, by the recognition that detention can contribute to pollution abatement and finally by the acquisition of a very much needed and extensive data base on urban rainfall runoff quantity and quality and practices of urban runoff pollution control through the US EPA/USGS Nationwide Urban Runoff Program. One of the effects of this latter program is that the concept of watershed‐wide management for environmental protection was sharpened in terms of the control of flooding and of the quality of urban runoff and of the impacts on receiving streams.These last four years witnessed a maturing of urban hydrology which was manifest in the publication of a number of books on the subject. Kibler (1982b), Sheafer et al. (1982), Whipple et al. (1982), Novotny and Chester (1981), American Public Works Association (1981) and Lazaro (1979).
Developments in digital seismology
Authors: Alexander Shelton S. 
Published: February 2008

Seismology has entered the 1980s with increasing challenges and opportunities presented by advances in the technology for gathering and analysis pf digital data. These developments have resulted in: 1) a rapid increase in the amount of data routinely recorded; 2) a shift in data collection from primarily analog towards digital recording; and 3) the increasing application of advanced computer technology in seismological studies. There is clearly the potential to increase the scientific returns from seismic data of all types significantly, provided the data problems occasioned by these technological advances are overcome.During the past four years there have been rapid advances in digital data storage and processing capability that are now making relatively sophisticated signal analysis simple to carry out even on microcomputers; minicomputers or mainframes that seismologists have used for many years are increasingly powerful and versatile. As a result of these developments high‐quality digital data sets are accessible in formats that are relatively easy to use, although standardized formats for data exchange are not universally agreed upon as yet. Unlike the situation only a few years ago, it is now feasible to analyze a large suite of seismic events in a typical study, rather than base conclusions or only a few events that can be digitized from analog paper or analog tape recordings. Moreover, the increased dynamic range afforded by modern digital systems (>120 db) allows one to study a large range of event magnitudes using the same source‐receiver combination.
Gravimetry
Authors: Moose Robert E. 
Published: February 2008

This report of the developments in gravimetry in the United States for the period 1983–86 was compiled from the cited published papers and from information contributed by selected individuals concerning their particular activities.The most significant development in gravity surveying during the last 4 years has been the utilization of the Global Positioning System (GPS) in all facets: land, sea and air of gravity data acquisition. Differential GPS is being used in land gravity surveys to provide accurate position and height information and carrier frequency Doppler observations are being used to accurately determine the velocity in moving base gravimetry. Using GPS, airborne gravity is now, and soon gradient measuring systems will be, able to map with ease previously inaccessible areas such as mountains, swamps and the arctic regions.
Waves and Turbulence
Authors: Busch N. E. , Vinnichenko N. K. , Waterman A. T. , Beard C. , Stewart R. W. , Scotti R. S. 
Published: February 2008

Observations on fluid flows indicate quite clearly that it may be feasible to distinguish between various classes of fluid motions with reasonably well‐defined properties.Before we try to investigate the feasibility of distinguishing waves from turbulence, it is important to notice that these two types of fluid motion are not the only ones. If all realizable flow patterns are assumed to be solutions to the same set of equations, then in principle they all possess the same degrees of freedom or possible modes of motion. The spatial and temporal boundary conditions appropriate for a given flow field determine which modes can and will be excited.
Biographical sketch of Dr. John Locke
Authors: Bauer L. A. 
Published: February 2008

The city of Cincinnati has the honor of having taken a leading part in the inauguration in this country of scientific work in astronomy, meteorology, and terrestrial magnetism—in astronomy, through the labors of Mitchell, the founder of the Cincinnati Observatory; in meteorology, through the vigorous impulse given to the science by Professor Cleveland Abbe, when he was director of the Cincinnati Observatory; and in terrestrial magnetism, through the enthusiasm and zeal of Dr. John Locke.I propose to speak here especially of the work of Dr. Locke, who was one of the foremost of the pioneers in terrestrial magnetism in this country. Through the kindness of his son, Colonel Joseph Morris Locke, who resides in Cincinnati, and whose acquaintance I have had the privilege of making, I am enabled to give the excellent portrait of his father herewith reproduced.
Note sur quelques anciennes déclinaisons
Authors: de Moidrey J. 
Published: February 2008

La très intéressante collection de données magnétiques, publiée par le Dr. van Bemmelen,1 me fait croire que plusieurs observations anciennes sont moins connues que je ne le pensais, puisque on ne les trouve citées ni par Hansteen, ni par le Dr. van Bemmelen. Bien qu'aucune ne soit manuscrite, il peut y avoir intérêt à les réunir.I. REMARQUES SUR LA LISTE DU DR. VAN BEMMELEN.
Regarding atmospheric electricity and its relation with solar activity
Authors: Bauer Louis A. 
Published: February 2008

The following quotation forms the concluding paragraph of Dr. K. Kähler's note, entitled “Das luftelektrische Potentialgefälle in Potsdam 1904 bis 1923,” which appeared in the February 1925 number of the “Meteorologische Zeitschrift,” pages 69‐71, this note being an excerpt from Dr. Kähler's contribution in the “Ergebnisse der Meteorologischen Beobachtungen in Potsdam in den Jahren 1921, 1922 und 1923, Berlin, 1924”:“Potentialgefälle und Sonnenflecken.—Aus diesem Grunde, eignet sich—darin hat L. A. Bauer recht—Potsdam wenig dafür, grössere säkulare Schwankungen wie den Sonnenfleckeneinfluss festzustellen. Das kann sehr wohl an den “Severe climatic disturbances” (Nature 112, 204, vgl. auch Terr. Mag. 29, 24) liegen. Wenn aber Bauer in demselben Zusammenhang von instrumentellen Änderungen in Potsdam spricht, so trifft das nicht zu. Das Instrumentarium ist unverändert and gut geblieben. Auch die Herabsetzung des Reduktionsfactors von 1.0 auf 0.8 hat keinen Einfluss, weil die Korrektion an alle 20 Jahre gleichmässig angebracht wurde. Der einzige Umstand, der auf kurze Zeit eine säkulare Änderung vrerschleiert haben könnte, ist das Zuwachsen der Messstelle in den Kriegsjahren» Aber auch die jetzt korrigierten Zahlen lassen keinen Parallelismus mit dem Sonnenfleckenzyklus erkennen, wie schon Markgraf1 hervorhebt. Markgraf zeigt an gleicher Stelle, dass auch die Leitfähigkeit in Potsdam, die doch von der Änderung des Reduktionsfaktors ganz unabhängig ist, in den Jahren 1912 bis 1921 keinen entgegengesetzten Gang zu den Sonnenflecken durchmacht ; sie schwankt vielmehr in den l0 Jahren um einen festen Mittelwert. Chree weist übrigens darauf hin, dass gerade diese 10 Jahre, die Bauer vorzugsweise seinen Schlüssen zugrunde legt, wenig für diesen Zweck geeignet waren. So trat in Kew der Sonnenfleckeneinfluss in dieser Zeit in allen meteorologischen Elementen weniger als sonst zutage. Für Kew nimmt Chree, wenn überhaupt, nur einen geringen Einfluss auf das Potentialgefälle an. Auch andere Stationen, beispielweise Heluan in Ägypten, fallen ebenso wie Potsdam heraus. Überdies kommt· Bauer in seiner letzten Arbeit (T.M., 29, p. 23, 1924) zu dem Schluss, das die Wirkung der Sonnenflecken auf das Potentialgefälle in den Messperioden vor 1901, vor allem um 1855 and 1889 herum, gerade umgekehrt gewesen sein muss wie in den letzten beiden Sonnenfleckenzyklen. Es wird also wohl einer ferneren Zukunft vorbehalten bleiben, diese sicherlich sehr interessante und wichtige Frage zu klären.”