The present book is the author's third on the subject of vertical seismic profiling (VSP). Ten years have elapsed since the pUblication of the fIrst book. During this period, VSP has become the principal method of seismic observations in boreholes and the chief method of experimental studies of seismic waves in the real earth. VSP combines borehole studies in the seismic frequency band, well velocity surveys, proximity or aplanatic surveys, all of which previously existed as separate methods. The high effectiveness ofVSP, its great practical value, the express nature and clarity of the results obtained have all contributed towards a very rapid acceptance of the method. In the USSR VSP has been used in an overwhelming majority of areas and is being used increasingly in many foreign countries as well. This has been greatly facilitated by the translation into English and the publication in the U. S. A. by the Society of Exploration Geophysicists of the book Vertical Seismic Profiling (Tulsa, Oklahoma, 1974). As the method has become more familiar, it has attracted growing interest outside the USSR This has been substantiated by the special seminar on VSP (Oklahoma, 1979) which was organized for 22 U. S. companies and universities and presented by the author.

Global risk potentials and their interplay with economic, social and ecological processes of change have emerged as a challenge to the international community. By presenting this report, the Council hopes to contribute constructively to an effective, efficient and objective management of the risks of global change. The approach taken by the Council is first to classify globally relevant risks and then to assign to these classes of risk both established and innovative risk assessment strategies and risk management tools. On this basis, management priorities can be set. The Council further recommends a number of cross-cutting strategies for international policies. These include worldwide alignment of liability law, creation of environmental liability funds, establishment of a United Nations Risk Assessment Panel and implementation of strategies aimed at reducing vulnerability to risk.

During the period April 25th to May 10th, 1984 the 3rd Course of the International School of Advanced Geodesy entitled "Optimization and Design of Geodetic Networks" took place in Erice. The main subject of the course is clear from the title and consisted mainly of that particular branch of network analysis, which results from applying general concepts of mathematical optimization to the design of geodetic networks. As al ways when dealing with optimization problems, there is an a-priori choice of the risk (or gain) function which should be minimized (or maximized) according to the specific interest of the "designer," which might be either of a scientific or of an economic nature or even of both. These aspects have been reviewed in an intro ductory lecture in which the particular needs arising in a geodetic context and their analytical representations are examined. Subsequently the main body of the optimization problem, which has been conven tionally divided into zero, first, second and third order design problems, is presented. The zero order design deals with the estimability problem, in other words with the definition of which parameters are estimable from a given set of observa tions. The problem results from the fact that coordinates of points are not univocally determined from the observations of relative quantities such as angles and distances, whence a problem of the optimal choice of a reference system, the so-called "datum problem" arises."

The experimental study of magnetospheric processes consists of several disci plines or methods, developing in two general directions. The first, internal trend covers the progress in experimental techniques and methods and re search specific to this discipline. The other trend combines with other methods in a mutual attempt at understanding the boiling whirlpool of the disturbed magnetosphere. Investigations of auroral X-rays began after Van Allen's (1957) discovery of hard radiation in the upper atmosphere of the auroral zone, and are based on high latitude balloon observations. Scientific apparatus, payload equip ment, and particular questions of scientific ballooning are discussed in Chap ter 1. Chapter 2 concludes the internal trend of the subject by describing the problems of X-ray generation at the boundary of the atmosphere and propa gation downward to balloon altitudes. Auroral X-rays are closely related to most of the processes of the disturbed magnetosphere through energetic auroral electrons; precipitating into the at mosphere, the latter create bremsstrahlung photons able to penetrate to an at mospheric depth of 10- 20 g cm - 2. In quiet periods auroral electron flux ex ists only in embryo, as a hot plasma layer at the inner edge of the plasma sheet: in general it is a transient phenomenon caused by magnetospheric distur bances and carrying valuable information of the magnetospheric dynamics."

As this excellent book demonstrates, the study of comets has now reached the fas cinating stage where we understand comets in general simple tenns while, at the same time, we are uncertain about practically all the details of cometary nature, structure, processes, and origin. In every aspect, even including dynamics, a choice among several or many competing theories is made impossible simply by the lack of detailed knowledge. The space missions, snapshot studies of two comets, partic ularly the one that immortalizes the name of Sir Edmund Halley, have produced a huge mass of valuable new infonnation and a number of surprises. Nonetheless, we face the tantalizing realization that we have obtained only a fleeting glance at two of perhaps a hundred billion (lOll) or more comets with possibly differing natures, origins, and physical histories. To my personal satisfaction, comets seem to have discrete nuclei made up of dirty snowballs, as I concluded four decades ago, but perhaps they are more like frozen rubbish piles.

The suggestion by Dr. Franklin S. Harris, Jr., that these books be written arose pursuant to the editor's plaints that despite the implicitly or explicitly ack nowledged importance of both aerosols and particulate matter in innumerable domains of technology and human welfare, investigations of these subjects were generally not supported independently of the narrowest conceivable domains of their appli cations. Frank Harris, who has long been a contributor in one of the important domains of aerosol macrophysics, atmospheric optics, challenged the editor to elaborate his views. Ideally, they would have taken the form of a monograph; however, there is as yet an insufficient body of information to present a unified treatment. At the same time, substantial efforts are in progress in the component fields to hold the promise for the emergence of unifying elements which will even tually facilitate their presentation to be made with a high degree of integrity. There are numerous pertinent and systematic tie-ins between project-oriented aerosol work and basic physical investigations which are themselves quite closely akin to much classical and current work in physical science. The most significant aspect of these tie-ins is their potential for making substantial contributions to the functional needs of the applications areas while stimulating significant questions of basic physics. For this to be possible, it is necessary that the most relevant areas of physics be identified in such a manner as to make clear their re levance for aerosol-related studies and vice versa."

Spacecraft study of the Solar system is one of humanity's most outstanding achievements. Thanks to this study, our present knowledge of properties of and conditions on the planets exceeds many-fold that of 20 years ago: planets have been rediscovered. This is especially the case for planetary atmospheres, whose properties were for the most part either not at all or only erroneously known. Much research has been invested in the study of the atmospheres of Mars and Venus, and their chemical composition and photochemistry are basic problems in these studies. In the present publication I have tried to summarize all findings in this field. The English version of the book includes new data in the field from the last 3 years since the book was published in Russian. I wish to thank U. von Zahn, who initiated my talks with Springer-Verlag and acted as technical editor. December 2, 1985 V. A. KRASNOPOLSKY Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 Chemical Composition and Structure of the Martian Atmosphere 4 1. 1 Carbon Dioxide and Atmospheric Pressure . . . . . . . . . . . . . . . . . . . 4 1. 2 CO and O Mixing Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2 1. 3 Ozone. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1. 4 Water Vapor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1. 5 Composition of the Upper Atmosphere as Determined from Airglow Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 1. 6 Mass Spectrometric Measurements of the Atmospheric Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1. 7 Ionospheric Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 1. 8 Temperature Profile of the Lower Atmosphere. . . . . . . . . . . . . . . . 36 1. 9 Temperature of the Upper Atmosphere . . . . . . . . . . . . . . . . . . . . . . 40 1. 10 Eddy Diffusion Coefficient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 2 Photochemistry of the Martian Atmosphere . . . . . . . . . . . . . . . . . .

The book is based on an international workshop on High Precision Navigation. The reader will find a wealth of information on - satellite navigation systems and their geodetic applications, especially using GPS - laser and radar techniques - image processing and image sequence analysis - autonomous vehicle guidance systems - inertial navigation systems - integration of different sensor systems.

Seasonal Snowpacks examines the processes which control the chemistry of seasonal snowcover and provides detailed information on the biogeographical distribution of snow (e.g. urban, alpine snowpacks), snow composition (e.g. micropollutants, stable isotopes) or the physical and biological processes which influence the chemical changes in snow (e.g. wind, microbiological activity). The fluxes of chemicals at the snow-atmosphere and snow-soil interfaces are examined, as are processes which modify composition within the snowcover. It is the first book in which the reader will find a comprehensive overview of the theoretical concepts, latest measurement techniques, process-oriented research methods, and models of studies in snow chemistry. The linkages between snow chemistry, atmospheric chemistry and hydrology will make this book of use to both research workers and students in the physical and biological sciences and to natural resource management personnel.

It is now well known that the mid-ocean flow is almost everywhere domi nated by so-called synoptic or meso-scale eddies, rotating about nearly vertical axes and extending throughout the water column. A typical mid ocean horizontal scale is 100 km and a time scale is 100 days: these meso scale eddies have swirl speeds of order 10 cm s -1 which are usually con siderably greater than the long-term average flow. Many types of eddies with somewhat different scales and characteristics have been identified. The existence of such eddies was suspected by navigators more than a century ago and confirmed by the world of C. O'D. Iselin and V. B. Stock man in the 1930's. Measurements from RIV Aries in 1959/60, using the then newly developed neutrally buoyant floats, indicated the main char acteristics of the eddies in the deep ocean of the NW Atlantic while a se ries of Soviet moored current-meter arrays culminated, in POLYGON- 1970, in the explicit mapping of an energetic anticyclonic eddy in the tropical NE Atlantic. In 1973 a large collaborative (mainly U. S., U. K. ) program, MODE-I, produced synoptic charts for an area of the NW At lantic and confirmed the existence of an open ocean eddy field and es tablished its characteristics. Meso-scale eddies are now known to be of interest and importance to marine chemists and biologists as well as to physical oceanographers and meteorologists."

Terrestrial Heat Flow and the Lithosphere Structure summarizes current problems of analyzing related data. The individual chapters are written by leading scientists in geothermics, and are arranged in three sections: - General Lithospheric Geothermics - Regional Lithospheric Geothermics - Worldwide Heat Flow Density Studies. Emphasis is laid on the interrelations between lithospheric structure and local heat flow fields.

The study of very long-distance and around-the-world propagation of HF radio waves becomes more urgent in connection with the problems of long distance ground-based radio communications, communications with space crafts and satellites, satellite-to-satellite communications, around-the-world radar scanning, around-the-world sounding of the ionosphere, etc. At pre sent, these investigations have acquired particular interest because transmit ters which make it possible to intentionally modify the ionospheric properties by powerful radio waves have become available. In the case of radio wave propagation over comparatively small distances (about 3000 - 5000 km, one - two hops), in a first approximation, the iono sphere can be considered homogeneous in the horizontal direction. The radio wave propagation theory in a horizontally-homogeneous, i. e., spherically symmetric ionosphere was developed with sufficient completeness as early as in the 1920-1940's by Appleton, Ratcliffe, Beynon, Booker, Martyn, and others. This theory is presented in detail in the well-known monographs by Ginzburg (1967), Bremmer (1946), and Budden (1961). Based on this theory, detailed methods for the calculation of radio paths, determination of field amplitude, and interpretation of vertical and oblique ionograms have been developed. All these methods are well-known and widely used in practice, see monographs by Al'pert (1974), Shchukin (1940), and Davies (1969). An altogether different situation takes place in the case of very long-dis tance multihop and around-the-world propagation."

The science of Geodesy has undergone far-reaching changes in the last half century. The impact of new technology, from electromag netic distance measurements to the use of artificial satellites, has been great, and is still largely to be felt. These changes have forced the practitioners of the ancient art of Earth measurement to alter their way of thinking about the space that surrounds us, something fundamentally more difficult than absorbing a new technology. A key influence in this modem change in geodetic thinking has been the work of Antonio Marussi, in his scientific publications from 1947 onwards, through his students and collaborators at the Uni versity of Trieste, and in the series of symposia on three-dimensional Geodesy which he organised with his great friend and collaborator, Martin Hotine. His influence on the latter, stemming from their first meeting at the General Assembly of the International Association of Geodesy in Oslo in 1948, was remarkable in itself, leading as it did to the ultimate publication of Hotine's Mathematical Geodesy in 1969."

The inaugural Symposium on Turbulent Shear Flows was held at The Pennsylvania State University in 1977. Thereafter the locations for the biennial symposium have alternated between the USA and Europe. However, the ninth Symposium on Turbu lent Shear Flows was awarded to Japan in recognition of the strong support researchers of the Pacific Rim countries have given previous symposia. The University of Kyoto was the host institution and the meeting was held in the Inter national Conference Hall. The Local Arrangements Committee did a superb job scheduling traditional Japanese dinners and arranging visits to the many cultural treasures in the Kyoto region. The meeting attracted more than 260 offers of papers. Thirty-three sessions were scheduled to accommodate the 138 papers accepted for oral presentation. In addition a poster session was scheduled on each of the three days to accommodate a total of 42 poster presentations. From the presentations at the symposium 24 have been selected for inclusion in this volume. The authors of these papers have revised them taking into consideration comments made during their oral presentation and recommendations made by the Editors. Four subject areas are identified, namely closures and fundamentals, free flows, wall flows, and combustion and recirculating flows. Eminent authorities have prepared introductory articles fot each topic to put the individual contributions in context with each other and with related research.

Apart from Hotine's work on Mathematical Geodesy, several previously unpublished reports are collected in this monograph, complemented by extensive comments on these contributions and a complete bibliography of Hotine by the editor.

Today western nations consume annually only a small percentage of their resources from the sea, despite the proclamation of Exclusive Economic Zones (EEZ) by many. In contrast, most Pacific Basin Countries obtain more than a quarter of their annual needs from the ocean. Determination of greater rewards from the development of marine resources is markedly inhibited by the limited technical abilities available to locate and assess them. Knowledge of Exclusive Economic Zone resources is schematic and generalised, and a detailed understanding of the geology and processes relating to the economic use of the seafloor is both fragmentary and very basic. Technology for mapping the mineral resources of continental shelves and ocean areas, except in active offshore hydrocarbon provinces, has been largely developed in pursuit of scientific objectives and competence to rapidly appraise economic potential is limited. Similarly, the capability to characterise and evaluate the other resources of the seas is rudimentary. The development of ocean resources will become increasingly urgent as the growth of the world population and the depletion of land reserves combine to enhance demand. Also, increasing environmental constraints will limit the availability of traditional land-based resources; nevertheless, new offshore development must proceed in a manner whereby the marine environment is not plundered but protected and conserved. The challenge to develop ocean resources with responsible environmental stewardship will require greater leadership than the development of the technologies of exploitation.

During the 30 years of space exploration, important discoveries in the near-earth environment such as the Van Allen belts, the plasmapause, the magnetotail and the bow shock, to name a few, have been made. Coupling between the solar wind and the magnetosphere and energy transfer processes between them are being identified. Space physics is clearly approaching a new era, where the emphasis is being shifted from discoveries to understanding. One way of identifying the new direction may be found in the recent contribution of atmospheric science and oceanography to the development of fluid dynamics. Hydrodynamics is a branch of classical physics in which important discoveries have been made in the era of Rayleigh, Taylor, Kelvin and Helmholtz. However, recent progress in global measurements using man-made satellites and in large scale computer simulations carried out by scientists in the fields of atmospheric science and oceanography have created new activities in hydrodynamics and produced important new discoveries, such as chaos and strange attractors, localized nonlinear vortices and solitons. As space physics approaches the new era, there should be no reason why space scientists cannot contribute, in a similar manner, to fundamental discoveries in plasma physics in the course of understanding dynamical processes in space plasmas.

The monograph being proposed for the English-speaking research community is concentrated on the atmospheric correction of satellite images as a part of thematic interpretation procedures while processing remote sensing data. For linguistic reasons a large section of the community may have been unaware of the progress made in Russia in this field of science and technology. Meanwhile, Russia was the first country to launch the first artificial satellite in 1957 and to obtain from space for the first time spectra of the Earth's atmosphere in the 1960's. New applications of the radiation transfer theory for the atmosphere underlying surface system appeared first in Russia in the 1970's. Direct and in verse problems of the atmospheric optics were then formulated giving the scientific basis for studies of natural resources from space. Since that time new mathematical treatments for the atmospheric correction procedures have been widely developed in Russia, including both analytical and numerical tech niques to simulate spectral, angular, and spatial distributions of the outgoing radiation in visual and infrared regions. The authors of the book were at the beginning of the scientific approach. A wide range of mathematical im provements to elaborate polinomial approximations for dependencies between atmospheric radiation field and parameters of space surveying was due to the necessity to process satellite images in real time using special software of ex isted computer means for the studies.

In exploration seismology, data are acquired at multiple source and receiver posi tions along a profile line. These data are subsequently processed and interpreted. The primary result of this process is a subsurface image of the exploration target. As part of this procedure, additional information is also obtained about the subsurface material properties, e.g., seismic velocities. The methods that are employed in the acquisition and processing of exploration seismic data are internally consistent. That is, principally near vertical incidence seismic waves are generated, recorded and subsequently imaged. The data processing methods commonly used are based upon a small angle of incidence approximation, thus making the imaging problem tractable for existing data processing technology. Although tremendously successful, the limitations of this method are generally recognized. Current and future exploration goals will likely require the use of additional seismic waves, i.e., both compressional and shear precritical and postcritical reflections and refractions. Also, in addition to making better use of seismic travel times, recent efforts to directly incorporate seismic amplitude variations show that the approach may lead to a better understanding of subsurface rock properties. In response to more demanding exploration goals, recent data acquisition techniques have improved significantly by increasing the spatial aperture and incorporating a large number of closely spaced receivers. The need for better subsurface resolution in depth and position has encouraged the use of 240, 512, and even 1024 recorded data channels with receiver separations of 5 to 25 m."

Climate is the most important component of the Earth's environment and climatic fluctuations have a strong impact on water supplies, vegetation, energy use etc. Thus our understanding of the climatic system is of utmost importance. Leading experts in the field of climate modelling and paleoclimatology present the most recent methods for reconstructing past climatic variations and for modelling the climatic system and its evolution. The first of three parts is devoted to the climatic system and the physical basis for its modelling; the second summarizes the evolution of the global atmosphere, the ocean, the continents, the biosphere, and the ice sheets during recent climatic cycles; the last part focusses on the understanding of past and future climatic changes.

The idea of writing a textbook on urban surveying and mapping originated with the Commission on Cartography of the Pan American Institute of Geography and History (PAIGH) because of the urgent need for planned and integrated surveying and mapping in urban communities of the American Hemisphere. It is obvious, however, that, with the exception of some European countries, the same situation exists in most cities of the world. The undersigned was asked to undertake the task. The task was not simple. The only available comprehensive text in the field 1 is Geodezja Miejska, which was published recently in Poland and reached the authors only after most of the present text was written. It is tailored to a very specific market and different requirements. Although it is an impressive book, it differs vastly from our own approach. Other reference texts are fragmentary or obsolete. During the last two decades, revolutionary changes have occurred in survey ing and mapping technology which have had a profound effect on actual procedures. In addition, the traditional concepts of urban surveying and map ping are undergoing rapid evolution. It is recognized that administration and planning require a great variety of continuously updated information which must be correlated with the actual physical fabric of the community, as de termined by surveying and mapping. Modern urban surveying and mapping is therefore the foundation of the broad and dynamic information system that is indispensable in any rational municipal effort."

The African continent is unique in that it has escaped widespread orogenic activity after the Pan African orogenic event. Therefore, the African Plate provides the world's best example of the relationship between extensional magmatism and structural setting. This first complete and up-to-date review, written by leading scientists, discusses the evolutionary model and offers a new and reliable basis for scientists working on plate tectonics and extensional areas in other continents.

This Encyclopedia aims, basically, at summanzmg the wealth of well established facts and outlining the relevant theories in the different branches of physics. With this as goal, the writers were asked to present their specific field in such a way that access is possible to any scientist without special a priori information in that field; the basic concepts of physics are assumed to be known to the reader. The survey given in each paper was also to be long lasting, so that even a few years after publication, each volume would be useful, for example as an introduction for newcomers or as a source of information for workers in a neighbouring field. In the field of geophysics, dealt with in Vols. 47--49 of the Encyclopedia, this task is difficult to achieve because during the last decades there has been a much faster development of basic information and theory than during the decades before. When I came to contribute to this work the famous Julius Bartels, then editor of the geophysical part, told me that Vol. 49 should certainly take into account the results of the "International Geophysical Year" 1957/58 (I. G. Y. ), and that we had better wait until these were accessible than produce a kind of information which might be obsolete in a short time."

In the USA, Western and Central Europe, there are many large-scale polluted sites that are too large to be cleaned up economically with available technologies. The pollution is caused by heavy industries to soils and sediments in waterways and reservoirs. Since these areas are expected to remain polluted for many years, it is necessary to take a long-term view to insure that the capacity to retain the contaminants is not diminished and to understand the potential for large-scale contaminant mobilization at these sites triggered by changing environmental conditions. This book provides information for predicting long-term changes and making risk assessments and describes the approach of geochemical engineering to handling large-scale polluted sites.

This book explores the basic principles and methods of paleomagnetology and gives a systematic description of paleomagnetic phenomena such as geomagnetic reversals, paleosecular variations, long-term intensity changes and apparent polar wandering paths. Special emphasis is laid on results obtained from research work done in the Soviet Union. Together with data from other parts of the world they allow the critical discussion of aspects of magnetostratigraphy, plate tectonics and accretion tectonics. In diesem Buch werden grundlegende Fragen der Palaomagnetologie und des Palaomagnetismus abgehandelt. Durch die Einbeziehung zahlreicher Daten aus der Sowjetunion werden Probleme der Magnetostratigraphie sowie der Platten- und Akkretionstektonik kritisch beleuchtet.