Granulites are, by definition, rocks that crystallized at high temperatures. It is generally agreed that they were formed in regions where the geothermal gradient exceeded normal continental values. These rocks commonly display coronitic mineral fabrics which may be used to trace the thermal and geodynamic history of the continental crust. In the same way that eclogites provide information on the earliest stages of some orogenic episodes, granulites usually tell us about later events, including thermal anomalies, thermal reequilibration, CO streaming, crustal melting, and 2 differentiation of the continental crust. Their study is particularly important if we are to under stand the nature of the middle and lower continental crust. Consistent with the contributions I received, the contents of this volume fall into four general areas: Crustal Evolution, Regional Syntheses, F1uids and Petrological Equilibria, Geochemistry and Geophysics. These represent an up-to-date reflection of the centres of interest in the field of granulites. The first manuscripts arrived in September 1988 while the conference was held, the last contribution arrived in November 1989, more than a year later. I apologize to those who were prompt and took deadlines seriously, but I believe that it was worth waiting to secure a product covering most of the important aspects concerning granulite genesis. All papers were vetted by at least two reviewers. I would like to thank RJ. Arculus, N.T. Arndt, P. Barbey, SR. Bohlen, AM. Boullier, M. Brown, T. Chacko, 1.D. Clemens, K.C. Condie, J.C. Duchesne, C. Dupuy, w.G."

Lightning represents a natural phenomenon of substantial interest. Due to its complex nature, research continues in many countries and reveals amazing results. Lightning is actively observed because of its relevance to Earth climate and air composition in addition to the classical aspects of related human fatalities and damage to forests, buildings, power lines, aircraft, structures and electronic devices. In this volume, the most important contemporary questions on lightning are addressed and analyzed under many experimental and theoretical aspects. Lightning detection techniques using ground-based and space-borne methods are described, along with network engineering and statistical analysis. Contributions detail research on atmospheric electricity, cloud physics, lightning physics, modeling of electrical storms and middle atmospheric events. Special phenomena such as triggered lightning and sprite observations are examined. Lightning-induced nitrogen oxides and their effects on atmospheric chemistry and climate are discussed. Each topic is presented by international experts in the field. Topics include: * air chemistry * convective storms * infrasound from lightning * lightning and climate change * lightning and precipitation * lightning and radiation * lightning and supercells * lightning and thunderstorms * lightning detection * lightning from space * lighting protection * lightning return strokes * observations and interpretations * spatial distribution and frequency * triggered lightning * weather extremes

The 34th Saas-Fee advanced course of the Swiss Society of Astronomy and Astrophysics (SSAA) took place from March 15 to 20, 2004, in Davos, on the subject of The Sun, Solar Analogs and the Climate. PresentlytheSwissmountainresortofDavosisprobablymostwellknown for hosting an event on globalization. However, it is because Davos also happens to be the seat of the Physikalisch-Meteorologisches Observatorium Davos and World Radiation Center, that this course on a "global" subject was hosted here. Exceptionally, the topic of this course was not purely astrophysical, but themembersoftheSSAAdecidedtosupportitallthesameduetothetimely topic of global warming and its possible link to solar variations. In these times of concern about global warming, it is important to und- stand solar variability and its interaction with the atmosphere. Only in this way can we distinguish between the solar and anthropogenic contributions to the rising temperatures. Therefore, this course addressed the observed va- ability of the Sun and the present understanding of the variability's origin and its impact on the Earth's climate. Comparing the solar variability with that of solar analog stars leads to a better understanding of the solar activity cycle and magnetic activity in general, and helps us to estimate how large the solar variations could be on longer time scales. Inspiteofthefantasticweatherandsnowconditionswhichreignedduring this week, the participants assiduously took part in the lectures. This is proof ofthehighqualityofthelecturesthatthethreespeakers, JoannaHaigh, Mike Lockwood and David Soderblom, delivered. We deeply thank them for their contributions and e?orts and hope that the readers will enjoy the book as much as we enjoyed their lectures.

Dynamics of Ice Sheets and Glaciers presents an introduction to the dynamics and thermodynamics of flowing ice masses on Earth. Based on an outline of general continuum mechanics, the different initial-boundary-value problems for the flow of ice sheets, ice shelves, ice caps and glaciers are systematically derived. Special emphasis is put on developing hierarchies of approximations for the different systems, and suitable numerical solution techniques are discussed. A separate chapter is devoted to glacial isostasy. The book is appropriate for graduate courses in glaciology, cryospheric sciences, environmental sciences, geophysics and related fields. Standard undergraduate knowledge of mathematics (calculus, linear algebra) and physics (classical mechanics, thermodynamics) provide a sufficient background for successfully studying the text.

Pays considerable attention to various aspects of light absorption inside particles, including internal field distributions, MDR resonances, and absorption in restricted regions inside particles. It contains many results (and more than 100 figures) computed for polydisperse particle systems and algorithms and provides the possibility to use them (web site).

TheideafortheselectureseriesaroseataWorkshoponsolarphysicswhichwas heldattheInterUniversityCentreforAstronomyandAstrophysics(IUCAA), Pune/IndiainDecember2000. ThisWorkshopaimedtopresentacompreh- siveandup-to-dateoverviewofsolarphysicsforinterestedstudentsandfaculty inotherbranchesofastrophysics. Itwasintendedtoshowthatthis?eld,c- centratingonourcloseststar,isavitalandexciting?eldofresearch. Forthis purposeanumberofcomprehensivereviewswereorganisedwhichassumedthat theaudiencewouldhaveonlyabasicphysicsbackgroundbuthadnoprior knowledgeaboutsolarphysics. Thesetoflecturescoveredtopicsrangingfrom thesolarcoretotheconvectionzone,thephotosphere,chromosphere,andcorona andextendingtothesolarwindintheinterplanetarymedium DuringandaftertheWorkshoptherewasmuchenthusiasmforthisform ofpresentationanditwasfeltthattheselectures,augmentedbyincludingthe latestresearch?ndingsinthe?eld,wouldbebene?cialtoamuchlargeraudience. Thustheplanforthisbookoriginatedwhichcouldthenberealisedthanksto thepublishers,Springer-Verlag. Thereare9articlesbasedonthelecturesgivenattheWorkshop. Thearticle byChitreon"OverviewofSolarPhysics"givesanintroductiontothewhole varietyofphenomenaofsolarphysics,theproblemsandtheirsolutionsand salientresults. Thearticleon"InstrumentationandObservationaltechniques relatedtoSolarPhysics"byBhatnagardescribesindetailtheprinciplesof- larinstrumentationnormallyusedtotakesimplewhitelight,monochromatic andspectroscopicobservations. Practicalmethodstomeasureimportantbasic parameters,likearea,positionandtheclassi?cationofsunspotsaredescribed indetail. Antia'sarticleon"SolarInteriorandSeismology"describesthesolar interior,thetechniqueofhelioseismologyandhowthisnewtechniqueallowsa determinationoftheinternalstructureanddynamicsoftheSunandconstrains theoriesofstellarstructure,evolutionandangularmomentumtransport. - bastha'sarticleon"TheActiveandExplosiveSun"givesanoverviewofhighly time-dependentphenomenainthephotosphere,chromosphereandcoronaofthe Sunandprovidessometheoreticalmodelsofthesolar?ares. Hasan'sarticle on"MagneticFluxTubesandActivityontheSun"discussesthegeneration, storageandemergenceofmagnetic?eldsintheformofsmall-scale?uxtubes andexaminestheirroleinheatingofthechromosphere. Ventakrishan'sar- cleon"SolarMagneticFields"givesatheoreticaloverviewofthegeneration VI Preface ofmagnetic?eldsbythedynamomechanism,thegeneralmagnetic?eldtop- ogyandhowthemagnetic?eldsaremeasured. Ulmschneider'scontributionon "ThePhysicsofChromospheresandCoronae"discusseswhyallstarslikethe Sunhavehotouterchromosphericandcoronallayers. Itidenti?estheheating mechanismsanddynamicalprocesseswhichtakeplacebothinthepresenceand absenceofmagnetic?elds. ThearticlebyDwivedion"TheSolarCorona"gives ageneraloverviewofthesolarcorona,howitisobservedandwhatthephy- calprocessesleadingtoitsformationare. FinallyManoharan'scontributionon "TheSolarWind"describesthegenerationandmeasurementofthesolarwind derivedfrominsituobservationsbyspacecraftandinterplanetaryscintillation studies. Wehopethatbyreadingtheselectures,interestedpeople,amateurs,graduate andpostgraduatestudentswillbemotivatedtotakeupsolarphysicsasanarea ofresearch,andshareourexcitementaboutthewondersofourneareststar- theSun. WearethankfultoT. PadmanabhanandtheInterUniversityCentrefor AstronomyandAstrophysics,PunefororganisingandhostingthisWorkshop onSolarPhysics. Mumbai,Udaipur,Heidelberg H. M. Antia February2003 A. Bhatnagar P. Ulmschneider ListofContributors AshokAmbastha S. S. Hasan Udaipur Solar Observatory Indian Institute of Astrophysics Physical Research Laboratory Bangalore560034,India P. O. Box No. 198 hasan@iiap. ernet. in Udaipur313001,India ambastha@prl. ernet. in P. K. Manoharan Radio Astronomy Centre H. M. Antia Tata Institute Tata Institute of Fundamental Research of Fundamental Research P. O. Box 8 Homi Bhabha Road Udhagamandalam (Ooty) 643001, Mumbai400005,India India antia@tifr. res. in mano@racooty. ernet. in ArvindBhatnagar Udaipur Solar Observatory P. Ulmschneider Physical Research Laboratory Institut fur TheideafortheselectureseriesaroseataWorkshoponsolarphysicswhichwas heldattheInterUniversityCentreforAstronomyandAstrophysics(IUCAA), Pune/IndiainDecember2000. ThisWorkshopaimedtopresentacompreh- siveandup-to-dateoverviewofsolarphysicsforinterestedstudentsandfaculty inotherbranchesofastrophysics. Itwasintendedtoshowthatthis?eld,c- centratingonourcloseststar,isavitalandexciting?eldofresearch. Forthis purposeanumberofcomprehensivereviewswereorganisedwhichassumedthat theaudiencewouldhaveonlyabasicphysicsbackgroundbuthadnoprior knowledgeaboutsolarphysics. Thesetoflecturescoveredtopicsrangingfrom thesolarcoretotheconvectionzone,thephotosphere,chromosphere,andcorona andextendingtothesolarwindintheinterplanetarymedium DuringandaftertheWorkshoptherewasmuchenthusiasmforthisform ofpresentationanditwasfeltthattheselectures,augmentedbyincludingthe latestresearch?ndingsinthe?eld,wouldbebene?cialtoamuchlargeraudience. Thustheplanforthisbookoriginatedwhichcouldthenberealisedthanksto thepublishers,Springer-Verlag. Thereare9articlesbasedonthelecturesgivenattheWorkshop. Thearticle byChitreon"OverviewofSolarPhysics"givesanintroductiontothewhole varietyofphenomenaofsolarphysics,theproblemsandtheirsolutionsand salientresults. Thearticleon"InstrumentationandObservationaltechniques relatedtoSolarPhysics"byBhatnagardescribesindetailtheprinciplesof- larinstrumentationnormallyusedtotakesimplewhitelight,monochromatic andspectroscopicobservations. Practicalmethodstomeasureimportantbasic parameters,likearea,positionandtheclassi?cationofsunspotsaredescribed indetail. Antia'sarticleon"SolarInteriorandSeismology"describesthesolar interior,thetechniqueofhelioseismologyandhowthisnewtechniqueallowsa determinationoftheinternalstructureanddynamicsoftheSunandconstrains theoriesofstellarstructure,evolutionandangularmomentumtransport. - bastha'sarticleon"TheActiveandExplosiveSun"givesanoverviewofhighly time-dependentphenomenainthephotosphere,chromosphereandcoronaofthe Sunandprovidessometheoreticalmodelsofthesolar?ares. Hasan'sarticle on"MagneticFluxTubesandActivityontheSun"discussesthegeneration, storageandemergenceofmagnetic?eldsintheformofsmall-scale?uxtubes andexaminestheirroleinheatingofthechromosphere. Ventakrishan'sar- cleon"SolarMagneticFields"givesatheoreticaloverviewofthegeneration VI Preface ofmagnetic?eldsbythedynamomechanism,thegeneralmagnetic?eldtop- ogyandhowthemagnetic?eldsaremeasured. Ulmschneider'scontributionon "ThePhysicsofChromospheresandCoronae"discusseswhyallstarslikethe Sunhavehotouterchromosphericandcoronallayers. Itidenti?estheheating mechanismsanddynamicalprocesseswhichtakeplacebothinthepresenceand absenceofmagnetic?elds. ThearticlebyDwivedion"TheSolarCorona"gives ageneraloverviewofthesolarcorona,howitisobservedandwhatthephy- calprocessesleadingtoitsformationare. FinallyManoharan'scontributionon "TheSolarWind"describesthegenerationandmeasurementofthesolarwind derivedfrominsituobservationsbyspacecraftandinterplanetaryscintillation studies. Wehopethatbyreadingtheselectures,interestedpeople,amateurs,graduate andpostgraduatestudentswillbemotivatedtotakeupsolarphysicsasanarea ofresearch,andshareourexcitementaboutthewondersofourneareststar- theSun. WearethankfultoT. PadmanabhanandtheInterUniversityCentrefor AstronomyandAstrophysics,PunefororganisingandhostingthisWorkshop onSolarPhysics. Mumbai,Udaipur,Heidelberg H. M. Antia February2003 A. Bhatnagar P. Ulmschneider ListofContributors AshokAmbastha S. S. Hasan Udaipur Solar Observatory Indian Institute of Astrophysics Physical Research Laboratory Bangalore560034,India P. O. Box No. 198 hasan@iiap. ernet. in Udaipur313001,India ambastha@prl. ernet. in P. K. Manoharan Radio Astronomy Centre H. M. Antia Tata Institute Tata Institute of Fundamental Research of Fundamental Research P. O. Box 8 Homi Bhabha Road Udhagamandalam (Ooty) 643001, Mumbai400005,India India antia@tifr. res. in mano@racooty. ernet. in ArvindBhatnagar Udaipur Solar Observatory P. Ulmschneider Physical Research Laboratory Institut fur .. Theoretische Astrophysik P. O. Box No. 198 Univ. Heidelberg Udaipur313001,India Tiergartenstr. 15 arvind@prl. ernet. in 69121Heidelberg,Germany ulm@ita. uni-heidelberg. de S. M. Chitre Department of Physics University of Mumbai P. Venkatakrishnan Mumbai400098,India Udaipur Solar Observatory kumarchitre@hotmail. com Physical Research Laboratory P. O. Box No. 198 BholaN. Dwivedi Udaipur313001,India Department of Applied Physics pvk@prl. ernet. in Institute of Technology Banaras Hindu University Varanasi221005,India dwivedi@banaras. ernet. in TableofContents OverviewofSolarPhysics S. M. Chitre...1 1 Introduction...1 2 CompositionandStructureoftheSun...3 2. 1 EquationsofStellarStructure...4 2. 2 TheStandardSolarModel...7 3 ProbesoftheSun'sInterior...10 3. 1 SolarNeutrinoProblem...

Natural disasters are a clear example of people living in conflict with the environment. Disasters cause human, social and environmental losses and, sometimes, even threaten geopolitical stability, as in many less developed countries. They are also a problem of global concern, even when damage is local: the mechanisms are often dependent on global meteoro-climatic circulation. Losses frequently affect several countries, as could be seen in the floods in central Europe in 2002. It is obvious that there is a clear need for a new approach, capable of incorporating the prevention of natural disasters, whilst mitigating strategies within the cycle of sustainable development. There are no thematic disciplines or political boundaries limitating initiatives: the integration of data providers, data users/information providers and information users, in a global and holistic manner, is the desired outcome of the new frontier. This book falls into this new category: multidisciplinary interventions and socio-economic point of views are the basic inputs for a changing science, implementing sustainable development for the benefit of citizens and society. It is comprised of studies and investigations which explain natural processes and modelling, as well as assessing hazards and risks and is rounded of with suggestions for sustainable development. Thus reflecting the best results of research on this topic funded by the European Commission.

This book presents comprehensive coverage of the Sun and space weather, two rapidly evolving topics. In this new edition, the information has been updated to include the latest results. In addition, new sections are included, like one on space weather data sources, as well as examples and information on new satellite missions.

Due to plate motions, tidal effects of the Moon and the Sun, atmosphe ric, hydrological, ocean loading and local geological processes, and due to the rotation of the Earth, all points on the Earth's crust are sub ject to deformation. Global plate motion models, based on the ocean floor spreading rates, transform fault azimuths, and earthquake slip vectors, describe average plate motions for a time period of the past few million years. Therefore, the investigation of present-day tectonic activities by global plate motion models in a small area with complex movements cannot supply satisfactory results. The contribution of space techniques Very Long Baseline Interferome try (VLBI); Satellite Laser Ranging (SLR); Global Positioning System (GPS)] applied to the present-day deformations ofthe Earth's surface and plate tectonics has increased during the last 20 to 25 years. Today one is able to determine by these methods the relative motions in the em to sub-em-range between points far away from each other."

In seismology an earthquake source is described in terms of a fault with a particular rupture size. The faulting process of large earthquakes has been investigated in the last two decades through analyses of long-period seismo grams produced by advanced digital seismometry. By long-period far-field approximation, the earthquake source has been represented by physical parameters such as s ismic moment, fault dimension and earthquake mag nitude. Meanwhile, destruction often results from strong ground motion due to large earthquakes at short distances. Since periods of strong ground motion are far shorter than those of seismic waves at teleseismic distances, the theory of long-period source process of earthquakes cannot be applied directly to strong ground motion at short distances. The excitation and propagation of high-frequency seismic waves are of special interest in recent earthquake seismology. In particular, the descrip tion and simulation of strong ground motion are very important not only for problems directly relevant to earthquake engineering, but also to the frac ture mechanics of earthquake faulting. Understanding of earthquake sources has been developed by investigating the complexity of faulting processes for the case of large earthquakes. Laboratory results on rock failures have also advanced the understanding of faulting mechanisms. Various attempts have been made to simulate, theoretically and empirically, the propagation of short-period seismic waves in the heterogeneous real earth."

Hydrogeology of Crystalline Rocks deals with deep groundwater in the granite and gneiss basement of the continents. It has become evident during the past years that highly mineralized water is present in an interconnected fracture network of the basement. Thus, the upper part of the crust of the continents can be viewed as an aquifer and investigated with tools common in hydrogeology. This book presents accounts on water-conducting features of crystalline rocks and summarizes the hydraulic properties of the basement. The volume includes reviews, new data and research on the often remarkable chemical composition of deep groundwater. Microbial processes in the deep basement aquifer are probably more important than previously thought. Two contributions focus on this recent extension of research of the biosphere to greater depth in the Earth. This book represents the first multidisciplinary and integrated account of deep groundwater hydrology in crystalline basement. It is of interest to hydrologists and hydrogeologists working with water in crystalline rocks, but also to solid earth geophysicists, geochemists and petrologists with an interest in fluids in the crust. Scientists involved in nuclear waste disposal programs and geothermal energy development will find a wealth of stimulating ideas in this volume.

This monograph is based on subsurface hydrodynamics and applied geomechanics and places them in a unifying framework. It focuses on the understanding of physical and mechanical properties of geomaterials by presenting mathematical models of deformation and fracture with related experiments.

Mechanics plays a fundamental role in aeolian processes and other environmental studies. This proposed book systematically presents the new progress in the research of aeolian processes, especially in the research on mechanism, theoretical modelling and computational simulation of aeolian processes from the viewpoint of mechanics. Nowadays, environmental and aeolian process related problems are attracting more and more attention. We hope this proposed book will provide scientists and graduate students in aeolian research and other environmental research some mechanical methods and principles and introduce aeolian related problems of environment to mathematical and mechanical scientists.

Since the start of hydrocarbon production in the Netherlands, measurement c- paigns have been performed to measure the resulting subsidence, to which gas and oil companies in the Netherlands are legally obliged. The majority of the gas elds in the Netherlands, including the Groningen gas eld, are operated by Nederlandse Aardolie Maatschappij B.V. (NAM). Different subsidence measurement techniques (leveling, GPS) have been utilized since the 1960s. Synchronously, geodetic esti- tion methodologies have been developed to estimate subsidence due to hydrocarbon production from the measurements, in which the Delft Institute of Earth Obser- tionandSpaceSystems(DEOS)hasbeencloselyinvolved.Sincethe1990s, satellite radar interferometry (InSAR) as a deformation monitoring technique has developed. However, the situation in the Groningen area is challenging (temporal decorrelation, rural areas, atmospheric disturbances, small deformation rates-several mm/year- over a large spatial extent). In 2003, the project 'Fundamenteel Onderzoek Radar - terferometrie' was approved (Regeling Technologische Samenwerking), which - abled a four year PhD research to investigate the feasibility of InSAR for monitoring subsidence due to hydrocarbon production, in cooperation between Delft University of Technology and NAM. This book describes the results of this scienti c research, that is directly coupled to the practical demand for subsidence monitoring te- niques. It covers the topic in a generic way: both precision and reliability of InSAR as a measurement technique and the estimation of earth surface deformation in the presence of multiple deformation causes are addressed.

Caribbean Tsunamis - A 500-Year History from 1498-1998 broadly characterizes the nature of tsunamis in the Caribbean Sea, while bearing in mind both scientific aspects as well as potential interest by the many governments and populations likely to be affected by the hazard. Comprehension of the nature of tsunamis and past effects is crucial for the awareness and education of populations at risk.
Audience: This book provides a thorough, yet highly accessible review of tsunamis in the Caribbean. It is of interest not only to tsunami and natural hazards specialists at academia and governmental institutes, but also to policy makers and to the general public.

Over the years, many leading European graduate schools in the field of astrophysical and space plasmas have operated within the framework of the research network, "Theory, Observations, and Simulations in Turbulence in Space Plasmas." This text is a set of lectures and tutorial reviews culled from the relevant work of all those schools. It emphasizes applications on solar coronae, solar flares, and the solar wind.

In bridging the gap between standard textbook material and state-of-the-art research, this text offers a broad flavor to postgraduate and postdoctoral students just coming to the field. And because of its unique mix, it will also be useful to lecturers looking for advanced teaching material for their seminars and courses.

viii debate of those earlier days has been beautifully summarized by H. H. Read in his famous "Granite Controversy" (1957). Read's formulation of the controversy occurred at the time when geochemistry was as a new and powerful tool. The new techniques opened era during which emerging an granites were considered mainly from this new viewpoint. Geochemical signatures have shown that mantle and crustal origins for granites were both possible, but the debate on how and why granites are emplaced did not progress much. Meanwhile, structural geology was essentially geometrical and mechanistic. In the early 70's, the structural approach began to widen to include solid state physics and fluid dynamics. Detailed structural maps of granitic bodies were again published, mainly in France, and analysed in terms of magmatic and plastic flow. The senior editor of this volume and his students deserve much of the credit for this new development. Via microstructural and petrofabric studies, they were able to discriminate between strain in the presence of residual melt or in the solid-state, and, by systematically measuring magnetic fabrics (AMS), they have been able to map magmatic foliations and lineations in ever finer detail, using the internal markers within granites coming from different tectonic environments. The traditional debate has been shifted anew. The burning question now seems to be how the necessary, large-scale or local, crustal extension required for granite emplacement can be obtained.

Neutrinos play an intriguing role in modern physics linking central questions of particle physics, cosmology and astrophysics. The contributions in this book reflect the present status of neutrino physics with emphasis on non-accelerator or beyond-accelerator experiments. Since a nonvanishing neutrino mass would yield an important boundary condition for GUT, SUSY or Superstring models and since neutrinos are the best candidates for dark matter in the universe, the many efforts to look for a neutrino mass, ranging from neutrino oscillation experiments using reactors, accelerators or the sun as neutrino sources, to tritium decay experiments and the search for neutrinoless double beta decay, are described in some detail. One of the sections is devoted to neutrinos from collapsing stars, including the supernova SN 1987 A. Possibilities for detecting cosmological neutrinos are discussed and an outlook to future experiments is given.

The physical processes driving the different manifestations of the phe nomenon of active galactic nuclei have been studied extensively during the last decade. A major obstacle in all attempts to understand the relevant pro cesses has always been the wide range of frequencies over which significant fractions of the total power are emitted. During the last decade, orbiting telescopes and instrumental improvements for ground-based instrumenta tion provided the means for major advancements on the observational side. The organizers felt that it was timely to organize a meeting to discuss the impact of this new situation on the understanding of the relevant physical processes. More then 400 astrophysicists were interested in participating in the meeting, in spite of the constraints on overseas travel which were imposed in early 1991. Unfortunately only 220 participants could be hosted by the Max-Planck-Haus, the site of the 1991 Heidelberg conference. The meet ing was organized by Sonderforschungsbereich 328 "Evolution of Galaxies". During 5 sessions, most of which lasted for one day each, 47 invited and con tributed talks and 150 poster papers were given, most, but not all, of which are included in these proceedings. With a few exceptions the order of the written texts follows that of the oral contributions during the meeting. The arrangement of posters into the five sections was not always unambiguous. We hope to have placed them in the most appropriate sections, in which they are listed in alphabetical order.

Provides an introduction to petroleum exploration methods, referring to both geophysical and geochemical techniques and the logistics of various drilling techniques and well logging methods for oil and gas exploration. The second part of the book focuses on using these methods for petroleum exploration within the context of northern Africa. The geology of northern Africa is described and computerized lithographic correlation charts are presented and applied to petroleum exploration targets from the region.

The author has sought to incorporate in the book some of the fundamental concepts and principles of the physics and dynamics of the atmosphere, a knowledge and understanding of which should help an average student of science to comprehend some of the great complexities of the earth-atmosphere system, in which a thr- way interaction between the atmosphere, the land and the ocean tends to maintain an overall mass and energy balance in the system through physical and dynamical processes. The book, divided into two parts and consisting of 19 chapters, introduces only those aspects of the subject that, according to the author, are deemed essential to meet the objective in view. The emphasis is more on clarity and understanding of physical and dynamical principles than on details of complex theories and ma- ematics. Attempt is made to treat each subject from ?rst principles and trace its development to present state, as far as possible. However, a knowledge of basic c- culus and differential equations is sine qua non especially for some of the chapters which appear later in the book.

Space weather has an enormous influence on modern telecommunication systems even though we may not always appreciate it. We shall endeavor throughout this monograph to expose the relationships between space weather factors and the performance (or lack thereof) of telecommunication, navigation, and surveillance systems. Space weather is a rather new term, having found an oMicial expression as the result of several government initiatives that use the term in the title of programs. But it is the logical consequence of the realization that space also has weather, just as the lower atmosphere has weather. While the weather in space will influence space systems that operate in that special environment, it is also true that space weather will influence systems that we understand and use here on terra firma. This brings space weather home as it were. It is not some abstract topic of interest to scientists alone; it is a topic of concern to all of us. I hope to make this clear as the book unfolds. Why have I written this book? First of all, I love the topic. While at the Naval Research Laboratory (NRL), I had the opportunity to do research on many topics including: Thomson scatter radar and satellite beacon studies of the ionosphere, utilization of the NASA Gemini platform for ionospheric investigations, microwave radar propagation studies, I-IF signal intercept and direction-finding experiments, and multi-disciplinary studies of certain physical phenomena relevant to weapon systems development.

Just as in the era of great achievements by scientists such as Newton and Gauss, the mathematical theory of geodesy is continuing the tradition of producing exciting theoretical results, but today the advances are due to the great technological push in the era of satellites for earth observations and large computers for calculations. Every four years a symposium on methodological matters documents this ongoing development in many related underlying areas such as estimation theory, stochastic modelling, inverse problems, and satellite-positioning global-reference systems. This book presents developments in geodesy and related sciences, including applied mathematics, among which are many new results of high intellectual value to help readers stay on top of the latest happenings in the field.

The Swiss Society for Astrophysics and Astronomy organizes each year in the late winter or early spring an advanced course. The format of the school is always iden tical: three leading lecturers are invited to cover the subject in nine or ten lectures each and to deliver a written version of their lecture notes. Lectures are held in the morning and late afternoon, thus leaving ample time for discussion and skiing. These arrangements prove very convivial and lead to an excellent atmosphere in which to learn exciting new subjects and establish contacts with colleagues. A wide variety of people attend the school, including many young students, mostly from Europe, and some experienced researchers. The 20th Advanced Course of the Swiss Society for Astrophysics and Astronomy took place in Les Diablerets from 1 to 6 April 1990. It was devoted to observational and theoretical aspects of active galactic nuclei. The previous advanced courses of the Swiss Society for Astrophysics and Astronomy have regularly taken place in Saas-Fee, a small resort in the Swiss Alps, hence the name "Saas-Fee" used to de scribe the courses and lecture notes. In the last three years, however, the course was organized in Leysin and in Les Diablerets, both also situated in the Swiss Alps."