Global change

Global change

199 scriptive techniques aimed at reducing the number of parameters needed to describe a seismic waveform and to reject non-seismic information. Simi...

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scriptive techniques aimed at reducing the number of parameters needed to describe a seismic waveform and to reject non-seismic information. Similar techniques are taken up in a reflection seismic context in two later articles using pattern recognition and clustering based on hierachical operations. The fourth and fifth articles are concerned with instantaneous frequency, and phase estimators using image processing techniques and adaptive Kalman filtering, respectively. The sixth article uses a novel transform scheme for the representation of seismic signals in terms of sets of elementary wavelets which can be expanded or contracted in their time scale (and thus shifted in frequency). The idea is interesting but does not, at this stage, appear to offer much advantage over existing frequency-time analysis methods. The next article concerns simultaneous deconvolution of a reflection seismogram for the source wavelet and impedance log using a variety of methods based on iterative stochastic gradient techniques. The last article uses game theory to outline as strategy for signal classification and consequent discrimination. Many of the ideas presented in this volume are of relevance in a range of seismological activities. The collection would have been useful to many more people if some attempt had been made to make the Contents more directly accessible to practising seismologists. B.L.N. KENNETF (Canberra, A.C.T., Australia)

Global Change. T.F. Malone and J.G. Roederer (Editors). The Proceedings of a Symposium sponsored by the International Council of Scientific Unions (ICSU) during its 20th General Assembly in Ottawa, Canada on September 25, 1984. Cambridge University Press, Cambridge, 1985, xxviii + 512 pp., £35.00, ISBN 0521 30670 1. Certainly the Earth has changed in many ways since the time it formed 4.6 Ga ago. Obviously what is meant by ‘global change’ are changes of the planet Earth as a whole, and not changes that manifest themselves on limited parts of the Earth’s

surface. Such changes of global significance are of a most heterogeneous nature. This is reflected by the different sections into which the subject matter of the Symposium is divided: (1) overview and unifying concepts; (2) atmosphere and hydrosphere; (3) life systems; (4) solid Earth; (5) solid states; (6) tools and technology; (7) geosphere, biosphere and human activity; and (8) summary presentations. A total of 52 papers were presented at the Symposium, including 17 from the United States and 5 from the Soviet Union. The book represents an agglomeration of 52 type scripts of papers which are highly heterogeneous not only in content but also in appearance. One might be inclined to find the book disappointing both in form and in content, were its pragmatic purpose not understood. This, however, is spelled out undisguised by Malone in his preface, ‘The Symposium was intended to be the first step in a 2-year systematic exploration by the International Council of Scientific Unions and its constituent bodies of the question: Is the time ripe to launch a cooperative, interdisciplinary, international program to illuminate the complex and synergic physical, chemical and biological processes in the Sun—Earth system that determine its changes?’ The organizers call for ‘well-coordinated international efforts’ to study global changes. Obviously, their intent is to provide funding for a multinational organized research project. For this reason it is not surprising that a large number of the papers deal with the question of what should be done in the future rather than with the accomplishments of the past. There are, however, also several papers that will be useful for those interested in the most recent advances and not primarily in future research planning. For example, the article by Herbert Friedman of the National Research Council, U.S.A., gives an overview of these advances over the past 5 y. One is surprised how much new research has been done since the monograph of the National Research Council on ‘Solar Variability, Weather and Climate’ was published in 1982. Unfortunately, Herb Friedman’s excellent paper gives neither references to pertinent publications nor names of their authors. As is always the case with proceedings of conferences, one finds a number of useful, interesting,

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and informative papers, but also many that do not offer anything really new and useful. Indications of some changes in the attitudes of meteorologists, oceanographers, and of other experts that deal with secular changes, can be recognized in the general approach to open problems. The effect of solar activity upon the climate is frequently mentioned as an open question that deserves further scrutiny. Slowly one is now prepared to accept the existence of a correlation of variations of sunspot activity with climate over periods of hundreds or thousands of years, although the physical explanation of such a correlation is considered elusive. This certainly should be a prime objective of future research. Another important field of future investigations involves the anthropogenic factors that are only now beginning to affect the global climate. Undoubtedly the fields of solar—terrestrial physics and the more general questions of solar terrestrial relations deserve thorough consideration as the most urgently needed future research objectives. Certainly well-coordinated international efforts are most desirable in studying these research objectives. One of them, that of anthropogenic effects upon the cliffiate, mainly from the increase of CO2 in the air, may deserve the highest priority. To distinguish them from natural changes in the radiation emitted and received from the sun, correlations with climate events will have to be monitored on a broad basis. Such studies are time-consuming and are becoming increasingly expensive. For many investigations observations lasting many decades are necessary. Others can be made only by use of a satellite. Certainly such expensive research needs planning by such organizations as the International Council of Scientific Unions. It can be hoped that in that respect the pragmatic purpose of the volume as well as of the Symposium will be successful. However, one should not forget that only a few decades ago the most valuable scientific progress was accomplished by independent individuals and not by multinational organized research. H.E. SUESS (La Jolla, CA, U.S.A.)

Recent Advances in Planetary Meteorology. Garry E. Hunt (Editor) 1985, Cambridge University Press, Cambridge, 1985, xi + 161 pp., ISBN 0521 258863. The study of planetary atmospheres has advanced considerably in the past two decades under the impetus of the space programme, and frequent symposia are held on various aspects of the subject. The short book under review presents written versions of the invited lectures delivered at one such symposium, held on the occasion of the 1983 General Assembly of the International Union of Geodesy and Geophysics in Hamburg, and dedicated to the memory of one of the pioneers of the subject, the late Professor Seymour L. Hess, whose distinguished career as a meteorologist and astronomer is outlined at the beginning of the book by Professor W.A. Baum, one of his colleagues at the Florida State University, Tallahassee. The main part of the book comprises several interesting articles on a mixture of topics, namely the sulphur cycle and clouds of Venus (R.G. Prinn M.I.T.); the photochemistry and clouds of Jupiter, Saturn and Uranus (S.K. Atreya and P.N Romani, University of Michigan); the interannual variability of Martian weather (C.B. Leovy, J.E. Tillman and W.R. Guest, University of Washington, Seattle, and J. Barnes, NASA Ames Research Center); Martian dust storms (P.B. James, University of Missouri-St. Louis); the meteorology of Jupiter and Saturn (G.E. Hunt, D. Godfrey, K. Haines and V. Moore, Imperial College London); and energy conversion processes in the outer planets (P.J. Gierasch Cornell University and B.J. Conrath Goddard Space Flight Center, Greenbelt, Maryland). The book ends with a short essay by Leovy and Hunt entitled ‘Planetary atmospheres as laboratories of geophysical fluid dynamics’, and a short subject index. The technical level is such that the general reader might be unable to judge whether these are conference proceedings at their worst, ‘filling a much needed gap in the literature’, or at their best, presenting insights capable of altering the course of modern research in planetary atmospheres. But most of the contributors are active workers and their reviews should prove useful to planetary sciences practitioners and students. R. HIDE (Bracknell, Gt. Britain)