Wind stress over the ocean. Edited by Ian S. F. Jones and Yoshiaki Toba. Cambridge University Press. 2001. viii +306 pp. Price £50.00 (hardback). ISBN 0 521 66243 5.

It is a play, perhaps a tragedy as I shall explain later, with parts resembling high opera, certainly not musicalcomedy—it is made of too serious stuff. The theatre is the upper ocean and overlying atmospheric boundary layer. Ofthe stage (or ‘set’) there is no doubt: it is the vast surface of the sea, flat when viewed from a far orbiting satellite butrough, even multiply-connected and sometimes two-phase, when seen near to. The principal players, or actors,staggering across the set in sometimes seemingly random (even gusty) fashion, are the wind, the stress it exerts on thesurface of the sea, and the waves. Among the minor players are the surface currents and the turbulent motions, with ahuge cast of lesser supporting roles played by surface tension, surface active contaminants, spray, rain, fetch,atmospheric stability, fronts, atmospheric rolls or other mesoscale processes and, more generally, ‘unsteadiness’—although I wondered whether the latter should have the status of a major part. The ‘props’ consist of field andlaboratory experiments and, more generally, fluid dynamical devices and concepts such as Reynolds stress, eddyviscosity, friction velocity, roughness length and wave age (‘The seven ages of waves’—ripples, short gravity waves,fetch-limited sea, local equilibrium, the well-developed sea, swell and surf?).

The composition of the ‘play’ was sponsored by the Scientific Committee for Oceanic Research (SCOR). The plotinvolves the linkage between the players and derives from a set of conundrums posed in the overture (or preface),developed scene by scene (or chapter by chapter). Do different ‘dynamic regimes’ exist in wave generation by wind?Why do the laboratory results differ from sea-going observations? Is momentum transferred to and from the surface atscales comparable with the longer waves (as allegedly assumed by ‘numerical modellers’) or at scales smaller than thedominant waves? Are stresses measured in steady winds different from those when it is changing? Is swell important ornot?

The prologue (introduction) introduces the cast to the general audience, particularly the relation of the wind to thewave field and the part it plays in wave generation. The intricacies of the interactions between the members of the hugecast are left for later development and, given their number, it will require several viewings of the play before anyonenot already familiar with the characters is able to comprehend their complexity or their subtle innuendo andcontribution to the plot! The level here and later is for the initiated, not the beginner.

The remainder of the play is divided into two acts (parts, with no interval in which to find refreshment, even in theform of a brief summary). Part one, so the programme tells us, is concerned with basic issues of wind stress dynamics.The directors or stage managers (editors), Ian Jones and Yoshiaki Toba, have allowed scenes to be written by 30different playwrights (experts in their areas) which adds colour and variety, if not charm, to the composition. Theexperts come from around the world—Australia, Canada, Denmark, France, Germany, Japan, the Netherlands, Norway,Russia, UK and USA—as merits the fundamental importance of the topic, even if it is only one of the ways in whichthe atmosphere and ocean interact. There are six scenes in act one dealing, respectively, with the grand subjects ofhistory, physics, spectra, mechanisms of drag generation, coupling (wind to waves, waves to subsurface etc.) andmeasurement. In act two the audience is thrust into the maelstrom of the many factors, portrayed largely by thesupporting cast, which provide the greatest known uncertainties in parametrization—swell, unsteadiness, wave age,mesoscale processes, factors leading to non-alignment of wind and stress, surface tension, spatial inhomogeneity, finitefetch and shallow water.

The questions referred to above, which have led the way in composing the book, were amongst those posed at aworkshop held during the International Union of Geodesy and Geophysics Assembly in 1991. SCOR subsequently setup a working group, chaired by the two editors, to survey the state of knowledge of wind stress on the sea and tosuggest where further research should be directed. The volume is the final report of the working group and representsan appreciable achievement in reviewing present knowledge. Unlike several books which I have recently reviewed, thetext and figures are well presented and clear.

What comes most vividly to mind after reading it? It is the table of 14 different formulae for the non-dimensionalroughness parameter, from Charnock in 1955 to Smith et al. in 1992, or maybe the still largely unexplained scatter ofpoints in graphs of drag coefficient versus wind speed and of roughness length versus wave age, and the severe airflowdistortion found, and now nicely quantified by Yelland and others, around platforms (ships) used to measure windspeed and stress, and the progress (but remaining problems) in understanding the effects of swell.

It would spoil the play for a future audience if I were to disclose the answers to the questions posed, but they canall be summarized in one word, ‘probably’. This also reveals the answer to the pertinent question, ‘Is the subject nowwell-understood?’ A glance at the very wide scatter of data portrayed in the many graphs in the book (too rarelyappended with error bars or estimates of their uncertainty) indicates that the answer is a resounding ‘No!’. Would I findthe book useful were I one who needs to include a representation of wind stress in a general-circulation model—is theexisting information presented and summarized in a fashion which renders it of easy access and translation? Well, no,not really. In sections headed ‘conclusions’ authors have tried hard to provide summary statements, but more often thannot this comes down to the sentiment expressed in the final sentence of the book, ‘The evidence is uncertain and furtherwork is needed’. An overview (a summary of the plot and principal actions of the play, pointing to its main movementand flow), drawing out those facts which modellers might find useful and strongly recommending those things whichremain to be done and should be done next, would have been useful.

The really serious problem with the subject, which undoubtedly makes the play (but not the book) a tragedy, is notthat the playwrights (or rather the working group commissioned to undertake the study) have not been able to describe,in a lucid and transparent form, the information required to produce substantial improvements in forecast models ormodels of climate, but rather that the information and understanding are not available for access; they do not yet exist.Almost 50 years since Charnock’s formulation of roughness length, the science potters on in its fragmented way, with

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bits being done here and there by experts scattered around the world and with no one having the ability orwherewithal to draw the various interests together into a co-ordinated thrust to solve the problems, or at least toestablish the means to estimate wind stress over the vast ocean surface area (and its consequences) to a degreecompatible with the requirements of present and foreseeable models. I cannot help thinking that SCOR, in asking thegroup to identify where further research should be directed, did not secretly hope to be told the means to improve itsco-ordination. Perhaps at least a IAMAP—IAPSO Commission for Wind Stress, like that for Mean Sea Level andTides, to standardize the accuracy of stress measurement and the collection of related factors, would help, but thesubject is important enough to justify a more powerful and effective international initiative on atmosphere–oceaninteraction.

So many of the audience who have paid for their theatre tickets, the modellers, go home disappointed. Theinformation presented is fascinating as a good description of the state of the art, but still not enough! More investmentis required, particularly in the study of the effects of swell and time variability, before really useful advances are made,before a future play will have world-changing impact on the culture of our times.

S. A. THORPE

Basic physical chemistry for the atmospheric sciences. By Peter Victor Hobbs. Cambridge University Press. Secondedition 2000. ix + 209 pp. Price £15.95 (paperback), £42.50 (hardback). ISBNs 0 521 78567 7, 0 521 78083 7.

This is a very welcome textbook for any researcher or student requiring an easily accessible reference for thebasic physical chemistry principles which underlie atmospheric science. Many readers will be familiar with Hobbs’scompanion book Introduction to atmospheric chemistry (Cambridge University Press, 2000). Following the publicationof this, the author has taken the opportunity to produce an updated second edition of his original book on basic physicalchemistry.

The book is aimed at the undergraduate level for atmospheric science students. However, in practice that meansthat it is suitable for people ranging from undergraduates undertaking a specialist degree to graduate students or post-doctoral researchers from a non-chemistry background who are beginning a career in the multidisciplinary subject ofatmospheric science.

In 7 chapters and 186 pages (including appendices) the author covers chemical equilibrium, chemical thermo-dynamics, chemical kinetics, solution chemistry and aqueous equilibria, acids and bases, oxidation-reductionreactions, and photochemistry. In each chapter the necessary equations are presented but not in an overlymathematical way. The amount of text is sufficient to explain the meaning of the equations and their relevance, butshort enough to keep the information concise and accessible. The author has also tried to provide a degree ofbackground text to explain the history of the disciplines covered. This helps to make the book more ‘readable’ than apure reference work.

As one would hope from such a textbook aimed at students, each chapter has a series of worked examplesinterspersed in the text. These examples reinforce the ideas presented. At the end of each chapter is a list of exercisesfor use in student classes. The numerical answers to these are, of course, provided.

As an introduction to basic physical chemistry I found the book excellent. However, it does deviate from thisapproach towards the end of chapter 7 on photochemistry. In this section the author describes the processes leading tothe formation of the Antarctic ozone hole. This is a major topic in atmospheric science but the discussion (aside fromthat on rate equations) seems somewhat misplaced in this book. There would have been the opportunity to describe thephysical chemistry relating to the formation of solid and liquid polar stratospheric clouds, and the mechanism forheterogeneous reactions on their surfaces, for example. Unfortunately, that opportunity was missed in favour of theusual qualitative description found in most atmospheric science textbooks.

This relatively short publication will be a useful addition to the bookshelf of anyone studying or teachingatmospheric chemistry. It will also be a useful reference for meteorologists and other non-chemistry-specialists whosework brings them into contact with such concepts as the Nernst equation, Le Chatelier’s principle, or the Lewis theory.

MARTYN CHIPPERFIELD

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Satellite meteorology: An introduction. By Stanley Q. Kidder and Thomas H. Vonder Haar. Academic Press. 1995. x +466 pp. Price $95.00 (hardback). ISBN 0 12 406430 2.

This is an interesting book, containing a wealth of facts and figures, theory and observations from just about everyimaginable aspect of meteorology using satellites. It provides, in places, valuable reviews of such diverse things asretrieval theory, the earth radiation budget, the design of the AVHRR post-telescope optical system, and a massive listof satellite missions, starting with Vanguard 2 in 1959 and ending with NOAA-14 in 1995. However, there is a problemwith books of this nature (as I know from experience with Earthwatch: The climate from space, last reprinted in 1996),which is that they date quickly. There is a definitely historical feel about this book, which will make it essential readingfor some readers, but perhaps not so useful for those wishing to find an up-to-date review of the field.

One puzzling fact is that the copy of the book supplied to me was published in 1995* with no mention of reprintsor later editions. This explains why the table of missions mentioned above ends when it does. I wonder why a reviewhas not been done before 2002?

But what of the book? It comprises 11 chapters and 5 appendices over 466 pages. There is a fascinatingintroduction which spells out the history of satellite meteorology, at least up to about 1988, and provides us with insightinto the excitement and originality of these many early missions. The chapter ends on a lyrical note: ‘Now, dear reader,welcome to the world of satellite meteorology. We hope that you enjoy the following tour.’ Well, enjoy it I did. Thereis a chapter on orbits and navigation that nicely explained the basic geometry and many of the intricacies underlyingcommon usages such as ‘sun synchronous orbit’. There is a chapter on radiative transfer; there are more extensive textselsewhere for the practitioner, of course, but this is a very useful summary of the main points. There follows a chapteron meteorological satellite instrumentation. This gives quite a lot of detail of satellites and instruments, classified by‘operational polar orbiting satellites’, ‘operational geostationary satellites’, ‘other satellite instruments’ and ‘satellitedata archives’. There is a lot of highly useful information, for example, about the ERB instruments, but again theinformation stops around the 1990 mark and some readers may like to know about more recent developments.

The book then turns to image interpretation, with a very interesting chapter which deals with surface effects, andextensively with cloud imagery and its interpretation, from which I learned a lot. This chapter ends with a commentthat does rather date the book, about images becoming available on the Internet via ftp or http servers. Since 1995, ofcourse, the availability of colour, even moving imagery, of powerful search engines such as Google, and of a hugeresource of data providers operating across the Web, has grown with breathtaking speed, to the point where my PhDstudents can connect to sites which, on demand, will process raw data into images or other forms, and downloaddatasets that just a few years ago would have been unimaginable. Not just this, but I can connect to sites where I canobtain images which are an hour or so old from all round the world. The progress since this book was written has beentruly mind-boggling.

There follow four core chapters of the book, which deal with sounding of temperature and trace gases, winds,clouds and aerosols, and precipitation. The first of these carries a valuable account of sounding, or retrieval theory, inwhich due credit is given to a number of familiar names, such as Chahine, House and Gille, Smith, Rodgers, and manyothers. Measurement of composition is also treated, leaning heavily on the pioneering results from the LIMSexperiment on Nimbus-7. The measurement of winds is described from cloud tracking and from the measuredtemperature field. Surface winds from radar scatterometers and from passive microwave observations are mentioned.The chapter on clouds and aerosols describes cloud measurements from sounders and from imagers, including the useof multi-spectral images to classify clouds. Stratospheric and tropospheric aerosols are discussed briefly. There followsa masterly (as might be expected from Tom Vonder Haar’s authorship) treatment of earth radiation budget and itsmeasurement, which provides an excellent primer to the subject. Finally, a chapter called ‘The future’ talks aboutupcoming NOAA satellites, NASA’s Mission to Planet Earth (which has for some years now been renamed the EarthScience Enterprise, I believe), and missions such as TRMM and ADEOS, the Japanese advanced earth-observingsatellite. These missions are now things of the past (no less important for that) rather than things of the future asdescribed in the book. The chapter ends with a description of the payloads on what are now known as EOS-Terra,EOS-Acqua, and EOS-Aura missions, the first already in orbit. As a sign of the times, each of these missions (and ahuge amount more) is now described in colourful detail on the NASA website (start at http://www.nasa.gov/NASA_homepage.html/ and work your way from there, but allow yourself some time—there is an awful lot of it!).

A final comment: the book is comprehensive, full of interesting material and facts (alright, slightly USA-centric,but so what?), and a book that I will enjoy having on my shelves. However, it is really a look back at satellitemeteorology to what might now be called the pre-Internet era. As such, it records material that you will not find on theWeb, and tells a fascinating story about this subject, which has become a cornerstone not only of meteorology but ofthe atmospheric, oceanic and climate sciences, too.

J. E. HARRIES

* This book was sent to us by the publisher dated 2001. We did not notice the publication date of 1995 in the flyleaf,and what we have now may just be a reprint of the original. However, the book was not reviewed in the QuarterlyJournal after its original publication, and we are grateful to Professor Harries for doing it now—Book Review Editor.

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Climate change 2001: The scientific basis. Edited by J. T. Houghton, Y. Ding, D. J. Griggs, N. Noguer, P. J. van derLinden, D. Xiaosu, K. Maskell and C. A. Johnson. Contribution of Working Group I to the Third Assessment Report ofthe Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge. 2001. 881 pp. Price £34.95(paperback). ISBN 0521 01495 6.

This volume provides an in-depth survey of things going on in understanding and characterizing the earth’schanging climate, with emphasis on new developments over the last 5 years. A lot of effort in the atmospheric scienceshas always been directed to application in the field of human endeavour, and the possibility of human influence onclimate on a worldwide basis provides both opportunity and obligation to those whose expertise lies in this area.Immediate application lies in the field of geopolitics related to the worldwide growth of population and associatedconsumption, which ultimately means energy and the political and business activities related thereto. Human activitiesare increasing to influence the atmosphere on the scale of the planet itself and thus demand our immediate attention.The book is one of three, with 14 chapters on specific topics. It is a major effort (it weights 3 kg), has 122 lead authorswith input from 515 other contributors and 420 reviewers. Previous Scientific Assessments appeared in 1990 (with asupplementary in 1992) and 1996. Society impacts and mitigation are discussed in companion volumes.

The overall theme is whether global civilization, expanding through urban, industrial and agricultural activities,is, is not, or may be leading to changes in our environment as defined by the hotchpotch of things which go to make upa changing climate. These are changes which we may notice, mainly temperature, precipitation, surface albedo (chapter2) and sea-level rise (chapter 11). There are more subtle changes as in atmospheric composition, requiring carefulmeasurement, such as increasing atmospheric concentrations of CO2 , CH4 , O3 and N2O (chapters 3 and 4), importantfor radiation transfer and absorption both at solar and thermal wavelengths (chapter 6). Radiation is also significantlyinfluenced by changes that result from changing load and type of aerosol and resulting cloud and precipitation particles(chapter 5). The overall water-vapour cycle through cloud lifetime ending in evaporation or precipitation relates toalmost everything.

The observational data of chapter 2 provide the basis for the whole book, covering a variety of techniques andtime-scales to serve as comparisons with the century time-scale at the centre of the current debate. The ways ofhandling large sets of data and combining them is deftly discussed here, as is the significance of extremes which tendsto attract attention, as do singular events such as volcanic activity and large meteor impact, and known periodic effectson an astronomical scale.

The reality of the problem lies in the simple fact that most of the changes resulting from human activity planet-wide have occurred over the last century, and much of the detailed record lies in a comparable time frame or, in somecases, less. Yet changes in components of climate inferred from the historical and geological record occur over avariety of time-scales from centuries and well beyond by many orders of magnitude. Modelling all these things(chapter 8) through examination of a variety of processes (chapter 7) provides opportunity for comparison of how wellwe think we can do in quantifying the basic assumptions of how our climate puts itself together.

At the beginning of the book is given a ‘Summary for policymakers’ of the graphs and measurements mostrelevant to recent climate matters. This attracts the reader’s attention at an early stage. Obviously something ishappening to the atmospheric composition and it is doing it now. In particular, it links to known increased emission ofgases leading directly to the changing atmospheric composition which can readily be measured. Something is alsohappening to surface temperatures; they are going up—sort of. The key figure (Fig. 1, p. 3 and elsewhere) showsincrease from 1975 to 2000; a similar increase exists from 1905 to 1945, with a 140-year base. Not much happensduring the 30 years in between, in spite of a continual increase of human activities. There is an interesting questionhere. Tree rings do something similar, with a 1000-year database so the effect appears to be real enough, along withconsequences such as more rapid water-vapour transport and precipitation resulting from the higher temperature. Towhat extent do these changes result from changes wrought by our growing civilization? Caveats are present throughout,but words are used that leave the reader with a sense that things are really happening: ‘There is new and strongerevidence that most of the warming observed over the last 50 years is attributable to human activities’ (p. 10). Maybe,but what is worrying is exemplified by Fig. 3 (p. 8 and elsewhere) where an estimate is made of the confidence in thelevel of understanding of the various topics discussed in this book. The changing atmospheric composition and itseffect is well documented and understood, whereas the role of a number of other players in the field has a very lowlevel of understanding. Included in this list is the indirect effect of aerosol and how it may change cloud properties togive an effect in the opposite direction (cooling) to that of the recognized heating effect of increasing CO2 . Bearing inmind the uncertainty, the two effects are about equal. This reviewer (having worked a little on the role of aerosol inclouds) cannot but agree that this is a reasonable evaluation. Clouds were deemed to comprise the major uncertainty inour understanding of climate more than a decade ago; that situation has not changed. Does this large uncertainty, whichhas existed throughout time (through the erratic occurrence, for example, of volcanism and lightning-caused forestfires), and the changing aerosol input through combustion by the same human activities in the same time frame as theCO2 increase, justify the reality of a recent warming—or could it really be a lot worse? Or could it be part of thenatural scheme of things in a highly variable, turbulent atmosphere?

I recount a cautionary tale. On one occasion, in a debate on the effects of black carbon aerosol on climate, adiscussion arose that an estimate needed to be made of its lifetime in the atmosphere. Arguments ensued that it wasprobably water-repellent and would be scavenged very slowly; an alternative argument suggested that photolysis wouldrender it hygroscopic and it would be rapidly removed as cloud droplets and thence to precipitation. A compromisesuggested running the model with the scavenging effect as 0.5 on a scale of zero to unity . . . The weakest link in thescientific chain needs mending and needs to be brought to the attention of the policymakers in comparison with thegreater certainty of other links.

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The scientific community itself is, in one sense, the policymaker in as far as we are consumers and can bringinformed opinion to where it can be heard best. This volume is stimulating in that the extent of coverage it gives to theproblems and the interconnections between different expertises bears in a meaningful way in sorting out theuncertainties of climate change and the difference between influences by known processes outside of our control andby those resulting directly from human activity. The serious extent of these uncertainties needs to be stressed incarrying these ideas to the population at large and to those who make decisions. We all make decisions—whether it bethe fuel consumption of one’s chosen car, one’s general life style in the use of resources and, for the chosen few,economic decisions on energy policy. In any democratic society, the policymakers, to whom the first section isaddressed, necessarily follow these trends. It is a major challenge to bring the concept of scientific uncertainty to thepeople concerned with high-level decisions, let alone the average person; but this challenge needs to be met and Iwould suggest that the scientific community has an obligation to do so.

From a more general viewpoint, there is an increasing tendency for highly controversial topics having seriousscientific discussion to use the vehicle of an international evaluation and review to provide a sounding board for factand informed opinion (Anon. 2001). We have issues involving disease, as foot and mouth and AIDS; there are issuesinvolving cloning and bioengineering. The issue of climate change has a multitude of ramifications and the use of suchtechniques employed to assemble the evaluation presented in this volume needs to be considered seriously as a modelfor such evaluations in other disciplines. One aspect of things clearly stands out—the lack of appreciation ofunderstanding of topics having a wide range of variability. A scientifically literate society is highly desirable in order tounderstand the mechanisms whereby things happen; but a numerically literate society (I make the distinction) isdesirable and necessary to appreciate arguments having large uncertainties. The magnitude of wind fluctuations overan irregular terrain, for example, is not too different from the mean value of the wind; both concepts are necessary toprovide a rational approach to any evaluation of the effect near the surface. I found this approach wanting in bothsummaries.

The book is excellently produced; diagrams are clear; there are good cross-references between sections and topics,and a useful index. It is not a book to be read from cover to cover (that would be a mammoth undertaking), but onerequiring careful selection of topic and a savouring of the interactions of the composite disciplines. There is a lot offood for thought, discussion and analysis. It should provide an endless source of ideas and perspectives to those of us inboth the research and the teaching communities concerned with an important problem both in atmospheric science andthe world at large.

And the future? Good progress is being made but must do better next term.

REFERENCE

Anon. 2001 Editorial. Nature, 412, p. 103

JOHN HALLETT

Introduction to micrometeorology. By S. Pal Arya. Academic Press. Second edition, 2001. xxv ‡ 420 pp. Price £53.95(hardback). ISBN 0 12 059354 8.

This is the second edition of a book, first published, according to the preface, in 1989. The 15 chapters of thisedition present a broad overview of micrometeorology and boundary-layer processes. There is a general introduction tomicrometeorology (chapter 1) followed by chapters on the near-surface energy and radiation budgets (one chapter oneach), and one on soil temperature and heat transfer. Air temperature, humidity in the planetary boundary layer andwind fields in the planetary boundary are all covered in separate chapters, as are introductions to viscous flows,turbulent flows and turbulence models and theory (one chapter on each). Separate chapters cover near-neutral, stratifiedand thermally stratified boundary layers, evaporation from homogeneous surfaces and non-homogeneous boundarylayers, respectively. The final chapter discusses agricultural and forest meteorology, although it is not clear why thistopic is singled out for special interest. The book is well presented, with clear diagrams and figures. There are 13 pagesof references and 9 pages of symbols.

The preface of this book notes that there is ‘no suitable text for an introductory undergraduate and graduate coursein micrometeorology’. I am not sure that I agree with this, particularly with some of the other books available today,and I have a problem working out which niche this book fills. The two reasons given for issuing a second edition arethat it provided an opportunity to update the reference list, and also to provide some updated material on atmosphericboundary-layer observations, theories and models. In many ways, the reference list is the most useful part of the bookas it lists many of the key texts in micrometeorology and boundary-layer meteorology over the past several decades,and the author has done a good job updating this; post-1989 references account for about 10% of those cited, and thereare references dated 2001 which are noted as being ‘in press’. In fact, many less well informed readers would be bettergoing to the reference list rather than the text in the first instance.

Whilst the flow of the book is good, most of the explanations are based on detailed mathematical descriptions,often presented with little introductory text. It is difficult to keep track of all the symbols used if one dips into specificsubjects, and constantly flicking to the front of the book to refresh one’s memory became tedious after a while. Whilsteach chapter concludes with a series of problems and exercises, there is clearly some expectation of supported learningin order to check the results of these as no answers are given, although some worked examples do appear in the bodies

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of the chapters. Consequently, this book is most clearly targeted towards those who either have had a formal educationin atmospheric physics and mathematics or, at least, have a thorough background knowledge of the subject.

Whilst there is no doubt that this book will assist students and professionals with a background in atmosphericscience, I doubt if researchers from other disciplines which need to draw on elements of micrometeorology will getmuch from it. Finally, I fear that the price of this book will be out of range of many of today’s undergraduates. By allmeans consult a library copy, but don’t go out and buy one.

P. J. A. BURT

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