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Climute, water and agriculture in the tropics. By I. J . Jackson. 2nd Edition. 1989. Longman Scientific and Technical. Pp. 377. Paperback fll.Y5.

The title of this book describes its contents accurately. Like its predecessor, i t provides an adrnirablc background over the range of topics suggested by the title, but 1 would not recommend it to any specialist as providing the detail that might be expected consistent with the ‘current state of knowledge’ as claimed by the publisher. It is more likely to be used as an introductory text, to give a descriptive background to those entering a part of the field for the first time.

It is also an excellent source book, particularly for those who do not have access to well-stocked libraries, and in this respect it should be made available to all applied climatologists and agriculturists in tropical developing countries. Indeed, the reference section is an outstanding feature, containing nearly a thousand items, around half of which date from the last ten years. Also, the range of sources is wide, with the inclusion of a number of items from Indian literature (which shows, perhaps, how the author has moved on from Africa since the research for the first edition). The fact that references and the indexes form nearly one fifth of the whole, emphasizes its value as a source book.

The limitations of this book must also be recognized. It does little to lead the reader towards the quantitative work which is essential for the development of the subject. For instance, there are passing references to the concept of stomata1 and other resistances but no indication of the utility of these concepts for generalizing results on water consumption by crops and water-use efficiency. References to various measurement techniques are also oblique, and a reader new to the subject would not be likely to realize the effort involved in making good and reliable observations. Another area largely missing from the book is consideration of the effects of the complex farming systems practised in the tropics, with their many forms of inter-cropping and agro-forestry.

There is also little synthesis of the material here. and Jackson’s style, although admirable in its conciseness, does tend to consist of staccato summaries of some facts interspersed with occasional short essays on general points. Among these is the last brief chapter on ‘Problems and Priorities’; one of the new sections which shows that Jackson’s revision has been thorough and thoughtful.

Overall, the criticisms are minor, and anyone who knows the first edition will not be disappointed by the second. In order to cover the wide range of topics which the title implies, Jackson had to be brief, and it is a considerable achievement to include so much useful material in a reasonably priced paperback. If readers are able to follow up all the leads which are given, sometimes by a single reference, they will find they have indeed gone deeply into a section of this vitally important subject.

J. R. MILFORD

The environmental record in glaciers and ice sheets. Edited by H. Oeschger and C. C. Langway, Jr. Dahlern Workshop Reports. Physical, Chemical and Earth Sciences Research Report 8. John Wiley and Sons, Chichester, England. 1989. Pp. 400. f47.50.

Scientific core drilling of polar ice began in 1956 when 305 m of core was taken in north-west Greenland. Since then around 30 short and medium length cores have been obtained and five deep cores, two from Greenland (Camp Century (1387 m) and Dye 3 (2037m)) and three from Antarctica (Byrd Station (2164m), Dome C (905 m) and Vostok (2200 m)). The Vostok core covers a period of some 160 000 years, completely through the last interglacial-glacial cycle, and its analysis is producing fascinating insights into the processes of climatic change.

This volume is the report of a Dahlern conference held in March 1988 to discuss the environmental data recorded in ice cores from glaciers and ice sheets. Dahlem conferences follow an unusual but very effective pattern. The participants produce a series of review papers, which are discussed in depth by interdisciplinary groups during the conference. Each group then prepares a report summarizing results in their area of science and suggesting future research. The result, in this case, is a beautifully prepared volume which covers all aspects of ice-core analysis clearly and coherently.

The first group investigated how glaciers record environmental processes. It cannot be assumed that concentrations of contaminants in an ice core are the same as, or even proportional to, the concentrations in the atmosphere at the time of deposition. Transfer functions have to be derived for each type of contaminant and each stage in the journey from its source region to the ice. The review papers cover aerosol transport, wet and dry deposition and processes in the deposited snow as it is gradually compressed. One key problem is the link between stable isotope concentrations in the ice and air temperature; linear relations have been derived from spatially distributed data but should these be used to interpret temporal isotopic changes?

The second group tackled the vexed question of how to establish a chronology for ice cores. Dating using seasonal variations and various types of reference horizon (for example the radioactive layers produced by nuclear weapons tests in the atmosphere and the acid layers from volcanic eruptions) may be complemented by mathematical modelling of flow paths in the ice. In cores taken from areas of high accumulation annual layers can be counted like tree-rings and an accurate time-scale established over hundreds of years. However, determination of deep ice core age-scales is still a problem. It is important to remember the potential dating errors (about t 15 ka in the oldest part of the Vostok core for example) in any application of ice-core data.

The third group was concerned with the impact of man recorded in the changing concentrations of major ions, trace gases, trace metals and organic compounds in ice cores. Trace gases trapped in air bubbles

776 REVIEWS

reveal a sorry story of increasing atmospheric pollution. Carbon-dioxide concentration has soared from the preindustrial level of about 280 ppmv to 350 ppmv today; methane concentrations in the troposphere have increased from 700 ppbv to 1670 ppbv. The potential impact of these changes is only too clear-rising average temperature at the earth’s surface with a predicted increase of around 1 degC over the next 50 years.

The long-term records from the deep ice cores allow us to look back at periods of major global environmental change in the past. The fourth group reviewed evidence from the deep ice cores and drew attention to several intriguing questions. Why does the transition between glacial and interglacial periods occur at the same time in each hemisphere although the Milankovitch forcing is in antiphase at opposite poles? Why does carbon-dioxide concentration vary simultaneously with temperature during transitions from glacial to interglacial but lag behind temperature in the transition back to glacial conditions? There is a wealth of information on complex environmental feed-back processes to be extracted from the depths of the polar ice sheets.

Next year deep drilling begins in central Greenland with the aim of extracting a 3000 m core covering at least 200 000 years. Drilling continues at Vostok and plans are afoot for deep drilling in west Antarctica. The Dahlem conference was a timely recognition of the importance of ice-core drilling and this proceedings’ volume will be an invaluable guide, not only for the scientists directly involved, but also for the interested bystander.

ELIZABETH MORRIS

Spacious skies. Edited by Richard Scorer and Arjen Verkaik. Publicity & Marketing, Newton Abbot, Devon 1989. Pp. 192. i20.00

This is the successor to Clouds of the World and I feel sure that most meteorologists will want to while away many happy hours in its company. The photographs are a delight combining both ground views and satellite images. It is much more than a coffee-table book, with detailed descriptions, without mathematics, of the dynamics and physics of clouds; however there is no attempt to make this into a textbook. The figure captions are informative with detailed interpretations of the photographs. In the more introductory parts of the text there is a rather florid poetic style which may not appeal to everyone’s literary taste: “Like the elusive images of dreams, clouds display their twinkling beauty in passing instants, flashes of vapoury charm”.

Here is a description of a few of my favourite photographs. Number one is a composite infra-red satellite image (Fig. 7.8) of the North Atlantic between Labrador and Finland on 29 January 1983. Before looking at the caption you are aware there is something unusual in this image but you cannot pin down what it is straightaway. Of course it is immediately stunning with a row of five cyclones connected by a continuous cloud band. With the caption title, ‘A row of upside-down cyclones’, the penny drops and upon turning the book upside-down a much more familiar view appears. The curled-up vortices are forming at the boundary between warm air to the north and colder air to the south. This unusual state has arisen by a previous cyclone family feeding warm air into the Norwegian and Greenland seas.

Next is Fig. 5.7 which is a series of seven photos of the development of a cell within an isolated cumulonimbus forming in the late afternoon over Alberta. The cloud glows first orange then red as the sun sets. The storm produced golfball-sized hail and incredibly was an isolated one on a day with no other clouds. One can quibble about the accuracy of some of the dynamical explanations but these are not important imperfections. For example the old Imperial College schematic, from Ludlam, of the flow in a squall line is reproduced as Fig 6.3. The beautiful simplicity of this model stands as an historical record of his genius in abstracting dynamical ideas from the simplest of observational evidence. However the model was only intended to be a cartoon of the relevant dynamics. Some of the interpretations of the model given here seem to take its structure too literally. For example, the origin of downdraught air is rarely, if ever, in the upper troposphere and the currents do not ‘exchange momentum’. The idea of a vigorous storm updraught ‘pushing back against the prevailing flow’ is not, I believe, instructive.

The Morning Glory photographs from Roger Smith are repeated here from Clouds of the World. Surely there are few more eerie cloud formations than these. Incidentally as a minor point of correction this phenomenon has now been observed in places other than Australia. The tornado photographs are a little disappointing but they are, of course, one of the hardest phenomena to capture. The authors, curiously, rely on a ‘personal communication’ to provide possible explanations of the origin of storm rotation; the last one was “complex dynamic processes . , . which are not yet understood”!

There is about an even split between colour and black-and-white photographs and of the latter variety about an even split between satellite and ground (with a few aircraft) images. The production quality is good; obviously there is always a conflict between cost and quality of photographic reproduction but this has been resolved well here. There are minor imperfections of typographical setting in some figure captions and elsewhere.

I enjoyed and will continue to enjoy browsing through this excellent book. The satellite images are an important component and the authors do a good job in showing us that for phenomena of synoptic scale, such as extra-tropical cyclones, they have a large potential for revealing gross structure unobtainable in almost any other way. One is left with the feeling that by an analysis of suitable combinations of the various channels a better four-dimensional view of these systems could be derived than that currently available. The colour photographs are at times breathtakingly beautiful. In conclusion I thoroughly recommend this book to all meteorologists.

ALAN J . THORPE