During the past thirty years, ozone has become one of the `hot properties' of the atmosphere. It is one of the two minor atmospheric constituents of which the general public is aware. It is the only one for which politicians of almost all persuasions, in almost all countries, have agreed that `something must be done'.
The book by Grant, originally published in 1989, provides a very useful source of detailed information on the fundamental observational methods from which our understanding of the variations of ozone concentration has been gleaned. Grant has taken seriously the issue of providing a comprehensive assembly of critical scientific papers. These papers describe in detail the techniques which have been developed to measure ozone density and column abundance. The individual scientific papers, having been published previously in the scientific literature, are informative, generally well written and describe instrument design, calibration and measurement.
Of considerable importance is the bibliography within each paper as well as the overall collation of key papers. Grant's book therefore does provide, as he claims, a background source for the scientist or engineer wishing to get anything from a passing perspective to a detailed running start, with the intricacies of calibration, data analysis and inter-calibration. The prospective post-graduate student is also well provided for, although for the scientist involved in current ozone research, the absence of an update covering the considerable advances during the last eight years is a drawback. Whether or not the book would appeal to the politician directly is questionable, although the compendium could certainly convey to the politician's diligent assistant an impression of the high level of intellectual, scientific and engineering effort devoted to the development of reliable and usable ozone-measuring systems.
Ozone, and stratospheric ozone in particular, reaches the public attention and imagination due to its role in protecting the earth's surface from the biologically damaging ultraviolet radiation from the sun at wavelengths shorter than approximately 320 nm. Most importantly, ozone nearly totally absorbs the highly destructive incoming solar radiation below 290 nm.
The first public ozone `scare' - the possible impact of a large fleet of supersonic aircraft plying the mid-stratospheric air corridors - proved unsound due to inadequate understanding of the fundamental physics and chemistry, and also the revised economics of supersonic transport in the wake of the various oil crises of the mid- to late 1970s.
The second public `scare' - the impact on stratospheric ozone of anthropogenically produced CFCs - turned out not only to be correct, but initially understated the severity of the problem. The discovery of the Antarctic ozone hole (or, more correctly, polar ozone hole now that the Arctic manifestation has also been observed) led to the discovery of the importance of heterogeneous phase chemistry - the joint culprit being CFCs and the extremely cold (natural) conditions found within the core of the stable polar stratospheric vortices which develop in both hemispheres during the winter period.
Grant's introduction provides a brief but informative review of the distribution of ozone in the atmosphere, noting the factor of two variations in the `normal' seasonal/latitudinal distribution as measured by total column abundance (even without CFC-assisted polar ozone holes). Day-by-day column abundance variations of 
, associated with stratospheric planetary waves, make the reliable determination of medium- and long-term trends very difficult. These variations are described in several of the reprinted papers, though not in Grant's introduction.
The book is given a structure by the five fundamental instrument approaches: direct-absorption measuring instruments, ground-based indirect-absorption measuring instruments, space-based indirect-absorption measuring instruments, emission measuring instruments, and miscellaneous in situ instruments. In total, more than 30 diverse techniques are described. In each case, Grant provides a brief summary of the method, its application and basic bibliography, followed by the reprint of a key research paper. The papers are well chosen to provide an overview and detailed description of the technique and of related measurements. There is a continuing need for in situ and remote measurements. Perhaps unfortunately, it is left to the individual reprinted papers to make the case for the importance of continuing a multi-pronged attack.
Given the advantage of hindsight, the balance and emphasis might have been changed. During the past decade, for example, the differential absorption lidar (DIAL) technique has provided highly detailed profiles of ozone distribution, with very good vertical resolution, literally from the South Pole to Nye Alesund in Svalbard (79N). The DIAL technique has provided dramatic evidence that ozone may be virtually destroyed through extended height regions within the Antarctic polar ozone hole. The CLAES instrument and LIMS instrument onboard the upper atmosphere research satellite, launched by NASA in 1992 have provided, during the past five years, spectacular global coverage of the distributions and variations of ozone and other minor stratospheric constituents.
Grant's book will not solve the layman's confusion between increasing surface-level photo-chemical ozone pollution and long-term stratospheric depletion (As long as we have the ozone somewhere, isn't that alright?). Grant also does not attempt to answer the questions often asked (Why do we need all these different techniques? Why do we need as many measurement, in all these places? Why, after 30 years of increasing attention, do we need to keep on making all these expensive measurements? Why can't the scientists agree on a single number?).
The detailed answers to these questions can certainly be found within the individual research papers, and their citations, and, of course, in the continuing trail of productive research and measurements regarding ozone distribution and trends.
The book is, as is claimed, a highly valuable source of information regarding methods of ozone measurement. It does not attempt to rank techniques or measurements. The individual authors of the reprinted research papers are established and respected scientists. Thus the 430 pages contain a great deal of information, valuable ideas and conclusions. I recommend the book, in particular, for the general science library and for any department or institute which fosters teaching or research in atmospheric sciences.
