A Change in the Air

1 498 BOOKS: ATMOSPHERE A Change in the Air Michael J. Prather spheric chemistry has been pushed, at least since the 1950s, by environ- mental change. Haagen-Smit’s research on ozone smog was driven by the then obvi- ously deteriorating air quality in the Los Angeles basin. The 1970s brought the imagined threat of supersonic The development of the field of atmo- SCIENCE&#39;S COMPASS views) and an independent essay by a well-known scientist. A list of references to scientific papers, tabulations of atmo- spheric chemistry data, and a sample set of useful problems (not keyed to the chap- ters) are gathered at the end. The individu- ally written chapters lack the coherence and consistency of notation possible when one author writes the entire text. The essays work excellently where they present unique or individual historical per- spectives. Some of my favorites were Mclntyre on dynamics, Schneider on cli- mate, Megie on measure- aircraft ﬂeets and the realized Atmospheﬂc ments, and Albritton on the threat of chlorofluorocarbons, chemist,’ and global perspective. Rodhe’s es- which focused the field on Glabalchange say on modeling is appropri- global patterns and processes. OWE Bmseu,’ ately dated: “Today (l996)....” A new book on “global change” conjures numerous questions: How can change be encapsulat- ed in a text? What can be said about the future? And, of course, for how long will such a book be useful? Aiming to 5105214 john]. Orlando, and Geoffrey S. Tyndall, Eds. Oxford University Press, Oxford, 1999. 672 pp. $75. £54. ISBN 0-19- These essayists develop inter- esting viewpoints that are oth- erwise not found in a current text. The essays work less well where their authors simply re- view material already covered in the chapter. produce an atmospheric chem- istry text adds further hurdles. One must balance well-established atmospheric physics and chemistry with the many unre- solved processes controlling atmospheric composition still under scrutiny. The new volume edited by Guy Brasseur, John Or- lando, and Geoffrey Tyndall handles the complexity of atmospheric chemistry well, but trips a little over the hurdles of timeli- ness and future change. A first lesson for anyone using this book is that the field has progressed since it was written. Like any text on global change, it is already outdated when pub- lished and it will become even more dated as a new generation of graduate students pore through it—as they probably should. The editors should have noted the book’s effective date in the preface. Although it includes some I998 references, I would have included “I996” in the title. Several key events of the past couple years—the slowdown in methane’s increase, the peak- ing of some halocarbons phased out by the Montreal Protocol—are not discussed. De- spite this shortcoming, the book provides the widest range of topics in atmospheric chemistry in a framework of global atmo- spheric change currently available (in 1999). The volume was written and edited pri- marily by the community of atmospheric scientists in Boulder, Colorado. Each of the 16 chapters includes a short list of rec- ommended readings (other texts and re- The author is at the Earth System Science Depart- ment, University of California, Irvine, CA 92697-3100. USA. E-maiL&#39; mprather@uci.edu When I went through the text with a sharp pencil in hand, I found irritations and inconsistencies. The intro- ductory chapter is daunting—even to this old hand—in the wealth of global change data it presents. I would prefer a more limited set of examples with a clear lesson be- hind each. More annoy- ing, however, is the sloppy treatment of at- mospheric physics. For example, the gravita- tional acceleration g is given as 9.80665 m s“2, making it appear to be a universal constant in- dependent of location and altitude (g’s magni- tude at sea level varies from 9.78 at the equa- tor to 9.83 at the poles). Also, nitrous oxide is not only photolyzed in the stratosphere but re- acts with the excited O(‘D) species, and it is the latter process (un- mentioned) that pro- duces the nitrogen ox- ides. Picking tropo- spheric ozone trends from a 1992 assess- ment, and selecting the largest (and possibly in- correct) example of Payerne is misleading. The chapter on photo- chemical processes suf- fers similarly. The discussions of atmospheric life- times can be misleading. The implication that methane sources are well enough known (summing to 535 Tg per year) to define the chemical lifetime is incorrect, because methane has many sources, each with significant uncertainty. Estimates of the current lifetime of methane are based on scaling from the empirically derived OH losses for the synthetic gas methyl chloroform. Standard atmospheric profiles and photolysis rates are presented without reference to their source or applicable year (the book is about changing atmospheric chemistry). The volume would also have been improved with the addition of oxygen chemistry (including spectra and energy levels for O2 and 0), more on the physics of the planetary boundary layer, and better discussion of rainfall and scavenging of gases and particles. Thus Atmospheric Chemistry and Global Change is a valuable, if dated, ref- erence, but it cannot be used as a text without substantial instructor oversight. The chapter on measurement techniques is a great and needed addition to books in the field. And the merging of measurements and models into a single scientific strate- gy—noted in the essays—represents the future of atmospheric chemistry. BROWSINGS Tornado Alley. Monster Storms of the Great Plains. Howard B. Bluestein. Oxford University Press, New York, 1999. 192 pp. $35. £17.99. ISBN 0-19-510552-4. Bluestein is renowned for his pioneering ﬁeld studies of tornadoes and the thunderstorms that produce them. His fascinating account of the origin, effects, and research on these violent whirlwinds incorporates experiences and spec- tacular photographs from two decades of storm chasing. In a mature supercell, tornadoes tend to be located under a wall cloud (a relatively precipitation-free lowered cloud base located under a rapidly growing convective cloud).. But this horseshoe-shaped wall cloud (near Norman, Oklahoma. 20 June 1979) was not associated with any tornadoes. BSEPTEMBER 1999 VOL 285 SCIENCE www.sciencemag.org CREDIT: H. MUESTEIN