REVIEWS 1181

Studies of the middle atmosphere. Edited by J . A. Pyle, L. Thomas and R. Wilson, Royal Society of London, 1987. Pp. 185. Price E35.00

This book is a set of papers presented at a Royal Society meeting on the middle atmosphere, dedicated to the memory of the late Sir Harrie Massie, F.R.S. The papers survey established knowledge and current research activities in the field and there are many references to published material to supply the detailed arguments so that a broad outlook is maintained. The papers also have the advantage of including some valuable discussion material especially from Dr McIntyre, whose contributions would together have made an interesting paper in themselves! Most of the papers are very well written and are enhanced by the high quality printing which contains only a few misprints. Two speakers were unable to supply a written version of their talks and this is particularly disappointing in the case of Dr Anderson. As a result, the book scarcely mentions measurement techniques from balloons which would be a serious omission if the book were a textbook but, of course, the editors cannot be blamed for this!

The reliance of middle atmosphere research on satellite data for chemical constituents and dynamical variables is clearly apparent. Several papers describe the data and the measuring techniques and in the first of these Dr Barnett provides an excellent review of middle atmosphere temperature radiometers from 1963 to several years into the future. The other satellite data papers, presented at the meeting by Drs Russell and Taylor, describe aerosol data from the SAM I1 and SAGE instruments and the measurement of chemical constituents by the LIMS and SAMS instruments. The feeling on reading these papers is of a definite attempt by the authors to expose the strengths and weaknesses in our understanding of atmospheric chemistry. Examples include the increased levels of HNO, observed in the polar night and the ‘double peaked’ structure in CH,, an explanation of which appears later in the paper by Pyle et al.

Measurements from rocket and radar instruments are then described. The paper by Greer et al. discusses the green line and atmospheric band emissions of the lower thermosphere, a region of the atmosphere perhaps not usually described as the ‘middle atmosphere’. The ways in which the measurements have contributed to our understanding of oxygen photochemistry are emphasized and the paper does contain some review material, but for my taste the paper is a little too detailed. The paper by Prof. Thomas is broader in scope and after a brief description of the technique used, goes on to give examples of radar measurements of temperature and density profiles, aerosols and ozone. The second radar paper (by Dr Rottger) discusses observations of turbulence and gravity waves which have attracted a major interest in theoretical studies in recent years.

The next set of papers is concerned with the theoretical interpretation of constituent measurements and in the first of these a lively discussion of the antarctic ozone hole is presented by Dr Farman. This contains a good description of the dynamics with the antarctic vortex viewed in broad terms as an isolated air mass under radiative control, a picture that still remains a reasonable first approximation. On the other hand, the chemistry in the paper seems now, after the Airborne Antarctic Ozone Experiment of austral spring 1987, to be a little confusing, although this is probably a reflection of the uncertainty prevailing at the time of the meeting. This paper is followed by a good overview from Prof. Thrush of stratospheric chemistry. Interspersed between the theory are sets of observations showing, for example, the large shortfall in model HO,. The need for laboratory measurements down to 190 K, to understand properly the antarctic ozone hole, is quite rightly emphasized but I fail to see a relationship between the nitrogen species in Antarctica and the Noxon cliff. The next paper, by Drs Solomon and Garcia, discusses the transport of constituents in the mesosphere. It perhaps could have been better placed after the radar papers since the theoretical framework for transport at this altitude relies strongly on the observation of breaking gravity waves. The final paper, on the chemistry of the middle atmosphere, by Pyle et a / . , shows ways in which simplified models can be used to interpret satellite data and provide powerful tests of atmospheric chemistry. The paper then briefly discusses some results from more complex models used to explain the double peak structure in the CHI and N,O satellite measurements but to my mind seems to lack the balance of a steady progression.

The final section of the book is devoted to the dynamics of the middle atmosphere, firstly, in a paper by Drs Fairlie and O’Neill using a 3-D primitive equation model. Here the emphasis is on comparisons with satellite data for a model-simulated stratospheric warming using potential vorticity as a diagnostic. The paper is, as far as I am aware, the first published evidence for the existence of stratospheric ‘fronts’, although how these relate to tropospheric fronts is, at present, unclear. The paper also illustrates how, under some conditions, the conventional wave, mean-flow theory is quite at odds with reality. A complementary view is presented in the paper by Dr Andrews who uses some simplified models to provide insight into the dynamics of the middle atmosphere. In particular, planetary waves are identified as responsible for driving the middle atmosphere away from radiative equilibrium.

This book contains an instructive blend of theory and observations in both dynamics and chemistry and I would strongly recommend it to any scientist with a strong interest in the middle atmosphere.

JOHN AUSTIN

Weather radar andflood forecasting. Edited by V. Collinge and C. Kirby. John Wiley and Sons, Chichester. 1987. Pp. 296 + x. f39

This book, published on behalf of the British Hydrological Society, is based on a symposium held in 1985 at the University of Lancaster. The papers are organized into four sections: the technical development of weather radar; operational experience of weather radars; modelling runoff using radar data; and weather technology in the future.