Cloud dynamics

Cloud dynamics

90 than the possibility of a warmer world, even such combinations will never get off the ground. Once again, where does the answer lie? Writers, or re...

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90 than the possibility of a warmer world, even such combinations will never get off the ground. Once again, where does the answer lie? Writers, or readers, of internal reports will recognise that the executive summary has moved from the beginning to the end of the book, becoming a three page Part 4. On other aspects of the book, the references are plentiful and, for a 1983 published book, up-to-date. Some of the model predictions discussed in the book have been revised over the last 3 years, but their method of derivation has remained essentially the same, so the book is still useful nonetheless. If it is customary to pick out a flaw, that of the footnote on page 50 is irritating. The statement that, in the Kelvin scale 1K = I ° C ; 273K = 0 ° C may seem a little strange to some readers. General production and print quality of the book are good. I have little doubt, therefore, in recommending this book as a good summary of the CO 2 'question', by borrowing from another branch of writing and declaring it 'a good read'. G R A H A M F A R M E R (Norwich, Gt. Britain)

Cloud Dynamics. E.M. Agee and T. Asai (Editors). Proceedings of a Symposium held at the Third General Assembly of IAMAP, Hamburg, West Germany, 17-28 August 1981. D. Reidel Publishing Co., Dordrecht, in co-edition with Terra Scientific Publishing Company, Tokyo, 1982, VII + 423 pp., Dfl.ll5.00, US$49.50, hardcover. Since 1984, Cloud Dynamics has a namesake. Cloud Dynamics by L.T. Matveev (340 pp., Dfl.190.00, US$71.00) also published by the D. Reidel Publishing Company, mainly deals with the dynamics and statistics of atmospheric moisture, moisture flux and cloudiness in general, with a certain emphasis on stratiform clouds. Differently, E.M. Agee's and T. Asai's Cloud Dynamics is strongly-though not entirely-restricted to convective clouds and cloud systems. The two superior headings of the book are 'Shallow Convective Systems' (covering 12 papers) and Deep Convective Systems (covering 13 papers), with a sub-partitioning to Observations and Models in each case. Fourteen of the 25 papers were contributed by scientists from U.S.A. institutions, four by scientists from France (France has a strong tradition in cloud physics' research), and the rest by authors from the F.R.G., Japan, South Africa, the Soviet Union, the United Kingdom (2 papers) and Yugoslavia. As told by the title, the volume largely addresses the dynamics of cloud formation and cloud behaviour, i.e., those air motions which are related to the development (and dissipation) of clouds and cloud systems, with clouds

91 essentially meaning convective clouds. Each of the two sections of the volume is introduced by a survey paper of E.M. Agee which both represent real short-courses in 'shallow convective systems' (28 pp.) and 'deep convective systems' (38 pp.), respectively, and were not presented at the symposium. Shallow convection may not be seen at all (in the case of dry convection), otherwise it is manifested by all those clouds and cloud systems that are confined, in the vertical, to the planetary boundary layer (PBL; upper limit at 1-2 km). Logically, deep convection then takes place when cumuli or, in general, cumulonimbi are penetrating a large depth or all of the troposphere. The fascinating phenomena due to shallow convection are certain patterns in which PBL-confined cumuli may arrange such as cloud bands, cloud streets, or convective cells of typical size and geometry (the latter also labelled mesoscale cellular convection--MCC). These cells may be closed (then also called Brnard cells) with upward motion at the cell's centres and downward motion along the common boundaries, or open with the opposite distribution of vertical motions; the notations 'closed' or 'open' are made according to meteorological evidence. In fact, the direct observation of MCC phenomena was not possible until the advent of satellite imagery. All these striking patterns require distinct distributions (especially in the vertical) of wind velocity, temperature (and often humidity) within the PBL as well as appropriate surface properties, and eventually relevant local Changes of those properties. These partly complex interrelationships produce much enticement for numerical modelling of the phenomena mentioned. The topics dealt with in the conference papers on shallow convection are: observational and theoretical treatment of geometrically exciting systems (4 papers); the interaction between cloud dynamics and infrared radiative effects (2 papers); the capability of deriving cloud distributions (both, horizontally and vertically) from satellite infrared radiance data; conditions for the maintenance of precipitation generating cells in stratiform clouds; the theory and role of downdrafts within clouds; the thermodynamics of cloudy air; and the mode (or conditions) of cumulus convection in a conditionally unstable atmosphere. The second part of the book deals with the hailstorm, the thunderstorm, the tornado cyclone as well as relevant aspects of tornados and multiple vortices. In particular, E.M. Agee, in his introductory paper, gives a detailed phenomenology of the thunderstorm which comprises a classification due to origin (three types of air mass and frontal thunderstorms are distinguished); the average number of thunderstorm days, globally, which are compared to hailstorm days (for the U.S.A.); overall tornado statistics; the merits of the post-World-War-II Thunderstorm Project (in providing information about the various stages of the development of air mass thunderstorms; summer-

92 time thunderstorms in Ohio and Florida were investigated); the features of a severe (e.g., tornadic) thunderstorm among which are the highest echo intensity, the forward overhang, the echo free vault, and the wall; as well as the characteristics of a few storm models. Finally, Agee summarizes the knowledge of tornado generation within a severe or supercell thunderstorm where, as a precursive stage, the tornado(s) itself (themselves) is (are) (mostly) preceded by a tornado cyclone--the area of high vorticity concentration. The conference papers on deep convective systems are concerned with such aspects as the high variabilities in space and time, respectively, of draft velocities and precipitation within thunderstorms; the influence of the mesoscale meteorological, and orographic, conditions on thunderstorms (to become, e.g., rain or hail storms) (4 papers); the differential reflectivity radar technique as an observational tool; the applicability of radar echos as means to localize appropriate portions of a thunderstorm for, e.g., silver iodide seeding (to suppress hail formation); the utilization of dual-doppler wind measurements of a tornadic storm as input into a storm model; the applicability of satellite infrared d a t a - - a m o n g data from other sources--to detect tornadic storms; special storm configurations as well as parameterization of subgrid scale turbulent processes. The usefulness of experimental investigations to provide insight into the dynamic structure of atmospheric vortices is 'demonstrated in one paper. Every paper is the copy of the respective author's typescript; so all references immediately follow their paper, and numbering of all figures and tables starts anew with each paper. Typing errors are very rare. Of a total of 197 figures, about 50 show, or are derived from, radar reflectivities. There are about 20 satellite photographs or imageries illustrating the text. In substance a suggestive selection of research items, the volume represents an informative reading for the not-on-the-field meteorologist as well as the oceanographer and forms a useful compilation of otherwise wide-spread papers for the cloud dynamicist. D I E T E R H E N N I N G (Bonn, F.R.G.)

Sea Fog. Wang Binhua (Editor). China Ocean Press, Beijing, 1985. Distributed by Springer Verlag, Berlin, 1985, 330 pp., 199 Figs., DM215.00, hardcover. There appear to be no previous books devoted to the topic of sea fog, and I approached this one with the objective of learning something about the subject. This objective was only partially realized. The book has been