The review below appeared in EOS (Transactions of the American Geophysical Union), Volume 81, Number 16, April 18, 2000.

**Reviewer:**

Jim Coakley, College of Oceanic and Atmospheric Sciences

Oregon State University, Corvallis USA

**Radiative Transfer in the Atmosphere and
Ocean**

Gary E. Thomas and Knut Stamnes

*Cambridge University Press, New York,
NY,*

xxvi + 517 pp., ISBN 0-521-40124-0, 1999, $85.

The Earth’s climate reflects the balance between the sunlight absorbed by the Earth-atmosphere system and the infrared radiation that the Earth emits to space. Change the composition of the atmosphere and the deposition of absorbed sunlight and the emission of infrared radiation by the atmosphere and surface are altered, upsetting existing balances, forcing temperatures to respond and the climate to change.

Understanding
the transfer of radiation in the atmosphere is the key to anticipating the
changes. In addition, with the
recent launch of *Terra*, the first
flagship of NASA’s Earth Observing System, observations of reflected
sunlight and emitted infrared and microwave radiation are being used
increasingly to probe atmospheric and surface processes as well as to monitor
the various components and thermodynamic states of the climate system. There is clearly a need for textbooks
that introduce newcomers to radiative transfer, given its central role in
climate and remote sensing. The
landmark references by S. Chandrasekhar [1950] and R.M. Goody [1964] served as
introductions to radiative transfer for many of today’s practitioners,
but they were not meant to be textbooks and have proven unwieldy when pressed
into that role. This new book
should fulfill this need.

In 12 chapters, and 5 appendices, with additional appendices to be made available on a Web site, the book provides a lucid and reasonably complete, practical treatment of the fundamentals of plane-parallel radiative transfer theory in the atmosphere and the ocean and the exchange of radiant energy between the atmosphere and ocean. The book is easy to read, and there are many examples to illustrate the concepts discussed in the text. Each chapter is followed by thoughtful problems. The focus is on heating and energy exchange; applications in remote sensing are not discussed. The book is remarkably free of errors, and the few errors that I managed to uncover were of little consequence.

Chapter 8 is the book’s cornerstone. It provides a thorough highly readable account of the discrete ordinate method for solving the equation of radiative transfer. This method was pioneered by Chandrasekhar but honed to a precision tool in the form of the readily available DISORT radiative transfer code by Stamnes and his coworkers. The chapter covers the many facets of the discrete ordinate method that have appeared in numbers, sometimes hard to obtain, journal publications during the past 2 decades. Students will find helpful the analytical treatment of the two-stream approximation, which chapter 7 probes in great detail. The two-stream approximation is the low-order form of the general, multistream discrete ordinate method, and it is employed to illustrate the procedures used to solve the multistream problem. The book only briefly touches on other approaches, such as the adding-doubling and Monte Carlo methods.

Another
noteworthy feature is the book’s treatment of the interaction of
radiation with matter. Chapter 3
is devoted to scattering, chapter 4 to absorption. These chapters are not meant to provide the background one
gains through reading other books on these subjects but, instead, rely on
simple models, such as the harmonic oscillator and the rigid rotor molecule, to
introduce concepts such as the scattering phase function, spectral line shape,
and line spacing. For those who
have backgrounds in electricity and magnetism and atomic and molecular spectra,
these chapters offer delightfully thoughtful reviews. Ultimately, when it comes to the treatment of scattering
within molecular absorption bands, students will again appreciate the
analytical derivation of *k*-distributions
for single, pressure-broadened, absorption lines as illustrations of the
general approach to approximating the transfer of broadband radiation with a
series of monochromatic calculations.

The
book should serve well as an introduction to radiative transfer. My only reservation is that for
applications, chapter 12 investigates the Earth’s energy budget by
modeling the atmosphere as window gray, sometimes in radiative equilibrium and
sometimes in radiative-convective equilibrium. True, the model, which relies on the two-stream
approximation, is analytic and when properly tuned also produces longwave
fluxes and albedos that seem realistic when compared with those at the top of
the Earth’s atmosphere.
However, the Earth’s atmosphere is definitely not gray, and one
wonders whether the agreement with observations simply reflects the limited
range of possible outcomes rather than a measure of success in describing the
major physical processes.
Numerical calculations for the Earth’s atmosphere in radiative
equilibrium put the stratospheric temperature (without ozone, as in the
window-gray model) at 160 K, not 214 K, as obtained by the window-gray model,
and is close to the average temperature of the lower stratosphere [*Manabe
and Strickler, 1964*]. In chapter 12, as in chapter 7 on the
two-stream approximation, the presentation appears to get caught up in the
simplicity and analytical aspects of the approximations.

For a finale, I would have preferred seeing comparisons of calculated and observed radiation fields that would have illustrated the successes and failures of the theoretical methods that had been presented. Unfortunately, few such comparisons have been undertaken in the literature and most of the comparisons have focused on problems related to remote sensing. With the advent of the Earth Observing System, observations will abound. Still, it may take years to sort through the best of observations and align them with the most suitable calculations to provide a fitting final chapter for a book such as this.

** **

Chandrasekhar, S., *Radiative Transfer*, Clarendon Press, Oxford, 1950, reprinted by Dover
Publications, New York, 393 pp., 1960.

Goody, R. M., *Atmospheric Radiation,
Theoretical Basis,* (second edition by R. M.

Goody and Y. Yung), Oxford University Press, 436 pp., 1964, 519 pp., 1989.

Manabe, S., and R. F. Strickler, *Thermal equilibrium in
the Atmosphere with a convective adjustment*,
J. Atmos., Sci., pp. 361-385, 1964.