Book Review: Earth Observations From Space

Bulletin of the American Meteorological Society

EARTH OBSERVATIONS FROM SPACE: THE FIRST 50 YEARS OF SCIENTIFIC ACHIEVEMENTS National Research Council, 2008, 144 pp., $34.75, paperbound, National Academies Press, ISBN 978-0-309-11095-2

The old adage, "a picture is worth a thousand words," is what best befits the value of the book, Earth Observations from Space: The First 50 Years of Scientific Achievements, a compilation published by the U.S. National Research Council (NRC) sum- marizing the value of Earth observations from the unique vantage point of space. For students of meteorology, it is sometimes easy to get lost in the governing equations that drive the physics of weather and global-change phenomena, but the images provided in this treatise help bring about an understanding that otherwise would not be appreciated.

The main objective of this book is to document how satellite observations uniquely contributed to the scientific understand- ing of the atmosphere, ocean, land, biosphere, and cryosphere. From a weather perspective, the book highlights how the satellite observations have im- proved weather forecasts and provided unique in- sight into tropical cyclone formation that could not otherwise have been obtained because of the lack of observations over the vast regions of the tropi- cal oceans. From a global-change perspective, the book is useful for informing the reader on how the radiation budget of the Earth has been accurately obtained globally from satellite observations so that scientists can now measure both the true global impact of increasing carbon dioxide concentra- tions and how the impact of chlorofluorocarbons has fed into the development of the ozone hole over Antarctica. The visualization of the disap- pearance of vast amounts of ice over both poles on time scales of weeks to decades provides stunning evidence that something is happening in response to global warming and that such evidence could not otherwise have been observed so clearly if satellites were not orbiting the planet to track geophysical events in even the most remote regions far away from civilization.

The book is also useful for bringing the reader up to date on the key issues that are in the forefront of global change. It is divided into nine sections: weather; the earth radiation budget; atmospheric composition; hydrology; cryosphere; ocean dynamics; ecosystems and the carbon cycle; land use and land-cover change; and solid Earth. Within each chapter, a brief history of spaceborne observations for that field is presented, and the relevant issues facing the current researchers in that field are summarized. From this perspective, the book would be useful as a supplemen- tal undergraduate text from which one or two lectures could be developed. Supplementing the impressive visual images in the book, a disk is provided that shows time-lapse depictions of satellite observations that truly bring home how the Earth has changed in response to forcing brought about by both natural phenomena (such as hurricanes) and anthropogenic developments (such as the ozone hole). Some of these videos are accompanied with text and music and can be used as stand-alone examples of geophysical phenomena. As a research scientist specializing in only one specific area of the book, I found the text to be extremely useful for bringing me up to date on many of the key issues facing scientists in other disciplines of Earth science.

There is, however, another reason for which this book was produced. It is a companion to a more comprehensive study conducted by the NRC, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, often referred to as the "Decadal Survey." Thus, whereas the Decadal Survey focused on what observations must be carried out over the next 10-20 years to ensure continuity in the existing observational capability of the planet, the purpose of Earth Observations from Space is to impress upon its readers - in particular, the decision makers who are reading this book- that progress in the Earth sciences would have been significantly di- minished over the past several decades if a robust sat- ellite program had not been in existence. The first two chapters present an excellent historical perspective of Earth observations, and the authors provide insight- ful biographies of some of the key people responsible for generating the robust program during the latter half of the twentieth century. It is fascinating to learn more about these satellite pioneers, such as James Van Allen and Verner Suomi. From the perspective of the challenges (both technological and political) faced by these monumental figures, this NRC panel interjects the difficult scenario that now faces the cur- rent community to keep this satellite program as alive and well as it has been in the past. "The complexity of today's bureaucratic and budgetary practices has created a time delay problem. . . . The ideas gener- ated by [satellite visionaries] were well supported and well funded with comparative ease. . . . This no longer seems to be the case." The theme presented in the Decadal Survey- that an actual "satellite gap" is likely to occur unless the funding situation is turned around in the very near future - comes through loud and clear in this book.

In some aspects of remote sensing, it is clear to this reviewer that the U.S. Earth observations already taken a back seat to our colleagues in Europe. As an atmospheric chemist, I would have to point out that the book neglected to talk about I consider the most important space observations of the past decade: the conclusive evidence from satellite observations that pollution has increased dramatically since the 1990s over eastern China (as discussed in Richter et al. 2005 and Fishman et al. 2008). In the chapter on atmospheric composition, the important documentation of the development of the ozone hole using Total Ozone Mapping Spectrometer (TOMS) ozone measurements and the finding of the existence of chlorine monoxide from the Microwave Limb Sounder (MLS) as the culprit responsible for generating huge amounts of stratospheric ozone loss are well documented. Both of these pioneering instruwere on U.S. satellites launched in the 1970s and 1990s, respectively (subsequent versions of these instruments have also been launched on more recent U.S. platforms). On the other hand, the finding of the trend of pollution emissions over China has been derived from observations from European instruments on satellites that were first launched in 1995 and continue to operate today. Thus, I cannot claim to be astute by discovering a key fact that I found to be missing; rather, I have to acknowledge the sad fact that non-U.S. satellites are now providing the observations that best quantify some key aspects of global change, at least with respect to the observations focusing on atmospheric composition.

This book concludes with the ominous statement that "this nation's commitment to Earth satellite missions must be renewed to realize the potential of this fertile area of science." I could not agree more with this statement.

With respect to the value of the book and its contents (exclusive of the message it is trying to get to key decision makers), I would strongly recommend it as one that many people should add to their libraries. The images, by themselves, provide a wealth of interesting talking points to the extent that the book could be worth its value as strictly a coffee-table book. For the interested layperson, the book is valuable as a primer in many basic aspects of Earth science. For the college educator, the book provides examples of global change that could be used as supplemental material for a wide range of lectures relating to global change issues. In addition, the compact disk that is included with this book contains image files that can be useful in a number of ways.

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