Book Review: Space Weather: Physics and Effects

At 438 pages, Space Weather: Physics and Effects seems like a daunting read. But its thickness belies its conversational tone, and its content provides a different presentation of material aimed at drawing in a new audience while satisfying the present space weather audience's interest in their subject. I found reading this book a pleasure. The editors’ ambition was “a state-of-the-art compendium of the importance and understanding of research in space weather.” They accomplish this while still keeping the introduction of concepts broad enough for people new to space physics, placing much of the emphasis on forecasting and the impact of space weather on human-made systems. Further, the authors of different chapters generally produced an excellent qualitative overview of their material. The book depends on good figures and descriptive text to deliver its message. It is well supported by a comprehensive contents list (down to the third order of subsections) and lists of figures, tables, and acronyms, plus a useful index at the back of the book. Each paper has a bibliography, sometimes extensive, and many papers published in 2005 are referenced with a few 2006 papers mentioned. Figures, of which there are many, are well drawn with a reasonably uniform style. They illustrate ideas well, and there is a color supplement at the center of the book. These features will appeal not only to the new reader, but also to people well versed in space weather topics. Further, while the price is possibly at the upper end of the current price range for space weather books, it is not seriously expensive by modern book standards. After a comprehensive first chapter, which maps the text ahead, the second chapter compares the current state of space weather forecasting with meteorological forecasts, drawing on parallels in the development of meteorology to help recognize the current state and potential future for space weather forecasting. Next, the Sun and solar wind properties (chapter 3) are extensively summarized. Several aspects of the solar output are revisited differently in later chapters without creating any feeling of redundancy. Rather, it helps keep the scope of the material in perspective. Chapter 4 provides a good overview of magnetospheric processes leading to geomagnetic storms and substorms. Magnetospheric coupling problems are hard for a novice to appreciate, and this account should help people respect the problems if not feel a greater understanding of them. The development of storm and substorm understanding is an interesting minisurvey within the main body of the chapter that is typical of similar features found elsewhere in the book. Chapter 5 is a good description of the solar system particle environment. This forms a useful bridge between the solar wind and the space environment, and its theme is revisited with different detail in later chapters. Some of the concepts about the radiation belts and ring current, developed in the previous two chapters, are revisited in chapter 6 in greater, though still qualitative detail. These challenges are embedded within a useful historical background that includes the development of theories of ring current dynamics. The ionosphere (chapter 7) is that part of the space weather environment with which humans have arguably the longest association—the earliest observations of aurorae began in prehistory. This chapter is a reminder of the many complex processes taking place in the ionosphere, especially the high-latitude ionosphere, as it forms the interface between the top of our atmosphere and the start of space, where interactions with the plasma universe commence. The Sun is inescapably our most important energy source, and it is only reasonable to expect that small changes in the solar output will be reflected in changes in our terrestrial environment. Though scientists have made great strides in understanding the space environment, the proposed relationships between the Sun and meteorology remain contentious. Chapter 8 reviews solar effects in the middle atmosphere, where clear solar effects are evident, and a section in chapter 11 reviews the possible effects of cosmic rays on cloud formation. Chapter 9 provides a wide-ranging review of space weather impacts from solar-induced currents on communications through telegraph wires (first experienced in 1847), to the possible threat due to solar radio emissions on a range of terrestrial systems. The massive solar bursts in December 2006 are a clear reminder of this last effect. Chapter 10 reviews space weather impacts on power grids. The failure of the Quebec power grid in March 1989 is possibly the best recognized example of how expensive a significant space weather storm can be. This event is placed in perspective here, together with a useful introduction to space weather currents in long conductors. This is not just a high-latitude problem. In northern Australia, the normal quiet-day currents can exceed safety margins on occasion, showing that the science community still has a lot to learn about making systems robust to even normal space weather effects. The wide-ranging impact of energetic particles on human existence from the astronaut in space to all of life on the surface of our planet is the area of space weather that probably captures the public interest more than any other. The biological effects of the radiation belts and major solar events are all covered in chapter 11, providing good summaries of the risks to astronauts in near and outer space and the associated mitigation procedures. Next is an especially useful review of particle effects on spacecraft as well as a reminder about how space weather can influence the behavior of particle sources. Chapter 12 draws together a number of effects already discussed, indicating how they will affect the design and operation of spacecraft. The authors list several space programs that provide routine space environment observations, and raise the threat of data continuity for valuable space-forecasting resources such as the Advanced Composition Explorer (ACE), a scientific satellite that currently has no follow-on program. Additionally, this chapter contains a good summary of space weather Internet resources. Global Navigation Satellite Systems (GNSS) services are vulnerable to space weather effects. Ionospheric variations are the major source of problems; in chapter 13, methods to minimize the effect of these variations on navigation are summarized. Finally, chapter 14 discusses forecasting within the perspective of information-based and physics-based models, providing an overview of several space weather forecasting models and highlighting the style of work being carried out in this area. What's missing? Very little, in my opinion. If I had to single out one topic I would have liked to see treated in greater detail, I would choose the important topic of forecast verification, including metrics of what we can do now, what we are aiming for, and maybe what it is essential that we attain to maintain the usefulness of space weather forecasts. In summary, the editors' aim for this book was, in their words, “an invaluable resource for space weather students, teachers and researchers.” They can feel confident they have achieved this aim. Phil Wilkinson is deputy director of IPS Radio and Space Services, the Australian government's space weather agency.