Climates and Weather Explained: an Introduction

This book is intended to be useful, interesting and easily understood by means of four features -

1. It deals primarily with general principles, applicable anywhere in the world. They are explained in a straightforward text with 264 drawings and 63 tables, suitable for a beginner in this field of study. This is supplemented by 171 separate notes, 31 more drawings and 16 tables, containing material for the more advanced student, all on a disk supplied with the hardback version of the book. The disk also includes recommendations of further reading, essay questions, numerical exercises for the student, suggestions for teachers of the subject, descriptions of simple experiments, and a full list of the literature used in writing the book. Students who have the softback version can easily obtain a copy of the disk from a teacher who has a hardback book.
2. We have tried to integrate meteorology and climatology to an extent that is unusual for a textbook, though increasingly common in practice.
3. The book contains numerous cases of the relevance of weather and climate to ordinary life. These include agriculture, droughts, housing, human comfort and newly important subjects like skin cancer, climate change, and the effects of temperature on mortality.
4. The examples are taken from the southern hemisphere, to complement other text-books, which almost all concentrate on the northern half of the world. The south has no equal to the huge Eurasian and North American landmasses. On the other hand, the greater area of ocean in the south leads to more evaporation and less variable temperatures, and the huge southern Pacific Ocean is the scene of El Niño episodes. Also, synoptic weather patterns are smaller and more mobile, and there is less air pollution on the whole than in the northern hemisphere. The Antarctic continent is more extensive and elevated than the Arctic, so the South Pole is far colder, which indirectly explains why the ozone over the Antarctic vanishes each spring. Related to this are the powerful winds blowing from west to east across the southern oceans. Another difference concerns the motions of oceans and winds; they circulate in the opposite direction in the southern hemisphere. This applies to circulations in entire ocean basins, as well as to fronts, tropical cyclones, sea breezes, even thunderstorms. In brief, southern hemisphere weather and climate are quite distinct, though few textbooks deal with this.

The arrangement of the book is as follows. In the first Part we discuss the atmosphere’s origin, composition and structure (Chapter 1). In the second is a consideration of the energy flows in the atmosphere, from the Sun (Chapter 2), to the air and ground (Chapter 3), and that used in evaporation (Chapter 4). Finally, Chapter 5 deals with the inter-relationships between these and other flows of energy.

Part 3 deals with the movement of water after it has evaporated, chiefly from the oceans. Evaporation (ie vapour formation) creates atmospheric humidity (Chapter 6), and temperature patterns in the air control the ascent of water vapour through the atmosphere (Chapter 7). As a result, clouds form (Chapter 8). Thereafter, various processes can occur within the clouds, notably the making of rain (Chapter 9). Then Chapter 10 outlines features of the precipitation. Much of it eventually flows back to the oceans, discussed in Chapter 11. Subsequently, there is evaporation again from the oceans, starting the next cycle of water through the atmosphere.

The fourth Part of the book is concerned with the winds that govern our weather. The Sun’s heating of the Earth’s equatorial regions, especially, induces patterns of winds on a global scale (Chapter 12). Within those vast movements are smaller regional-scale circulations, discussed in Chapter 13. Then there are local winds (Chapter 14) on a yet smaller scale. Winds at various scales combine with radiation (Part 2) and water (Part 3) to determine the weather. This and the resulting climates are considered in Part 5, i.e. in Chapters 15 & 16, to draw everything together. At every stage there is an emphasis on the interaction between the surface and the atmosphere.

Unfortunately, the apparent logic of this or any other order of topics is contrived, imposed on a subject of enormous complexity. In fact, items in Part 5 do not depend exclusively on those in Part 4, nor those in turn on Part 3, for instance. On the contrary, some matters discussed in Part 1, for example, depend on what is considered in later chapters, because the atmosphere is a single entity, each of whose individual aspects affects all the rest. Indeed, it is one of our aims to help the reader to appreciate the complexity of the inter-relationships. This is done by means of considerable cross-referencing.