An Introduction to the Meteorology and Climate of the Tropics

What do we mean by the tropics? The weather and the climates it produces across the tropical zone are significantly different from those experienced by the people living in higher latitudes, so forecasters across Europe and much of North America are unfamiliar with its effects. In this book, Jim Galvin demystifies the topic in this zone that is increasingly of interest to those studying weather and climate.   This book was written for weather forecasters, meteorology, environmental science and geography students as an introductory guide. It builds on the experience of the author, his professional experience in the World Area Forecast Centre at the Met Office, Exeter, using studies into the weather and climate seen within the tropical air mass conducted over many years. Its unique approach presents a practical approach to tropical weather studies, drawing on both academic and practical knowledge, covering air mass dynamics, seasonal changes, moist and dry weather, climate variability and human health in chapters and appendices that build up the overall picture, summarising our current state of knowledge.    As an overview, it covers the broad range of effects connected with climate and weather in a straightforward way and is clearly illustrated throughout. 

About the author

Preface

Acknowledgements

Chapter 1. Setting the scene

1.1 Introduction

1.2 What do we mean by the tropics?

1.3 The geography of the tropics

1.4 The tropical troposphere

1.5 Climate and population in the tropics

1.6 Question

Chapter 2. The energy balance and the dynamics of weather in the tropics

2.1 The tropical ′heat engine′

2.2 Absorption, reflection and apparent solar elevation

2.3 Emission from the surface

2.4 The radiation balance and the tropical zone

2.5 The dynamics of weather systems in the tropics

2.6 Questions

Chapter 3. Winds, temperature and weather in the tropical zone

3.1 Winds

3.2 Temperature

3.3 The weather patterns and climates of the tropics

3.4 Clouds and fog in the tropics

3.5 Questions

Chapter 4. The subtropical jet streams

4.1 The formation of jet streams at the margins of the tropics

4.2 Weather associated with the subtropical jet streams

4.3 Folds and bifurcations in the flow

4.4 Clear–air turbulence

4.5 Questions

Chapter 5. Synoptic–scale weather systems

5.1 Introduction

5.2 Convection in the tropics

5.3 The inter–tropical convergence zone

5.4 The depth of convective clouds

5.5 Layer clouds and shallow convection

5.6 The effects of heavy rainfall in the tropics

5.7 Atmospheric teleconnections

5.8 Questions

Chapter 6. Climate, flora and fauna

6.1 The relationship of climate to plants and animals

6.2 Tropical rainforest

6.3 Seasonal tropical forest

6.4 The savannas

6.5 Tropical deserts and scrublands

6.6 Mountain climates

6.7 Tropical oceans and coasts

6.8 Climatic variability

6.9 Questions

Chapter 7. Dry environments

7.1 Background

7.2 Wind and weather in the deserts

7.3 Fog and low cloud

7.4 Severe weather in the dry tropics

7.5 The effects of desert weather

7.6 Settlement and the over–use of scarce water supplies

7.7 Questions

Chapter 8. Monsoons

8.1 Introduction

8.2 The summer monsoon over southern Asia

8.3 The summer monsoon over East Asia

8.4 Variations of rainfall in the Asian summer monsoon

8.5 The Asian winter monsoon

8.6 The West African summer monsoon

8.7 The West African winter monsoon

8.8 Rainfall and the monsoons in East Africa

8.9 The South American–Caribbean monsoons

8.10 The Australian summer monsoon

8.11 Variable broad–scale factors affecting the monsoons

8.12 Questions

Chapter 9. Tropical revolving storms

9.1 Broad–scale convection and the development of tropical storms

9.2 Tropical storm development and decline

9.3 The effects of tropical revolving storms

9.4 Storm tracks in the Pacific Ocean

9.5 The formation and tracks of hurricanes in the North Atlantic–Caribbean

9.6 Tropical cyclones in the Indian Ocean

9.7 Tropical revolving storms in the south–west Pacific

9.8 Variability in the development of tropical storms

9.9 Extra–tropical transition

9.10 Conclusion

9.11 Questions

Chapter 10. Mesoscale weather systems

10.1 Introduction

10.2 Mesoscale convective complexes

10.3 Sea– and land–breeze convergence zones

10.4 Easterly waves and squall lines

10.5 Mesoscale convective systems in northern India

10.6 Depressions in north–west India, north Pakistan and Afghanistan

10.7 Cross–equatorial flows

10.8 Mesoscale convective systems in the Gulf of Guinea

10.9 Local convection

10.10 Extra–tropical interaction with moist tropical air masses

10.11 Conclusion

10.12 Questions

Chapter 11. Forecasting clouds and weather

11.1 Background

11.2 Distribution of significant cloud

11.3 The effect of high ground as an elevated heat source

11.4 Tropical upper–tropospheric troughs

11.5 Effects of severe convection on aviation

11.6 Questions

Chapter 12. The variability of weather and climate change in the tropics

12.1 Introduction

12.2 El Niño–la niña

12.3 The Madden–Julian Oscillation

12.4 The quasi–biennial oscillation

12.5 A discussion of anthropogenic climate change 

12.6 How is climate likely to change in the tropical zone?

12.7 Modelling climate change

12.8 Conclusions

12.9 Questions

Chapter 13. Tropical agriculture

13.1 Agricultural productivity and tropical environments

13.2 Agriculture in the humid tropics and the effects of forest clearance

13.3 Agriculture in the savannas

13.4 Dry–land agriculture

13.5 Weather and locust swarms

13.6 The effects of agriculture in the tropics

13.7 Agriculture and climate change

13.8 Question

Chapter 14. The importance of the tropical ozone layer

14.1 Background

14.2 The role of the tropics in replenishing extra–tropical stratospheric ozone

14.3 The effect of global warming on stratospheric ozone destruction in the tropics

14.4 The effects of exposure to short–wave radiation

14.5 The current state of the stratospheric ozone layer

14.6 Question

Chapter 15. Remote sensing of tropical weather

15.1 Background

15.2 Satellite remote sensing

15.3 Precipitation

15.4 Wind profilers

15.5 Thunderstorm observation

15.6 Monitoring surface cover and volcanic eruptions

15.7 Question

Chapter 16. Tropical weather and health

16.1 Introduction

16.2 The effects of tropical sunshine and warmth

16.3 Lifted dust and its effects on health

16.4 Industrial and smoke pollution

16.5 Parasitic and infectious diseases

16.6 Response of the meteorological community

16.7 Questions

Chapter 17. Conclusions and a look into the future

17.1 A summary

17.2 Forecasting the weather

17.3 Questions

Appendix 1. Observations from the tropics

Appendix 2. Named winds of the tropics

Appendix 3. An introduction to cloud types, cloud species and precipitation

A3.1 Introduction

A3.2 The high clouds

A3.3 The medium–level clouds

A3.4 The low clouds

A3.5 Cloud species and varieties

Appendix 4. An introduction to meteorological diagrams, stability, instability and aviation weather charts

A4.1 Temperature–pressure graphs

A4.2 Stability and instability

A4.3 Aviation significant weather charts

Appendix 5. Snow in the desert

A5.1 Introduction

A5.2 Development of a depression over the desert

A5.3 The weather features associated with the upper low

A5.4 Summary

Appendix 6. A climatic summary for tropical countries and states

Appendix 7. Two easterly waves in West Africa in summer 2009 a case study

A7.1 Introduction

A7.2 The wave of 28 August to 5 September 2009

A7.3 The wave of 2–11 September 2009 and the development of Hurricane Fred

A7.4 A model for the development of squall lines in the Sahel

A7.5 Conclusion

References

Glossary

Index

Jim Galvin has had a long interest in tropical meteorology. He is a Senior Operational Meteorologist in the Met Office World Area Forecast Centre in Exeter, UK and also produces the Shipping Forecast. In 2014, he became Editor of the RMetS journal Weather. He enjoys photography and singing in a choir.