Tropical atmosphere and ocean are receiving increased attention in relation to the functioning of the global climate system, the remarkable climatic variability in low latitudes, and the associated manifold environmental and societal consequences. Beyond the traditional emphasis of meteor­ ology on weather analysis and forecasting, there is a growing interest in the climate and large­ scale circulation of the tropics. This book may serve as a text for graduate and upper-division undergraduate students in meteorology, and is also intended as a reference work for practicing meteorologists, and researchers in the atmospheric, oceanic, and other environmental sciences. I began writing this book in 1979, but the roots reach further back. Early experiences in North Africa fuelled my curiosity about the low latitudes. In 1960 I seized the opportunity to work in the National Meteorological Service of El Salvador in Central America. My interest in the tropics continued after joining the University of Wisconsin in 1963. Field research brought me to the equatorial Pacific, and many times to the tropical Americas and Africa. This involved visits and correspondence with many weather services. My acquaintance with Australasia and South Asia is limited to short study visits, but includes continuous contacts with colleagues at key research institutions in India, namely the India Meteorological Department, the Indian Institute of Tropical Meteorology, and Andhra University. A guest semester at the University of the Witwatersrand in 1971 and related travels provided a perspective on the problems of Southern Africa.

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1. Introduction.- References.- 2. Diurnal Forcings and Local Circulations.- 2.1. Insolation and Heat Budget Forcing.- 2.2. Atmospheric Tides.- 2.3. Circulations on the Local and Meso-Scale.- 2.4. Diurnal Marches of Sea-Air Exchange, Cloudiness, and Precipitation.- 2.5. Synthesis.- References.- 3. Planetary Scale Atmospheric Circulation.- 3.1. Mean Meridional Distribution of Temperature and Humidity.- 3.2. Zonal Wind Regime.- 3.3. Mean Meridional Circulation.- 3.4. Maintenance of the Global Circulation: Angular Momentum.- 3.5. Maintenance of the Global Circulation: Kinetic Energy.- 3.6. Synthesis.- References.- 4. Ocean Circulation.- 4.1. Wind Stress and Motion Field in the Upper Ocean.- 4.2. The Subtropical Gyres.- 4.3. Equatorial Current Systems.- 4.3.1. Overview of Surface Circulation.- 4.3.2. Balance of Forces.- 4.3.3. The North Equatorial Countercurrent.- 4.3.4. Wind Stress, Vertical Motion, Thermocline and Surface Topography.- 4.3.5. The Equatorial Undercurrent.- 4.3.6. Equatorial Waves and Remote Forcing.- 4.3.7. Recent Discoveries of Subsurface Currents.- 4.4. The Monsoon Ocean.- 4.5. Deep Circulation.- 4.6. Synthesis.- References.- 5. Heat and Water Budgets.- 5.1. Basic Theory.- 5.2. Net Radiation at the Top of the Atmosphere.- 5.3. Oceanic Heat Budget.- 5.4. Atmospheric Heat Budget.- 5.5. Water Budget.- 5.6. Relative Roles of Oceanic Versus Atmospheric Heat Transports.- 5.7. Synthesis.- References.- 6. Regional Circulation Sytems.- 6.1. Overview of the Global Tropics.- 6.2. Jet Streams.- 6.2.1. Basic Dynamics.- 6.2.2. Subtropical Westerly Jet.- 6.2.3. Tropical Easterly Jet.- 6.2.4. West African Mid-Tropospheric Jet.- 6.2.5. East African Low Level Jet.- 6.3. Subtropical Highs.- 6.4. Trades.- 6.5. Trade Inversion.- 6.5.1. Spatial Patterns.- 6.5.2. Origin and Maintenance.- 6.5.3. Climatic Implications.- 6.6. Mid-Tropospheric Inversions.- 6.7. Equatorial Trough Zone.- 6.7.1. The Large-Scale Setting.- 6.7.2. Structure of the Intertropical Convergence Zone.- 6.7.2.1. Atlantic and Pacific Oceans.- 6.7.2.2. Indian Ocean.- 6.7.2.3. Africa.- 6.7.2.4. On Atmospheric and Oceanic Controls.- 6.7.3. Dynamics of Cross-Equatorial Flow.- 6.7.4. Equatorial Dry Zone.- 6.8. Monsoons.- 6.8.1. Definition and Global Perspective.- 6.8.2. Africa.- 6.8.3. Indian Ocean Sector.- 6.8.4. On the Heat and Moisture Budget of the Indian Monsoons.- 6.8.5. Numerical Modelling of the Indian Summer Monsoon.- 6.9. Zonal Circulations.- 6.10. Upper-Tropospheric Anticyclones.- 6.11. Wind Regimes of the Equatorial Stratosphere.- 6.12. Synthesis.- References.- 7. Climatology of Weather Systems.- 7.1. Clouds and Convection.- 7.2. Tropical Storms.- 7.3. Waves in the Easterlies.- 7.4. Squall Lines.- 7.5. Dust Storms of the Sudan.- 7.6. Monsoon Depressions.- 7.7. Subtropical Cyclones.- 7.8. Temporales of Pacific Central America.- 7.9. Cold Surges.- 7.10. Interannual Variability.- 7.11. Synthesis.- References.- 8. Interannual Variability of the Atmosphere-Ocean System.- 8.1. Surface Patterns of the Southern Oscillation.- 8.2. El Niño.- 8.3. Rainfall Anomalies in Indonesia.- 8.4. Upper-Air Patterns of ENSO.- 8.5. Vagaries of the Indian Monsoon.- 8.6. The Sêcas of Northeast Brazil.- 8.7. Rainfall Variations in the Central American - Caribbean Region.- 8.8. Drought and Flood Regimes in Subsaharan Africa.- 8.9. Climate Anomalies at the Angola Coast.- 8.10. Hydrometeorological Anomalies in the Zaïre (Congo) Basin.- 8.11. Time Scales of Climate Variability.- 8.12. Synthesis.- References.- 9. Climate Prediction.- 9.1. Indian Monsoon.- 9.2. Indonesia Rainfall.- 9.3. El Niño.- 9.4. The Droughts of Northeast Brazil.- 9.5. Subsaharan Drought.- 9.6. Southern Africa.- 9.7. Kenya Rainfall.- 9.8. North Atlantic Hurricanes.- 9.9. Hong Kong Climate.- 9.10. Synthesis and Outlook.- References.- 10. The Human Impact.- 10.1. Deforestation.- 10.2. Land Use and Surface Albedo.- 10.3. Effects of Dust on Climate.- 10.4. Intentional Climate Modification.- 10.5. Ocean Climate and Fisheries.- 10.6. India.- 10.7. Northeast Brazil.- 10.8. Subsaharan Africa.- 10.9. The Use of Climate Prediction.- 10.10. Synthesis.- References.- 11. Tropical Glaciers and Climate.- 11.1. Spatial Patterns.- 11.2. History of Glacier Variations.- 11.3. Climatic Forcing and Terminus Response.- 11.4. Ice Cores.- 11.5. Synthesis.- References.- 12. Past Climates of the Tropics.- 12.1. Causes of Climate Variations.- 12.2. Vegetation.- 12.3. Lakes.- 12.4. Glaciers.- 12.5. Deep-Sea Cores.- 12.6. Pacific and Australasia.- 12.7. The Indian Ocean and Surrounding Continents.- 12.8. Africa and the Adjacent Tropical Atlantic.- 12.9. Americas.- 12.10. Numerical Modelling.- 12.11. Synthesis.- References.- Author Index.