In the course of a decade's work on the mountains of East Africa, I met some of the most wonderful people on Earth. It is impossible to record all those who have helped me in this study in one way or other. Glacier research in East Africa has some history. Nearly half a century ago, Carl Troll completed the first detailed mapping of Lewis Glacier. I had the good fortune of exchanging ideas with him at his home in Bonn in 1974, shortly before his death. Paul C. Spink, Ulceby, North lincolnshire, England, shared with me his photographs and observations on Kilimanjaro and Mount Kenya in the 1940s. When I joined the University of Nairobi in 1973, several members of the 1957-58 IGY Mc)Unt Kenya :Expedition were still there. I received generous advice and help from Igor Loupekine, John Loxton, but especially from Robert A. Caukwell and Frank Charnley. Their continuous coopera- tion was a great encouragement over the years. Heinz Loeffler, University of Vienna, informed me about the depth of Lewis Tarn. Helmut Heuberger, University of Munich, provided me data on his measurements of glacier terminus positions. Peter Gollmer of Geosurveys and Alan Root, Nairobi, gave me aerial photographs of Kibo f~om the early 1970s. I acknowledge support from various other colleagues at the University of Nairobi: Raouf Rostom of the Department of Surveying and Photogrammetry; Neville Skinner of the Department of Physics; G. C. Asnani, John Ng'anga, J. K.

The first edition of my book "Climate and Circulation of the Tropics" was reasonably up to date to the middle of 1985. In a second printing in 1988 it was possible to complete a few literature references and to correct some misprints. However, vigorous research has taken place over the past five years in various areas of tropical climate dynamics, especially in the atmosphere-ocean mechanisms of climate anomalies, climate prediction, ocean circulation, and paleoclimates. Promising progress has also been made in the application of general circulation modelling to tropical climate problems. In the present second edition, named "Climate Dynamics of the Tropics," I have attempted to incorporate much of the recent work to late 1990. Chapters 8 and 9 have been essentially re-written, and major additions have been made to Chapters 4 and 12 in particular. I would like to acknowledge the continued support by the U.S. National Science Foundation over the past five years. B. Parthasarathy, Poona, and H. Lessmann, San Salvador, sent me updates of data series not easily accessible. I have benefitted from discussions with numerous colleagues in the United States and overseas. In the preparation of this second edition, Marilyn Wolff patiently transferred my illegible hand-written drafts onto word processor. Dierk Polzin and Dan Skemp assisted me with the creation of the page masters and the subject index and Christopher Collimore with the author index.

In the course of a decade's work on the mountains of East Africa, I met some of the most wonderful people on Earth. It is impossible to record all those who have helped me in this study in one way or other. Glacier research in East Africa has some history. Nearly half a century ago, Carl Troll completed the first detailed mapping of Lewis Glacier. I had the good fortune of exchanging ideas with him at his home in Bonn in 1974, shortly before his death. Paul C. Spink, Ulceby, North lincolnshire, England, shared with me his photographs and observations on Kilimanjaro and Mount Kenya in the 1940s. When I joined the University of Nairobi in 1973, several members of the 1957-58 IGY Mc)Unt Kenya :Expedition were still there. I received generous advice and help from Igor Loupekine, John Loxton, but especially from Robert A. Caukwell and Frank Charnley. Their continuous coopera- tion was a great encouragement over the years. Heinz Loeffler, University of Vienna, informed me about the depth of Lewis Tarn. Helmut Heuberger, University of Munich, provided me data on his measurements of glacier terminus positions. Peter Gollmer of Geosurveys and Alan Root, Nairobi, gave me aerial photographs of Kibo f~om the early 1970s. I acknowledge support from various other colleagues at the University of Nairobi: Raouf Rostom of the Department of Surveying and Photogrammetry; Neville Skinner of the Department of Physics; G. C. Asnani, John Ng'anga, J. K.

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."

The first edition of my book "Climate and Circulation of the Tropics" was reasonably up to date to the middle of 1985. In a second printing in 1988 it was possible to complete a few literature references and to correct some misprints. However, vigorous research has taken place over the past five years in various areas of tropical climate dynamics, especially in the atmosphere-ocean mechanisms of climate anomalies, climate prediction, ocean circulation, and paleoclimates. Promising progress has also been made in the application of general circulation modelling to tropical climate problems. In the present second edition, named "Climate Dynamics of the Tropics," I have attempted to incorporate much of the recent work to late 1990. Chapters 8 and 9 have been essentially re-written, and major additions have been made to Chapters 4 and 12 in particular. I would like to acknowledge the continued support by the U.S. National Science Foundation over the past five years. B. Parthasarathy, Poona, and H. Lessmann, San Salvador, sent me updates of data series not easily accessible. I have benefitted from discussions with numerous colleagues in the United States and overseas. In the preparation of this second edition, Marilyn Wolff patiently transferred my illegible hand-written drafts onto word processor. Dierk Polzin and Dan Skemp assisted me with the creation of the page masters and the subject index and Christopher Collimore with the author index.