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Part III - The physics and dynamics of the Indian Ocean during the summer monsoon
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- By Sir James Lighthill, University College London
- James Lighthill, R. P. Pearce
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- Book:
- Monsoon Dynamics
- Published online:
- 05 November 2011
- Print publication:
- 19 March 1981, pp 443-444
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Summary
Introduction
The Indian Ocean is of especial significance to oceanographers because of its unique feature of currents that switch direction on an annual cycle. This feature makes the Indian Ocean a natural ‘laboratory’ where oceanographers can seek to test their understanding of the dynamics of how ocean currents respond to changing wind patterns. In addition, Parts I and II of this book have suggested how the oceanography of the Indian Ocean may be of crucial importance to meteorologists. Charney and Shukla, in Chapter 6 of this book, indicated the potential ‘predictability’ of monsoon meteorology given a prediction of boundary values, including, especially, sea-surface temperatures. In this context, they emphasized that timescales of oceanic responses are all relatively slower than their atmospheric counterparts, so that longer-term forecasting of ocean boundary values (for use as the input to atmospheric models) might ultimately be attainable.
They are certainly right about timescales of response. Indeed, it has long been known for a midlatitude ocean that the timescale associated with the accumulation of the baroclinic part of its response to wind stress (including its western boundary current) may be as much as a decade (Veronis and Stommel, 1956). On the other hand, for a low-latitude system such as the Indian Ocean, the response is by no means as slow as that, and almost a decade ago Lighthill (1969) suggested that the corresponding timescale would be about a month rather than a decade.
Part V - Storm surges and flood forecasting
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- By Sir James Lighthill, University College London
- James Lighthill, R. P. Pearce
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- Book:
- Monsoon Dynamics
- Published online:
- 05 November 2011
- Print publication:
- 19 March 1981, pp 657-658
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Summary
The final part of this book is devoted to the last part of the cycle of important fluid-dynamical processes which constitutes monsoon dynamics. The analysis of these concluding processes gains interest primarily from the hope that it can lead to practical methods for producing adequate and reliable advance warning of flooding dangers.
First, we have two chapters by leading experts on the prediction of marine flooding associated with storm surges. The numerical modelling involved allows for the combined input from atmospheric processes and astronomical tide-raising forces, together with a comprehensive treatment of depth-distribution effects and boundary conditions. These chapters describe both the successful present use of these techniques in connection with flood prediction for the British Isles, and their potential for application in the Bay of Bengal to forecast flooding surges resulting from monsoon wind stresses acting upon the shallow water at the mouth of the Ganges delta.
Although in these chapters the storm-surge experts concentrate on flooding dangers associated with monsoons, they were, of course, consulted during their stay in Delhi on the implications of the tragic events of the month (November, 1977) immediately preceding the Symposium upon which this book is based. Flooding of great severity was produced by a tropical cyclone in the state of Tamil Nadu. This was followed, within a few days, by a still more devastating, and indeed unprecedented, degree of flooding in Andhra Pradesh caused by another cyclone.
The Presidential Address
- from PART II - THE INVITED PAPERS
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- By Sir James Lighthill, Department of Applied Mathematics and Theoretical Physics, Silver Street, Cambridge
- Edited by A. G. Howson
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- Book:
- Developments in Mathematical Education
- Published online:
- 07 September 2011
- Print publication:
- 23 August 1973, pp 88-100
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Summary
Introduction
It has given me profound pleasure to be able to welcome such a very large and such a very distinguished audience to this opening session of the Second International Congress on Mathematical Education. Although records of discussion about mathematical education go back at least 2500 years, to the days of Plato's Academy, it seems that the twentieth century brought a new tempo and urgency to such discussions, while we have during the past decade seen a great and growing ferment of activity in the field all over the world. Prominent in discussion of the subject throughout this twentieth century has been our International Commission, founded in 1899 by H. Fehr and C. A. Laisant, while this past decade of intensified and increasing recognition of the importance of mathematical education and of the new approaches and opportunities within it, coincides with the first decade of existence, as a fully-fledged Commission within the International Mathematical Union, of the International Commission on Mathematical Instruction, ICMI.
Up to 1960, the energetic study of mathematical teaching methods and curricula within individual countries was supplemented and strengthened by the holding of meetings arranged by our Commission, by its review journal L'Enseignement Mathématique, and by international discussion every four years in the educational section of the International Congress of Mathematicians. Those useful discussions were, nevertheless, rather limited in scope and in the number of interested persons involved.