Book contents
- Frontmatter
- Contents
- Contributors
- Editors' preface
- Keynote address to the 1977 Symposium SIR JAMES LIGHTHILL
- Part I The large-scale climatology of the tropical atmosphere
- Part II The summer monsoon over the Indian subcontinent and East Africa
- 12 The monsoon as reflected in the behaviour of the tropical high-pressure belt
- 13 On the onset of the Indian southwest monsoon and the monsoon general circulation
- 14 Medium-range forecasting of monsoon rains
- 15 Sea-surface temperature and the monsoon
- 16 The effect of elevation on monsoon rainfall distribution in the central Himalayas
- 17 Use of the equation of continuity of water vapour for computation of average precipitation over peninsular India during the summer monsoon
- 18 Determination of cloud cluster properties from MONSOON-77 data
- 19 Analysis of superpressure balloon trajectories and conventional observations over the Indian Ocean during different phases of the 1975 southwest monsoon
- 20 An experiment in monitoring cross-equatorial airflow at low level over Kenya and rainfall of western India during the northern summers
- 21 Structure of the Somali Jet deduced from aerial observations taken during June–July, 1977
- 22 Certain aspects of monsoonal precipitation dynamics over Lake Victoria
- 23 A numerical model of the monsoon trough
- 24 On the monsoonal midtropospheric cyclogenesis over western India
- 25 Downstream development of baroclinic waves in the uppertropospheric monsoon easterlies suggested by a simple model experiment
- 26 The stability of the monsoon zonal flow with a superposed stationary monsoon wave
- 27 Growth of monsoon disturbances over western India
- 28 Topographic Rossby waves in the summer monsoon
- Part III The physics and dynamics of the Indian Ocean during the summer monsoon
- Part IV Some important mathematical modelling techniques
- Part V Storm surges and flood forecasting
- Index
20 - An experiment in monitoring cross-equatorial airflow at low level over Kenya and rainfall of western India during the northern summers
Published online by Cambridge University Press: 05 November 2011
- Frontmatter
- Contents
- Contributors
- Editors' preface
- Keynote address to the 1977 Symposium SIR JAMES LIGHTHILL
- Part I The large-scale climatology of the tropical atmosphere
- Part II The summer monsoon over the Indian subcontinent and East Africa
- 12 The monsoon as reflected in the behaviour of the tropical high-pressure belt
- 13 On the onset of the Indian southwest monsoon and the monsoon general circulation
- 14 Medium-range forecasting of monsoon rains
- 15 Sea-surface temperature and the monsoon
- 16 The effect of elevation on monsoon rainfall distribution in the central Himalayas
- 17 Use of the equation of continuity of water vapour for computation of average precipitation over peninsular India during the summer monsoon
- 18 Determination of cloud cluster properties from MONSOON-77 data
- 19 Analysis of superpressure balloon trajectories and conventional observations over the Indian Ocean during different phases of the 1975 southwest monsoon
- 20 An experiment in monitoring cross-equatorial airflow at low level over Kenya and rainfall of western India during the northern summers
- 21 Structure of the Somali Jet deduced from aerial observations taken during June–July, 1977
- 22 Certain aspects of monsoonal precipitation dynamics over Lake Victoria
- 23 A numerical model of the monsoon trough
- 24 On the monsoonal midtropospheric cyclogenesis over western India
- 25 Downstream development of baroclinic waves in the uppertropospheric monsoon easterlies suggested by a simple model experiment
- 26 The stability of the monsoon zonal flow with a superposed stationary monsoon wave
- 27 Growth of monsoon disturbances over western India
- 28 Topographic Rossby waves in the summer monsoon
- Part III The physics and dynamics of the Indian Ocean during the summer monsoon
- Part IV Some important mathematical modelling techniques
- Part V Storm surges and flood forecasting
- Index
Summary
The identification of the core of the major low-level air current of the northern summer monsoon at a topographically locked position over eastern Africa has led to experiments in monitoring the airflow and relating its pulsations to the rainfall of parts of western India.
Using five-day overlapping means, it is found that pulsations in the airflow across eastern Africa near the Equator are reflected in the rainfall of western Maharashtra Province, sometimes with a lag of a few days.
The mean airflow in July has also been compared with the mean July rainfall of western Maharashtra Province and, when two-year overlapping means are used, a pronounced lag of one year is evident. It is demonstrated that this lag might be usefully exploited in experimental work towards the development of long-range rainfall forecasting techniques.
Introduction
A special feature of the low-level airflow over eastern Africa and the western Indian Ocean during the northern summer is that it is organized into a relatively narrow high-speed transequatorial current in the western periphery of the monsoon regime. The flow is strongest where the current is blocked or guided by high ground, and is weakest in the vicinity of the oceanic Equator. The current is characterized by a system of daily low-level jet streams, sufficiently persistent to show up markedly in monthly-averaged wind data.
The characteristics of the major current and the daily low-level jet streams have been described in detail by Findlater (1966, 1967, 1969a, b, 1970, 1971a, b, 1972, 1974, 1977b), but the general form of the current at the 1 km level in July can be seen in Fig. 20.1.
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- Monsoon Dynamics , pp. 309 - 320Publisher: Cambridge University PressPrint publication year: 1981
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