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
26 - The stability of the monsoon zonal flow with a superposed stationary monsoon wave
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
Using a two-level quasi-geostrophic model, the effect of the inclusion of a long stationary monsoon wave (basic meridional wind) on the combined barotropicbaroclinic instability of the monsoon current has been investigated. Both barotropic and baroclinic interactions of the perturbation with the monsoon wave and the zonal flow are included. This analysis, using realistic velocity profiles, yields fast-growing westward-moving upper-tropospheric waves corresponding to easterly waves, and lower-tropospheric modes corresponding to monsoon disturbances.
Introduction
The stability of the monsoon zonal flow has been studied by Shukla (1977) and Keshavamurty et al. (1977). They found that the monsoon atmosphere is not baroclinically unstable. Shukla found that the CISK mechanism can lead to a growth of disturbances of the same scale as the observed monsoon disturbances, but that there was no preferred scale with a fastest rate of growth. Keshavamurty et al. found that the monsoon zonal flow is barotropically unstable in the lower and midtroposphere and that this instability can yield disturbances of reasonable growth rate and scale. Mak (1975) studied the effect of the meridonal motion on baroclinic instability of a monsoon flow, but found that the meridonal components required for growth were very large compared to those obtained from observed winds. Lorenz (1972) studied the barotropic instability of Rossby waves and found that shorter waves can be barotropically unstable. The observed monsoon flow is seen to have an appreciable meridional component.
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- Monsoon Dynamics , pp. 403 - 414Publisher: Cambridge University PressPrint publication year: 1981
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