The role of the Indian Ocean in the global climate system : the propagation of Indian Ocean Kelvin waves in the Indonesian Seas and their influence on western Pacific sea level variability
The role of the Indian Ocean in the global climate system : the propagation of Indian Ocean Kelvin waves in the Indonesian Seas and their influence on western Pacific sea level variability
Linking the Pacific Ocean to the Indian oceans, the Indonesian archipelago is the only tropical inter-ocean passage. Moreover, the Indo-Pacific region is where El Niño-Southern Oscillation (ENSO) takes birth. Generally, studies do not take into account Indian Ocean oceanic signals which may contribute to the generation of ENSO. These are essentially Indian Ocean Kelvin waves (KW) which have been observed to propagate into the Indonesian Seas.
The present study focuses on the propagation of KW through the Indonesian Seas and into the Pacific. A simple numerical layer-model was used to study the propagation of a Indian Ocean KW through the Indonesian archipelago, with an ocean at rest. Results show that part of the incoming energy propagates into the Pacific Ocean as an equatorial Kelvin wave. The amount of energy found in the Pacific depends on the initial wave frequency and on the friction coefficient used in the model. Typical values show that 5% of the intraseasonal KW will propagation into the western Pacific as an equatorial KW.
This result remains valid when the KW is generated during the annual cycle. To demonstrate this, the model was spun-up with climatology winds. A westerly wind burst was superimposed on the wind forcing at different times of the year. Results show that the annual cycle has little influence on the propagation of the KW. Thus it may be concluded that Indian Ocean KW does contribute to sea level variability in the western Pacific. The effect of such perturbations on local air-sea interactions remains to be investigated.
University of Southampton
Le Blanc, Jean-Luc
fc6da570-5bf9-4f99-8ea2-8f58a57f18a7
2003
Le Blanc, Jean-Luc
fc6da570-5bf9-4f99-8ea2-8f58a57f18a7
Le Blanc, Jean-Luc
(2003)
The role of the Indian Ocean in the global climate system : the propagation of Indian Ocean Kelvin waves in the Indonesian Seas and their influence on western Pacific sea level variability.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Linking the Pacific Ocean to the Indian oceans, the Indonesian archipelago is the only tropical inter-ocean passage. Moreover, the Indo-Pacific region is where El Niño-Southern Oscillation (ENSO) takes birth. Generally, studies do not take into account Indian Ocean oceanic signals which may contribute to the generation of ENSO. These are essentially Indian Ocean Kelvin waves (KW) which have been observed to propagate into the Indonesian Seas.
The present study focuses on the propagation of KW through the Indonesian Seas and into the Pacific. A simple numerical layer-model was used to study the propagation of a Indian Ocean KW through the Indonesian archipelago, with an ocean at rest. Results show that part of the incoming energy propagates into the Pacific Ocean as an equatorial Kelvin wave. The amount of energy found in the Pacific depends on the initial wave frequency and on the friction coefficient used in the model. Typical values show that 5% of the intraseasonal KW will propagation into the western Pacific as an equatorial KW.
This result remains valid when the KW is generated during the annual cycle. To demonstrate this, the model was spun-up with climatology winds. A westerly wind burst was superimposed on the wind forcing at different times of the year. Results show that the annual cycle has little influence on the propagation of the KW. Thus it may be concluded that Indian Ocean KW does contribute to sea level variability in the western Pacific. The effect of such perturbations on local air-sea interactions remains to be investigated.
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Published date: 2003
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Local EPrints ID: 465260
URI: http://eprints.soton.ac.uk/id/eprint/465260
PURE UUID: a8d38b17-db81-4ac6-8154-ba60d6658880
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Date deposited: 05 Jul 2022 00:32
Last modified: 23 Jul 2022 01:13
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Author:
Jean-Luc Le Blanc
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