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Record Details

Record 7 of 18544
Evidence of Boundary Reflection of Kelvin and First-Mode Rossby Waves from Topex/Poseidon Sea Level Data
External Online Source: doi:10.1029/96JC01282
Author and Affiliation:
Boulanger, Jean-Philippe(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA United States)
Fu, Lee-Lueng(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA United States)
Abstract: The TOPEX/POSEIDON sea level data lead to new opportunities to investigate some theoretical mechanisms suggested to be involved in the El Nino-Southern Oscillation phenomenon in the tropical Pacific ocean. In particular, we are interested in studying the western boundary reflection, a process crucial for the delayed action oscillator theory, by using the TOPEX/POSEIDON data from November 1992 to May 1995. We first projected the sea level data onto Kelvin and first-mode Ross waves. Then we estimated the contribution of wind forcing to these waves by using a single baroclinic mode simple wave model forced by the ERS-1 wind data. Wave propagation was clearly observed with amplitudes well explained by the wind forcing in the ocean interior. Evidence of wave reflection was detected at both the western and eastern boundaries of the tropical Pacific ocean. At the eastern boundary, Kelvin waves were seen to reflect as first-mode Rossby waves during the entire period. The reflection efficiency (in terms of wave amplitude) of the South American coasts was estimated to be 80% of that of an infinite meridional wall. At the western boundary, reflection was observed in April-August 1993, in January-June 1994, and, later, in December 1994 to February 1995. Although the general roles of these reflection events in the variability observed in the equatorial Pacific ocean are not clear, the data suggest that the reflections in January-June 1994 have played a role in the onset of the warm conditions observed in late 1994 to early 1995. Indeed, during the January-June 1994 period, as strong downwelling first-mode Rossby waves reflected into downwelling Kelvin waves, easterly wind and cold sea surface temperature anomalies located near the date line weakened and eventually reversed in June-July 1994. The presence of the warm anomalies near the date line then favored convection and westerly wind anomalies that triggered strong downwelling Kelvin waves propagating throughout the basin simultaneously with the beginning of the 1994-1995 warm conditions.
Publication Date: Jul 15, 1996
Document ID:
19990076696
(Acquired Oct 08, 1999)
Subject Category: GEOPHYSICS
Report/Patent Number: Paper-96JC01282
Document Type: Reprint
Publication Information: Journal of Geophysical Research (ISSN 0148-0227); Volume 101; No. C7; 16,361-16,371
Publisher Information: American Geophysical Union, United Kingdom
Financial Sponsor: Jet Propulsion Lab., California Inst. of Tech.; Pasadena, CA United States
Organization Source: Jet Propulsion Lab., California Inst. of Tech.; Pasadena, CA United States
Description: In English; Original contains color illustrations
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: BAROCLINIC WAVES; EL NINO; KELVIN WAVES; PACIFIC OCEAN; PLANETARY WAVES; SEA LEVEL; SEA SURFACE TEMPERATURE; SOUTHERN OSCILLATION; WIND EFFECTS; ATMOSPHERIC CIRCULATION; ANOMALIES; POSEIDON SATELLITE; TOPEX; TROPICAL REGIONS
Availability Source: Other Sources
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