High Resolution Altimetry Reveals New Characteristics of the December 2004 Indian Ocean Tsunami

Type Article
Date 2006-09
Language English
Author(s) Ablain Michaël1, Dorandeu Joël1, Le Traon Pierre-Yves2, Sladen Anthony3
Affiliation(s) 1 : Collecte Localisat Satellites, Space Oceanog Div, F-31526 Ramonville St Agne, France.
2 : IFREMER, Ctr Brest, F-29280 Plouzane, France.
3 : CEA, DASE, LDG, RSG, F-91680 Bruyeres Le Chatel, France.
Source Geophysical Research Letters ( GRL ) (0094-8276) (American Geophysical Union), 2006-09 , Vol. 33 , N. 21 , P. NIL_58-NIL_63
DOI 10.1029/2006GL027533
WOS© Times Cited 28
Keyword(s) Wave analysis, Tsunamis, Earthquakes, Sea level changes, Satellite altimetry
Abstract The Indian Ocean tsunami, which occurred on December 26, 2004, was the first to be clearly observed using satellite altimeters. The wave amplitude observed in deep-ocean by TOPEX and Jason-1 was close to 60 cm about 2 hours after the earthquake. Envisat crossed the tsunami wave 3h15 after the earthquake and measured a 35 cm wave. Even though it flew over the tsunami 7h20 after the earthquake, GFO still observed a wave close to 20 cm. To better extract the tsunami signal from altimeter measurements, a specific ocean variability mapping technique is used. This technique proves to be mandatory for discriminating tsunami waves from other ocean signals. Altimeter signals are then compared with those derived from the CEA (Commissariat à l'Energie Atomique) model outputs. For the first time with altimeter data, peculiar short wavelengths signals along Jason-1 and Envisat profiles have been detected from the analysis of 20-Hz altimeter measurements. Such high wavenumber signals can be explained by the dispersive propagation of tsunami waves. These observations highlight the essential role of satellite altimeter measurements to better understand and to improve models of tsunami wave propagation and dissipation.
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