Extracting the 2004 Indian Ocean tsunami signals from sea surface height data observed by satellite altimetry

摘要

Altimeter-equipped satellites flew over the propagating area of the Indian Ocean tsunami caused by the 2004 Sumatra-Andaman earthquake on 26 December 2004. Tsunami signals can be detected as differences in sea level changes of multiple tracks. However, observed changes in sea level differences involve not only tsunami signals but also effects from various ocean phenomena and errors due to observation technology and data processing. A multisatellite time-spatial interpolation method is performed to define reference sea surface heights. After applying the method to the products on sea level anomalies along tracks of altimeter-equipped satellites, quality tsunami-height profiles with only 4- to 5-cm root mean square errors were obtained for the Indian Ocean tsunami along five tracks from four satellites (Jason-1, TOPEX/POSEIDON, ENVISAT, and Geosat Follow-On). Maximum tsunami height in the open ocean for the 2004 Indian Ocean tsunami as observed from satellite altimetry was 1.1 m trough-to-crest 115 min after the main shock. Reliable tsunami-height profiles from satellite altimetry were extracted for the first time. The method employed in this study has the potential to extract tsunami signals of 0.1 m or greater trough-to-crest height from satellite altimetry observation data on the deep sea by ongoing satellite missions.