Jason 1 detects the 26 December 2004 tsunami

Satellite altimeters have detected mid‐ocean tsunami waves only once in the past, with relatively small amplitude [ Okal et al ., 1999], according to published reports. The 26 December 2004 tsunami changes this picture dramatically. This event was the strongest to have occurred since satellite altimetry started in the 1970s. Instruments now in orbit can measure sea surface height with sufficient resolution (a few centimeters for the average of a 5‐km circle of ocean), but measure only along their tracks, and cannot provide a full picture of an event. Also, they are unlikely to be optimally placed for early detection near the source earthquake. By chance, however, Jason 1 was in the right place at the right time.