Large-area tsunami signatures in ionosphere observed by GPS TEC after the 2011 Tohoku earthquake
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The internal gravity waves (IGWs) produced by a tsunami can travel into the ionosphere and trigger traveling ionospheric disturbances (TIDs). In this study, we report ionospheric measurements related to the huge transpacific tsunami induced by the 2011 Tohoku earthquake. The total electron content (TEC) extracted from far-field GPS network in the US is employed to detect the TIDs induced by the tsunami. We observed the large-area tsunami-driven TIDs in TEC, which have similar propagation characteristics regarding waveform, arrival time, period, horizontal velocity and direction compared to the tsunami measurements at sea-level. Furthermore, the large-area tsunami-driven TIDs are observed in the ionosphere over not only the ocean but also land, illustrating effectively that the IGWs propagate into the ionosphere along the slant direction. In addition, the raypaths of GPS satellites along the propagation direction of IGWs can observe more significant signatures. These observed results provide a more comprehensive propagation characteristic for tsunami-driven TIDs, which can help to better know the tsunami-ionosphere coupling process.
KeywordsTsunami Internal gravity waves Traveling ionospheric disturbances GPS Total electron content
The GPS data used in this study are provided by the UNAVCO (http://www.unavco.org/). The DART data are provided by the National Data Buoy Center (NDBC) of US National Oceanic and Atmospheric Administration (NOAA) (http://www.ndbc.noaa.gov/). This study was supported by National Natural Science Foundation of China (Grant no. 41504013) and Natural Science Foundation of Guangdong Province (Grant no. 2017A030310242).
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