CubeSat GPS Observation of Traveling Ionospheric Disturbances After the 2022 Hunga-Tonga Hunga-Ha'apai Volcanic Eruption and Its Potential Use for Tsunami Warning

Multiple passages of the atmospheric (Lamb) waves were recorded globally after the Hunga Tonga-Hunga Ha'apai (HTHH) volcanic eruption on 15 January 2022. The waves perturbed the ionosphere and produced traveling ionospheric disturbances (TIDs) that were observed from the ground network of Global Positioning System (GPS) receivers. This study presents new observations of TIDs at higher altitudes (>550 km) from CubeSat GPS tracking data. The satellite sampling along many CubeSat orbits enable to map broader spatio-temporal patterns of the TID propagation compared to ground receivers. Due to the larger spatial coverage over a shorter period of time, the CubeSat measurements provide complementary information to stationary ground receivers. We found that the amplitude of the HTHH-induced ionospheric perturbations at high altitudes (>550 km) are as large as 10 TECU (1 TECU = 10(16) electrons/m(2)) in slant total electron content between CubeSats and GPS satellites. The TIDs traveled along with the Lamb waves and were recorded by CubeSats above India 12 hr after the eruption and at the antipode of the eruption 16 hr after. These suggest that the ionospheric disturbances reached to the high altitudes and traveled globally as a speed of similar to 350 m/s. The TIDs were also detected by CubeSats above the Australian continent several hours before the (conventional) tsunami made landfall on the Australian coasts. We discuss a new opportunity to study the upper ionosphere and its coupling with the solid Earth and to develop advanced monitoring systems of geohazards by the advent of low-cost small satellite technology.