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We use high temporal‐resolution mesoscale imagery from the Geostationary Operational Environmental Satellite‐R (GOES‐R) series to track the Lamb and gravity waves generated by the 15 January 2022 Hunga Tonga‐Hunga Ha'apai eruption. The 1‐min cadence of these limited area (∼1,000×1,000 km2) brightness temperatures ensures an order of magnitude better temporal sampling than full‐disk imagery available at 10‐min or 15‐min cadence. The wave patterns are visualized in brightness temperature image differences, which represent the time derivative of the full waveform with the level of temporal aliasing being determined by the imaging cadence. Consequently, the mesoscale data highlight short‐period variations, while the full‐disk data capture the long‐period wave packet envelope. The full temperature anomaly waveform, however, can be reconstructed reasonably well from the mesoscale waveform derivatives. The reconstructed temperature anomaly waveform essentially traces the surface pressure anomaly waveform. The 1‐min imagery reveals waves with ∼40–80 km wavelengths, which trail the primary Lamb pulse emitted at ∼04:29 UTC. Their estimated propagation speed is ∼315 ± 15 m s−1, resulting in typical periods of 2.1–4.2 min. Weaker Lamb waves were also generated by the last major eruption at ∼08:40–08:45 UTC, which were, however, only identified in the near field but not in the far field. We also noted wind effects such as mean flow advection in the propagation of concentric gravity wave rings and observed gravity waves traveling near their theoretical maximum speed. Plain Language Summary: The record‐setting eruption of the Hunga Tonga‐Hunga Ha'apai volcano on 15 January 2022 was observed by geostationary satellites, which take an image of the full Earth disk every 10–15 min. Several smaller areas (∼1,000 km on a side) are, however, imaged every 1 min. The eruption generated various waves in the atmosphere, including acoustic waves traveling at the speed of sound and slower gravity waves. These atmospheric waves can be tracked by the subtle brightness temperature changes they cause in the images. We show that the 1‐min images used in our study capture finer details of the wave patterns and allow a better estimation of wave properties than the relatively infrequent full disk images. The high temporal frequency imagery also allows to determine the eruption sequence more precisely and reveal how the background winds affect the propagation of the waves. Key Points: Propagation of surface pressure anomalies explains the Lamb waveform derivative patterns seen in brightness temperature image differences1‐min mesoscale imagery depicts the short‐period variations within the long‐period wave packet envelope captured in full disk imageryThe Lamb wave train appears dispersive, main pulse is followed by waves with decreasing wavelength of ∼40–80 km and period of ∼2.1–4.2 min [ABSTRACT FROM AUTHOR]

The strongest volcanic eruption since the 19th century occurred on 15 January 2022 at Hunga Tonga‐Hunga Ha'apai, generating unprecedented atmospheric waves not seen before in observations. We used satellite microwave observations from (a) Advanced Technology Microwave Sounder (ATMS) on board the National Oceanic and Atmospheric Administration (NOAA)‐20 and the Suomi‐National Polar‐orbiting Partnership (SNPP) and (b) Advanced Microwave Sounding Unit (AMSU)‐A on board Meteorological operational satellite (MetOp)‐B/MetOp‐C to study these waves in the stratosphere immediately after the eruption. The NOAA Microwave Integrated Retrieval System (MiRS) was applied to these microwave observations to produce atmospheric temperature profiles. The atmospheric Lamb wave and fast‐traveling gravity waves are clearly revealed in both the brightness temperatures and the MiRS retrieved temperatures, revealing their vertical phase structures. This study is the first attempt to perform a detailed analysis of the stratospheric impact of the Tonga eruption on operational satellite microwave observations and the corresponding MiRS retrievals. Plain Language Summary: The strongest volcanic eruption since the 19th century occurred on 15 January 2022 at Hunga Tonga‐Hunga Ha'apai. The microwave instruments onboard the currently operational satellites observed the area in the vicinity of the eruption. The eruption impacts were most obvious at high altitudes (the stratosphere) in the observed microwave brightness temperatures. Additionally, atmospheric temperature profiles have been retrieved using the satellite measured microwave brightness temperatures. The retrieved atmospheric temperature fields also show the impacts of the volcanic eruption in the stratosphere. This study is the first attempt to perform a detailed analysis of the impact of the Tonga volcanic eruption using operational satellite microwave observations and the corresponding retrievals. Key Points: Microwave observations from multiple satellites capture stratospheric waves from the Tonga eruption, including Lamb and gravity wavesMiRS atmospheric temperature retrievals also resolve wave perturbations in the stratosphere after the eruptionThe Lamb wave and the lead gravity wave show no apparent phase change with height, whereas the trailing gravity waves do [ABSTRACT FROM AUTHOR]

Using a network of global navigation satellite systems receivers in New Zealand, located 2,000–3,300 km southwest of Hunga Tonga‐Hunga Ha'apai volcano, we found at least three different kinds of ionospheric disturbances from changes in total electron contents (TEC). Ionospheric signatures of the near‐field acoustic wave propagating ∼0.8 km/s were not clear in New Zealand due possibly to large geometric decay. The first disturbance emerged ∼1 hr after the eruption and traveled toward southwest with a speed of ∼0.6 km/s. This, together with the subsequent disturbance propagating by ∼0.4 km/s, suggests its link to the ahead‐of‐tsunami ionospheric disturbance, excited by the Lamb wave and subsequent tsunamis traveling in the Pacific Ocean. The second disturbance started ∼2 hr after the eruption as tens of waves with periods 10–15 min propagating by ∼0.3 km/s, possibly internal gravity waves (IGW) excited by the passages of the Lamb wave. Such IGW wave trains continued until ∼10 hr after the eruption. The Lamb wave traveled round the earth, and its second and third passages disturbed the ionosphere in New Zealand on the next day as similar IGW wave trains following the Lamb wave. The third disturbance occurred as an enhancement of the harmonic oscillation of TEC with frequency of ∼3.7 mHz, ∼14 hr after the eruption. This might be an atmospheric mode excited by the eruption, but its propagation and sudden activation remain unexplained. Key Points: Long‐period disturbance emerged in New Zealand ∼1 hr prior to the arrival of the atmospheric Lamb wave, and propagated at ∼0.6 km/s and ∼0.4 km/s toward southwestRepeated passages of the atmospheric Lamb wave caused suites of internal gravity waves, propagating at ∼0.3 km/sAtmospheric mode of ∼3.7 mHz became stronger ∼14 hr after eruption in New Zealand [ABSTRACT FROM AUTHOR]

We simulate the gravity waves (GWs) and traveling ionospheric disturbances (TIDs) created by the Hunga Tonga‐Hunga Ha'apai (hereafter "Tonga") volcanic eruption on 15 January 2022 at ∼04:15 UT. We calculate the primary GWs and forces/heatings generated where they dissipate with MESORAC, the secondary GWs with HIAMCM, and the TIDs with SAMI3. We find that medium and large‐scale TIDs (MSTIDs and LSTIDs) are induced by the secondary GWs, with horizontal phase speeds cH ≃ 100–750 m/s, horizontal wavelengths λH ≃ 600–6,000 km, and ground‐based periods τr ≃ 30 min to 3 hr. The LSTID amplitudes over New Zealand are ≃2–3 TECU, but decrease sharply ≃ 5,000 km from Tonga. The LSTID amplitudes are extremely small over Australia and South Africa because body forces create highly asymmetric GW fields and the GWs propagate perpendicular to the magnetic field there. We analyze the TIDs from SAMI3 and find that a 30 min detrend window eliminates the fastest far‐field LSTIDs. We analyze the GPS/TEC via detrending with 2–3 hr windows, and find that the fastest LSTIDs reach the US and South America at ∼8:30–9:00 UT with cH ≃ 680 m/s, λH ≃ 3,400 km, and τr ≃ 83 min, in good agreement with model results. We find good agreement between modeled and observed TIDs over New Zealand, Australia, Hawaii, Japan and Norway. The observed F‐peak height, hmF2, drops by ≃ 110–140 km over the western US with a 2.8 hr periodicity from 8:00 to 13:00 UT. We show that the Lamb waves (LWs) observed by AIRS with λH = 380 km have amplitudes that are ≃ 2.3% that of the primary GWs at z ≃ 110 km. We conclude that the observed TIDs can be fully explained by secondary GWs rather than by "leaked" LWs. Plain Language Summary: Gravity waves (GWs) are created by various processes, such as volcanic eruptions. A breaking GW imparts momentum and energy to the atmosphere, which creates secondary GWs. Traveling ionospheric disturbances (TIDs) are created by GWs through collisions between neutral and ion molecules. We simulate the GWs and TIDs created by the Tonga eruption on 15 January 2022. We find that medium and large‐scale TIDs (MSTIDs and LSTIDs) are induced by the secondary GWs. These TIDs propagate globally, and have speeds of 100–750 m/s and horizontal scales of hundreds to thousands of km. The fastest TIDs reach the United States and South America at ∼8:30–9:00 UT; these TIDs have large scales and large periods, in agreement with observations. These LSTIDs can only be seen if they are not "detrended out" when processing the ionospheric data. Previous studies eliminated these LSTIDs by restricting their detrend windows, and then incorrectly suggested that Lamb waves were responsible for the TIDs they observed. Using longer detrend windows, we find good agreement between the modeled and observed TIDs. We find that the observed TIDs can be fully explained by secondary GWs, rather than by the leakage of Lamb waves into GWs. Key Points: Globally‐propagating concentric TIDs are induced by secondary GWs from the Tonga eruption with cH = 100−750 m/s and τr = 30 min to 3 hrThe fastest LSTIDs from Tonga in the far field are eliminated when detrending SAMI3 and GPS/TEC data with a 30 min windowThe fastest modeled LSTIDs from Tonga reach the US and South America at 8:30‐9:00 UT with cH = 600 m/s, in good agreement with data [ABSTRACT FROM AUTHOR]

The Hunga Tonga‐Hunga Ha'apai (hereafter HTHH) submarine volcano erupted at 04:14:45 UT on 15 January 2022, causing ionospheric disturbances. This paper uses carrier phase observations from GNSS tracking stations in New Zealand and Australia to calculate the vertical total electron content. At 06:10, the ground‐based GNSS tracking station in New Zealand observes a maximum amplitude of 2.26 TECU anomaly caused by a mesoscale traveling ionospheric disturbance (MSTID) with a wavelength of 200–250 km, a period of 6–13 min, and a maximum propagation velocity of 330 m/s. The anomaly developed with time along the north‐south island direction toward the south island and lasted for about three and a half hours, with the ionosphere returning to pre‐eruption levels after 09:50, indicating a correlation between ionospheric activity and volcanic eruption. An ionospheric anomaly caused by an MSTID was also observed off the east coast of Australia around 08:11, with a maximum amplitude of 3.17 TECU and a maximum propagation velocity of 356 m/s. The ionospheric anomaly in Australia spreads out in a plane. In the process of propagation, it continuously impacts the area it passes through, and the entire anomaly process lasts for more than 7 hr. Still, the anomalous propagation velocities are more significant than in New Zealand, indicating that the Lamb waves excited by the eruption of the HTHH submarine volcano are directional in propagation speed; westward travels faster than southward. This finding will provide more references for scholars to study the mechanism and characteristics of anomaly propagation. Plain Language Summary: This paper reports on the Hunga Tonga‐Hunga Ha'apai submarine volcanic eruption event at Tonga on 15 January 2022, which caused air pressure waves in the form of Lamb waves to propagate to ionospheric heights and caused traveling ionospheric disturbances. Analysis of the filtered total electron content in the ionosphere using dense GNSS tracking stations in Australia and New Zealand revealed large‐scale, intense ionospheric disturbances. The propagation of the anomaly is also directional, with the New Zealand ionospheric anomaly initially propagating from north to south in a ripple pattern with a maximum mesoscale traveling ionospheric disturbance (MSTID) propagation velocity of ∼330 m/s. The impact of Lamb waves on the ionosphere in Australia is more pronounced, with the disturbance unfolding in a faceted pattern from east to west for up to 7 hr, during which the maximum MSTID propagation velocity is ∼356 m/s. In addition, the anomaly is affected by small‐amplitude gravity waves and excites multiple ionospheric disturbance phenomena during its propagation in both locations. This result confirms the natural phenomenon of ionospheric disturbances induced by extreme natural hazards and shows that severe explosive events can have a lasting and far‐reaching impact on the ionosphere. Key Points: Evidence of widespread traveling ionospheric disturbances caused by volcanic eruptionsThe propagation of the anomaly is directional, propagating westward at a greater rate than southwardSmall‐scale gravity waves have caused multiple transient ionospheric disturbances in both New Zealand and Australia [ABSTRACT FROM AUTHOR]

The 2022 volcanic eruption in Tonga caused an unusually large tsunami around the Pacific. It travels with a faster apparent velocity and has larger amplitudes at long distances than what would be expected from a conventional tsunami from the volcanic source. This tsunami was generated by the moving atmospheric Lamb wave and traveled at the speed of the Lamb wave (0.31 km/s). Japanese data showed the amplitude of this first tsunami becomes small when approaching the coast, due to the weaker air‐sea coupling at the shallow depth. This wave split when passing the continental slope, and traveled at the speed of the ocean gravity wave. Therefore, the tsunami observed at the coast is delayed by thousands of seconds from the passage of the Lamb wave. Tsunamis generated by this atmospheric mechanism have not been previously observed by modern digital recording systems and should be considered in the tsunami warning systems. Plain Language Summary: A tsunami is usually generated by the sudden changes of the water heights, and caused by offshore earthquakes, coastal landslides, and submarine volcanic eruptions. The generated vertical displacement of the water propagates as a very long wave, and the tsunami waves become compressed with increased heights as they approach the coast. The 2022 volcanic eruption in Tonga caused an unusually large tsunami, which cannot be explained by conventional sources. The speed and amplitude are very different from theoretical values: the speed is about 0.31 km/s, whereas the average tsunami speed in the Pacific is 0.2 km/s. These data suggest that the tsunami from the Tonga eruption was excited by a pulse of atmospheric pressure as it traveled from the volcano. This source of the tsunami in the atmosphere needs to be considered for the tsunami warning system in the future. Key Points: Lamb wave produced by the volcanic eruption excites the sea surface as it travels across the Pacific and generates a tsunami pulseThe effect of the air‐sea coupling becomes weaker as the Lamb wave approaches the coastThe tsunami wave splits when passing the continental slope of Japan causing more complex waves [ABSTRACT FROM AUTHOR]

This paper investigates the local and global ionospheric responses to the 2022 Tonga volcano eruption, using ground‐based Global Navigation Satellite System total electron content (TEC), Swarm in situ plasma density measurements, the Ionospheric Connection Explorer (ICON) Ion Velocity Meter (IVM) data, and ionosonde measurements. The main results are as follows: (a) A significant local ionospheric hole of more than 10 TECU depletion was observed near the epicenter ∼45 min after the eruption, comprising of several cascading TEC decreases and quasi‐periodic oscillations. Such a deep local plasma hole was also observed by space‐borne in situ measurements, with an estimated horizontal radius of 10–15° and persisted for more than 10 hr in ICON‐IVM ion density profiles until local sunrise. (b) Pronounced post‐volcanic evening equatorial plasma bubbles (EPBs) were continuously observed across the wide Asia‐Oceania area after the arrival of volcano‐induced waves; these caused a Ne decrease of 2–3 orders of magnitude at Swarm/ICON altitude between 450 and 575 km, covered wide longitudinal ranges of more than 140°, and lasted around 12 hr. (c) Various acoustic‐gravity wave modes due to volcano eruption were observed by accurate Beidou geostationary orbit (GEO) TEC, and the huge ionospheric hole was mainly caused by intense shock‐acoustic impulses. TEC rate of change index revealed globally propagating ionospheric disturbances at a prevailing Lamb‐wave mode of ∼315 m/s; the large‐scale EPBs could be seeded by acoustic‐gravity resonance and coupling to less‐damped Lamb waves, under a favorable condition of volcano‐induced enhancement of dusktime plasma upward E×B drift and postsunset rise of the equatorial ionospheric F‐layer. Plain Language Summary: The catastrophic 2022 Tonga volcano eruption triggered giant atmospheric waves that propagated into and strongly impacted Earth's ionosphere. Using ground‐based multi‐Global Navigation Satellite System total electron content (TEC) and ionosonde measurements as well as space‐borne Swarm and Ionospheric Connection Explorer satellites observations, we found large‐scale, intense ionospheric disturbances. The eruption created a large ionospheric hole near the epicenter embedded with cascading TEC drops and periodic oscillations, resulting from various shock‐acoustic wave impulses. Atmospheric Lamb waves propagated globally at a velocity of ∼315 m/s, coupled to ionosphere heights possibly via acoustic‐gravity resonance, and caused global‐scale ionospheric disturbances. We report for the first time that strong nighttime equatorial plasma bubbles were continuously observed over the vast Asia‐Oceania area of more than 140° longitudinal range, lasting around 12 hr following the consecutive arrival of volcano‐induced waves and the dusk terminator. These results demonstrate far‐reaching and long‐lasting atmosphere‐ionosphere impacts from a devastating natural disaster, and highlight new ways in which surface conditions can impact the upper atmosphere. Key Points: Shock‐acoustic impulses created a significant ionospheric hole of 10+ TECU depletion near the epicenter, with an estimated radius of 10–15°Pronounced post‐volcanic equatorial plasma bubbles were continuously developed across the Asia‐Oceania area covering ∼140° longitudesStrong plasma bubbles were likely triggered by gravity wave resonance with Lamb waves and volcano‐increased PRE/PSSR of equatorial F‐layer [ABSTRACT FROM AUTHOR]