First Detection of the Pekeris Internal Global Atmospheric Resonance: Evidence from the 2022 Tonga Eruption and from Global Reanalysis Data

Abstract

We used observations and model simulation to examine the atmospheric pulses that dominate the far field in the hours after the January 2022 Tonga eruption. We analyzed radiance observations taken from the Himawari-8 geostationary satellite and showed that both a Lamb wave front with the expected horizontal phase speed ∼315 m-s−1 and a distinct front with phase speed ∼245 m-s−1 can be detected. The slower phase speed is consistent with that expected for the global internal resonant mode that had been proposed by Pekeris in 1937 and in other idealized theoretical studies over the past century, but which had never been detected in the atmosphere. A simulation of the eruption aftermath was performed with a high resolution atmospheric general circulation model. A hot anomaly over the volcano location was introduced instantaneously to the model fields and the model was integrated for another 12 hours. This produced a simulated wave pulse that, in the far field, agreed reasonably well with barograph observations of the Lamb wave. The model results also showed the presence of the slower pulse and that this disturbance had a vertical structure with a 180° phase shift in the stratosphere, in agreement with the theoretical prediction for the internal resonant mode. An implication is that the continuously ringing Lamb wave global normal modes that have been seen in analyses of long observational records ought to have lower frequency internal Pekeris mode counterparts, a prediction that we confirm though analysis of 67 years of hourly global reanalysis data.

Tsunami Triggered by the Lamb Wave From the 2022 Tonga Volcanic Eruption and Transition in the Offshore Japan Region

“…Watanabe et al. (2022) explained the negative pulse in Figure 2b as one of the acoustic gravity wave modes. The air‐sea coupling between the acoustic gravity wave and ocean gravity wave is similar to the mechanism of Proudman resonance (matching of the speeds of ocean gravity water wave and atmospheric wave) (Hibiya & Kajiura, 1982; S̆epić et al., 2015).…”

“…A classical tsunami source, such as sea‐floor crustal deformations and mass movements, can also generate tsunamis traveling at the same speed (Lynett, 2022). A slower atmospheric wave, such as an acoustic gravity wave, also contributes to the amplification of tsunamis, as its velocity is closer to the average speed of a tsunami (Carvajal et al., 2022; Kubota et al., 2022; Watanabe et al., 2022; Wright et al., 2022). Watanabe et al.…”

“…Rapid analysis revealed that the tsunami was generated by the atmospheric pressure wave from the volcanic eruption (Kubota et al., 2022; Kulichkov et al., 2022; Lynett, 2022; Matoza et al., 2022; Watanabe et al., 2022). Two major atmospheric waves are involved; the atmospheric Lamb wave, a non‐dispersive atmospheric wave traveling along the earth's surface horizontally at the speed of 0.31 km/s (Lamb, 1881; Nishida et al., 2014; Press & Harkrider, 1962), and some modes of the acoustic gravity waves traveling at the speed 0.2–0.22 km/s (Harkrider & Press, 1967; Kubota et al., 2022; Press & Harkrider, 1966).…”

Multiwave Structure of Traveling Ionospheric Disturbances Excited by the Tonga Volcanic Eruptions Observed by a Dense GNSS Network in China

“…Using the radiance observation from Himawari‐8 geostationary satellite, Watanabe et al. (2022) observed a Lamb wavefront with the horizontal phase speed ∼315 m/s and a subsequent front with phase speed ∼245 m/s in the atmosphere during the eruption event. The velocities of both waves basically coincide with the observation results of the first and third TIDs in our study.…”

The 2022 Tonga Volcanic Tsunami: Lessons from a Global Event

“…Behind the (surface-trapped) Lamb waves, there were atmospheric gravity waves traveling at 200-220 ms -1 , about the speed of long waves in the deep ocean. Recent work has confirmed the presence of a slower horizontal phase speed internal Perkeris wave (Perkeris, 1937;1939) which has provided a resolution of long-standing issues about atmospheric resonance (Watanabe et al, 2022). In the ocean, a wave of depression caused by mass conservation drove the oceanic tsunami in the Pacific Ocean (Kubota et al, 2022).…”