Abstract
Characteristic features of infrasound waves observed in the Antarctic reveal physical interaction involving surface environments around the continent and Southern Ocean. In December 2015, an infrasound array (100 m spacing) by three sensors (Chaparral Physics Model 25, with a detectable frequency range of 0.1-200 Hz), together with a broadband barometer (Digiquartz Nano-Resolution Model 6000-16B Barometer, with a detectable frequency range of 0-22 Hz) were installed at Jang Bogo Staion, Terra Nova Bay, Antarctica by the Korea Arctic and Antarctic Research Program (KAARP). The initial data recorded by the broadband barometer contain characteristic signals originated by surrounding environment, including local noises such as katabatic winds. Clear oceanic signals (microbaroms) are continuously recorded as the background noises with predominant frequency around 0.2 s at the austral summer on December. Variations in their frequency context and amplitude strength in Power Spectral Density had been affected by an evolution of sea-ice surrounding the Terra Nova Bay. Microbaroms measurement is a useful tool for characterizing ocean wave climate, complementing other oceanographic, cryospheric and geophysical data in the Antarctic. Continuous infrasound observations in Terra Nova Bay attain a new proxy for monitoring environmental changes such as the global warming, involving cryosphere dynamics, as well as the volcanic eruptions in Northern Victoria Land, Antarctica.
Highlights
Infrasound is a pressure wave with a frequency range from cut-off frequency of sound (3.21 mHz, for a 15°C isothermal atmosphere) to the lowest limit of human audible band (20 Hz) [Hedlin et al 2002]
The Station is located in Terra Nova Bay, Northern Victoria Land on the eastern flank of the Ross Sea rift, part of the West Antarctic rift system, one of several large tectonic provinces of the Earth formed by Cretaceous to Cenozoic extension (Figure 2)
Characteristic features of infrasound waves were observed in Terra Nova Bay, Northern Victoria Land, Antarctica by using the data from a broadband barometer deployed at Jang Bogo Station in mid-December 2015
Summary
Infrasound is a pressure wave with a frequency range from cut-off frequency of sound (3.21 mHz, for a 15°C isothermal atmosphere) to the lowest limit of human audible band (20 Hz) [Hedlin et al 2002]. At the Sumatra-Andaman earthquake of 26 December 2004, in addition to the great ‘tsunami waves’ induced infrasound waves were observed as disturbances in upper atmosphere [Iyemori et al 2005]. Another remarkable example is the 2011 Tohoku-Oki, Japan earthquake (Mw = 9.0) which produced unequivocal infrasound signals associated with the large tsunami [Arai et al 2011]. The Station is located in Terra Nova Bay, Northern Victoria Land on the eastern flank of the Ross Sea rift, part of the West Antarctic rift system, one of several large tectonic provinces of the Earth formed by Cretaceous to Cenozoic extension (Figure 2).
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