TITLE:
Long-Term Variations in Infrasound Signals Observed at Syowa Station, Antarctica: 2008-2014
AUTHORS:
Yoshiaki Ishihara, Masa-Yuki Yamamoto, Takahiko Murayama, Takeshi Matsushima, Masaki Kanao
KEYWORDS:
Infrasound, Long-Term Monitoring, Antarctica, Surface Environment, Microbaroms, High-Frequency Tremors
JOURNAL NAME:
InfraMatics,
Vol.3 No.1,
March
5,
2017
ABSTRACT: Long-term Infrasound data at Syowa Station (SYO; 39E, 69S), in the Lützow-Holm Bay (LHB),
East Antarctica was analyzed during the period from 2008 to 2014. Seasonal
variations in microbaroms and high-frequency harmonic tremors were especially
investigated. Infrasound data were strongly involved in local dynamics of
surface environments. The microbaroms have relatively low amplitudes in austral
winters by extending area of sea-ice around LHB, with decreasing oceanic swell
loading effects. The other reasons of seasonal variations in microbaroms
amplitudes were caused by the affections of a number of storms during whole
year and snow accumulation over the porous hoses on the infrasound station at
SYO. In contrast, non-linear high-frequency harmonic tremors were considered to
be caused by the katabatic winds from Antarctic continent flowing in northeast
dominant orientation. The high-frequency tremors had characteristics of daily
variations in particular in austral summer. It is required to continue more
than a few years of observation in order to identify relationships with climate
change and global warming effects in the Antarctic. Continuous measurement of infrasound
in the coastal margin of Antarctica is a proxy for monitoring multi-sphere
interaction between the continent and surrounding Southern Ocean.