Characterizing the global ocean ambient noise as recorded by the dense seismo-acoustic Kazakh network

• Main Authors: Smirnov, Alexandr, Carlo, Marine, Pichon, Alexis, Shapiro, Nikolai M., Kulichkov, Sergey
• Format: Text
• Language: English
• Published: 2020
• Subjects: Pacific; North Atlantic
• Online Access: https://doi.org/10.5194/se-2020-8; https://se.copernicus.org/preprints/se-2020-8/

The dense seismo-acoustic network of the Institute of Geophysical Research (IGR), National Nuclear Center of the Republic of Kazakhstan, has been operating in Kazakhstan since the late nineties of the last century. It consists of four seismic and three infrasonic arrays. The IGR network includes stations part of several national and global monitoring systems. Infrasonic and seismic data are processed using the Progressive Multi-Channel Correlation (PMCC) detector to characterize the temporal variability of microbarom and microseism signals from 2014 to 2017. The non-linear interaction of ocean waves is simulated using the microseism source model distributed by the French Research Institute for Exploitation of the Sea (IFREMER). The wave attenuation is calculated using a semi-empirical propagation law in a range independent atmosphere. Comparing the observed and predicted seismic and infrasonic signals reveals the dominating directions of arrivals at each station of the IGR network and the associated source regions. Both multi-year and intra-seasonal parameter variations are analysed. The level of low-frequency noise is significantly higher in winter than in summer. In winter, sources of infrasound ambient noise are mainly located in the North Atlantic and in the North Pacific during Sudden Stratospheric Warming (SSW) events. Signals observed in summer, likely originating from source regions in the southern hemisphere, are discussed.