Estimates of geoacoustic parameters and source range using airgun sound in the East Siberian Sea, Arctic Ocean

Abstract

In a shallow-water waveguide, low-frequency sound propagating over several kilometers has dispersive properties and thus the dispersion curves can be used for the inversion of geoacoustic parameters. In September 2019, seismic survey was conducted by the icebreaking research vessel Araon, operated by Korea Polar Research Institute. A single hydrophone was moored at East Siberian Shelf, a nearly range-independent shallow water (<70 m), to receive seismic airgun sounds generated from the R/V Araon. It was observed that the arrivals corresponding to the first two modes were clearly dispersed in the spectrogram of the received signal. In order to use these dispersion curves for the geoacoustic inversion, the dispersion curves corresponding to the first two modes were extracted using the warping transform combined with the wavelet synchrosqueezing transform. Geoacoustic parameters including sound speed and density in the sediment and the distance between the source and receiver were then estimated by comparing the extracted dispersion curves to the model replicas predicted by the KRAKEN normal-mode acoustic propagation model. Finally, the inversion results and their error analysis will be discussed in this talk. [This research was a part of the project titled ‘Korea-Arctic Ocean Warming and Response of Ecosystem (K-AWARE, KOPRI, 1525011760)’, funded by the Ministry of Oceans and Fisheries, Korea and supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (2020R1A2C2007772).]