Microseism Variations In Response To Antarctic Sea Ice Change

The temporal and spatial distributions of Antarctic sea ice play important roles in both the generation mechanisms and the signal characteristics of microseisms.This link paves the way for seismological investigations of Antarctic sea ice.In this paper,the sea ice research based on seismic background noise,an important branch of polar seismology in recent years,is studied.The spatial and temporal characteristics of the microseisms and the relationship between the microseisms and the variation of Antarctic sea ice are analyzed comprehensively by using the microseism signals of Antarctic seismic stations.The short-period double frequency microseisms along the Antarctic coast are located by using the microseism signals of the Antarctic seismic array.In this paper,the characteristics of Antarctic microseisms are analyzed based on the continuous data of Antarctic coastal stations PMSA,KOLR,BEAR,EFI(island station outside Antarctica)and sea ice concentration.In order to locate the source area of microseisms along the coast of Antarctica,we use frequency wavenumber analysis method to locate the double frequency microseism(0.18-0.22Hz)of XH seismic array along the coast of Antarctica.Research indicates:(1)The seasonal growth of sea ice along the coast of Antarctica has a significant inhibitory effect on the microseism signals in the west Antarctica,in particular,the short period double frequency microseisms,with maximum intensities every February-March and minimum intensities around every September-October,and the strong seasonal periodicity of Antarctic sea ice is in better agreement with this observed microseism;(2)Based on the cross-correlation between the short period double frequency microseisms power and the coastal sea ice concentration,it is found that there is a long-term inverse correlation between these power and the coastal sea ice concentration at BEAR station;(3)Based on the cross-correlation between the power of short period double frequency microseisms and the distances between the station and sea ice boundaries,it is found that there is an inverse correlation between the these power and the distance between BEAR station and sea ice boundaries,and the correlation coefficient is about-0.7905;(4)The microseisms power received by stations located in different regions of Antarctica is not completely consistent.Relatively speaking,the microseisms power of PMSA station on the Antarctic Peninsula is stronger than other stations;(5)The microseisms from the coastal regions of West Antarctica exhibit clear seasonal variations,although there are also some differences in the annual microseism changes,their long-term dependence on sea ice changes remains relatively stable;(6)The frequency wavenumber analysis method can detect the microseism signals in the coastal area by XH seismic array on Ross Ice Shelf,Antarctica,and the strong Rayleigh surface wave signal is observed in the southwest of the array in February 2016.The research in this paper show that it is feasible to research and observe Antarctic sea ice through Antarctic microseisms,and has shown good development potential.