TY - JOUR
T1 - Least squares self-coherence for sub-nGal signal detection in the superconducting gravimeter records
AU - El-Gelil, Mahmoud Abd
AU - Pagiatakis, Spiros
N1 - Funding Information:
This research was financially supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada and by the GEOIDE National Centre of Excellence. We thank the managers of Cantley, Moxa and Canberra stations for making the SG data available to us. Two anonymous reviewers and Professor David Crossley provided very useful comments and suggestions that improved significantly the manuscript.
PY - 2009/12
Y1 - 2009/12
N2 - In this paper, we use superconducting gravimeter (SG) data recorded at three stations of the global geodynamics project (GGP) network, with good geographical distribution, to search for possible significant peaks in the gravity spectrum that are in the assumed period range of the Slichter triplet. Seven-year long series from Cantley (Canada), and four-year long series from both Canberra (Australia) and Moxa (Germany) stations are used. First, a solid Earth and ocean tide model is subtracted from the data, followed by a local atmospheric pressure correction based on a frequency-, and location-dependent admittance estimated by the least squares response method. Subsequently, the residual series are filtered with a Parzen-based bandpass filter with a passband (12 h-78 s). A sub-nGal detection level is confirmed by injecting an artificial sine wave of different amplitudes. The Least Squares Self-Coherency spectrum shows the existence of many apparently statistically significant peaks at the 95% confidence level in the band (3-8 h). Although a few peaks are close to the claimed Slichter periods in previous research, the large number of candidate peaks may be related to other mechanisms such as global pressure variations, or hydrology.
AB - In this paper, we use superconducting gravimeter (SG) data recorded at three stations of the global geodynamics project (GGP) network, with good geographical distribution, to search for possible significant peaks in the gravity spectrum that are in the assumed period range of the Slichter triplet. Seven-year long series from Cantley (Canada), and four-year long series from both Canberra (Australia) and Moxa (Germany) stations are used. First, a solid Earth and ocean tide model is subtracted from the data, followed by a local atmospheric pressure correction based on a frequency-, and location-dependent admittance estimated by the least squares response method. Subsequently, the residual series are filtered with a Parzen-based bandpass filter with a passband (12 h-78 s). A sub-nGal detection level is confirmed by injecting an artificial sine wave of different amplitudes. The Least Squares Self-Coherency spectrum shows the existence of many apparently statistically significant peaks at the 95% confidence level in the band (3-8 h). Although a few peaks are close to the claimed Slichter periods in previous research, the large number of candidate peaks may be related to other mechanisms such as global pressure variations, or hydrology.
KW - Least squares self-coherence
KW - Least squares spectrum
KW - Slichter mode
KW - Superconducting gravimeter
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U2 - 10.1016/j.jog.2009.09.018
DO - 10.1016/j.jog.2009.09.018
M3 - Article
AN - SCOPUS:72049111752
SN - 0264-3707
VL - 48
SP - 310
EP - 315
JO - Journal of Geodynamics
JF - Journal of Geodynamics
IS - 3-5
ER -