Updated Global Reference Models of Broadband Coherent Infrasound Signals for Atmospheric Studies and Civilian Applications. Issue 7 (22nd July 2022)

• Record Type: Journal Article
• Authors: Kristoffersen, S. K.; Le Pichon, A.; Hupe, P.; Matoza, R. S.
• Is Part Of: Earth and space science. Volume 9:Issue 7(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-22
• Subjects: infrasound -- IMS -- ambient coherent signal -- CTBT; Space sciences -- Periodicals; Geophysics -- Periodicals; 500.5
• DOI: 10.1029/2022EA002222
• Languages: English
• ISSNs: 2333-5084

Abstract

Abstract: The International Monitoring System (IMS) infrasound network has been established to detect nuclear explosions and other signals of interest embedded in the station‐specific ambient noise. The ambient noise can be separated into coherent infrasound (e.g., real infrasonic signals) and incoherent noise (such as that caused by wind turbulence). Previous work statistically and systematically characterized coherent infrasound recorded by the IMS. This paper expands on this analysis of the coherent ambient infrasound by including updated IMS data sets with data up to the end of 2020 for all 53 of the currently certified IMS infrasound stations using an updated configuration of the Progressive Multi‐Channel Correlation (PMCC) method. This paper presents monthly station‐dependent reference curves for the back azimuth, trace velocity, and root mean squared amplitude, which provides a means to determine the deviation from the nominal monthly behavior. In addition, a daily Ambient Noise Stationarity (ANS) factor based on deviations from the reference curves is determined for a quick reference to the coherent signal quality compared to the nominal situations. Newly presented histograms provide a higher resolution spectrum, including the observations of the microbarom peak, as well as additional peaks reflecting station‐dependent environmental noise. The aim of these reference curves is to identify periods of suboptimal operation (e.g., nonoperational sensor) or instances of strong abnormal signals of interest. Key Points: A new and updated analysis of the coherent ambient infrasound is presented Monthly reference back azimuth, trace velocity, and root mean squared (RMS) amplitude curves for each station are provided with descriptions Updated Progressive Multi‐Channel Correlation (PMCC) algorithm allows for additional peaks in the coherent RMS amplitude histogram spectra to be resolved