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Systems Check

Systems Check. PMCC analyses of signals from the North American and Pacific Infrasound Network. Milton Garces and Claus Hetzer Infrasound Laboratory, University of Hawaii, Manoa. 2003 Infrasound Technology Workshop, San Diego, California. Outline.

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Systems Check

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  1. Systems Check

  2. PMCC analyses of signals from the North American and Pacific Infrasound Network Milton Garces and Claus Hetzer Infrasound Laboratory, University of Hawaii, Manoa 2003 Infrasound Technology Workshop, San Diego, California

  3. Outline • Apply Progressive Multiple Channel Correlation (PMCC) detector to various events and array geometries • Bolides, microbaroms, aircraft, surf, volcanoes, and Columbia reentry for small aperture and large aperture arrays

  4. PMCC: Consistency Consistency is based on closure relationship for plane waves arriving on elements i,j,k: Dtij+Dtjk+Dtki = 0 • Define consistency threshold • Can also define correlation filter • Select different frequency bands • Provides detailed frequency information • Can add F-stat for further screening April 23, 2001

  5. Automatic processing at IS59: Operations

  6. Automatic processing at IS59Microbaroms • 14415 arrivals, Jan 1-Oct 24 • Max consistency for im (0.1-0.5 Hz): 0.5 s

  7. Microbaroms: blocking by topography

  8. Portable Stations • Airport and coastline (19.7421 N, 156.05221 W)

  9. Portable Station: Keahole Point • Airport and coastline

  10. Surf • High Surf: Arrivals

  11. Surf • High Surf: Arrivals

  12. Surf • High Surf: Acoustic amplitude

  13. Surf

  14. Volcano infrasound Kuju, Japan Sound timbre is determined by gas and/or lava composition, temperature, and speed, as well as by structure of conduit Cookie Monster, Hawaii

  15. Volcano infrasound

  16. Volcano infrasound • Kilauea volcano: discovered continuous infrasonic vibration

  17. Detector response to different array sites and configurations • Columbia reentry STS-107 • Looked at 30s and 5s windows

  18. STS-107 at NVIAR • N-wave and later arrivals corresponding to approach

  19. STS-107 at TXIAR • No N-wave, multiple pulses from multipathing

  20. STS-107 at SGAR • Backazimuth points south of trajectory: February 1, 2003

  21. Shuttle reentries with orbital declination of 39o

  22. STS-78 at SGAR • N-wave, approach, and departure • July 7, 1996 – Summer!

  23. Concluding Remarks • PMCC detector can be optimized to find particular signal features • Detector handles well different array geometries • Yearly microbarom detections highlight shadow zones from topography and possible phase inconsistencies between Chaparral sensors • Portable stations permit better source location and characterization • STS-107 Columbia reentry over Western US detected by most of the N American Infrasound Network • Tuned detector to search for relatively brief coherent bursts corresponding to the approach trajectory • Infrasound from STS-107 does not appear to be much different from other Shuttle reentries with a similar orbital inclination • Infrasonic studies are consistent with NASA’s interpretation

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