Current News (Research Highlights)
Tornado Detection
The National Center for Physical Acoustics (NCPA) at the University of Mississippi is conducting research to detect and monitor severe storms under NOAA Specific Cooperative Agreement NA08NWS4680044. NCPA collected and analyzed infrasound data that points to a possible capability for advanced warning and accurate tracking of tornados. Analysis of data collected during a tornado outbreak in central Oklahoma on May 24, 2011 indicates that two field-deployed infrasound arrays detected and tracked three tornadoes. The infrasound signals were quite large and distinct, indicating that detections at significantly larger ranges would have been possible. A network of infrasound arrays deployed through a region could provide the weather services with detections and tracks of tornadoes throughout the region. Given that it takes about 3 minutes for sound to travel from a tornado to an array 40 miles away, it is conceivable that warnings could be issues within tens of minutes.
Bearings from the infrasound arrays to the Stillwater (left) and Chickasha–Blanchard-Newcastle tornados as determined from the infrasound data. Generally good agreement with the known position and track of the tornado was obtained. Similar results were obtained for the Calumet-El Reno-Piedmont–Guthrie storm.
Hurricane Monitoring
The infrasound group at the National Center for Physical Acoustics (NCPA) at the University of Mississippi has been investigating the use of the microbarom signal to probe the interior of hurricanes. Microbaroms are infrasonic signals produced by the collision of counter-propagating ocean waves of equal periods. These signals are routinely detected thousands of kilometers from their source. Hurricanes are known to be a large source of microbarom radiation. Researchers at the NCPA have shown that the source of microbaroms from hurricanes is the collision of waves produced by the storm with the background ocean swell. The region where these collisions occur tends to be hundreds of kilometers south of the eye of the storm.
NCPA deployed infrasound arrays along the eastern seaboard for the 2010, 2011, and 2012 hurricane seasons to test the idea that the microbarom signal can be severely refracted by the storm winds, providing a possible tool for the determination of these winds. It was demonstrated conclusively that such severe refraction occurs and is a robust effect. If the hurricane is observed from the south, the microbarom signal reaches the array without passing through the storm along a straight line from the source to the receiving array. In this case, the back azimuth determined at the array points directly towards the microbarom source region. If the hurricane is observed from the north, the microbarom signal passes through the storm before reaching the receiving array and undergoes severe refraction. In this case, the back azimuth determined at the array does not point towards the microbarom source region. NCPA proposes to use the refraction of the microbarom signal by the hurricane to monitor the interior of the hurricane and to determine intensity. Hurricane intensity would be determined continuously and remotely. The time required for the signal to propagate to the array and for the data to be processed can be expected to be less than one hour.
In the figures above, the array deployment, the track and back azimuth determinations for Hurricane Igor (2010) are shown for detections north of the storm and south of the storm.
Treaty Compliance Verification
NCPA has been performing infrasound research in support of the monitoring regime of the Comprehensive Nuclear Test Ban Treaty under Contract W9113M-06-C-0029. Significant achievements for this effort include developing and licensing a next generation, low-cost infrasound sensor, developing of laboratory calibration facilities, development of a technique for in-situ calibration of infrasound array elements, conducting large-scale experiments for infrasound propagation studies in the Middle East in 2009 and 2011 and at the Utah Test and Training Range in 2009 and 2010, conducting fundamental wind noise studies leading to the development of new physical and signal processing wind noise reduction methods, and developing and improving infrasound propagation models at atmospheric specifications.
Current publications (Note: these are publications by members of the Infrasound Group dating back to 2010. Not all publications relate to infrasound.)
- J. D. Assink, R. Waxler, W. G. Frazier and J. Lonzaga, The estimation of upper atmospheric wind model updates from infrasound data, Submitted to J. Geophys. Res.
- David Fee, Roger Waxler, Jelle Assink, Yefim Gitterman, Jeffrey Given, John Coyne, Pierrick Mialle, Milton Garces, Douglas Drob, Daniel E. Kleinert, Rami Hofstetter, Patrick Grenard, “Overview of the 2009 and 2011 Sayarim Infrasound Calibration Experiments,” J. Geoph. Res., DOI: 10.1002/jgrd.50398 (2013).
- Phillip S. Blom, Roger Waxler, “Impulse propagation in the nocturnal boundary layer: analysis of the geometric component,” J. Acoust. Soc. Am. Vol 131, Num. 5, p 3680-3690 (2012)
- Jelle D. Assink, Roger Waxler, and Douglas P. Drob, “On the sensitivity of infrasonic travel times in the equatorial region to the atmospheric tides,” J. Geophys. Res., doi:10.1029/2011JD016107 (2012).
- Richard Raspet, “Review of Wind Turbine Noise, by Dick Bowdler, Geoff Leventhall,” J. Acoust. Soc. Am. 132, 1233 (2012).
- I. P. Chunchuzov, S. N. Kulichkov, O. E. Popov, R. Waxler, and J. Assink, “Infrasound Scattering from Atmospheric Anisotropic Inhomogeneities,” Izvestiya, Atmospheric and Oceanic Physics, Vol. 47, No. 5, pp. 540–557 (2011).
- Maarten Hornikx, Roger Waxler, and Jens Forssen, “The extended Fourier pseudospectral time-domain (PSTD) method for atmospheric sound propagation,” J. Acoust. Soc. Am. 128, 1632-1646 (2010).
- Bonner, J. L., R. Waxler, Y. Gitterman, and R. Hofstetter, “Seismo-acoustic energy partitioning at near-source and local distances from the 2011 Sayarim Explosions in the Negev Desert, Israel,” Bulletin of the Seismological Society of America, April 2013, v. 103, p. 741-758, doi:10.1785/0120120181
- Jiao Yu, Richard Raspet, Jeremy Webster, and JohnPaul Abbott, “Improved prediction of the turbulence-shear contribution to wind noise pressure spectra,” J. Acoust. Soc. Am. 130, 3590 (2011)
- Jiao Yu, Richard Raspet, Jeremy Webster, and JohnPaul Abbott, “Wind noise measured at the ground surface,” J. Acoust. Soc. Am. 129, 622 (2011)
- Carl Jensen and Richard Raspet, “Thermoacoustic power conversion using a piezoelectric transducer,” J. Acoust. Soc. Am.128, 98 (2010)
- Carl Jensen and Richard Raspet, “Thermoacoustic properties of fibrous materials,” J. Acoust. Soc. Am.127, 3470 (2010)
- Jeremy Webster, Richard Raspet, Jiao Yu, and Wayne E. Prather, “Measurement of wind noise levels in streamlined probes,” J. Acoust. Soc. Am. 127, 2764 (2010)
- Jin H. Soh, Kenneth E. Gilbert, Wm. Garth Frazier, Carrick L. Talmadge, and Roger Waxler, “A direct method for measuring acoustic ground impedance in long-range propagation experiments,” J. Acoust. Soc. Am. 128, Issue 5, pp. EL286-EL293 (2010).
Newly funded awards (PI and Co-PI names, funding agency, award title, date awarded) (Note: These date back to 2010)
- Daniel E. Kleinert, Jr., Weston Geophysical Corporation (Air Force Research Laboratory), Humming Skunk Installations, Validation and Preliminary Data Analysis, February 2013.
- Richard Raspet, Army Research Laboratory, Cooperative work on infrasonic wind noise and infrasound applications – University of Mississippi and Army Research Laboratory, May 2013.
- Richard Raspet, Army Research Office, Measurement and prediction of infrasonic wind noise in forests, September 2012.
- Roger Waxler, Quanterra, Inc. (Incorporated Research Institutions for Seismology (IRIS)), Infrasound Sensors for the USArray, July 2010.
3 – 5 pictures (e.g. pictures of someone in your group working with major equipment)
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Events/workshops your group is sponsoring/hosting
- Infrasound Calibration Working Group. The University of Mississippi sponsored a meeting of the Infrasound Calibration Working Group at the National Center for Physical Acoustics on 15-16 January 2013. The purpose of the group is to provide an unbiased forum for all interested parties (excluding vendors) to develop, approve, and recommend procedures and processes for the characterization and calibration of infrasound sensing systems. The group will also evaluate sensor/digitizer calibration facilities. The next meeting is scheduled to occur at Sandia National Laboratory in Summer 2013.
Other relevant information
Also, we would like to have a page on the website reserved for former graduate students (MA/MS & PhD). Please provide us with the following information for former graduate students you advised.
Student’s name: Jelle D. Assink
Advisors: Roger Waxler and Adnan Aydin
Degree: Doctor of Philosophy, Geology & Geological Engineering
Year degree completed: 2012
Title of dissertation: Infrasound as upper atmospheric monitor
Student’s name: Phillip S. Blom
Advisor: Roger Waxler
Degree: Doctor of Philosophy, Physics
Year degree completed: 2013
Title of dissertation: Interaction of the Cyclonic Winds with the Infrasonic Signal Generated by a Large Maritime Storm
Student’s name: Jericho E. Cain
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 2013
Title of dissertation: Large Eddy Simulation of Surface Pressure Fluctuations Generated by Elevated Gusts
Student’s name: JohnPaul Abbott
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 2013
Title of dissertation: Optimization of Wind Fences for Infrasonic Wind Noise Reduction
Student’s name: Vijay Emani
Advisor: Carrick L. Talmadge
Degree: Master of Science
Year degree completed: 2004
Title of dissertation: Highway Noise Prediction Model and Validation
Student’s name: Shantharam V. Dravida
Advisor: Carrick L. Talmadge
Degree: Doctor of Philosophy, Engineering
Year degree completed: 2007
Title of dissertation: Development of a Self- Calibrating Infrasound Microphone and its Adaptability to Lower Audible Frequencies
Student’s name: Shantharam V. Dravida
Advisor: Carrick L. Talmadge
Degree: Master of Science, Mechanical Engineering
Year degree completed: 2003
Title of dissertation: Experimental characterization of modified and thin film piezoceramic sensors
Student’s name: Venugopal R. Male
Advisor: Carrick L. Talmadge
Degree: Master of Science
Year degree completed: 2007
Title of dissertation: Modeling of acoustic and E&M Wave Propagation for Remote Sensing Applications in Atmospheric Boundary Layer
Student’s name: Amy Chrestman
Advisor: Richard Raspet
Degree: Master of Science, Physics
Year degree completed: 1989
Title of dissertation: Validity of the ray approximation applied to sound propagation in the atmosphere
Student’s name: Mark W. Sprague
Advisor: Richard Raspet
Degree: Master of Science, Physics
Year degree completed: 1991
Title of dissertation: A comparison of techniques for the measurement of acoustic ground impedance at low frequency
Student’s name: Mark W. Sprague
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 1994
Title of dissertation: The prediction of sound levels in the atmosphere using a two dimensional fast field program
Student’s name: Michael Scott Morgan
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 1993
Title of dissertation: An investigation of the sources and attenuation of wind noise in measurement microphones
Student’s name: Michael Scott Morgan
Advisor: Richard Raspet
Degree: Master of Science, Physics
Year degree completed: 1989
Title of dissertation: Digital-to-analog conversion of acoustic signals
Student’s name: Wei Wei
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 1994
Title of dissertation: Underwater measurement of the sound-intensity vector: its use in locating sound sources, and in measuring the sound power of stationary and moving sources
Student’s name: Patrice Marc Boulanger
Advisor: Richard Raspet
Degree: Master of Science, Physics
Year degree completed: 1992
Title of dissertation: Sound propagation from the advanced turboprop aircraft in a turbulent atmosphere
Student’s name: Patrice Marc Boulanger
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 1994
Title of dissertation: Sonic boom propagation through a realistic turbulent atmosphere
Student’s name: David W. Craig
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 1995
Title of dissertation: Acoustic propagation in fractal porous media
Student’s name: James R. Belcher
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 1996
Title of dissertation: A study of element interactions in thermoacoustic engines
Student’s name: Jay A. Lightfoot
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 1997
Title of dissertation: Thermoacoustic engines in alternate geometry resonators
Student’s name: Mark C. Kelly
Advisor: Richard Raspet
Degree: Master of Science, Physics
Year degree completed: 1997
Title of dissertation: Scattering of sonic booms by anisotropic turbulence in the atmosphere
Student’s name: Wayne Prather
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 1999
Title of dissertation: Parametric excitation of a resonant acoustic mode
Student’s name: Gordon Smith
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 2000
Title of dissertation: Examination of streaming regions within a heat-driven thermoacoustic refrigerator
Student’s name: Michael L. Oelze
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 2000
Title of dissertation: Roughness characterization of porous soil using acoustic backscatter
Student’s name: William V. Slaton
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 2001
Title of dissertation: Inert gas: vapor mixtures in thermoacoustics
Student’s name: Timothy G. Simmons
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 2003
Title of dissertation: Experimental determination of thermoacoustic stack properties
Student’s name: Pasquale Montanaro
Advisor: Richard Raspet
Degree: Master of Science, Physics
Year degree completed: 2004
Title of dissertation: The acoustics of fluid motion in porous media
Student’s name: Kevin Dillion
Advisor: Richard Raspet
Degree: Master of Science, Physics
Year degree completed: 2005
Title of dissertation: An investigation of wind noise over a flat plate
Student’s name: Jiao Yu
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed: 2009
Title of dissertation: Calculation of wind noise measured at the surface under turbulent wind fields
Student’s name: Jiao Yu
Advisor: Richard Raspet
Degree: Master of Science, Physics
Year degree completed: 2007
Title of dissertation: Infrasound wind noise predictions
Student’s name: Carl Jensen
Advisor: Richard Raspet
Degree: Doctor of Philosophy, Physics
Year degree completed:
Title of dissertation: Computational thermoacoustics in fibrous stacks