The amplitude and waveform shape of atmospheric acoustic pulses propagating horizontally over a seasonal snow cover are profoundly changed by the air forced into the snow pores as the pulses move over the surface. This interaction greatly reduces the pulse amplitude and elongates the waveform compared to propagation above other ground surfaces. To investigate variations in snow-cover effects, acoustic pulses were recorded while propagating horizontally over 11 different naturally occurring snow covers during two winters. Two inversion procedures were developed to automatically match the observed waveforms by varying the snow-cover parameters in theoretical calculations. A simple frequency-domain technique to match the dominant frequency of the measured waveform suffered from multiple solutions and poor waveform matching, while a time-domain minimization method gave unique solutions and excellent waveform agreement. Results show that the effective flow resistivity and depth of the snow are the parameters controlling waveform shape, with the pore shape factor ratio of secondary importance. Inversion estimates gave flow resistivities ranging from 11 to 29 kN s m−4, except for two late-season cases where values of 60 and 140 were determined (compared to 345 for the vegetation-covered site in the summer). Acoustically determined snow depths agreed with the measured values in all but one case, when the depth to a snow layer interface instead of the total snow depth was determined. Except for newly fallen snow, the pore shape factor ratio values clustered near two values that appear to correspond to wet (1.0) or dry (0.8) snow.
REFERENCES
1.
K.
Attenborough
, “Ground parameter information for propagation modeling
,” J. Acoust. Soc. Am.
92
, 418
–427
(1992
).2.
T. F. W.
Embleton
, J. E.
Piercy
, and N.
Olson
, “Outdoor sound propagation over ground of finite impedance
,” J. Acoust. Soc. Am.
59
, 267
–277
(1976
).3.
T. F. W.
Embleton
, J. E.
Piercy
, and G. A.
Daigle
, “Effective flow resistivity of ground surfaces determined by acoustical measurements
,” J. Acoust. Soc. Am.
74
, 1239
–1244
(1983
).4.
D. G.
Albert
and J. A.
Orcutt
, “Observations of low frequency acoustic-to-seismic coupling in the summer and winter
,” J. Acoust. Soc. Am.
86
, 352
–359
(1989
).5.
R. A.
Sommerfeld
, “A review of snow acoustics
,” Rev. Geophys. Space Phys.
20
, 62
–66
(1982
).6.
G.
Seligman
, “Sound absorption of snow
,” Nature (London)
143
, 1071
(1939
).7.
8.
G. W. C.
Kaye
and E. J.
Evans
, “Sound absorption of snow
,” Nature (London)
143
, 80
(1939
).9.
R. B.
Watson
, “On the propagation of sound over snow
,” J. Acoust. Soc. Am.
20
, 846
–848
(1948
).10.
T.
Ishida
and S.
Onodera
, “Sound absorption by a snow layer
,” Low Temp. Sci., Ser. A
12
, 17
–24
(1954
).11.
T.
Ishida
, “Acoustic impedance of a snow layer
,” Low Temp. Sci., Ser. A
15
, 81
–91
(1956
).12.
T.
Ishida
, “Acoustic impedance of a snow layer II
,” Low Temp. Sci., Ser. A
16
, 241
–248
(1957
).13.
T. Ishida and H. Shimizu, “Resistance to air flow through snow layers (Part 1),” SIPRE Translation 60 [Translation of Low Temp. Sci., Ser. A 14, 32–42 (1955)] (1958).
14.
15.
16.
17.
H.
Oura
, “Reflection of sound at snow surface and mechanism of sound propagation in snow
,” Low Temp. Sci. Ser. A
9
, 179
–186
(1953
).18.
H. Oura, “A study on the optical and the acoustical properties of the snow cover,” General Assembly of Rome, 1954, IASH Publication No. 4, pp. 71–81 (1954).
19.
S. M.
Lee
and J. C.
Rodgers
, “Characterization of snow by acoustic sounding: A feasibility study
,” J. Sound Vib.
99
, 247
–266
(1985
).20.
J. G.
Tillotson
, “Attenuation of sound over snow-covered fields
,” J. Acoust. Soc. Am.
39
, 171
–173
(1965
).21.
H.
Gubler
, “Artificial release of avalanches by explosives
,” J. Glaciol.
19
, 419
–429
(1977
).22.
J. B.
Johnson
, “On the application of Biot’s theory to acoustic wave propagation in snow
,” Cold Regions Sci. Technol.
6
, 49
–60
(1982
).23.
M. A.
Biot
, “Theory of propagation of elastic waves in a fluid-saturated porous solid. I. Low-frequency range
,” J. Acoust. Soc. Am.
28
, 168
–178
(1956
).24.
M. A.
Biot
, “Theory of propagation of elastic waves in a fluid-saturated porous solid. II. Higher frequency range
,” J. Acoust. Soc. Am.
28
, 179
–191
(1956
).25.
M. A.
Biot
, “Mechanics of deformation and acoustic propagation in porous media
,” J. Appl. Phys.
33
, 1482
–1498
(1962
).26.
K.
Attenborough
, “Review of ground effects on outdoor sound propagation from continuous broadband sources
,” Appl. Acoust.
24
, 289
–319
(1988
).27.
M. E.
Delaney
and E. N.
Bazley
, “Acoustical properties of fibrous absorbent materials
,” Appl. Acoust.
3
, 105
–116
(1970
).28.
K.
Attenborough
, “Acoustical impedance models for outdoor ground surfaces
,” J. Sound Vib.
99
, 521
–544
(1985
).29.
J.
Nicolas
, J.-L.
Berry
, and G. A.
Daigle
, “Propagation of sound above a finite layer of snow
,” J. Acoust. Soc. Am.
77
, 67
–73
(1985
).30.
H. M.
Moore
, K.
Attenborough
, J.
Rogers
, and S.
Lee
, “In situ acoustical investigations of deep snow
,” Appl. Acoust.
33
, 281
–301
(1991
).31.
D. G.
Albert
and J. A.
Orcutt
, “Acoustic pulse propagation above grassland and snow: Comparison of theoretical and experimental waveforms
,” J. Acoust. Soc. Am.
87
, 93
–100
(1990
).32.
O.
Buser
, “A rigid frame model of porous media for the acoustic impedance of snow
,” J. Sound Vib.
111
, 71
–92
(1986
).33.
K.
Attenborough
and O.
Buser
, “On the application of rigid-porous models to impedance data for snow
,” J. Sound Vib.
124
, 315
–327
(1988
).34.
S. C.
Colbeck
, “An overview of seasonal snow metamorphism
,” Rev. Geophys. Space Phys.
20
(1
), 45
–61
(1982
).35.
S. Colbeck, E. Akitaya, R. Armstrong, H. Gubler, J. Lafeuille, K. Lied, D. McClung, and E. Morris, “International Classification for Seasonal Snow on the Ground,” International Comm. Snow and Ice (IAHS), World Data Center A for Glaciology, University of Colorado, Boulder (1990).
36.
D. G. Albert, “Observations of acoustic surface waves propagating above a snow cover,” Proceedings of the Fifth International Conference on Long Range Sound Propagation (The Open University, Milton Keynes, England, 1992), pp. 10–16.
37.
H. A. J. M. van Hoof and K. W. F. M. Doorman, “Coupling of airborne sound in a sandy soil,” TNO/LEOK Rep. No. TR 1983-09, Netherlands Organization for Applied Scientific Research, Laboratory for Electronic Developments for the Armed Forces, Oegstgeest, NL (1983).
38.
C. Madshus and A. M. Kanyia, “Ground response to propagating airblast,” Inter-Noise 96 (Institute of Acoustics, Liverpool, UK, 1996), pp. 1433–1438.
39.
H. E.
Bass
, L. N.
Bolen
, D.
Cress
, J.
Lundien
, and M.
Flohr
, “Coupling of airborne sound into the earth: Frequency dependence
,” J. Acoust. Soc. Am.
67
, 1502
–1506
(1980
).40.
J. M.
Sabatier
, H. E.
Bass
, and L. N.
Bolen
, “Acoustically induced seismic waves
,” J. Acoust. Soc. Am.
80
, 646
–649
(1986
).41.
A. J.
Cramond
and C. G.
Don
, “Reflection of impulses as a method of determining acoustic impedance
,” J. Acoust. Soc. Am.
75
, 382
–389
(1984
).42.
C. G.
Don
and A. J.
Cramond
, “Soil impedance measurements by an acoustic pulse technique
,” J. Acoust. Soc. Am.
77
, 1601
–1609
(1985
).43.
R.
Raspet
, H. E.
Bass
, and J.
Ezell
, “Effect of finite ground impedance on the propagation of acoustic pulses
,” J. Acoust. Soc. Am.
74
, 267
–274
(1983
).44.
R.
Raspet
, J.
Ezell
, and H. E.
Bass
, Additional comments on and erratum for “Effect of finite ground impedance on the propagation of acoustic pulses” [J. Acoust. Soc. Amer. 74, 267–274 (1983)]
, J. Acoust. Soc. Am.
77
, 1955
–1958
(1985
).45.
A. J.
Cramond
and C. G.
Don
, “Effects of moisture content on soil impedance
,” J. Acoust. Soc. Am.
82
, 293
–301
(1987
).46.
C. G.
Don
and A. J.
Cramond
, “Impulse propagation in a neutral atmosphere
,” J. Acoust. Soc. Am.
81
, 1341
–1349
(1987
).47.
K.
Attenborough
, S. I.
Hayek
, and J. M.
Lawther
, “Propagation of sound above a porous half-space
,” J. Acoust. Soc. Am.
68
, 1493
–1501
(1980
).48.
K. U.
Ingard
, “On the reflection of a spherical wave from an infinite plane
,” J. Acoust. Soc. Am.
23
, 329
–335
(1951
).49.
I.
Rudnick
, “Propagation of an acoustic wave along a boundary
,” J. Acoust. Soc. Am.
19
, 348
–356
(1947
).50.
L. M. Brekhovskikh, Waves in Layered Media, 2nd ed. (Academic, New York, 1980).
51.
J. F. Allard, Propagation of Sound in Porous Media (Elsevier, London, 1993), p. 284.
52.
S. C.
Constable
, R. L.
Parker
, and C. G.
Constable
, “Occam’s inversion: A practical algorithm for generating smooth models from electromagnetic sounding data
,” Geophysics
52
, 289
–300
(1987
).53.
W. H. Press, B. P. Flannery, S. A. Teukolsky, and W. T. Vetterling, Numerical Recipes: The Art of Scientific Computing (Cambridge University Press, New York, 1986).
54.
R. Jordan, “Effects of capillary discontinuities on water flow and water retention in layered snow covers,” International Symposium on Snow and Related Manifestations, Manali, India (1994).
55.
D.
Hillel
and R. S.
Baker
, “A descriptive theory of fingering during infiltration into layered soils
,” Soil Sci.
146
, 51
–56
(1988
).56.
H. M.
Hess
, K.
Attenborough
, and N. W.
Heap
, “Ground characterization by short-range propagation measurements
,” J. Acoust. Soc. Am.
87
, 1975
–1986
(1990
).57.
J. M.
Sabatier
, H.
Hess
, W. P.
Arnott
, K.
Attenborough
, M. J. M.
Roemkens
, and E. H.
Grissinger
, “In situ measurements of soil physical properties by acoustical techniques
,” Soil Sci. Soc. Am. J.
54
, 658
–672
(1990
).58.
Care is needed in comparing these values with other work, since in many cases a different definition of effective flow resistivity is used. For example, Hess et al. (Ref. 56) use Reducing the values reported here according to the above definition gives agreement with Hess et al.’s low reported values of 1 to 3 kN s m−4.
59.
Y.
Champoux
and M. R.
Stinson
, “On acoustical models for sound propagation in rigid frame porous materials and the influence of shape factors
,” J. Acoust. Soc. Am.
92
, 1120
–1131
(1992
).60.
M. R.
Stinson
and Y.
Champoux
, “Propagation of sound and the assignment of shape factors in model porous materials having simple pore geometries
,” J. Acoust. Soc. Am.
91
, 685
–695
(1992
).61.
K.
Attenborough
, “Models for the acoustical properties of air-saturated granular media
,” Acta Acust. (China)
1
, 213
–226
(1993
).62.
D. K.
Wilson
, “Relaxation-matched modeling of propagation through porous media, including fractal pore structure
,” J. Acoust. Soc. Am.
94
, 1136
–1145
(1993
).63.
T.
Yamamoto
and A.
Turgut
, “Acoustic wave propagation through porous media with arbitrary pore size distribution
,” J. Acoust. Soc. Am.
83
, 1744
–1751
(1988
).64.
D. G. Albert, “Environmental effects on acoustic wave propagation at Ft. Greely, Alaska,” 1998 Meeting of the IRIS Specialty Group on Acoustic and Seismic Sensing (Johns Hopkins University, Laurel, MD, 1999), pp. 273–280.
65.
P. R.
Shaw
and J. A.
Orcutt
, “Waveform inversion of seismic refraction data and applications to young Pacific crust
,” Geophys. J. R. Astron. Soc.
82
, 375
–414
(1985
).66.
E. F.
Chacho
, Jr. and J. B.
Johnson
, “Air permeability of snow
,” EOS Trans. Am. Geophys. Union
68
, 1271
(abstract) (1987
).67.
J. P. Hardy and D. G. Albert, “The permeability of temperate snow: Preliminary links to microstructure,” Proceedings of the 50th Eastern Snow Conference, Quebec, Canada (1993), pp. 149–156.
This content is only available via PDF.
© 2001 Acoustical Society of America.
2001
Acoustical Society of America
You do not currently have access to this content.
