Two sets of equations, covering all world oceans and seas, are presented to calculate pressure from depth for the computation of sound speed, and depth from pressure for use in ocean engineering. They are based on the algorithm of UNESCO 1983 [N. P. Fofonoff and R. C. Millard, Jr., Unesco Tech. Papers in Mar. Sci. No. 44 (1983)], and on calculations from temperature and salinity profiles. The pressure to depth conversion is presented first. The equations can be used in those cases where the desired accuracy is reduced to ±0.8 m. The equations to convert depth to pressure provide an overall accuracy between ±8000 Pa and ±1000 Pa. This leads to errors in sound speed consistently smaller than ±0.02 m/s. The discussion, and comparisons with results and other formulas, suggest that the new equations are a substantial improvement on the previous simplified ones, which should now be abandoned.

Topics
Speed of sound, Oceanography
1.
S. Levitus, Climatological Atlas of the World Ocean, NOAA prof. Paper No. 13 (U.S. Government Printing Office, Washington, DC, 1982).
2.
C. C.
Leroy
, “
Formulae for the calculation of underwater pressure in acoustics
,”
J. Acoust. Soc. Am.
44
,
651
–
653
(
1968
).
Google Scholar
Crossref
Search ADS
 
3.
J. R.
Lovett
, “
Merged seawater sound-speed equations
,”
J. Acoust. Soc. Am.
63
,
1713
–
1718
(
1978
).
Google Scholar
Crossref
Search ADS
 
4.
IPA Siess, “Relation entre pression et immersion dans l’océan,” (relationship between pressure and depth in the ocean), Annex to letter 293 EPSHOM/E/OC (1982) (in French).
5.
C. C. Leroy, “La vitesse du son dans les eaux neptuniennes—Synthèse et mise à jour” (Speed of sound in Neptunian waters—Review and updating), Consultant Report for CERDSM No. ACS 88/02/03 (1988) (in French).
6.
N. P. Fofonoff and R. C. Millard, Jr., “Algorithms for computation of fundamental properties of seawater,” Unesco Tech. Papers in Mar. Sci., No. 44 (1983).
7.
H. U. Sverdrup, M. W. Johnson, and R. H. Fleming, “The water masses and currents in the oceans,” in The Oceans—Their Physics, Chemistry, and General Biology (Prentice-Hall, Englewood Cliffs, NJ, 1942, reissued 1970), Chap. XV, pp. 735–738.
8.
“Instruction manual for salinity/temperature/depth/sound velocity measuring systems models 9040” (Bisset Berman, San Diego, CA, 1971).
9.
E. L. Bialek, “Handbook of oceanographic tables,” U.S. Naval Ocean Office, SP-68 (1966).
10.
V. A.
Del Grosso
, “
New equation for the speed of sound in natural waters (with comparisons to other equations)
,”
J. Acoust. Soc. Am.
56
,
1084
–
1091
(
1974
).
Google Scholar
Crossref
Search ADS
 
11.
K. V.
Mackenzie
, “
Nine-term equation for sound speed in the oceans
,”
J. Acoust. Soc. Am.
70
,
807
–
812
(
1981
).
Google Scholar
Crossref
Search ADS
 
12.
N. P. Fofonoff and C. Froese, “Program for oceanographic computations and data processing on the electronic computer ALWAC III-E,” Fish. Res. Board of Canada, Rep. 25 (1958).
13.
N. P. Fofonoff and S. Sabata (same title as above), Fish. Res. Board of Canada, Rep. 27 (1958).
14.
H. E. Sweers, “A comparison of methods used to calculate sigma-T, specific volume anomaly and dynamic height,” J. Marine Tech. Soc. 5, 7–26 (1971).
15.
C. C. Leroy, “A universal formula for the calculation of underwater pressure in acoustic studies,” SACLANT ASW Research Centre Technical Report No. 108 (1968).
This content is only available via PDF.
© 1998 Acoustical Society of America.
1998
Acoustical Society of America
You do not currently have access to this content.