Function SW_svel(S,T,P)

'SW_SVEL  $Revision: 1.3 $  $Date: 1994/10/10 05:53:00 $
'          Copyright (C) CSIRO, Phil Morgan 1993.
'
'USAGE:  SndVel = sw_svel(S,T,P)
'
'DESCRIPTION:
'   Sound Velocity in sea water using UNESCO 1983 polynomial.
'
' INPUT:  (all must have same dimensions)
'   S = salinity    [psu      (PSS-78)]
'   T = temperature [degree C (IPTS-68)]
'   P = pressure    [db]
'
' OUTPUT:
'   SW_vel = sound velocity  [m/s] 
' 
'AUTHOR:  Phil Morgan 93-04-20  (morgan@ml.csiro.au)
'
' DISCLAIMER:
'   This software is provided "as is" without warranty of any kind.  
'   See the file sw_copy.m for conditions of use and licence.
'
' REFERENCES:
'    Fofonoff, P. and Millard, R.C. Jr
'    Unesco 1983. Algorithms for computation of fundamental properties of 
'    seawater, 1983. _Unesco Tech. Pap. in Mar. Sci._, No. 44, 53 pp.

' Convert db to bars as used in UNESCO routines

P = P/10 

c00 = 1402.388
c01 =    5.03711
c02 =   -5.80852e-2
c03 =    3.3420e-4
c04 =   -1.47800e-6
c05 =    3.1464e-9

c10 =  0.153563
c11 =  6.8982e-4
c12 = -8.1788e-6
c13 =  1.3621e-7
c14 = -6.1185e-10

c20 =  3.1260e-5
c21 = -1.7107e-6
c22 =  2.5974e-8
c23 = -2.5335e-10
c24 =  1.0405e-12

c30 = -9.7729e-9
c31 =  3.8504e-10
c32 = -2.3643e-12

Cw =  c00 + c01*T + c02*T^2 + c03*T^3 + c04*T^4 + c05*T^5 + (c10 + c11*T + c12*T^2 + c13*T^3 + c14*T^4)*P + (c20 + c21*T + c22*T^2 + c23*T^3 + c24*T^4)*P^2 + (c30 + c31*T + c32*T^2)*P^3
 
a00 =  1.389
a01 = -1.262e-2
a02 =  7.164e-5
a03 =  2.006e-6
a04 = -3.21e-8

a10 =  9.4742e-5
a11 = -1.2580e-5
a12 = -6.4885e-8
a13 =  1.0507e-8
a14 = -2.0122e-10

a20 = -3.9064e-7
a21 =  9.1041e-9
a22 = -1.6002e-10
a23 =  7.988e-12

a30 =  1.100e-10
a31 =  6.649e-12
a32 = -3.389e-13

A =  a00 + a01*T + a02*T^2 + a03*T^3 + a04*T^4 + (a10 + a11*T + a12*T^2 + a13*T^3 + a14*T^4)*P + (a20 + a21*T + a22*T^2 + a23*T^3)*P^2 + (a30 + a31*T + a32*T^2)*P^3

b00 = -1.922e-2
b01 = -4.42e-5
b10 =  7.3637e-5
b11 =  1.7945e-7

B = b00 + b01*T + (b10 + b11*T)*P

d00 =  1.727e-3
d10 = -7.9836e-6

D = d00 + d10*P

SW_svel = Cw + A*S + B*S^1.5 + D*S^2

End Function