Function POTENTMP(S, T0, P0, PR)

'% NOTE:  This routine calls Adiabat; BE SURE TO LOAD THAT MODULE AS WELL!!!

'TO COMPUTE LOCAL POTENTIAL TEMPERATURE AT PR
'USING BRYDEN 1973 POLYNOMIAL FOR ADIABATIC LAPSE RATE
'AND RUNGE-KUTTA 4-TH ORDER INTEGRATION ALGORITHM.

'INPUTS:         SALINITY        S        (IPSS-78)
'                TEMPERATURE     T0       DEG CELSIUS (IPTS-68)
'                PRESSURE        P0       DECIBARS
'                REFERENCE PRS   PR       DECIBARS
'
'OUTPUT:         POTENTIAL TMP.  THETA    DEG CELSIUS

'CHECKVALUE:     S=40 (IPSS-78)
'                T0=40 DEG C
'                P0=10000 DECIBARS
'                PR=0 DECIBARS
'                THETA= 36.89073 C

'SET-UP INTERMEDIATE TEMPERATURE AND PRESSURE VARIABLES

  P = P0
  T = T0

'CALCULATE POTENTMP

  H = PR - P
  XK = H * ADIABAT(S, T, P)
  T = T + 0.5 * XK
  Q = XK
  P = P + 0.5 * H
  XK = H * ADIABAT(S, T, P)
  T = T + 0.29289322 * (XK - Q)
  Q = 0.58578644 * XK + 0.121320344 * Q
  XK = H * ADIABAT(S, T, P)
  T = T + 1.707106781 * (XK - Q)
  Q = 3.414213562 * XK - 4.121320344 * Q
  P = P + 0.5 * H
  XK = H * ADIABAT(S, T, P)
  POTENTMP = T + (XK - 2 * Q) / 6

End Function