BLO2.FOR

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      SUBROUTINE BL O2 (PO2,TEMP,O2 CAP,SO2,DISS O2,COMB O2, O2 TOT,
     A   PH,PCO2,NKNOWN)
C
C     SUBROUTINE BLOOD O2
C     CALCULATE BLOOD OXYGEN CONCENTRATIONS.  MOSTLY FROM WEST, 1974.
C        SOLUBILITY EQN. FROM KELMAN, 1966, RESP. PHYSIOL., 1.335.
C
C     BLOOD O2 = DISS O2 + O2 COMB WITH HGB
C        DISS O2 = SOLUBILITY * PO2
C        COMB O2 = O2 CAP * SO2  (FACTOR OF 100 CONVERTS SO2 FROM PCT)
C
      SOL = TEMP * (TEMP * 0.0000013 - 0.0001266) + 0.0059519
      IF (NKNOWN .EQ. 2)  GO TO 200
C
      DISS O2 = SOL * PO2
      COMB O2 = O2 CAP * SO2 / 100.0
      O2 TOT = DISS O2 + COMB O2
      GO TO 9900
C
C     CALCULATE PO2 FROM O2 CONCENTRATION, BY ITERATION.  ON 1ST APPROX
C     ASSUME DISS O2 = 0.  2 ITERATIONS ARE OK FOR SMALL PO2 VALUES,
C     BUT AS PO2 INCREASES, SO DOES # OF NEEDED ITERATIONS.  WE USE 5.
C     ** WARNING **  THIS ALGORITHM BLOWS UP FOR PO2 .GT. 110 (1ST
C     APPROX TO SO2 .GT. 100 PCT).  HOWEVER, THIS IS SIGNIFICANTLY
C     GREATER THAN THE MAX. PIO2 OF 97.5 AT SEA LEVEL.
C
  200 SO2 = 100.0 * O2 TOT / O2 CAP
      DO 220  J = 1,5
      CALL O2 DISS (SO2,PH,PO2,TEMP,PCO2,3)
      SO2 = 100.0 * (O2 TOT - PO2) / O2 CAP
  220 CONTINUE
C
 9900 RETURN
      END