anchor.diff:  C
         IF(MASS.EQ.0) GO TO 50
   C       N2 variation factor at Zlb
  -      G28=SW(21)*GLOBE7(YRD,SEC,GLAT,GLONG,STL,F107A,F107,
  +      G28=SW(21)*GLOBE7(YRD,SEC,GLAT,GLONG,STL,F107A,F107, 
        & AP,PD(1,3))
         DAY=AMOD(YRD,1000.)
   C        VARIATION OF TURBOPAUSE HEIGHT
  
positive.code:       DO 12 K=N-1,1,-1
          Y2(K)=Y2(K)*Y2(K+1)+U(K)
     12 CONTINUE
  
        END Subroutine Spline
  C-----------------------------------------------------------------------
        SUBROUTINE SPLINT(XA,YA,Y2A,N,X,Y)
  C        CALCULATE CUBIC SPLINE INTERP VALUE
  
negative.code:         KHI=KHI+1
          GOTO 1
        ENDIF
        RETURN
        END
  C-----------------------------------------------------------------------
        FUNCTION DNET(DD,DM,ZHM,XMM,XM)
  C       TURBOPAUSE CORRECTION FOR MSIS MODELS
  