SUBROUTINE TNPREP(A1,A2,B1,B2,C2,GDENOM,GCOEFF, 2
1 GCONST,CPHCHG,TSTART,IWATER,
2 TBAR,TCTOP,TCBOT,FI,ZPOND,TBAR1P,
3 ISAND,ILG,IL1,IL2,JL,IG )
C
C * AUG 19/04 - Y.DELAGE. REGROUP COMMON BLOCKS
C * MAKE DECLARATIONS EXPLICIT
C * AUG 06/02 - D.VERSEGHY. SHORTENED CLASS3 COMMON BLOCK,
C * JUN 17/02 - D.VERSEGHY. USE NEW LUMPED SOIL AND PONDED
C * WATER TEMPERATURE FOR FIRST LAYER;
C * SHORTENED COMMON BLOCK.
C * MAR 28/02 - D.VERSEGHY. CHANGE POND THRESHOLD VALUE FOR
C * CALCULATION OF "IWATER".
C * JUN 20/97 - D.VERSEGHY. CLASS - VERSION 2.7.
C * INCORPORATE EXPLICITLY CALCULATED
C * THERMAL CONDUCTIVITIES AT TOPS AND
C * BOTTOMS OF SOIL LAYERS.
C * SEP 27/96 - D.VERSEGHY. CLASS - VERSION 2.5.
C * SURFACE TREATED AS WATER ONLY IF
C * ZPOND > 1 MM.
C * AUG 18/95 - D.VERSEGHY. CLASS - VERSION 2.4.
C * REVISIONS TO ALLOW FOR INHOMOGENEITY
C * BETWEEN SOIL LAYERS AND FRACTIONAL
C * ORGANIC MATTER CONTENT.
C * NOV 28/94 - M. LAZARE. CLASS - VERSION 2.3.
C * TCSATW,TCSATI DECLARED REAL(16).
C * APR 10/92 - M. LAZARE. CLASS - VERSION 2.1.
C * DIVIDE PREVIOUS SUBROUTINE "T3LAYR"
C * INTO "TNPREP" AND "TNPOST" AND
C * VECTORIZE.
C * APR 11/89 - D.VERSEGHY. CALCULATE COEFFICIENTS FOR GROUND HEAT
C * FLUX, EXPRESSED AS A LINEAR FUNCTION
C * OF SURFACE TEMPERATURE. COEFFICIENTS
C * ARE CALCULATED FROM LAYER TEMPERATURES,
C * THICKNESSES AND THERMAL CONDUCTIVITIES,
C * ASSUMING A QUADRATIC VARIATION OF
C * TEMPERATURE WITH DEPTH WITHIN EACH
C * SOIL LAYER. SET THE SURFACE LATENT
C * HEAT OF VAPORIZATION OF WATER AND
C * THE STARTING TEMPERATURE FOR THE
C * ITERATION IN "TSOLVC"/"TSOLVE".
C
IMPLICIT NONE
INTEGER ILG,IL1,IL2,JL,IG,I
REAL DELZ1,A3,B3,C3
C
C * OUTPUT ARRAYS.
C
REAL A1 (ILG), A2 (ILG), B1 (ILG),
1 B2 (ILG), C2 (ILG), GDENOM(ILG), GCOEFF(ILG),
2 GCONST(ILG), CPHCHG(ILG), TSTART(ILG)
C
INTEGER IWATER(ILG)
C
C * INPUT ARRAYS.
C
REAL TBAR (ILG,IG), TCTOP (ILG,IG), TCBOT (ILG,IG)
C
REAL FI (ILG), ZPOND (ILG), TBAR1P(ILG)
C
INTEGER ISAND (ILG,IG)
C
#include "class_com.cdk"
C-----------------------------------------------------------------------
C * INITIALIZATION OF ARRAYS.
C
DO 100 I=IL1,IL2
IF(FI(I).GT.0.) THEN
DELZ1=DELZ(1)+ZPOND(I)
IF(ZPOND(I).GT.0.5E-3) THEN
IWATER(I)=1
ELSE
IF(ISAND(I,1).GT.-4) THEN
IWATER(I)=0
ELSE
IWATER(I)=2
ENDIF
ENDIF
C
IF(IWATER(I).EQ.2) THEN
CPHCHG(I)=CLHVAP+CLHMLT
ELSE
CPHCHG(I)=CLHVAP
ENDIF
C
A1(I)=DELZ1/(3.0*TCTOP(I,1))
A2(I)=DELZ1/(2.0*TCTOP(I,1))
A3=A2(I)
B1(I)=DELZ1/(6.0*TCBOT(I,1))
B2(I)=DELZ1/(2.0*TCBOT(I,1))+DELZ(2)/(3.0*TCTOP(I,2))
B3=DELZ1/(2.0*TCBOT(I,1))+DELZ(2)/(2.0*TCTOP(I,2))
C2(I)=DELZ(2)/(6.0*TCBOT(I,2))
C3=DELZ(2)/(2.0*TCBOT(I,2))+DELZ(3)/(3.0*TCTOP(I,3))
GDENOM(I)=A1(I)*(B2(I)*C3-B3*C2(I))-B1(I)*(A2(I)*C3-
1 A3*C2(I))
GCOEFF(I)=(B2(I)*C3-B3*C2(I)-B1(I)*(C3-C2(I)))/GDENOM(I)
GCONST(I)=(-TBAR1P(I)*(B2(I)*C3-B3*C2(I))+
1 TBAR(I,2)*B1(I)*C3-
2 TBAR(I,3)*B1(I)*C2(I))/GDENOM(I)
TSTART(I)=TBAR(I,1)
ENDIF
100 CONTINUE
C
RETURN
END