!copyright (C) 2001  MSC-RPN COMM  %%%RPNPHY%%%
***S/R MTHTAW  -  CALCULE TW OU THETAW
*
#include "phy_macros_f.h"

      SUBROUTINE MTHTAW(TW,HU,TX,PX,LNPS,MODP,SWTT,,2
     $                  SWPH,SWTH,NI,NK,N)
*
#include "impnone.cdk"
*
      INTEGER NI, NK, N, MODP
      REAL TW(NI,NK), HU(NI,NK), TX(NI,NK)
      REAL PX(NK), LNPS(NI,*)
      REAL TEMP1
      LOGICAL SWTT, SWPH, SWTH
*
*Author
*          N. Brunet  (Jan91)
*
*Revision
* 001      B. Bilodeau  (August 1991)- Adaptation to UNIX
* 002      N. Brunet (May 1994) - change to l2ocprv in order to
*          obtain results closer to those of tephigram
* 003      B. Bilodeau (Jan 2001) - Automatic arrays
* 004      M. Lepine (March 2003) -  CVMG... Replacements
*
*Object
*          to calculate TW or THETAW (according to the value SWTT)
*          from specific humidity, temperature and pressure
*
*Arguments
*
*          - Output -
* TW       TW or THETAW in Kelvins
*
*          - Input -
* HU       specific humidity in kg/kg
* TX       temperature or virtual temperature in Kelvins
* PX       see MODP
* LNPS     see MODP
* MODP     pressure mode (SI units only):
*          =0; pressure level in PX
*          =1; sigma level in PX and PS(surface pressure) in LNPS
*          =2; sigma level in PX and logarithm of sigma level in
*          LNPS
*          =3; all points of pressure in LNPS(NI,*) in Pascals
*          =4; sigma level in PX and logarithm of sigma level in
*          LNPS(in millibars unless using SI units)
*          =5; logarithm of pressure level in PX(in millibars unless
*          using SI units)
* SWTT     .TRUE. to pass TT for argument
*          .FALSE. to pass TV for argument
* SWPH     .TRUE. to consider water and ice phase
*          .FALSE. to consider water phase only
* SWTH     .TRUE. to calculate THETAW
*          .FALSE. to calculate TW
* NI       horizontal dimension
* NK       vertical dimension
* N        number of treated points
*
*IMPLICITES
#include "consphy.cdk"
*
*MODULES
      EXTERNAL INCTPHY
*
**
*--------------------------------------------------------------------
*
************************************************************************
*     AUTOMATIC ARRAYS
************************************************************************
*
      AUTOMATIC ( PN , REAL , (N))
*
************************************************************************
*
      REAL Q1, DQ1, Q0, TH, H, FT0, DFT0, PRN
      REAL DLP, D, L2OCPRV, QP, FAC
      INTEGER ITER, I, K, NN, J
*
#include "dintern.cdk"
#include "fintern.cdk"
*--------------------------------------------------------------------
#include "initcph.cdk"
*
      L2OCPRV = 1.35E+07
*
      DO 10 K=1,NK
*
#include "modpr2.cdk"
         IF(SWTT)THEN
            DO 100 I=1,N
               TW(I,K) = TX(I,K)
100         CONTINUE
         ELSE
            DO 105 I=1,N
               TW(I,K) = FOTTV(TX(I,K),HU(I,K))
105         CONTINUE
         END IF
*
*
*
         DO 200 I=1,N
*
*     ON TROUVE 'TW' EN SOLUTIONNANT PAR METHODE
*     DE NEWTON DU 1ER ORDRE AVEC 4 ITERATIONS.
*
            Q0 = HU(I,K)
*
            DO 300 ITER=1,4
               H = HTVOCP(TW(I,K))
               TEMP1 = PN(I)
               IF(SWPH)THEN
                  Q1 = FOQST(TW(I,K),TEMP1)
                  DQ1 = FODQS(Q1,TW(I,K))
               ELSE
                  Q1 = FOQSA(TW(I,K),TEMP1)
                  DQ1 = FODQA(Q1,TW(I,K))
               END IF
               FT0 = -H*(Q1 - Q0)
               DFT0 = -1.0 -(H*DQ1)
               TW(I,K) = TW(I,K) - FT0/DFT0
               Q0 = Q0 + FT0/(DFT0*H)
300         CONTINUE
*
            IF(SWTH)THEN
*
*     ON TROUVE THETAW EN UTILISANT LA PENTE DE L'ADIABATIQUE
*     MOUILLEE ET EN FAISANT LES CALCULS PAR TRANCHE DE
*     1000 PA ('DLP') EN PASSANT DE 'PN' A 100000.
*
               IF(PN(I).NE.100000.)THEN
                  DLP = 1000.
                  D = 100000. - PN(I)
                  NN = INT(ABS(D/DLP))
                  IF(D.LT.0.)DLP = -DLP
                  D = D - FLOAT(NN)*DLP
                  IF(D.NE.0.)THEN
                     NN = NN + 1
                  ELSE
                     D = DLP
                  END IF
*
                  PRN = PN(I)
                  TH = TW(I,K)
*
                  DO 400 J=1,NN
                     QP = D/PRN
                     Q1 = FOQST(TH,PRN)
                     IF(.NOT.SWPH)Q1 = FOQSA(TH,PRN)
                     H = HTVOCP(TH)
                     FAC = (CAPPA + (H*Q1/TH))/(1. +
     +               L2OCPRV*Q1/(TH*TH))
                     TH = TH*(1. + QP*FAC)
*
                     PRN = PRN + D
                     IF(J.EQ.1)D = DLP
400               CONTINUE
*
                  TW(I,K) = TH
*
               END IF
*
            END IF
200      CONTINUE
*
10    CONTINUE
*
*
      CONTAINS
#include "flatscp.cdk"
      END