!> @file !> @brief lfmfld_gfs() computes layer mean LFM fields. !> !> This routine computes three layer mean relative humidities !> and a precipitable water field from ETA level data. The !> computed fields are intended to mimic similar fields com- !> puted by the LFM. The algorithm used here is fairly pri- !> mative. !> 
!> In each column above a mass point on the ETA grid we set the following target pressures:
!>     Sigma layer 1.00 pressure:  Surface pressure
!>     Sigma layer 0.66 pressure:  0.50 * Surface pressure
!>     Sigma layer 0.33 pressure:  0.4356 * Surface pressure
!>
!> Given there pressures a surface up summation is made of !> relative humidity and/or precipitable water between these !> target pressures. Each term in the summation is weighted !> By the thickness of the ETA layer. The final layer mean !> is this sum normalized by the total depth of the layer. !> There is, obviously, no normalization for precipitable water. !> !> @param[out] RH3310 Sigma layer 0.33-1.00 mean relative humidity. !> @param[out] RH6610 Sigma layer 0.66-1.00 mean relative humidity. !> @param[out] RH3366 Sigma layer 0.33-0.66 mean relative humidity. !> @param[out] PW3310 Sigma layer 0.33-1.00 precipitable water. !> !> ### Program History Log !> Date | Programmer | Comments !> -----|------------|--------- !> 1992-12-22 | Russ Treadon | Initial !> 1993-07-27 | Russ Treadon | Modified summation limits from 0.66*PSFC to 0.75*PSFC and 0.33*PSFC to 0.50*PSFC, where PSFC is the surfaces pressure. The reason for this change was recognition that in the LFM 0.33 and 0.66 were measured from the surface to the tropopause not the top of the model. !> 1993-09-13 | Russ Treadon | RH calculations were made internal to the routine. !> 1996-03-04 | Mike Baldwin | Change PW CALC to include CLD WTR !> 1998-06-16 | T Black | Conversion from 1-D to 2-D !> 1998-08-17 | Mike Baldwin | Compute RH over ice !> 1998-12-22 | Mike Baldwin | Back out RH over ice !> 2000-01-04 | Jim Tuccillo | MPI Version !> 2002-04-24 | Mike Baldwin | WRF Version !> 2006-11-06 | H CHUANG | Modify to output GFS LFM fields which have different thickness as MESO and use DP rather than DZ !> 2019-10-30 | Bo Cui | Remove "GOTO" statement !> 2020-11-10 | Jesse Meng | Use UPP_PHYSICS Module !> 2021-10-14 | JESSE MENG | 2D DECOMPOSITION !> !> @author Russ Treadon W/NP2 @date 1992-12-22 SUBROUTINE LFMFLD_GFS(RH4410,RH7294,RH4472,RH3310) ! ! use vrbls3d, only: pint, q, t, pmid use masks, only: lmh use params_mod, only: d00 use ctlblk_mod, only: jsta, jend, spval, im, ista, iend use upp_physics, only: FPVSNEW ! implicit none ! real,PARAMETER :: RHOWAT=1.E3 real,parameter:: con_rd =2.8705e+2 ! gas constant air (J/kg/K) real,parameter:: con_rv =4.6150e+2 ! gas constant H2O real,parameter:: con_eps =con_rd/con_rv real,parameter:: con_epsm1 =con_rd/con_rv-1 real,parameter:: strh1=0.44,strh2=0.72,strh3=0.44,strh4=0.33 & ,sbrh1=1.00,sbrh2=0.94,sbrh3=0.72,sbrh4=1.00 ! ! DECLARE VARIABLES. ! REAL ALPM, DZ, ES, PM, PWSUM, QM, QS REAL,dimension(ista:iend,jsta:jend),intent(out) :: RH4410, RH7294, RH4472 & ,RH3310 ! integer I,J,L,LLMH real P4410, P7294,P4472,P3310,Q4410,Q7294,Q4472,Q3310,QS4410, & QS7294,QS4472,QS3310,PS,P33,DP1,DP2,DP3,DP4 !*********************************************************************** ! START LFMFLD HERE ! ! ! LOOP OVER HORIZONTAL GRID. ! DO 30 J=JSTA,JEND DO 30 I=ISTA,IEND ! ! ZERO VARIABLES. RH4410(I,J) = D00 RH4472(I,J) = D00 RH7294(I,J) = D00 RH3310(I,J) = D00 P4410 = D00 P7294 = D00 P4472 = D00 P3310 = D00 Q4410 = D00 Q7294 = D00 Q4472 = D00 Q3310 = D00 QS4410 = D00 QS7294 = D00 QS4472 = D00 QS3310 = D00 ! ! SET BOUNDS FOR PRESSURES AND SURFACE L. LLMH = NINT(LMH(I,J)) PS=PINT(I,J,LLMH+1) P33 = 0.33*PS ! ! ACCULMULATE RELATIVE HUMIDITIES AND PRECIPITABLE WATER. ! DO 10 L = LLMH,1,-1 ! ! GET P, Z, T, AND Q AT MIDPOINT OF ETA LAYER. DP1 = MAX(MIN(PINT(I,J,L+1),SBRH1*PS) & -MAX(PINT(I,J,L),STRH1*PS),0.) DP2 = MAX(MIN(PINT(I,J,L+1),SBRH2*PS) & -MAX(PINT(I,J,L),STRH2*PS),0.) DP3 = MAX(MIN(PINT(I,J,L+1),SBRH3*PS) & -MAX(PINT(I,J,L),STRH3*PS),0.) DP4 = MAX(MIN(PINT(I,J,L+1),SBRH4*PS) & -MAX(PINT(I,J,L),STRH4*PS),0.) PM = PINT(I,J,L) QM = Q(I,J,L) QM = MAX(QM,D00) ES = min(FPVSNEW(T(I,J,L)),PMID(I,J,L)) QS=CON_EPS*ES/(PMID(I,J,L)+CON_EPSM1*ES) ! ! ! JUMP OUT OF THIS LOOP IF WE ARE ABOVE THE HIGHEST TARGET PRESSURE. IF (PM<=P33) exit ! ! 0.44-1.00 RELATIVE HUMIDITY. ! IF ((PM<=P10).AND.(PM>=P44)) THEN P4410 = P4410 + DP1 Q4410 = Q4410 + QM*DP1 QS4410 = QS4410+ QS*DP1 ! ENDIF ! ! 0.33-1.00 RELATIVE HUMIDITY ! IF ((PM<=P10).AND.(PM>=P33)) THEN P3310 = P3310 + DP4 Q3310 = Q3310 + QM*DP4 QS3310 = QS3310+ QS*DP4 ! ENDIF ! ! 0.44-0.72 RELATIVE HUMIDITY. ! IF ((PM<=P66).AND.(PM>=P33)) THEN P4472 = P4472 + DP3 Q4472 = Q4472 + QM*DP3 QS4472 = QS4472+ QS*DP3 ! ENDIF ! 0.72-0.94 RELATIVE HUMIDITY. ! IF ((PM<=P66).AND.(PM>=P33)) THEN P7294 = P7294 + DP2 Q7294 = Q7294 + QM*DP2 QS7294 = QS7294+ QS*DP2 ! ENDIF ! 10 CONTINUE ! ! NORMALIZE TO GET MEAN RELATIVE HUMIDITIES. AT ! ONE TIME WE DIVIDED PRECIPITABLE WATER BY DENSITY ! TO GET THE EQUIVALENT WATER DEPTH IN METERS. NO MORE. IF (P4410>D00) THEN RH4410(I,J) = Q4410/QS4410 ELSE RH4410(I,J) = SPVAL ENDIF ! IF (P3310>D00) THEN RH3310(I,J) = Q3310/QS3310 ELSE RH3310(I,J) = SPVAL ENDIF ! IF (P4472>D00) THEN RH4472(I,J) = Q4472/QS4472 ELSE RH4472(I,J) = SPVAL ENDIF IF (P7294>D00) THEN RH7294(I,J) = Q7294/QS7294 ELSE RH7294(I,J) = SPVAL ENDIF 30 CONTINUE ! ! END OF ROUTINE. ! RETURN END