! $Id: emisop.f,v 1.2 2009/11/30 19:57:57 ccarouge Exp $ FUNCTION EMISOP( I, J, IJLOOP, SUNCOS, TMMP, XNUMOL ) ! !****************************************************************************** ! Subroutine EMISOP_GRASS computes ISOPRENE EMISSIONS in units of ! [atoms C/box/step]. (bdf, bmy, 8/1/01, 6/16/05) ! ! Arguments as Input: ! ============================================================================ ! (1-2) I, J (INTEGER ) : 2-D grid box indices ! (3 ) IJLOOP (INTEGER ) : 1-D grid box index ! (4 ) SUNCOS (REAL*8 ) : 1-D array of cos( solar zenith angle ) ! (5 ) TMMP (REAL*8 ) : Local air temperature (K) ! (6 ) XNUMOL (REAL*8 ) : Number of atoms C / kg C ! ! Important Common Block Variables: ! ============================================================================ ! (1 ) XYLAI (F77_CMN_VEL ) : Leaf Area Index of land type for current MONTH ! (2 ) IJREG (F77_CMN_VEL ) : Number of Olson land types per grid box ! (3 ) IJLAND+1 (F77_CMN_VEL ) : Olson land type index ! (4 ) IJUSE (F77_CMN_VEL ) : Olson land type fraction per box (in mils) ! (5 ) SOPCOEFF (F77_CMN_ISOP) : 2nd order polynomial coeffs for light correction ! (6 ) BASEISOP (F77_CMN_ISOP) : Baseline ISOPRENE emissions [kg C/box/step] ! ! NOTES: ! (1 ) Now force double precision with DBLE and "D" exponents. Also updated ! comments, made cosmetic changes (bmy, 4/4/03) ! (2 ) Now pass I, J via the arg list. Now reference CLDFRC directly from ! "dao_mod.f" instead of referencing CFRAC from "F77_CMN_DEP". Now ! remove reference to F77_CMN_DEP. (bmy, 12/9/03) ! (3 ) Now scale ISOP emissions to 400 Tg C/yr for GEOS-4 (bmy, 3/5/04) ! (4 ) Now force ISOP totals to be the same for GEOS-3 and GEOS-4 met fields ! for the year 2001. This will facilitate cross-model intercomparison. ! (jal, bmy, 3/15/05) ! (5 ) Bug fix: replace #else with #elif (swu, bmy, 6/16/05) ! (6 ) Move XLTMMP to module MEGANUT_MOD (ccc, 11/20/09) !****************************************************************************** ! ! References to F90 modules USE DAO_MOD, ONLY : CLDFRC USE MEGANUT_MOD, ONLY : XLTMMP USE CMN_SIZE_MOD ! Size parameters USE CMN_ISOP_MOD ! SOPCOEFF, BASEISOP USE CMN_VEL_MOD ! IJREG, IJLAND, IJUSE IMPLICIT NONE # include "define.h" ! Arguments INTEGER, INTENT(IN) :: IJLOOP, I, J REAL*8, INTENT(IN) :: SUNCOS(MAXIJ), TMMP, XNUMOL ! Local variables INTEGER :: INVEG REAL*8 :: TLAI, EMBIO, CLIGHT ! External functions !-- XLTMMP moved to meganut_mod.f (ccc, 11/20/09) ! REAL*8, EXTERNAL :: XLTMMP, BIOFIT, TCORR REAL*8, EXTERNAL :: BIOFIT, TCORR ! Function value REAL*8 :: EMISOP !================================================================= ! EMISOP begins here! !================================================================= ! Initialize EMISOP = 0.d0 TLAI = 0.d0 ! Compute total of Leaf Area Index * baseline isoprene ! over all Olson land types that are in this grid box DO INVEG = 1, IJREG(IJLOOP) TLAI = TLAI + XYLAI(IJLOOP,INVEG) * BASEISOP(IJLOOP,INVEG) ENDDO !================================================================= ! Apply light & temperature corrections to baseline emissions -- ! only if it is daytime and if there is nonzero isoprene emission ! (e.g. XYLAI * BASEISOP > 0 ) !================================================================= IF ( ( SUNCOS(IJLOOP) > 0d0 ) .AND. ( TLAI > 0d0 ) ) THEN ! Initialize EMBIO = 0d0 ! Loop over each Olson land type in this grid box DO INVEG = 1, IJREG(IJLOOP) ! If the product of leaf area index and baseline ISOP > 0 ... IF ( XYLAI(IJLOOP,INVEG) * & BASEISOP(IJLOOP,INVEG) > 0d0 ) THEN ! Compute light correction -- polynomial fit CLIGHT = BIOFIT( SOPCOEFF, XYLAI(IJLOOP,INVEG), & SUNCOS(IJLOOP), CLDFRC(I,J) ) ! Apply light correction to baseline ISOPRENE emissions. ! Also multiply by the fraction of the grid box occupied ! by this Olson landtype. Units are [kg C/box/step]. ! BASEISOP emission rate is set in setbase.f EMBIO = EMBIO + & ( BASEISOP(IJLOOP,INVEG) * CLIGHT * & DBLE( IJUSE(IJLOOP,INVEG) ) ) / 1000.d0 ENDIF ENDDO ! Apply the temperature correction from Gunther et al 92 to the ! ISOPRENE emissions. Units are still [kg C/box/step]. IF ( TMMP > 273d0 ) THEN EMISOP = TCORR(TMMP) * EMBIO ELSE EMISOP = 0d0 ENDIF ENDIF !================================================================= ! EMISOP is the amount of ISOP emitted in [kg/box/step]. ! Convert to [atoms C/box/step] and return. !================================================================= EMISOP = EMISOP * XNUMOL #if defined( GEOS_3 ) ! GEOS-3 meteorology results in 579 Tg C/yr from ISOP. Scale ! this down to 400 Tg C/yr, which is what we get from GEOS-STRAT ! (mje, djj, bmy, 8/26/02) ! ! NOTE: This actually produces more like 341 Tg for 2001 GEOS-3 ! met fields, but that is OK (jal, bmy, 3/15/05) EMISOP = EMISOP * ( 400d0 / 579d0 ) #elif defined( GEOS_4 ) ! Original GEOS-4 scaling produced 443 Tg C/yr w/ 2003 "V3" met ! fields. However we have since switched to GEOS-4 "V4" met fields ! and need to rescale the ISOP total. A recent run with GEOS-4 "V4" ! met fields for 2001 produced 443 Tg C/yr. We need to force the ! total to be the same as for GEOS-3, for comparison purposes. ! Therefore apply a second scale factor so that we get 341 Tg C/yr ! of ISOP for GEOS-4 "V4" met fields for 2001. (bmy, 3/15/05) EMISOP = EMISOP * ( 400d0 / 443d0 ) EMISOP = EMISOP * ( 341.2376d0 / 442.7354d0 ) #endif ! Return to calling program END FUNCTION EMISOP