moistconvection.f90

CCSM Research Tools: Community Atmosphere Model (CAM)

#include <misc.h>
#include <params.h>
module moistconvection
!
! Moist convection. Primarily data used by both Zhang-McFarlane convection
! and Hack shallow convective schemes.
!
! $Id: moistconvection.F90,v 1.1.4.3 2002/04/22 19:10:05 erik Exp $
!
   use precision, only: r8
   implicit none

   private
   save
!
! Public interfaces
!
   public mfinti   !  Initialization of data for moist convection
   public cmfmca   !  Hack shallow convection
!
! Public Data for moist convection
!
   real(r8), public :: cp          ! specific heat of dry air
   real(r8), public :: grav        ! gravitational constant       
   real(r8), public :: rgrav       ! reciprocal of grav
   real(r8), public :: rgas        ! gas constant for dry air
   integer, public :: limcnv       ! top interface level limit for convection
!
! Private data used for Hack shallow convection
!
   real(r8) :: hlat        ! latent heat of vaporization
   real(r8) :: c0          ! rain water autoconversion coefficient
   real(r8) :: betamn      ! minimum overshoot parameter
   real(r8) :: rhlat       ! reciprocal of hlat
   real(r8) :: rcp         ! reciprocal of cp
   real(r8) :: cmftau      ! characteristic adjustment time scale
   real(r8) :: rhoh2o      ! density of liquid water (STP)
   real(r8) :: dzmin       ! minimum convective depth for precipitation
   real(r8) :: tiny        ! arbitrary small num used in transport estimates
   real(r8) :: eps         ! convergence criteria (machine dependent)
   real(r8) :: tpmax       ! maximum acceptable t perturbation (degrees C)
   real(r8) :: shpmax      ! maximum acceptable q perturbation (g/g)           

   integer :: iloc         ! longitude location for diagnostics
   integer :: jloc         ! latitude  location for diagnostics
   integer :: nsloc        ! nstep for which to produce diagnostics
!
   logical :: rlxclm       ! logical to relax column versus cloud triplet

contains

subroutine mfinti (rair    ,cpair   ,gravit  ,latvap  ,rhowtr  )
!----------------------------------------------------------------------- 
! 
! Purpose: 
! Initialize moist convective mass flux procedure common block, cmfmca
! 
! Method: 
! <Describe the algorithm(s) used in the routine.> 
! <Also include any applicable external references.> 
! 
! Author: J. Hack
! 
!-----------------------------------------------------------------------
   use pmgrid, only: plev, plevp, masterproc

#include <comhyb.h>
!------------------------------Arguments--------------------------------
!
! Input arguments
!
   real(r8), intent(in) :: rair              ! gas constant for dry air
   real(r8), intent(in) :: cpair             ! specific heat of dry air
   real(r8), intent(in) :: gravit            ! acceleration due to gravity
   real(r8), intent(in) :: latvap            ! latent heat of vaporization
   real(r8), intent(in) :: rhowtr            ! density of liquid water (STP)

   integer k              ! vertical level index
!
!-----------------------------------------------------------------------
!
! Initialize physical constants for moist convective mass flux procedure
!
   cp     = cpair         ! specific heat of dry air
   hlat   = latvap        ! latent heat of vaporization
   grav   = gravit        ! gravitational constant
   rgas   = rair          ! gas constant for dry air
   rhoh2o = rhowtr        ! density of liquid water (STP)
!
! Initialize free parameters for moist convective mass flux procedure
!
   c0     = 1.0e-4        ! rain water autoconversion coeff (1/m)
   dzmin  = 0.0           ! minimum cloud depth to precipitate (m)
   betamn = 0.10          ! minimum overshoot parameter
   cmftau = 3600.         ! characteristic adjustment time scale
!
! Limit convection to regions below 40 mb
!
   if (hypi(1) >= 4.e3) then
      limcnv = 1
   else
      do k=1,plev
         if (hypi(k) < 4.e3 .and. hypi(k+1) >= 4.e3) then
            limcnv = k
            goto 10
         end if
      end do
      limcnv = plevp
   end if

10 continue

   if (masterproc) then
      write(6,*)'MFINTI: Convection will be capped at intfc ',limcnv, &
                ' which is ',hypi(limcnv),' pascals'
   end if

   tpmax  = 1.50          ! maximum acceptable t perturbation (deg C)
   shpmax = 1.50e-3       ! maximum acceptable q perturbation (g/g)
   rlxclm = .true.        ! logical variable to specify that relaxation
!                                time scale should applied to column as
!                                opposed to triplets individually
!
! Initialize miscellaneous (frequently used) constants
!
   rhlat  = 1.0/hlat      ! reciprocal latent heat of vaporization
   rcp    = 1.0/cp        ! reciprocal specific heat of dry air
   rgrav  = 1.0/grav      ! reciprocal gravitational constant
!
! Initialize diagnostic location information for moist convection scheme
!
   iloc   = 1             ! longitude point for diagnostic info
   jloc   = 1             ! latitude  point for diagnostic info
   nsloc  = 1             ! nstep value at which to begin diagnostics
!
! Initialize other miscellaneous parameters
!
   tiny   = 1.0e-36       ! arbitrary small number (scalar transport)
   eps    = 1.0e-13       ! convergence criteria (machine dependent)
!
   return
end subroutine mfinti

subroutine cmfmca(lchnk   ,ncol    , &
                  nstep   ,ztodt     ,pmid    ,pdel    , &
                  rpdel   ,zm      ,tpert   ,qpert   ,phis    , &
                  pblht   ,t       ,q       ,cmfdt   ,dq      , &
                  cmfmc   ,cmfdqr  ,cmfsl   ,cmflq   ,precc   , &
                  qc      ,cnt     ,cnb     ,icwmr   )
!----------------------------------------------------------------------- 
! 
! Purpose: 
! Moist convective mass flux procedure:
! 
! Method: 
! If stratification is unstable to nonentraining parcel ascent,
! complete an adjustment making successive use of a simple cloud model
! consisting of three layers (sometimes referred to as a triplet)
!
! Code generalized to allow specification of parcel ("updraft")
! properties, as well as convective transport of an arbitrary
! number of passive constituents (see q array).  The code
! is written so the water vapor field is passed independently
! in the calling list from the block of other transported
! constituents, even though as currently designed, it is the
! first component in the constituents field.
! 
! Author: J. Hack
!
! BAB: changed code to report tendencies in cmfdt and dq, instead of
! updating profiles. Cmfdq contains water only, made it a local variable
! made dq (all constituents) the argument.
! 
!-----------------------------------------------------------------------

!#######################################################################
!#                                                                     #
!# Debugging blocks are marked this way for easy identification        #
!#                                                                     #
!#######################################################################
   use tracers,   only: pcnst, pnats
   use ppgrid,    only: pcols, pver, pverp
   use phys_grid, only: get_lat_all_p, get_lon_all_p
   use wv_saturation, only: aqsatd, vqsatd

   real(r8) ssfac               ! supersaturation bound (detrained air)
   parameter (ssfac = 1.001)

!------------------------------Arguments--------------------------------
!
! Input arguments
!
   integer, intent(in) :: lchnk                ! chunk identifier
   integer, intent(in) :: ncol                 ! number of atmospheric columns
   integer, intent(in) :: nstep                ! current time step index

   real(r8), intent(in) :: ztodt               ! 2 delta-t (seconds)
   real(r8), intent(in) :: pmid(pcols,pver)    ! pressure
   real(r8), intent(in) :: pdel(pcols,pver)    ! delta-p
   real(r8), intent(in) :: rpdel(pcols,pver)   ! 1./pdel
   real(r8), intent(in) :: zm(pcols,pver)      ! height abv sfc at midpoints
   real(r8), intent(in) :: tpert(pcols)        ! PBL perturbation theta
   real(r8), intent(in) :: qpert(pcols,pcnst+pnats)  ! PBL perturbation specific humidity
   real(r8), intent(in) :: phis(pcols)         ! surface geopotential
   real(r8), intent(in) :: pblht(pcols)        ! PBL height (provided by PBL routine)
   real(r8), intent(in) :: t(pcols,pver)       ! temperature (t bar)
   real(r8), intent(in) :: q(pcols,pver,pcnst+pnats) ! specific humidity (sh bar)
!
! Output arguments
!
   real(r8), intent(out) :: cmfdt(pcols,pver)   ! dt/dt due to moist convection
   real(r8), intent(out) :: cmfmc(pcols,pver )  ! moist convection cloud mass flux
   real(r8), intent(out) :: cmfdqr(pcols,pver)  ! dq/dt due to convective rainout
   real(r8), intent(out) :: cmfsl(pcols,pver )  ! convective lw static energy flux
   real(r8), intent(out) :: cmflq(pcols,pver )  ! convective total water flux
   real(r8), intent(out) :: precc(pcols)        ! convective precipitation rate
   real(r8), intent(out) :: qc(pcols,pver)      ! dq/dt due to rainout terms
   real(r8), intent(out) :: cnt(pcols)          ! top level of convective activity
   real(r8), intent(out) :: cnb(pcols)          ! bottom level of convective activity
   real(r8), intent(out) :: dq(pcols,pver,pcnst+pnats) ! constituent tendencies
   real(r8), intent(out) :: icwmr(pcols,pver)
!
!---------------------------Local workspace-----------------------------
!
   real(r8) cmfdq(pcols,pver)   ! dq/dt due to moist convection
   real(r8) gam(pcols,pver)     ! 1/cp (d(qsat)/dT)
   real(r8) sb(pcols,pver)      ! dry static energy (s bar)
   real(r8) hb(pcols,pver)      ! moist static energy (h bar)
   real(r8) shbs(pcols,pver)    ! sat. specific humidity (sh bar star)
   real(r8) hbs(pcols,pver)     ! sat. moist static energy (h bar star)
   real(r8) shbh(pcols,pverp)   ! specific humidity on interfaces
   real(r8) sbh(pcols,pverp)    ! s bar on interfaces
   real(r8) hbh(pcols,pverp)    ! h bar on interfaces
   real(r8) cmrh(pcols,pverp)   ! interface constituent mixing ratio
   real(r8) prec(pcols)         ! instantaneous total precipitation
   real(r8) dzcld(pcols)        ! depth of convective layer (m)
   real(r8) beta(pcols)         ! overshoot parameter (fraction)
   real(r8) betamx(pcols)       ! local maximum on overshoot
   real(r8) eta(pcols)          ! convective mass flux (kg/m^2 s)
   real(r8) etagdt(pcols)       ! eta*grav*dt
   real(r8) cldwtr(pcols)       ! cloud water (mass)
   real(r8) rnwtr(pcols)        ! rain water  (mass)
   real(r8) sc  (pcols)         ! dry static energy   ("in-cloud")
   real(r8) shc (pcols)         ! specific humidity   ("in-cloud")
   real(r8) hc  (pcols)         ! moist static energy ("in-cloud")
   real(r8) cmrc(pcols)         ! constituent mix rat ("in-cloud")
   real(r8) dq1(pcols)          ! shb  convective change (lower lvl)
   real(r8) dq2(pcols)          ! shb  convective change (mid level)
   real(r8) dq3(pcols)          ! shb  convective change (upper lvl)
   real(r8) ds1(pcols)          ! sb   convective change (lower lvl)
   real(r8) ds2(pcols)          ! sb   convective change (mid level)
   real(r8) ds3(pcols)          ! sb   convective change (upper lvl)
   real(r8) dcmr1(pcols)        ! q convective change (lower lvl)
   real(r8) dcmr2(pcols)        ! q convective change (mid level)
   real(r8) dcmr3(pcols)        ! q convective change (upper lvl)
   real(r8) estemp(pcols,pver)  ! saturation vapor pressure (scratch)
   real(r8) vtemp1(2*pcols)     ! intermediate scratch vector
   real(r8) vtemp2(2*pcols)     ! intermediate scratch vector
   real(r8) vtemp3(2*pcols)     ! intermediate scratch vector
   real(r8) vtemp4(2*pcols)     ! intermediate scratch vector
   integer indx1(pcols)     ! longitude indices for condition true
   logical etagt0           ! true if eta > 0.0
   real(r8) sh1                 ! dummy arg in qhalf statement func.
   real(r8) sh2                 ! dummy arg in qhalf statement func.
   real(r8) shbs1               ! dummy arg in qhalf statement func.
   real(r8) shbs2               ! dummy arg in qhalf statement func.
   real(r8) cats                ! modified characteristic adj. time
   real(r8) rtdt                ! 1./ztodt
   real(r8) qprime              ! modified specific humidity pert.
   real(r8) tprime              ! modified thermal perturbation
   real(r8) pblhgt              ! bounded pbl height (max[pblh,1m])
   real(r8) fac1                ! intermediate scratch variable
   real(r8) shprme              ! intermediate specific humidity pert.
   real(r8) qsattp              ! sat mix rat for thermally pert PBL parcels
   real(r8) dz                  ! local layer depth
   real(r8) temp1               ! intermediate scratch variable
   real(r8) b1                  ! bouyancy measure in detrainment lvl
   real(r8) b2                  ! bouyancy measure in condensation lvl
   real(r8) temp2               ! intermediate scratch variable
   real(r8) temp3               ! intermediate scratch variable
   real(r8) g                   ! bounded vertical gradient of hb
   real(r8) tmass               ! total mass available for convective exch
   real(r8) denom               ! intermediate scratch variable
   real(r8) qtest1              ! used in negative q test (middle lvl)
   real(r8) qtest2              ! used in negative q test (lower lvl)
   real(r8) fslkp               ! flux lw static energy (bot interface)
   real(r8) fslkm               ! flux lw static energy (top interface)
   real(r8) fqlkp               ! flux total water (bottom interface)
   real(r8) fqlkm               ! flux total water (top interface)
   real(r8) botflx              ! bottom constituent mixing ratio flux
   real(r8) topflx              ! top constituent mixing ratio flux
   real(r8) efac1               ! ratio q to convectively induced chg (btm lvl)
   real(r8) efac2               ! ratio q to convectively induced chg (mid lvl)
   real(r8) efac3               ! ratio q to convectively induced chg (top lvl)
   real(r8) tb(pcols,pver)      ! working storage for temp (t bar)
   real(r8) shb(pcols,pver)     ! working storage for spec hum (sh bar)
   real(r8) adjfac              ! adjustment factor (relaxation related)
   real(r8) rktp
   real(r8) rk
#if ( defined DIAGNS )
!
!  Following 7 real variables are used in diagnostics calculations
!
   real(r8) rh                  ! relative humidity
   real(r8) es                  ! sat vapor pressure
   real(r8) hsum1               ! moist static energy integral
   real(r8) qsum1               ! total water integral
   real(r8) hsum2               ! final moist static energy integral
   real(r8) qsum2               ! final total water integral
   real(r8) fac                 ! intermediate scratch variable
#endif
   integer i,k              ! longitude, level indices
   integer ii               ! index on "gathered" vectors
   integer len1             ! vector length of "gathered" vectors
   integer m                ! constituent index
   integer ktp              ! tmp indx used to track top of convective layer
#if ( defined DIAGNS )
   integer n                ! vertical index     (diagnostics)
   integer kp               ! vertical index     (diagnostics)
   integer kpp              ! index offset, kp+1 (diagnostics)
   integer kpm1             ! index offset, kp-1 (diagnostics)
   integer lat(pcols)       ! latitude indices
   integer lon(pcols)       ! longitude indices
#endif
!
!---------------------------Statement functions-------------------------
!
   real(r8) qhalf
   qhalf(sh1,sh2,shbs1,shbs2) = min(max(sh1,sh2),(shbs2*sh1 + shbs1*sh2)/(shbs1+shbs2))
!
!-----------------------------------------------------------------------

!** BAB initialize output tendencies here
!       copy q to dq; use dq below for passive tracer transport
   cmfdt(:ncol,:)  = 0.
   cmfdq(:ncol,:)  = 0.
   dq(:ncol,:,2:)  = q(:ncol,:,2:)
   cmfmc(:ncol,:)  = 0.
   cmfdqr(:ncol,:) = 0.
   cmfsl(:ncol,:)  = 0.
   cmflq(:ncol,:)  = 0.
   qc(:ncol,:)     = 0.
!