SUBROUTINE newsedim(ngrid,nlay,naersize,ptimestep, & pplev,masse,epaisseur,pt,rd,rho,pqi,wq) IMPLICIT NONE !================================================================== ! ! Purpose ! ------- ! Calculates sedimentation of 1 tracer ! of radius rd (m) and density rho (kg.m-3) ! !================================================================== !----------------------------------------------------------------------- ! declarations ! ------------ #include "dimensions.h" #include "dimphys.h" #include "comcstfi.h" ! arguments ! --------- integer,intent(in) :: ngrid ! number of atmospheric columns integer,intent(in) :: nlay ! number of atmospheric layers integer,intent(in) :: naersize ! number of particle sizes (1 or number ! of grid boxes) real,intent(in) :: ptimestep ! physics time step (s) real,intent(in) :: pplev(ngrid,nlay+1) ! inter-layer pressures (Pa) real,intent(in) :: pt(ngrid,nlay) ! mid-layer temperatures (K) real,intent(in) :: masse (ngrid,nlay) ! atmospheric mass (kg) real,intent(in) :: epaisseur (ngrid,nlay) ! thickness of atm. layers (m) real,intent(in) :: rd(naersize) ! particle radius (m) real,intent(in) :: rho ! particle density (kg.m-3) real,intent(inout) :: pqi(ngrid,nlay) ! tracer (e.g. ?/kg) real,intent(out) :: wq(ngrid,nlay+1) ! flux of tracer during timestep (?/m-2) c local: c ------ INTEGER l,ig, k, i REAL rfall LOGICAL,SAVE :: firstcall=.true. c Traceurs : c ~~~~~~~~ real traversee (ngrid,nlayermx) real vstokes(ngrid,nlayermx) real w(ngrid,nlayermx) real ptop, dztop, Ep, Stra c Physical constant c ~~~~~~~~~~~~~~~~~ c Gas molecular viscosity (N.s.m-2) real,parameter :: visc=1.e-5 ! CO2 c Effective gas molecular radius (m) real,parameter :: molrad=2.2e-10 ! CO2 c local and saved variable real,save :: a,b c ** un petit test de coherence c -------------------------- !print*,'temporary fixed particle rad in newsedim!!' IF (firstcall) THEN firstcall=.false. !======================================================================= ! Preliminary calculations for sedimenation velocity ! - Constant to compute stokes speed simple formulae ! (Vstokes = b * rho* r**2 avec b= (2/9) * rho * g / visc b = 2./9. * g / visc ! - Constant to compute gas mean free path ! l= (T/P)*a, avec a = ( 0.707*8.31/(4*pi*molrad**2 * avogadro)) a = 0.707*8.31/(4*3.1416* molrad**2 * 6.023e23) c - Correction to account for non-spherical shape (Murphy et al. 1990) c (correction = 0.85 for irregular particles, 0.5 for disk shaped particles) c a = a * 0.85 ENDIF c----------------------------------------------------------------------- c 1. initialisation c ----------------- c Sedimentation velocity (m/s) c ~~~~~~~~~~~~~~~~~~~~~~ c (stokes law corrected for low pressure by the Cunningham c slip-flow correction according to Rossow (Icarus 36, 1-50, 1978) do l=1,nlay do ig=1, ngrid if (naersize.eq.1) then rfall=rd(1) else i=ngrid*(l-1)+ig rfall=rd(i) ! how can this be correct!!? endif vstokes(ig,l) = b * rho * rfall**2 * & (1 + 1.333* ( a*pt(ig,l)/pplev(ig,l) )/rfall) c Layer crossing time (s) : traversee(ig,l)= epaisseur(ig,l)/vstokes(ig,l) end do end do c Calcul de la masse d'atmosphere correspondant a q transferee c ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ c (e.g. on recherche le niveau en dessous de laquelle le traceur c va traverser le niveau intercouche l : "dztop" est sa hauteur c au dessus de l (m), "ptop" est sa pression (Pa)) do l=1,nlay do ig=1, ngrid dztop = vstokes(ig,l)* ptimestep Ep=0 k=0 w(ig,l) = 0. !! JF+AS ajout initialisation (LK MARS) c ************************************************************** c Simple Method cc w(ig,l) = cc & (1- exp(-dztop*g/(r*pt(ig,l))))*pplev(ig,l) / g cc write(*,*) 'OK simple method l,w =', l, w(ig,l) cc write(*,*) 'OK simple method dztop =', dztop w(ig,l) = 1. - exp(-dztop*g/(r*pt(ig,l))) !!! Diagnostic: JF. Fix: AS. Date: 05/11 !!! Probleme arrondi avec la quantite ci-dessus !!! ---> vaut 0 pour -dztop*g/(r*pt(ig,l)) trop petit !!! ---> dans ce cas on utilise le developpement limite ! !!! ---> exp(-x) = 1 - x lorsque x --> 0 avec une erreur de x^2 / 2 IF ( w(ig,l) .eq. 0. ) THEN w(ig,l) = ( dztop*g/(r*pt(ig,l)) ) * pplev(ig,l) / g ELSE w(ig,l) = w(ig,l) * pplev(ig,l) / g ENDIF ! LK borrowed simple method from Mars model (AS/JF) !************************************************************** cccc Complex method : if (dztop.gt.epaisseur(ig,l)) then cccc Cas ou on "epuise" la couche l : On calcule le flux cccc Venant de dessus en tenant compte de la variation de Vstokes Ep= epaisseur(ig,l) Stra= traversee(ig,l) do while(dztop.gt.Ep.and.l+k+1.le.nlay) k=k+1 dztop= Ep + vstokes(ig,l+k)*(ptimestep -Stra) Ep = Ep + epaisseur(ig,l+k) Stra = Stra + traversee(ig,l+k) enddo Ep = Ep - epaisseur(ig,l+k) ! ptop=pplev(ig,l+k)*exp(-(dztop-Ep)*g/(r*pt(ig,l+k))) ptop=exp(-(dztop-Ep)*g/(r*pt(ig,l+k))) IF ( ptop .eq. 1. ) THEN !PRINT*, 'newsedim: exposant trop petit ', ig, l ptop=pplev(ig,l+k) * ( 1. - (dztop-Ep)*g/(r*pt(ig,l+k))) ELSE ptop=pplev(ig,l+k) * ptop ENDIF w(ig,l) = (pplev(ig,l) - ptop)/g endif !!! complex method c cc write(*,*) 'OK new method l,w =', l, w(ig,l) cc write(*,*) 'OK new method dztop =', dztop cc if(l.eq.7)write(*,*)'l=7,k,pplev,Ptop',pplev(ig,l),Ptop cc if(l.eq.7)write(*,*)'l=7,dztop,Ep',dztop,Ep cc if(l.eq.6)write(*,*)'l=6,k, w',k, w(1,l) cc if(l.eq.7)write(*,*)'l=7,k, w',k, w(1,l) cc if(l.eq.8)write(*,*)'l=8,k, w',k, w(1,l) c ************************************************************** end do end do call vlz_fi(ngrid,pqi,2.,masse,w,wq) c write(*,*) ' newsed: wq(6), wq(7), q(6)', c & wq(1,6),wq(1,7),pqi(1,6) RETURN END