!WRF:model_layer:physics ! ! ! ! module module_bl_gwdo contains !------------------------------------------------------------------------------- subroutine gwdo(u3d,v3d,t3d,qv3d,p3d,p3di,pi3d,z, & rublten,rvblten, & dtaux3d,dtauy3d,dusfcg,dvsfcg, & var2d,oc12d,oa2d1,oa2d2,oa2d3,oa2d4,ol2d1,ol2d2,ol2d3,ol2d4, & znu,znw,p_top, & cp,g,rd,rv,ep1,pi, & dt,dx,kpbl2d,itimestep, & ids,ide, jds,jde, kds,kde, & ims,ime, jms,jme, kms,kme, & its,ite, jts,jte, kts,kte) !------------------------------------------------------------------------------- implicit none !------------------------------------------------------------------------------- ! !-- u3d 3d u-velocity interpolated to theta points (m/s) !-- v3d 3d v-velocity interpolated to theta points (m/s) !-- t3d temperature (k) !-- qv3d 3d water vapor mixing ratio (kg/kg) !-- p3d 3d pressure (pa) !-- p3di 3d pressure (pa) at interface level !-- pi3d 3d exner function (dimensionless) !-- rublten u tendency due to pbl parameterization (m/s/s) !-- rvblten v tendency due to pbl parameterization (m/s/s) !-- znu eta values (sigma values) !-- cp heat capacity at constant pressure for dry air (j/kg/k) !-- g acceleration due to gravity (m/s^2) !-- rd gas constant for dry air (j/kg/k) !-- z height above sea level (m) !-- rv gas constant for water vapor (j/kg/k) !-- dt time step (s) !-- dx model grid interval (m) !-- ep1 constant for virtual temperature (r_v/r_d - 1) (dimensionless) !-- ids start index for i in domain !-- ide end index for i in domain !-- jds start index for j in domain !-- jde end index for j in domain !-- kds start index for k in domain !-- kde end index for k in domain !-- ims start index for i in memory !-- ime end index for i in memory !-- jms start index for j in memory !-- jme end index for j in memory !-- kms start index for k in memory !-- kme end index for k in memory !-- its start index for i in tile !-- ite end index for i in tile !-- jts start index for j in tile !-- jte end index for j in tile !-- kts start index for k in tile !-- kte end index for k in tile ! !------------------------------------------------------------------------------- integer, intent(in ) :: ids,ide, jds,jde, kds,kde, & ims,ime, jms,jme, kms,kme, & its,ite, jts,jte, kts,kte integer, intent(in ) :: itimestep ! real, intent(in ) :: dt,dx,cp,g,rd,rv,ep1,pi ! real, dimension( ims:ime, kms:kme, jms:jme ) , & intent(in ) :: qv3d, & p3d, & pi3d, & t3d, & z real, dimension( ims:ime, kms:kme, jms:jme ) , & intent(in ) :: p3di ! real, dimension( ims:ime, kms:kme, jms:jme ) , & intent(inout) :: rublten, & rvblten real, dimension( ims:ime, kms:kme, jms:jme ) , & intent(inout) :: dtaux3d, & dtauy3d ! real, dimension( ims:ime, kms:kme, jms:jme ) , & intent(in ) :: u3d, & v3d ! integer, dimension( ims:ime, jms:jme ) , & intent(in ) :: kpbl2d real, dimension( ims:ime, jms:jme ) , & intent(inout ) :: dusfcg, & dvsfcg ! real, dimension( ims:ime, jms:jme ) , & intent(in ) :: var2d, & oc12d, & oa2d1,oa2d2,oa2d3,oa2d4, & ol2d1,ol2d2,ol2d3,ol2d4 ! real, dimension( kms:kme ) , & optional , & intent(in ) :: znu, & znw ! real, optional, intent(in ) :: p_top ! !local ! real, dimension( its:ite, kts:kte ) :: delprsi, & pdh real, dimension( its:ite, kts:kte+1 ) :: pdhi real, dimension( its:ite, 4 ) :: oa4, & ol4 integer :: i,j,k,kdt,kpblmax ! do k = kts,kte if(znu(k).gt.0.6) kpblmax = k + 1 enddo ! do j = jts,jte do k = kts,kte+1 do i = its,ite if(k.le.kte)pdh(i,k) = p3d(i,k,j) pdhi(i,k) = p3di(i,k,j) enddo enddo ! do k = kts,kte do i = its,ite delprsi(i,k) = pdhi(i,k)-pdhi(i,k+1) enddo enddo do i = its,ite oa4(i,1) = oa2d1(i,j) oa4(i,2) = oa2d2(i,j) oa4(i,3) = oa2d3(i,j) oa4(i,4) = oa2d4(i,j) ol4(i,1) = ol2d1(i,j) ol4(i,2) = ol2d2(i,j) ol4(i,3) = ol2d3(i,j) ol4(i,4) = ol2d4(i,j) enddo call gwdo2d(dudt=rublten(ims,kms,j),dvdt=rvblten(ims,kms,j) & ,dtaux2d=dtaux3d(ims,kms,j),dtauy2d=dtauy3d(ims,kms,j) & ,u1=u3d(ims,kms,j),v1=v3d(ims,kms,j) & ,t1=t3d(ims,kms,j),q1=qv3d(ims,kms,j) & ,del=delprsi(its,kts) & ,prsi=pdhi(its,kts) & ,prsl=pdh(its,kts),prslk=pi3d(ims,kms,j) & ,zl=z(ims,kms,j),rcl=1.0 & ,kpblmax=kpblmax & ,dusfc=dusfcg(ims,j),dvsfc=dvsfcg(ims,j) & ,var=var2d(ims,j),oc1=oc12d(ims,j) & ,oa4=oa4,ol4=ol4 & ,g=g,cp=cp,rd=rd,rv=rv,fv=ep1,pi=pi & ,dxmeter=dx,deltim=dt & ,kpbl=kpbl2d(ims,j),kdt=itimestep,lat=j & ,ids=ids,ide=ide, jds=jds,jde=jde, kds=kds,kde=kde & ,ims=ims,ime=ime, jms=jms,jme=jme, kms=kms,kme=kme & ,its=its,ite=ite, jts=jts,jte=jte, kts=kts,kte=kte ) enddo ! end subroutine gwdo !------------------------------------------------------------------------------- ! !------------------------------------------------------------------------------- subroutine gwdo2d(dudt,dvdt,dtaux2d,dtauy2d, & u1,v1,t1,q1, & del, & prsi,prsl,prslk,zl,rcl,kpblmax, & var,oc1,oa4,ol4,dusfc,dvsfc, & g,cp,rd,rv,fv,pi,dxmeter,deltim,kpbl,kdt,lat, & ids,ide, jds,jde, kds,kde, & ims,ime, jms,jme, kms,kme, & its,ite, jts,jte, kts,kte) !------------------------------------------------------------------------------- ! ! this code handles the time tendencies of u v due to the effect of mountain ! induced gravity wave drag from sub-grid scale orography. this routine ! not only treats the traditional upper-level wave breaking due to mountain ! variance (alpert 1988), but also the enhanced lower-tropospheric wave ! breaking due to mountain convexity and asymmetry (kim and arakawa 1995). ! thus, in addition to the terrain height data in a model grid gox, ! additional 10-2d topographic statistics files are needed, including ! orographic standard deviation (var), convexity (oc1), asymmetry (oa4) ! and ol (ol4). these data sets are prepared based on the 30 sec usgs orography ! hong (1999). the current scheme was implmented as in hong et al.(2008) ! ! coded by song-you hong and young-joon kim and implemented by song-you hong ! ! program history log: ! 2014-10-01 Hyun-Joo Choi (from KIAPS) flow-blocking drag of kim and doyle ! with blocked height by dividing streamline theory ! ! references: ! hong et al. (2008), wea. and forecasting ! kim and doyle (2005), Q. J. R. Meteor. Soc. ! kim and arakawa (1995), j. atmos. sci. ! alpet et al. (1988), NWP conference. ! hong (1999), NCEP office note 424. ! ! notice : comparible or lower resolution orography files than model resolution ! are desirable in preprocess (wps) to prevent weakening of the drag !------------------------------------------------------------------------------- ! ! input ! dudt (ims:ime,kms:kme) non-lin tendency for u wind component ! dvdt (ims:ime,kms:kme) non-lin tendency for v wind component ! u1(ims:ime,kms:kme) zonal wind / sqrt(rcl) m/sec at t0-dt ! v1(ims:ime,kms:kme) meridional wind / sqrt(rcl) m/sec at t0-dt ! t1(ims:ime,kms:kme) temperature deg k at t0-dt ! q1(ims:ime,kms:kme) specific humidity at t0-dt ! ! rcl a scaling factor = reciprocal of square of cos(lat) ! for gmp. rcl=1 if u1 and v1 are wind components. ! deltim time step secs ! del(kts:kte) positive increment of pressure across layer (pa) ! ! output ! dudt, dvdt wind tendency due to gwdo ! !------------------------------------------------------------------------------- implicit none !------------------------------------------------------------------------------- integer :: kdt,lat,latd,lond,kpblmax, & ids,ide, jds,jde, kds,kde, & ims,ime, jms,jme, kms,kme, & its,ite, jts,jte, kts,kte ! real :: g,rd,rv,fv,cp,pi,dxmeter,deltim,rcl real :: dudt(ims:ime,kms:kme),dvdt(ims:ime,kms:kme), & dtaux2d(ims:ime,kms:kme),dtauy2d(ims:ime,kms:kme), & u1(ims:ime,kms:kme),v1(ims:ime,kms:kme), & t1(ims:ime,kms:kme),q1(ims:ime,kms:kme), & zl(ims:ime,kms:kme),prsl(its:ite,kts:kte), & prslk(ims:ime,kms:kme) real :: prsi(its:ite,kts:kte+1),del(its:ite,kts:kte) real :: oa4(its:ite,4),ol4(its:ite,4) ! integer :: kpbl(ims:ime) real :: var(ims:ime),oc1(ims:ime), & dusfc(ims:ime),dvsfc(ims:ime) ! ! critical richardson number for wave breaking : ! larger drag with larger value ! real,parameter :: ric = 0.25 ! real,parameter :: dw2min = 1. real,parameter :: rimin = -100. real,parameter :: bnv2min = 1.0e-5 real,parameter :: efmin = 0.0 real,parameter :: efmax = 10.0 real,parameter :: xl = 4.0e4 real,parameter :: critac = 1.0e-5 real,parameter :: gmax = 1. real,parameter :: veleps = 1.0 real,parameter :: factop = 0.5 real,parameter :: frc = 1.0 real,parameter :: ce = 0.8 real,parameter :: cg = 0.5 integer,parameter :: kpblmin = 2 ! ! local variables ! integer :: i,k,lcap,lcapp1,nwd,idir, & klcap,kp1,ikount,kk ! real :: rcs,rclcs,csg,fdir,cleff,cs,rcsks, & wdir,ti,rdz,temp,tem2,dw2,shr2,bvf2,rdelks, & wtkbj,tem,gfobnv,hd,fro,rim,temc,tem1,efact, & temv,dtaux,dtauy ! logical :: ldrag(its:ite),icrilv(its:ite), & flag(its:ite),kloop1(its:ite) ! real :: taub(its:ite),taup(its:ite,kts:kte+1), & xn(its:ite),yn(its:ite), & ubar(its:ite),vbar(its:ite), & fr(its:ite),ulow(its:ite), & rulow(its:ite),bnv(its:ite), & oa(its:ite),ol(its:ite), & roll(its:ite),dtfac(its:ite), & brvf(its:ite),xlinv(its:ite), & delks(its:ite),delks1(its:ite), & bnv2(its:ite,kts:kte),usqj(its:ite,kts:kte), & taud(its:ite,kts:kte),ro(its:ite,kts:kte), & vtk(its:ite,kts:kte),vtj(its:ite,kts:kte), & zlowtop(its:ite),velco(its:ite,kts:kte-1), & coefm(its:ite) ! integer :: kbl(its:ite),klowtop(its:ite) ! logical :: iope integer,parameter :: mdir=8 integer :: nwdir(mdir) data nwdir/6,7,5,8,2,3,1,4/ ! ! variables for flow-blocking drag ! real,parameter :: frmax = 10. real,parameter :: olmin = 1.0e-5 real,parameter :: odmin = 0.1 real,parameter :: odmax = 10. real,parameter :: erad = 6371.315e+3 integer :: komax(its:ite) integer :: kblk real :: cd real :: zblk,tautem real :: pe,ke real :: delx,dely,dxy4(4),dxy4p(4) real :: dxy(its:ite),dxyp(its:ite) real :: ol4p(4),olp(its:ite),od(its:ite) real :: taufb(its:ite,kts:kte+1) ! !---- constants ! rcs = sqrt(rcl) cs = 1. / sqrt(rcl) csg = cs * g lcap = kte lcapp1 = lcap + 1 fdir = mdir / (2.0*pi) ! !--- calculate length of grid for flow-blocking drag ! delx = dxmeter dely = dxmeter dxy4(1) = delx dxy4(2) = dely dxy4(3) = sqrt(delx*delx + dely*dely) dxy4(4) = dxy4(3) dxy4p(1) = dxy4(2) dxy4p(2) = dxy4(1) dxy4p(3) = dxy4(4) dxy4p(4) = dxy4(3) ! ! !-----initialize arrays ! dtaux = 0.0 dtauy = 0.0 do i = its,ite klowtop(i) = 0 kbl(i) = 0 enddo ! do i = its,ite xn(i) = 0.0 yn(i) = 0.0 ubar (i) = 0.0 vbar (i) = 0.0 roll (i) = 0.0 taub (i) = 0.0 taup(i,1) = 0.0 oa(i) = 0.0 ol(i) = 0.0 ulow (i) = 0.0 dtfac(i) = 1.0 ldrag(i) = .false. icrilv(i) = .false. flag(i) = .true. enddo ! do k = kts,kte do i = its,ite usqj(i,k) = 0.0 bnv2(i,k) = 0.0 vtj(i,k) = 0.0 vtk(i,k) = 0.0 taup(i,k) = 0.0 taud(i,k) = 0.0 dtaux2d(i,k)= 0.0 dtauy2d(i,k)= 0.0 enddo enddo ! do i = its,ite taup(i,kte+1) = 0.0 xlinv(i) = 1.0/xl enddo ! ! initialize array for flow-blocking drag ! taufb(its:ite,kts:kte+1) = 0.0 komax(its:ite) = 0 ! do k = kts,kte do i = its,ite vtj(i,k) = t1(i,k) * (1.+fv*q1(i,k)) vtk(i,k) = vtj(i,k) / prslk(i,k) ro(i,k) = 1./rd * prsl(i,k) / vtj(i,k) ! density kg/m**3 enddo enddo ! ! determine reference level: maximum of 2*var and pbl heights ! do i = its,ite zlowtop(i) = 2. * var(i) enddo ! do i = its,ite kloop1(i) = .true. enddo ! do k = kts+1,kte do i = its,ite if(kloop1(i).and.zl(i,k)-zl(i,1).ge.zlowtop(i)) then klowtop(i) = k+1 kloop1(i) = .false. endif enddo enddo ! do i = its,ite kbl(i) = max(kpbl(i), klowtop(i)) kbl(i) = max(min(kbl(i),kpblmax),kpblmin) enddo ! ! determine the level of maximum orographic height ! komax(:) = kbl(:) ! do i = its,ite delks(i) = 1.0 / (prsi(i,1) - prsi(i,kbl(i))) delks1(i) = 1.0 / (prsl(i,1) - prsl(i,kbl(i))) enddo ! ! compute low level averages within pbl ! do k = kts,kpblmax do i = its,ite if (k.lt.kbl(i)) then rcsks = rcs * del(i,k) * delks(i) rdelks = del(i,k) * delks(i) ubar(i) = ubar(i) + rcsks * u1(i,k) ! pbl u mean vbar(i) = vbar(i) + rcsks * v1(i,k) ! pbl v mean roll(i) = roll(i) + rdelks * ro(i,k) ! ro mean endif enddo enddo ! ! figure out low-level horizontal wind direction ! ! nwd 1 2 3 4 5 6 7 8 ! wd w s sw nw e n ne se ! do i = its,ite wdir = atan2(ubar(i),vbar(i)) + pi idir = mod(nint(fdir*wdir),mdir) + 1 nwd = nwdir(idir) oa(i) = (1-2*int( (nwd-1)/4 )) * oa4(i,mod(nwd-1,4)+1) ol(i) = ol4(i,mod(nwd-1,4)+1) ! !----- compute orographic width along (ol) and perpendicular (olp) !----- the direction of wind ! ol4p(1) = ol4(i,2) ol4p(2) = ol4(i,1) ol4p(3) = ol4(i,4) ol4p(4) = ol4(i,3) olp(i) = ol4p(mod(nwd-1,4)+1) ! !----- compute orographic direction (horizontal orographic aspect ratio) ! od(i) = olp(i)/max(ol(i),olmin) od(i) = min(od(i),odmax) od(i) = max(od(i),odmin) ! !----- compute length of grid in the along(dxy) and cross(dxyp) wind directions ! dxy(i) = dxy4(MOD(nwd-1,4)+1) dxyp(i) = dxy4p(MOD(nwd-1,4)+1) enddo ! !--- saving richardson number in usqj for migwdi ! do k = kts,kte-1 do i = its,ite ti = 2.0 / (t1(i,k)+t1(i,k+1)) rdz = 1./(zl(i,k+1) - zl(i,k)) tem1 = u1(i,k) - u1(i,k+1) tem2 = v1(i,k) - v1(i,k+1) dw2 = rcl*(tem1*tem1 + tem2*tem2) shr2 = max(dw2,dw2min) * rdz * rdz bvf2 = g*(g/cp+rdz*(vtj(i,k+1)-vtj(i,k))) * ti usqj(i,k) = max(bvf2/shr2,rimin) bnv2(i,k) = 2.0*g*rdz*(vtk(i,k+1)-vtk(i,k))/(vtk(i,k+1)+vtk(i,k)) bnv2(i,k) = max( bnv2(i,k), bnv2min ) enddo enddo ! !----compute the "low level" or 1/3 wind magnitude (m/s) ! do i = its,ite ulow(i) = max(sqrt(ubar(i)*ubar(i) + vbar(i)*vbar(i)), 1.0) rulow(i) = 1./ulow(i) enddo ! do k = kts,kte-1 do i = its,ite velco(i,k) = (0.5*rcs) * ((u1(i,k)+u1(i,k+1)) * ubar(i) & + (v1(i,k)+v1(i,k+1)) * vbar(i)) velco(i,k) = velco(i,k) * rulow(i) if ((velco(i,k).lt.veleps) .and. (velco(i,k).gt.0.)) then velco(i,k) = veleps endif enddo enddo ! ! no drag when critical level in the base layer ! do i = its,ite ldrag(i) = velco(i,1).le.0. enddo ! ! no drag when velco.lt.0 ! do k = kpblmin,kpblmax do i = its,ite if (k .lt. kbl(i)) ldrag(i) = ldrag(i).or. velco(i,k).le.0. enddo enddo ! ! no drag when bnv2.lt.0 ! do k = kts,kpblmax do i = its,ite if (k .lt. kbl(i)) ldrag(i) = ldrag(i).or. bnv2(i,k).lt.0. enddo enddo ! !-----the low level weighted average ri is stored in usqj(1,1; im) !-----the low level weighted average n**2 is stored in bnv2(1,1; im) !---- this is called bnvl2 in phys_gwd_alpert_sub not bnv2 !---- rdelks (del(k)/delks) vert ave factor so we can * instead of / ! do i = its,ite wtkbj = (prsl(i,1)-prsl(i,2)) * delks1(i) bnv2(i,1) = wtkbj * bnv2(i,1) usqj(i,1) = wtkbj * usqj(i,1) enddo ! do k = kpblmin,kpblmax do i = its,ite if (k .lt. kbl(i)) then rdelks = (prsl(i,k)-prsl(i,k+1)) * delks1(i) bnv2(i,1) = bnv2(i,1) + bnv2(i,k) * rdelks usqj(i,1) = usqj(i,1) + usqj(i,k) * rdelks endif enddo enddo ! do i = its,ite ldrag(i) = ldrag(i) .or. bnv2(i,1).le.0.0 ldrag(i) = ldrag(i) .or. ulow(i).eq.1.0 ldrag(i) = ldrag(i) .or. var(i) .le. 0.0 enddo ! ! set all ri low level values to the low level value ! do k = kpblmin,kpblmax do i = its,ite if (k .lt. kbl(i)) usqj(i,k) = usqj(i,1) enddo enddo ! do i = its,ite if (.not.ldrag(i)) then bnv(i) = sqrt( bnv2(i,1) ) fr(i) = bnv(i) * rulow(i) * 2. * var(i) * od(i) fr(i) = min(fr(i),frmax) xn(i) = ubar(i) * rulow(i) yn(i) = vbar(i) * rulow(i) endif enddo ! ! compute the base level stress and store it in taub ! calculate enhancement factor, number of mountains & aspect ! ratio const. use simplified relationship between standard ! deviation & critical hgt ! do i = its,ite if (.not. ldrag(i)) then efact = (oa(i) + 2.) ** (ce*fr(i)/frc) efact = min( max(efact,efmin), efmax ) !!!!!!! cleff (effective grid length) is highly tunable parameter !!!!!!! the bigger (smaller) value produce weaker (stronger) wave drag cleff = sqrt(dxy(i)**2. + dxyp(i)**2.) cleff = 3. * max(dxmeter,cleff) coefm(i) = (1. + ol(i)) ** (oa(i)+1.) xlinv(i) = coefm(i) / cleff tem = fr(i) * fr(i) * oc1(i) gfobnv = gmax * tem / ((tem + cg)*bnv(i)) taub(i) = xlinv(i) * roll(i) * ulow(i) * ulow(i) & * ulow(i) * gfobnv * efact else taub(i) = 0.0 xn(i) = 0.0 yn(i) = 0.0 endif enddo ! ! now compute vertical structure of the stress. ! do k = kts,kpblmax do i = its,ite if (k .le. kbl(i)) taup(i,k) = taub(i) enddo enddo ! do k = kpblmin, kte-1 ! vertical level k loop! kp1 = k + 1 do i = its,ite ! ! unstablelayer if ri < ric ! unstable layer if upper air vel comp along surf vel <=0 (crit lay) ! at (u-c)=0. crit layer exists and bit vector should be set (.le.) ! if (k .ge. kbl(i)) then icrilv(i) = icrilv(i) .or. ( usqj(i,k) .lt. ric) & .or. (velco(i,k) .le. 0.0) brvf(i) = max(bnv2(i,k),bnv2min) ! brunt-vaisala frequency squared brvf(i) = sqrt(brvf(i)) ! brunt-vaisala frequency endif enddo ! do i = its,ite if (k .ge. kbl(i) .and. (.not. ldrag(i))) then if (.not.icrilv(i) .and. taup(i,k) .gt. 0.0 ) then temv = 1.0 / velco(i,k) tem1 = coefm(i)/dxy(i)*(ro(i,kp1)+ro(i,k))*brvf(i)*velco(i,k)*0.5 hd = sqrt(taup(i,k) / tem1) fro = brvf(i) * hd * temv ! ! rim is the minimum-richardson number by shutts (1985) ! tem2 = sqrt(usqj(i,k)) tem = 1. + tem2 * fro rim = usqj(i,k) * (1.-fro) / (tem * tem) ! ! check stability to employ the 'saturation hypothesis' ! of lindzen (1981) except at tropospheric downstream regions ! if (rim .le. ric) then ! saturation hypothesis! if ((oa(i) .le. 0.).or.(kp1 .ge. kpblmin )) then temc = 2.0 + 1.0 / tem2 hd = velco(i,k) * (2.*sqrt(temc)-temc) / brvf(i) taup(i,kp1) = tem1 * hd * hd endif else ! no wavebreaking! taup(i,kp1) = taup(i,k) endif endif endif enddo enddo ! if(lcap.lt.kte) then do klcap = lcapp1,kte do i = its,ite taup(i,klcap) = prsi(i,klcap) / prsi(i,lcap) * taup(i,lcap) enddo enddo endif do i = its,ite if(.not.ldrag(i)) then ! !------- determine the height of flow-blocking layer ! kblk = 0 pe = 0.0 do k = kte, kpblmin, -1 if(kblk.eq.0 .and. k.le.komax(i)) then pe = pe + bnv2(i,k)*(zl(i,komax(i))-zl(i,k))*del(i,k)/g/ro(i,k) ke = 0.5*((rcs*u1(i,k))**2.+(rcs*v1(i,k))**2.) ! !---------- apply flow-blocking drag when pe >= ke ! if(pe.ge.ke) then kblk = k kblk = min(kblk,kbl(i)) zblk = zl(i,kblk)-zl(i,kts) endif endif enddo if(kblk.ne.0) then ! !--------- compute flow-blocking stress ! cd = max(2.0-1.0/od(i),0.0) taufb(i,kts) = 0.5 * roll(i) * coefm(i) / dxy(i)**2 * cd * dxyp(i) & * olp(i) * zblk * ulow(i)**2 tautem = taufb(i,kts)/float(kblk-kts) do k = kts+1, kblk taufb(i,k) = taufb(i,k-1) - tautem enddo ! !----------sum orographic GW stress and flow-blocking stress ! taup(i,:) = taup(i,:) + taufb(i,:) endif endif enddo ! ! calculate - (g)*d(tau)/d(pressure) and deceleration terms dtaux, dtauy ! do k = kts,kte do i = its,ite taud(i,k) = 1. * (taup(i,k+1) - taup(i,k)) * csg / del(i,k) enddo enddo ! ! limit de-acceleration (momentum deposition ) at top to 1/2 value ! the idea is some stuff must go out the 'top' ! do klcap = lcap,kte do i = its,ite taud(i,klcap) = taud(i,klcap) * factop enddo enddo ! ! if the gravity wave drag would force a critical line ! in the lower ksmm1 layers during the next deltim timestep, ! then only apply drag until that critical line is reached. ! do k = kts,kpblmax-1 do i = its,ite if (k .le. kbl(i)) then if(taud(i,k).ne.0.) & dtfac(i) = min(dtfac(i),abs(velco(i,k) & /(deltim*rcs*taud(i,k)))) endif enddo enddo ! do i = its,ite dusfc(i) = 0. dvsfc(i) = 0. enddo ! do k = kts,kte do i = its,ite taud(i,k) = taud(i,k) * dtfac(i) dtaux = taud(i,k) * xn(i) dtauy = taud(i,k) * yn(i) dtaux2d(i,k) = dtaux dtauy2d(i,k) = dtauy dudt(i,k) = dtaux + dudt(i,k) dvdt(i,k) = dtauy + dvdt(i,k) dusfc(i) = dusfc(i) + dtaux * del(i,k) dvsfc(i) = dvsfc(i) + dtauy * del(i,k) enddo enddo ! do i = its,ite dusfc(i) = (-1./g*rcs) * dusfc(i) dvsfc(i) = (-1./g*rcs) * dvsfc(i) enddo ! return end subroutine gwdo2d !------------------------------------------------------------------- end module module_bl_gwdo