!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, & sina,cosa,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) !-- sina sine rotation angle !-- cosa cosine rotation angle !-- 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, & sina,cosa ! 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 ) :: ugeo, vgeo, dudt, dvdt, dtaux, dtauy real, dimension( its:ite ) :: dusfc, dvsfc real, dimension( its:ite, kts:kte+1 ) :: pdhi real, dimension( its:ite, 4 ) :: oa4, & ol4 integer :: i,j,k,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) ! rotate winds to zonal/meridional ugeo(i,k) = u3d(i,k,j)*cosa(i,j) - v3d(i,k,j)*sina(i,j) vgeo(i,k) = u3d(i,k,j)*sina(i,j) + v3d(i,k,j)*cosa(i,j) dudt(i,k) = 0.0 dvdt(i,k) = 0.0 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=dudt(its,kts),dvdt=dvdt(its,kts) & ,dtaux2d=dtaux(its,kts),dtauy2d=dtauy(its,kts) & ,u1=ugeo(its,kts),v1=vgeo(its,kts) & ,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) & ,kpblmax=kpblmax & ,var=var2d(ims,j),oc1=oc12d(ims,j) & ,oa4=oa4,ol4=ol4 & ,dusfc=dusfc(its),dvsfc=dvsfc(its) & ,g_=g,cp_=cp,rd_=rd,rv_=rv,fv_=ep1,pi_=pi & ,dxmeter=dx,deltim=dt & ,kpbl=kpbl2d(ims,j),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 ) do k = kts,kte do i = its,ite ! rotate tendencies from zonal/meridional to model grid rublten(i,k,j) = rublten(i,k,j)+dudt(i,k)*cosa(i,j) + dvdt(i,k)*sina(i,j) rvblten(i,k,j) = rvblten(i,k,j)-dudt(i,k)*sina(i,j) + dvdt(i,k)*cosa(i,j) dtaux3d(i,k,j) = dtaux(i,k)*cosa(i,j) + dtauy(i,k)*sina(i,j) dtauy3d(i,k,j) =-dtaux(i,k)*sina(i,j) + dtauy(i,k)*cosa(i,j) if(k.eq.kts)then dusfcg(i,j) = dusfc(i)*cosa(i,j) + dvsfc(i)*sina(i,j) dvsfcg(i,j) =-dusfc(i)*sina(i,j) + dvsfc(i)*cosa(i,j) endif enddo enddo enddo ! end subroutine gwdo !------------------------------------------------------------------------------- !------------------------------------------------------------------------------- subroutine gwdo2d(dudt, dvdt, dtaux2d, dtauy2d, & u1, v1, t1, q1, & del, & prsi, prsl, prslk, zl, & kpblmax, & var, oc1, oa4, ol4, dusfc, dvsfc, & g_, cp_, rd_, rv_, fv_, pi_, & dxmeter, deltim, kpbl, lat, & ids, ide, jds, jde, kds, kde, & ims, ime, jms, jme, kms, kme, & its, ite, jts, jte, kts, kte) !------------------------------------------------------------------------------- ! ! abstract : ! 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 ! choi and hong (2015), which names kim gwdo since it was developed by ! kiaps staffs for kiaps integrated model system (kim). the scheme ! additionally includes the effects of orographic anisotropy and ! flow-blocking drag. ! coded by song-you hong and young-joon kim and implemented by song-you hong ! ! history log : ! 2015-07-01 hyun-joo choi add flow-blocking drag and orographic anisotropy ! ! references : ! choi and hong (2015), j. geophys. res. ! hong et al. (2008), wea. 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 ! ! input : ! dudt, dvdt - non-lin tendency for u and v wind component ! u1, v1 - zonal and meridional wind m/sec at t0-dt ! t1 - temperature deg k at t0-dt ! q1 - mixing ratio at t0-dt ! deltim - time step (s) ! del - positive increment of pressure across layer (pa) ! kpblmax, kpbl - vertical index of pbl height ! prslk, zl, prsl, prsi - pressure and height variables ! oa4, ol4, omax, var, oc1 - orographic statistics ! ! output : ! dudt, dvdt - wind tendency due to gwdo ! dtaux2d, dtauy2d - diagnoised orographic gwd ! dusfc, dvsfc - gw stress ! !------------------------------------------------------------------------------- implicit none ! integer , intent(in ) :: lat, kpblmax, & ids, ide, jds, jde, & kds, kde, ims, ime, & jms, jme, kms, kme, & its, ite, jts, jte, & kts, kte integer, dimension(ims:ime) , intent(in ) :: kpbl real , intent(in ) :: g_, pi_, rd_, rv_, fv_,& cp_, deltim real , intent(in ) :: dxmeter real, dimension(its:ite,kts:kte) , intent(inout) :: dudt, dvdt real, dimension(its:ite,kts:kte) , intent( out) :: dtaux2d, dtauy2d real, dimension(its:ite,kts:kte) , intent(in ) :: u1, v1 real, dimension(ims:ime,kms:kme) , intent(in ) :: t1, q1, prslk, zl ! real, dimension(its:ite,kts:kte) , intent(in ) :: prsl, del real, dimension(its:ite,kts:kte+1), intent(in ) :: prsi real, dimension(its:ite,4) , intent(in ) :: oa4, ol4 ! real, dimension(ims:ime) , intent(in ) :: var, oc1 real, dimension(its:ite) , intent( out) :: dusfc, dvsfc ! real, parameter :: ric = 0.25 ! critical richardson number 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 :: frc = 1.0 real, parameter :: ce = 0.8 real, parameter :: cg = 0.5 integer,parameter :: kpblmin = 2 ! ! local variables ! integer :: latd,lond integer :: i,k,lcap,lcapp1,nwd,idir, & klcap,kp1,ikount,kk ! real :: fdir,cs,rcsks, & wdir,ti,rdz,temp,tem2,dw2,shr2,bvf2,rdelks, & wtkbj,tem,gfobnv,hd,fro,rim,temc,tem1,efact, & temv,dtaux,dtauy ! logical, dimension(its:ite) :: ldrag, icrilv, flag,kloop1 real, dimension(its:ite) :: coefm ! real, dimension(its:ite) :: taub, xn, yn, ubar, vbar, fr, & ulow, rulow, bnv, oa, ol, rhobar, & dtfac, brvf, xlinv, delks,delks1, & zlowtop,cleff real, dimension(its:ite,kts:kte+1) :: taup real, dimension(its:ite,kts:kte-1) :: velco real, dimension(its:ite,kts:kte) :: bnv2, usqj, taud, rho, vtk, vtj ! integer, dimension(its:ite) :: kbl, klowtop integer, parameter :: mdir=8 integer, dimension(mdir) :: nwdir 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 :: fbdcd real :: zblk, tautem real :: fbdpe, fbdke real, dimension(its:ite) :: delx, dely real, dimension(its:ite,4) :: dxy4, dxy4p real, dimension(4) :: ol4p real, dimension(its:ite) :: dxy, dxyp, olp, od real, dimension(its:ite,kts:kte+1) :: taufb ! integer, dimension(its:ite) :: komax integer :: kblk !------------------------------------------------------------------------------- ! ! constants ! lcap = kte lcapp1 = lcap + 1 fdir = mdir / (2.0*pi_) ! ! calculate length of grid for flow-blocking drag ! delx(its:ite) = dxmeter dely(its:ite) = dxmeter dxy4(its:ite,1) = delx(its:ite) dxy4(its:ite,2) = dely(its:ite) dxy4(its:ite,3) = sqrt(delx(its:ite)**2. + dely(its:ite)**2.) dxy4(its:ite,4) = dxy4(its:ite,3) dxy4p(its:ite,1) = dxy4(its:ite,2) dxy4p(its:ite,2) = dxy4(its:ite,1) dxy4p(its:ite,3) = dxy4(its:ite,4) dxy4p(its:ite,4) = dxy4(its:ite,3) ! cleff(its:ite) = dxmeter ! ! initialize arrays ! ldrag = .false. ; icrilv = .false. ; flag = .true. ! klowtop = 0 ; kbl = 0 ! dtaux = 0. ; dtauy = 0. ; xn = 0. ; yn = 0. ubar = 0. ; vbar = 0. ; rhobar = 0. ; ulow = 0. oa = 0. ; ol = 0. ; taub = 0. ! usqj = 0. ; bnv2 = 0. ; vtj = 0. ; vtk = 0. taup = 0. ; taud = 0. ; dtaux2d = 0. ; dtauy2d = 0. ! dtfac = 1.0 ; xlinv = 1.0/xl ! ! initialize arrays for flow-blocking drag ! komax = 0 taufb = 0.0 ! 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) rho(i,k) = 1./rd_ * prsl(i,k) / vtj(i,k) ! density kg/m**3 enddo enddo ! 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 ! ! determine reference level: 2*var ! kbl(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 = 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 rhobar(i) = rhobar(i) + rdelks * rho(i,k) ! pbl rho 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 wind direction ! 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(i,MOD(nwd-1,4)+1) dxyp(i) = dxy4p(i,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 = 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)) 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 * ((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 ! ! 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 phy_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) * 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 ) coefm(i) = (1. + ol(i)) ** (oa(i)+1.) xlinv(i) = coefm(i) / cleff(i) tem = fr(i) * fr(i) * oc1(i) gfobnv = gmax * tem / ((tem + cg)*bnv(i)) taub(i) = xlinv(i) * rhobar(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)*(rho(i,kp1)+rho(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 fbdpe = 0.0 fbdke = 0.0 do k = kte, kpblmin, -1 if (kblk.eq.0 .and. k.le.kbl(i)) then fbdpe = fbdpe + bnv2(i,k)*(zl(i,kbl(i))-zl(i,k)) & *del(i,k)/g_/rho(i,k) fbdke = 0.5*(u1(i,k)**2.+v1(i,k)**2.) ! ! apply flow-blocking drag when fbdpe >= fbdke ! if (fbdpe.ge.fbdke) 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 ! fbdcd = max(2.0-1.0/od(i),0.0) taufb(i,kts) = 0.5*rhobar(i)*coefm(i)/dxmeter**2*fbdcd*dxyp(i) & *olp(i)*zblk*ulow(i)**2 tautem = taufb(i,kts)/real(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)) * g_ / del(i,k) 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*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_) * dusfc(i) dvsfc(i) = (-1./g_) * dvsfc(i) enddo ! return end subroutine gwdo2d !------------------------------------------------------------------------------- !------------------------------------------------------------------------------- end module module_bl_gwdo