module SoilTemperatureMod !----------------------------------------------------------------------- !BOP ! ! !MODULE: SoilTemperatureMod ! ! !DESCRIPTION: ! Calculates snow and soil temperatures including phase change ! ! !PUBLIC TYPES: implicit none save ! ! !PUBLIC MEMBER FUNCTIONS: public :: SoilTemperature ! Snow and soil temperatures including phase change ! ! !PRIVATE MEMBER FUNCTIONS: private :: SoilThermProp ! Set therm conductivities and heat cap of snow/soil layers private :: PhaseChange ! Calculation of the phase change within snow and soil layers ! ! !REVISION HISTORY: ! Created by Mariana Vertenstein ! !EOP !----------------------------------------------------------------------- contains !----------------------------------------------------------------------- !BOP ! ! !IROUTINE: SoilTemperature ! ! !INTERFACE: subroutine SoilTemperature(lbl, ubl, lbc, ubc, num_urbanl, filter_urbanl, & num_nolakec, filter_nolakec, xmf, fact) ! ! !DESCRIPTION: ! Snow and soil temperatures including phase change ! o The volumetric heat capacity is calculated as a linear combination ! in terms of the volumetric fraction of the constituent phases. ! o The thermal conductivity of soil is computed from ! the algorithm of Johansen (as reported by Farouki 1981), and the ! conductivity of snow is from the formulation used in ! SNTHERM (Jordan 1991). ! o Boundary conditions: ! F = Rnet - Hg - LEg (top), F= 0 (base of the soil column). ! o Soil / snow temperature is predicted from heat conduction ! in 10 soil layers and up to 5 snow layers. ! The thermal conductivities at the interfaces between two ! neighboring layers (j, j+1) are derived from an assumption that ! the flux across the interface is equal to that from the node j ! to the interface and the flux from the interface to the node j+1. ! The equation is solved using the Crank-Nicholson method and ! results in a tridiagonal system equation. ! ! !USES: use shr_kind_mod , only : r8 => shr_kind_r8 use clmtype use clm_atmlnd , only : clm_a2l use clm_time_manager , only : get_step_size use clm_varctl , only : iulog use clm_varcon , only : sb, capr, cnfac, hvap, istice_mec, isturb, & icol_roof, icol_sunwall, icol_shadewall, & icol_road_perv, icol_road_imperv, istwet use clm_varpar , only : nlevsno, nlevgrnd, max_pft_per_col, nlevurb use TridiagonalMod, only : Tridiagonal ! ! !ARGUMENTS: implicit none integer , intent(in) :: lbc, ubc ! column bounds integer , intent(in) :: num_nolakec ! number of column non-lake points in column filter integer , intent(in) :: filter_nolakec(ubc-lbc+1) ! column filter for non-lake points integer , intent(in) :: lbl, ubl ! landunit-index bounds integer , intent(in) :: num_urbanl ! number of urban landunits in clump integer , intent(in) :: filter_urbanl(ubl-lbl+1) ! urban landunit filter real(r8), intent(out) :: xmf(lbc:ubc) ! total latent heat of phase change of ground water real(r8), intent(out) :: fact(lbc:ubc, -nlevsno+1:nlevgrnd) ! used in computing tridiagonal matrix ! ! !CALLED FROM: ! subroutine Biogeophysics2 in module Biogeophysics2Mod ! ! !REVISION HISTORY: ! 15 September 1999: Yongjiu Dai; Initial code ! 15 December 1999: Paul Houser and Jon Radakovich; F90 Revision ! 12/19/01, Peter Thornton ! Changed references for tg to t_grnd, for consistency with the ! rest of the code (tg eliminated as redundant) ! 2/14/02, Peter Thornton: Migrated to new data structures. Added pft loop ! in calculation of net ground heat flux. ! 3/18/08, David Lawrence: Change nlevsoi to nlevgrnd for deep soil ! 03/28/08, Mark Flanner: Changes to allow solar radiative absorption in all snow layers and top soil layer ! !LOCAL VARIABLES: ! ! local pointers to original implicit in arguments ! integer , pointer :: pgridcell(:) ! pft's gridcell index integer , pointer :: plandunit(:) ! pft's landunit index integer , pointer :: clandunit(:) ! column's landunit integer , pointer :: ltype(:) ! landunit type integer , pointer :: ctype(:) ! column type integer , pointer :: npfts(:) ! column's number of pfts integer , pointer :: pfti(:) ! column's beginning pft index real(r8), pointer :: pwtcol(:) ! weight of pft relative to column real(r8), pointer :: pwtgcell(:) ! weight of pft relative to corresponding gridcell real(r8), pointer :: forc_lwrad(:) ! downward infrared (longwave) radiation (W/m**2) integer , pointer :: snl(:) ! number of snow layers real(r8), pointer :: htvp(:) ! latent heat of vapor of water (or sublimation) [j/kg] real(r8), pointer :: emg(:) ! ground emissivity real(r8), pointer :: cgrnd(:) ! deriv. of soil energy flux wrt to soil temp [w/m2/k] real(r8), pointer :: dlrad(:) ! downward longwave radiation blow the canopy [W/m2] real(r8), pointer :: sabg(:) ! solar radiation absorbed by ground (W/m**2) integer , pointer :: frac_veg_nosno(:) ! fraction of vegetation not covered by snow (0 OR 1 now) [-] (new) real(r8), pointer :: eflx_sh_grnd(:) ! sensible heat flux from ground (W/m**2) [+ to atm] real(r8), pointer :: qflx_evap_soi(:) ! soil evaporation (mm H2O/s) (+ = to atm) real(r8), pointer :: qflx_tran_veg(:) ! vegetation transpiration (mm H2O/s) (+ = to atm) real(r8), pointer :: zi(:,:) ! interface level below a "z" level (m) real(r8), pointer :: dz(:,:) ! layer depth (m) real(r8), pointer :: z(:,:) ! layer thickness (m) real(r8), pointer :: t_soisno(:,:) ! soil temperature (Kelvin) real(r8), pointer :: eflx_lwrad_net(:) ! net infrared (longwave) rad (W/m**2) [+ = to atm] real(r8), pointer :: tssbef(:,:) ! temperature at previous time step [K] real(r8), pointer :: t_building(:) ! internal building temperature (K) real(r8), pointer :: t_building_max(:) ! maximum internal building temperature (K) real(r8), pointer :: t_building_min(:) ! minimum internal building temperature (K) real(r8), pointer :: hc_soi(:) ! soil heat content (MJ/m2) real(r8), pointer :: hc_soisno(:) ! soil plus snow plus lake heat content (MJ/m2) real(r8), pointer :: eflx_fgr12(:) ! heat flux between soil layer 1 and 2 (W/m2) real(r8), pointer :: eflx_traffic(:) ! traffic sensible heat flux (W/m**2) real(r8), pointer :: eflx_wasteheat(:) ! sensible heat flux from urban heating/cooling sources of waste heat (W/m**2) real(r8), pointer :: eflx_wasteheat_pft(:) ! sensible heat flux from urban heating/cooling sources of waste heat (W/m**2) real(r8), pointer :: eflx_heat_from_ac(:) !sensible heat flux put back into canyon due to removal by AC (W/m**2) real(r8), pointer :: eflx_heat_from_ac_pft(:) !sensible heat flux put back into canyon due to removal by AC (W/m**2) real(r8), pointer :: eflx_traffic_pft(:) ! traffic sensible heat flux (W/m**2) real(r8), pointer :: eflx_anthro(:) ! total anthropogenic heat flux (W/m**2) real(r8), pointer :: canyon_hwr(:) ! urban canyon height to width ratio real(r8), pointer :: wtlunit_roof(:) ! weight of roof with respect to landunit real(r8), pointer :: eflx_bot(:) ! heat flux from beneath column (W/m**2) [+ = upward] ! ! local pointers to original implicit inout arguments ! real(r8), pointer :: t_grnd(:) ! ground surface temperature [K] ! ! local pointers to original implicit out arguments ! real(r8), pointer :: eflx_gnet(:) ! net ground heat flux into the surface (W/m**2) real(r8), pointer :: dgnetdT(:) ! temperature derivative of ground net heat flux real(r8), pointer :: eflx_building_heat(:) ! heat flux from urban building interior to walls, roof (W/m**2) ! variables needed for SNICAR real(r8), pointer :: sabg_lyr(:,:) ! absorbed solar radiation (pft,lyr) [W/m2] real(r8), pointer :: h2osno(:) ! total snow water (col) [kg/m2] real(r8), pointer :: h2osoi_liq(:,:) ! liquid water (col,lyr) [kg/m2] real(r8), pointer :: h2osoi_ice(:,:) ! ice content (col,lyr) [kg/m2] ! Urban building HAC fluxes real(r8), pointer :: eflx_urban_ac(:) ! urban air conditioning flux (W/m**2) real(r8), pointer :: eflx_urban_heat(:) ! urban heating flux (W/m**2) ! ! ! !OTHER LOCAL VARIABLES: !EOP ! integer :: j,c,p,l,g,pi ! indices integer :: fc ! lake filtered column indices integer :: fl ! urban filtered landunit indices integer :: jtop(lbc:ubc) ! top level at each column real(r8) :: dtime ! land model time step (sec) real(r8) :: at (lbc:ubc,-nlevsno+1:nlevgrnd) ! "a" vector for tridiagonal matrix real(r8) :: bt (lbc:ubc,-nlevsno+1:nlevgrnd) ! "b" vector for tridiagonal matrix real(r8) :: ct (lbc:ubc,-nlevsno+1:nlevgrnd) ! "c" vector for tridiagonal matrix real(r8) :: rt (lbc:ubc,-nlevsno+1:nlevgrnd) ! "r" vector for tridiagonal solution real(r8) :: cv (lbc:ubc,-nlevsno+1:nlevgrnd) ! heat capacity [J/(m2 K)] real(r8) :: tk (lbc:ubc,-nlevsno+1:nlevgrnd) ! thermal conductivity [W/(m K)] real(r8) :: fn (lbc:ubc,-nlevsno+1:nlevgrnd) ! heat diffusion through the layer interface [W/m2] real(r8) :: fn1(lbc:ubc,-nlevsno+1:nlevgrnd) ! heat diffusion through the layer interface [W/m2] real(r8) :: brr(lbc:ubc,-nlevsno+1:nlevgrnd) ! temporary real(r8) :: dzm ! used in computing tridiagonal matrix real(r8) :: dzp ! used in computing tridiagonal matrix real(r8) :: hs(lbc:ubc) ! net energy flux into the surface (w/m2) real(r8) :: dhsdT(lbc:ubc) ! d(hs)/dT real(r8) :: lwrad_emit(lbc:ubc) ! emitted longwave radiation real(r8) :: dlwrad_emit(lbc:ubc) ! time derivative of emitted longwave radiation integer :: lyr_top ! index of top layer of snowpack (-4 to 0) [idx] real(r8) :: sabg_lyr_col(lbc:ubc,-nlevsno+1:1) ! absorbed solar radiation (col,lyr) [W/m2] real(r8) :: eflx_gnet_top ! net energy flux into surface layer, pft-level [W/m2] real(r8) :: hs_top(lbc:ubc) ! net energy flux into surface layer (col) [W/m2] logical :: cool_on(lbl:ubl) ! is urban air conditioning on? logical :: heat_on(lbl:ubl) ! is urban heating on? !----------------------------------------------------------------------- ! Assign local pointers to derived subtypes components (gridcell-level) forc_lwrad => clm_a2l%forc_lwrad ! Assign local pointers to derived subtypes components (landunit-level) ltype => clm3%g%l%itype t_building => clm3%g%l%lps%t_building t_building_max => clm3%g%l%lps%t_building_max t_building_min => clm3%g%l%lps%t_building_min eflx_traffic => clm3%g%l%lef%eflx_traffic canyon_hwr => clm3%g%l%canyon_hwr eflx_wasteheat => clm3%g%l%lef%eflx_wasteheat eflx_heat_from_ac => clm3%g%l%lef%eflx_heat_from_ac wtlunit_roof => clm3%g%l%wtlunit_roof ! Assign local pointers to derived subtypes components (column-level) ctype => clm3%g%l%c%itype clandunit => clm3%g%l%c%landunit npfts => clm3%g%l%c%npfts pfti => clm3%g%l%c%pfti snl => clm3%g%l%c%cps%snl htvp => clm3%g%l%c%cps%htvp emg => clm3%g%l%c%cps%emg t_grnd => clm3%g%l%c%ces%t_grnd hc_soi => clm3%g%l%c%ces%hc_soi hc_soisno => clm3%g%l%c%ces%hc_soisno eflx_fgr12 => clm3%g%l%c%cef%eflx_fgr12 zi => clm3%g%l%c%cps%zi dz => clm3%g%l%c%cps%dz z => clm3%g%l%c%cps%z t_soisno => clm3%g%l%c%ces%t_soisno eflx_building_heat => clm3%g%l%c%cef%eflx_building_heat tssbef => clm3%g%l%c%ces%tssbef eflx_urban_ac => clm3%g%l%c%cef%eflx_urban_ac eflx_urban_heat => clm3%g%l%c%cef%eflx_urban_heat eflx_bot => clm3%g%l%c%cef%eflx_bot ! Assign local pointers to derived subtypes components (pft-level) pgridcell => clm3%g%l%c%p%gridcell plandunit => clm3%g%l%c%p%landunit pwtcol => clm3%g%l%c%p%wtcol pwtgcell => clm3%g%l%c%p%wtgcell frac_veg_nosno => clm3%g%l%c%p%pps%frac_veg_nosno cgrnd => clm3%g%l%c%p%pef%cgrnd dlrad => clm3%g%l%c%p%pef%dlrad sabg => clm3%g%l%c%p%pef%sabg eflx_sh_grnd => clm3%g%l%c%p%pef%eflx_sh_grnd qflx_evap_soi => clm3%g%l%c%p%pwf%qflx_evap_soi qflx_tran_veg => clm3%g%l%c%p%pwf%qflx_tran_veg eflx_gnet => clm3%g%l%c%p%pef%eflx_gnet dgnetdT => clm3%g%l%c%p%pef%dgnetdT eflx_lwrad_net => clm3%g%l%c%p%pef%eflx_lwrad_net eflx_wasteheat_pft => clm3%g%l%c%p%pef%eflx_wasteheat_pft eflx_heat_from_ac_pft => clm3%g%l%c%p%pef%eflx_heat_from_ac_pft eflx_traffic_pft => clm3%g%l%c%p%pef%eflx_traffic_pft eflx_anthro => clm3%g%l%c%p%pef%eflx_anthro sabg_lyr => clm3%g%l%c%p%pef%sabg_lyr h2osno => clm3%g%l%c%cws%h2osno h2osoi_liq => clm3%g%l%c%cws%h2osoi_liq h2osoi_ice => clm3%g%l%c%cws%h2osoi_ice ! Get step size dtime = get_step_size() ! Compute ground surface and soil temperatures ! Thermal conductivity and Heat capacity call SoilThermProp(lbc, ubc, num_nolakec, filter_nolakec, tk, cv) ! Net ground heat flux into the surface and its temperature derivative ! Added a pfts loop here to get the average of hs and dhsdT over ! all PFTs on the column. Precalculate the terms that do not depend on PFT. do fc = 1,num_nolakec c = filter_nolakec(fc) lwrad_emit(c) = emg(c) * sb * t_grnd(c)**4 dlwrad_emit(c) = 4._r8*emg(c) * sb * t_grnd(c)**3 end do hs(lbc:ubc) = 0._r8 dhsdT(lbc:ubc) = 0._r8 do pi = 1,max_pft_per_col do fc = 1,num_nolakec c = filter_nolakec(fc) if ( pi <= npfts(c) ) then p = pfti(c) + pi - 1 l = plandunit(p) g = pgridcell(p) ! Note: Some glacier_mec pfts may have zero weight if (pwtgcell(p)>0._r8 .or. ltype(l)==istice_mec) then if (ltype(l) /= isturb) then eflx_gnet(p) = sabg(p) + dlrad(p) & + (1-frac_veg_nosno(p))*emg(c)*forc_lwrad(g) - lwrad_emit(c) & - (eflx_sh_grnd(p)+qflx_evap_soi(p)*htvp(c)) else ! For urban columns we use the net longwave radiation (eflx_lwrad_net) because of ! interactions between urban columns. ! All wasteheat and traffic flux goes into canyon floor if (ctype(c) == icol_road_perv .or. ctype(c) == icol_road_imperv) then eflx_wasteheat_pft(p) = eflx_wasteheat(l)/(1._r8-wtlunit_roof(l)) eflx_heat_from_ac_pft(p) = eflx_heat_from_ac(l)/(1._r8-wtlunit_roof(l)) eflx_traffic_pft(p) = eflx_traffic(l)/(1._r8-wtlunit_roof(l)) else eflx_wasteheat_pft(p) = 0._r8 eflx_heat_from_ac_pft(p) = 0._r8 eflx_traffic_pft(p) = 0._r8 end if ! Include transpiration term because needed for previous road ! and include wasteheat and traffic flux eflx_gnet(p) = sabg(p) + dlrad(p) & - eflx_lwrad_net(p) & - (eflx_sh_grnd(p) + qflx_evap_soi(p)*htvp(c) + qflx_tran_veg(p)*hvap) & + eflx_wasteheat_pft(p) + eflx_heat_from_ac_pft(p) + eflx_traffic_pft(p) eflx_anthro(p) = eflx_wasteheat_pft(p) + eflx_traffic_pft(p) end if dgnetdT(p) = - cgrnd(p) - dlwrad_emit(c) hs(c) = hs(c) + eflx_gnet(p) * pwtcol(p) dhsdT(c) = dhsdT(c) + dgnetdT(p) * pwtcol(p) end if end if end do end do ! Additional calculations with SNICAR: ! Set up tridiagonal matrix in a new manner. There is now ! absorbed solar radiation in each snow layer, instead of ! only the surface. Following the current implementation, ! absorbed solar flux should be: S + ((delS/delT)*dT), ! where S is absorbed radiation, and T is temperature. Now, ! assume delS/delT is zero, then it is OK to just add S ! to each layer ! Initialize: sabg_lyr_col(lbc:ubc,-nlevsno+1:1) = 0._r8 hs_top(lbc:ubc) = 0._r8 do pi = 1,max_pft_per_col do fc = 1,num_nolakec c = filter_nolakec(fc) lyr_top = snl(c) + 1 if ( pi <= npfts(c) ) then p = pfti(c) + pi - 1 l = plandunit(p) if (pwtgcell(p)>0._r8 .or. ltype(l)==istice_mec) then g = pgridcell(p) if (ltype(l) /= isturb )then eflx_gnet_top = sabg_lyr(p,lyr_top) + dlrad(p) + (1-frac_veg_nosno(p))*emg(c)*forc_lwrad(g) & - lwrad_emit(c) - (eflx_sh_grnd(p)+qflx_evap_soi(p)*htvp(c)) hs_top(c) = hs_top(c) + eflx_gnet_top*pwtcol(p) do j = lyr_top,1,1 sabg_lyr_col(c,j) = sabg_lyr_col(c,j) + sabg_lyr(p,j) * pwtcol(p) enddo else hs_top(c) = hs_top(c) + eflx_gnet(p)*pwtcol(p) sabg_lyr_col(c,lyr_top) = sabg_lyr_col(c,lyr_top) + sabg(p) * pwtcol(p) endif endif endif enddo enddo ! Restrict internal building temperature to between min and max ! and determine if heating or air conditioning is on do fl = 1,num_urbanl l = filter_urbanl(fl) if (ltype(l) == isturb) then cool_on(l) = .false. heat_on(l) = .false. if (t_building(l) > t_building_max(l)) then t_building(l) = t_building_max(l) cool_on(l) = .true. heat_on(l) = .false. else if (t_building(l) < t_building_min(l)) then t_building(l) = t_building_min(l) cool_on(l) = .false. heat_on(l) = .true. end if end if end do ! Determine heat diffusion through the layer interface and factor used in computing ! tridiagonal matrix and set up vector r and vectors a, b, c that define tridiagonal ! matrix and solve system do j = -nlevsno+1,nlevgrnd do fc = 1,num_nolakec c = filter_nolakec(fc) l = clandunit(c) if (j >= snl(c)+1) then if (j == snl(c)+1) then if (ctype(c)==icol_sunwall .or. ctype(c)==icol_shadewall .or. ctype(c)==icol_roof) then fact(c,j) = dtime/cv(c,j) else fact(c,j) = dtime/cv(c,j) * dz(c,j) / (0.5_r8*(z(c,j)-zi(c,j-1)+capr*(z(c,j+1)-zi(c,j-1)))) end if fn(c,j) = tk(c,j)*(t_soisno(c,j+1)-t_soisno(c,j))/(z(c,j+1)-z(c,j)) else if (j <= nlevgrnd-1) then fact(c,j) = dtime/cv(c,j) fn(c,j) = tk(c,j)*(t_soisno(c,j+1)-t_soisno(c,j))/(z(c,j+1)-z(c,j)) dzm = (z(c,j)-z(c,j-1)) else if (j == nlevgrnd) then fact(c,j) = dtime/cv(c,j) ! For urban sunwall, shadewall, and roof columns, there is a non-zero heat flux across ! the bottom "soil" layer and the equations are derived assuming a prescribed internal ! building temperature. (See Oleson urban notes of 6/18/03). if (ctype(c)==icol_sunwall .or. ctype(c)==icol_shadewall .or. ctype(c)==icol_roof) then fn(c,j) = tk(c,j) * (t_building(l) - cnfac*t_soisno(c,j))/(zi(c,j) - z(c,j)) else fn(c,j) = eflx_bot(c) end if end if end if enddo end do do j = -nlevsno+1,nlevgrnd do fc = 1,num_nolakec c = filter_nolakec(fc) l = clandunit(c) if (j >= snl(c)+1) then if (j == snl(c)+1) then dzp = z(c,j+1)-z(c,j) at(c,j) = 0._r8 bt(c,j) = 1+(1._r8-cnfac)*fact(c,j)*tk(c,j)/dzp-fact(c,j)*dhsdT(c) ct(c,j) = -(1._r8-cnfac)*fact(c,j)*tk(c,j)/dzp ! changed hs to hs_top rt(c,j) = t_soisno(c,j) + fact(c,j)*( hs_top(c) - dhsdT(c)*t_soisno(c,j) + cnfac*fn(c,j) ) else if (j <= nlevgrnd-1) then dzm = (z(c,j)-z(c,j-1)) dzp = (z(c,j+1)-z(c,j)) at(c,j) = - (1._r8-cnfac)*fact(c,j)* tk(c,j-1)/dzm bt(c,j) = 1._r8+ (1._r8-cnfac)*fact(c,j)*(tk(c,j)/dzp + tk(c,j-1)/dzm) ct(c,j) = - (1._r8-cnfac)*fact(c,j)* tk(c,j)/dzp ! if this is a snow layer or the top soil layer, ! add absorbed solar flux to factor 'rt' if (j <= 1) then rt(c,j) = t_soisno(c,j) + cnfac*fact(c,j)*( fn(c,j) - fn(c,j-1) ) + (fact(c,j)*sabg_lyr_col(c,j)) else rt(c,j) = t_soisno(c,j) + cnfac*fact(c,j)*( fn(c,j) - fn(c,j-1) ) endif else if (j == nlevgrnd) then ! For urban sunwall, shadewall, and roof columns, there is a non-zero heat flux across ! the bottom "soil" layer and the equations are derived assuming a prescribed internal ! building temperature. (See Oleson urban notes of 6/18/03). if (ctype(c)==icol_sunwall .or. ctype(c)==icol_shadewall .or. ctype(c)==icol_roof) then dzm = ( z(c,j)-z(c,j-1)) dzp = (zi(c,j)-z(c,j)) at(c,j) = - (1._r8-cnfac)*fact(c,j)*(tk(c,j-1)/dzm) bt(c,j) = 1._r8+ (1._r8-cnfac)*fact(c,j)*(tk(c,j-1)/dzm + tk(c,j)/dzp) ct(c,j) = 0._r8 rt(c,j) = t_soisno(c,j) + fact(c,j)*( fn(c,j) - cnfac*fn(c,j-1) ) else dzm = (z(c,j)-z(c,j-1)) at(c,j) = - (1._r8-cnfac)*fact(c,j)*tk(c,j-1)/dzm bt(c,j) = 1._r8+ (1._r8-cnfac)*fact(c,j)*tk(c,j-1)/dzm ct(c,j) = 0._r8 rt(c,j) = t_soisno(c,j) - cnfac*fact(c,j)*fn(c,j-1) + fact(c,j)*fn(c,j) end if end if end if enddo end do do fc = 1,num_nolakec c = filter_nolakec(fc) jtop(c) = snl(c) + 1 end do call Tridiagonal(lbc, ubc, -nlevsno+1, nlevgrnd, jtop, num_nolakec, filter_nolakec, & at, bt, ct, rt, t_soisno(lbc:ubc,-nlevsno+1:nlevgrnd)) ! Melting or Freezing do j = -nlevsno+1,nlevgrnd do fc = 1,num_nolakec c = filter_nolakec(fc) l = clandunit(c) if (j >= snl(c)+1) then if (j <= nlevgrnd-1) then fn1(c,j) = tk(c,j)*(t_soisno(c,j+1)-t_soisno(c,j))/(z(c,j+1)-z(c,j)) else if (j == nlevgrnd) then ! For urban sunwall, shadewall, and roof columns, there is a non-zero heat flux across ! the bottom "soil" layer and the equations are derived assuming a prescribed internal ! building temperature. (See Oleson urban notes of 6/18/03). ! Note new formulation for fn, this will be used below in brr computation if (ctype(c)==icol_sunwall .or. ctype(c)==icol_shadewall .or. ctype(c)==icol_roof) then fn1(c,j) = tk(c,j) * (t_building(l) - t_soisno(c,j))/(zi(c,j) - z(c,j)) fn(c,j) = tk(c,j) * (t_building(l) - tssbef(c,j))/(zi(c,j) - z(c,j)) else fn1(c,j) = 0._r8 end if end if end if end do end do do fc = 1,num_nolakec c = filter_nolakec(fc) l = clandunit(c) if (ltype(l) == isturb) then eflx_building_heat(c) = cnfac*fn(c,nlevurb) + (1-cnfac)*fn1(c,nlevurb) if (cool_on(l)) then eflx_urban_ac(c) = abs(eflx_building_heat(c)) eflx_urban_heat(c) = 0._r8 else if (heat_on(l)) then eflx_urban_ac(c) = 0._r8 eflx_urban_heat(c) = abs(eflx_building_heat(c)) else eflx_urban_ac(c) = 0._r8 eflx_urban_heat(c) = 0._r8 end if end if end do do j = -nlevsno+1,nlevgrnd do fc = 1,num_nolakec c = filter_nolakec(fc) l = clandunit(c) if (j >= snl(c)+1) then if (j == snl(c)+1) then brr(c,j) = cnfac*fn(c,j) + (1._r8-cnfac)*fn1(c,j) else brr(c,j) = cnfac*(fn(c,j)-fn(c,j-1)) + (1._r8-cnfac)*(fn1(c,j)-fn1(c,j-1)) end if end if end do end do call PhaseChange (lbc, ubc, num_nolakec, filter_nolakec, fact, brr, hs, dhsdT, xmf, hs_top, sabg_lyr_col) do fc = 1,num_nolakec c = filter_nolakec(fc) t_grnd(c) = t_soisno(c,snl(c)+1) end do ! Initialize soil heat content do fc = 1,num_nolakec c = filter_nolakec(fc) l = clandunit(c) if (ltype(l) /= isturb) then hc_soisno(c) = 0._r8 hc_soi(c) = 0._r8 end if eflx_fgr12(c)= 0._r8 end do ! Calculate soil heat content and soil plus snow heat content do j = -nlevsno+1,nlevgrnd do fc = 1,num_nolakec c = filter_nolakec(fc) l = clandunit(c) eflx_fgr12(c) = -cnfac*fn(c,1) - (1._r8-cnfac)*fn1(c,1) if (ltype(l) /= isturb) then if (j >= snl(c)+1) then hc_soisno(c) = hc_soisno(c) + cv(c,j)*t_soisno(c,j) / 1.e6_r8 endif if (j >= 1) then hc_soi(c) = hc_soi(c) + cv(c,j)*t_soisno(c,j) / 1.e6_r8 end if end if end do end do end subroutine SoilTemperature !----------------------------------------------------------------------- !BOP ! ! !IROUTINE: SoilThermProp ! ! !INTERFACE: subroutine SoilThermProp (lbc, ubc, num_nolakec, filter_nolakec, tk, cv) ! ! !DESCRIPTION: ! Calculation of thermal conductivities and heat capacities of ! snow/soil layers ! (1) The volumetric heat capacity is calculated as a linear combination ! in terms of the volumetric fraction of the constituent phases. ! ! (2) The thermal conductivity of soil is computed from the algorithm of ! Johansen (as reported by Farouki 1981), and of snow is from the ! formulation used in SNTHERM (Jordan 1991). ! The thermal conductivities at the interfaces between two neighboring ! layers (j, j+1) are derived from an assumption that the flux across ! the interface is equal to that from the node j to the interface and the ! flux from the interface to the node j+1. ! ! !USES: use shr_kind_mod, only : r8 => shr_kind_r8 use clmtype use clm_varcon , only : denh2o, denice, tfrz, tkwat, tkice, tkair, & cpice, cpliq, istice, istice_mec, istwet, & icol_roof, icol_sunwall, icol_shadewall, & icol_road_perv, icol_road_imperv use clm_varpar , only : nlevsno, nlevgrnd, nlevurb, nlevsoi ! ! !ARGUMENTS: implicit none integer , intent(in) :: lbc, ubc ! column bounds integer , intent(in) :: num_nolakec ! number of column non-lake points in column filter integer , intent(in) :: filter_nolakec(ubc-lbc+1) ! column filter for non-lake points real(r8), intent(out) :: cv(lbc:ubc,-nlevsno+1:nlevgrnd)! heat capacity [J/(m2 K)] real(r8), intent(out) :: tk(lbc:ubc,-nlevsno+1:nlevgrnd)! thermal conductivity [W/(m K)] ! ! !CALLED FROM: ! subroutine SoilTemperature in this module ! ! !REVISION HISTORY: ! 15 September 1999: Yongjiu Dai; Initial code ! 15 December 1999: Paul Houser and Jon Radakovich; F90 Revision ! 2/13/02, Peter Thornton: migrated to new data structures ! 7/01/03, Mariana Vertenstein: migrated to vector code ! ! !LOCAL VARIABLES: ! ! local pointers to original implicit in scalars ! integer , pointer :: ctype(:) ! column type integer , pointer :: clandunit(:) ! column's landunit integer , pointer :: ltype(:) ! landunit type integer , pointer :: snl(:) ! number of snow layers real(r8), pointer :: h2osno(:) ! snow water (mm H2O) ! ! local pointers to original implicit in arrays ! real(r8), pointer :: watsat(:,:) ! volumetric soil water at saturation (porosity) real(r8), pointer :: tksatu(:,:) ! thermal conductivity, saturated soil [W/m-K] real(r8), pointer :: tkmg(:,:) ! thermal conductivity, soil minerals [W/m-K] real(r8), pointer :: tkdry(:,:) ! thermal conductivity, dry soil (W/m/Kelvin) real(r8), pointer :: csol(:,:) ! heat capacity, soil solids (J/m**3/Kelvin) real(r8), pointer :: dz(:,:) ! layer depth (m) real(r8), pointer :: zi(:,:) ! interface level below a "z" level (m) real(r8), pointer :: z(:,:) ! layer thickness (m) real(r8), pointer :: t_soisno(:,:) ! soil temperature (Kelvin) real(r8), pointer :: h2osoi_liq(:,:) ! liquid water (kg/m2) real(r8), pointer :: h2osoi_ice(:,:) ! ice lens (kg/m2) real(r8), pointer :: tk_wall(:,:) ! thermal conductivity of urban wall real(r8), pointer :: tk_roof(:,:) ! thermal conductivity of urban roof real(r8), pointer :: tk_improad(:,:) ! thermal conductivity of urban impervious road real(r8), pointer :: cv_wall(:,:) ! thermal conductivity of urban wall real(r8), pointer :: cv_roof(:,:) ! thermal conductivity of urban roof real(r8), pointer :: cv_improad(:,:) ! thermal conductivity of urban impervious road integer, pointer :: nlev_improad(:) ! number of impervious road layers ! ! ! !OTHER LOCAL VARIABLES: !EOP ! integer :: l,c,j ! indices integer :: fc ! lake filtered column indices real(r8) :: bw ! partial density of water (ice + liquid) real(r8) :: dksat ! thermal conductivity for saturated soil (j/(k s m)) real(r8) :: dke ! kersten number real(r8) :: fl ! fraction of liquid or unfrozen water to total water real(r8) :: satw ! relative total water content of soil. real(r8) :: thk(lbc:ubc,-nlevsno+1:nlevgrnd) ! thermal conductivity of layer real(r8) :: thk_bedrock = 3.0_r8 ! thermal conductivity of 'typical' saturated granitic rock ! (Clauser and Huenges, 1995)(W/m/K) !----------------------------------------------------------------------- ! Assign local pointers to derived subtypes components (landunit-level) ltype => clm3%g%l%itype ! Assign local pointers to derived subtypes components (column-level) ctype => clm3%g%l%c%itype clandunit => clm3%g%l%c%landunit snl => clm3%g%l%c%cps%snl h2osno => clm3%g%l%c%cws%h2osno watsat => clm3%g%l%c%cps%watsat tksatu => clm3%g%l%c%cps%tksatu tkmg => clm3%g%l%c%cps%tkmg tkdry => clm3%g%l%c%cps%tkdry csol => clm3%g%l%c%cps%csol dz => clm3%g%l%c%cps%dz zi => clm3%g%l%c%cps%zi z => clm3%g%l%c%cps%z t_soisno => clm3%g%l%c%ces%t_soisno h2osoi_liq => clm3%g%l%c%cws%h2osoi_liq h2osoi_ice => clm3%g%l%c%cws%h2osoi_ice tk_wall => clm3%g%l%lps%tk_wall tk_roof => clm3%g%l%lps%tk_roof tk_improad => clm3%g%l%lps%tk_improad cv_wall => clm3%g%l%lps%cv_wall cv_roof => clm3%g%l%lps%cv_roof cv_improad => clm3%g%l%lps%cv_improad nlev_improad => clm3%g%l%lps%nlev_improad ! Thermal conductivity of soil from Farouki (1981) ! Urban values are from Masson et al. 2002, Evaluation of the Town Energy Balance (TEB) ! scheme with direct measurements from dry districts in two cities, J. Appl. Meteorol., ! 41, 1011-1026. do j = -nlevsno+1,nlevgrnd do fc = 1, num_nolakec c = filter_nolakec(fc) ! Only examine levels from 1->nlevgrnd if (j >= 1) then l = clandunit(c) if (ctype(c) == icol_sunwall .OR. ctype(c) == icol_shadewall) then thk(c,j) = tk_wall(l,j) else if (ctype(c) == icol_roof) then thk(c,j) = tk_roof(l,j) else if (ctype(c) == icol_road_imperv .and. j >= 1 .and. j <= nlev_improad(l)) then thk(c,j) = tk_improad(l,j) elseif (ltype(l) /= istwet .AND. ltype(l) /= istice & .AND. ltype(l) /= istice_mec) then satw = (h2osoi_liq(c,j)/denh2o + h2osoi_ice(c,j)/denice)/(dz(c,j)*watsat(c,j)) satw = min(1._r8, satw) if (satw > .1e-6_r8) then fl = h2osoi_liq(c,j)/(h2osoi_ice(c,j)+h2osoi_liq(c,j)) if (t_soisno(c,j) >= tfrz) then ! Unfrozen soil dke = max(0._r8, log10(satw) + 1.0_r8) dksat = tksatu(c,j) else ! Frozen soil dke = satw dksat = tkmg(c,j)*0.249_r8**(fl*watsat(c,j))*2.29_r8**watsat(c,j) endif thk(c,j) = dke*dksat + (1._r8-dke)*tkdry(c,j) else thk(c,j) = tkdry(c,j) endif if (j > nlevsoi) thk(c,j) = thk_bedrock else if (ltype(l) == istice .OR. ltype(l) == istice_mec) then thk(c,j) = tkwat if (t_soisno(c,j) < tfrz) thk(c,j) = tkice else if (ltype(l) == istwet) then if (j > nlevsoi) then thk(c,j) = thk_bedrock else thk(c,j) = tkwat if (t_soisno(c,j) < tfrz) thk(c,j) = tkice endif endif endif ! Thermal conductivity of snow, which from Jordan (1991) pp. 18 ! Only examine levels from snl(c)+1 -> 0 where snl(c) < 1 if (snl(c)+1 < 1 .AND. (j >= snl(c)+1) .AND. (j <= 0)) then bw = (h2osoi_ice(c,j)+h2osoi_liq(c,j))/dz(c,j) thk(c,j) = tkair + (7.75e-5_r8 *bw + 1.105e-6_r8*bw*bw)*(tkice-tkair) end if end do end do ! Thermal conductivity at the layer interface do j = -nlevsno+1,nlevgrnd do fc = 1,num_nolakec c = filter_nolakec(fc) if (j >= snl(c)+1 .AND. j <= nlevgrnd-1) then tk(c,j) = thk(c,j)*thk(c,j+1)*(z(c,j+1)-z(c,j)) & /(thk(c,j)*(z(c,j+1)-zi(c,j))+thk(c,j+1)*(zi(c,j)-z(c,j))) else if (j == nlevgrnd) then ! For urban sunwall, shadewall, and roof columns, there is a non-zero heat flux across ! the bottom "soil" layer and the equations are derived assuming a prescribed internal ! building temperature. (See Oleson urban notes of 6/18/03). if (ctype(c)==icol_sunwall .OR. ctype(c)==icol_shadewall .OR. ctype(c)==icol_roof) then tk(c,j) = thk(c,j) else tk(c,j) = 0._r8 end if end if end do end do ! Soil heat capacity, from de Vires (1963) ! Urban values are from Masson et al. 2002, Evaluation of the Town Energy Balance (TEB) ! scheme with direct measurements from dry districts in two cities, J. Appl. Meteorol., ! 41, 1011-1026. do j = 1, nlevgrnd do fc = 1,num_nolakec c = filter_nolakec(fc) l = clandunit(c) if (ctype(c)==icol_sunwall .OR. ctype(c)==icol_shadewall) then cv(c,j) = cv_wall(l,j) * dz(c,j) else if (ctype(c) == icol_roof) then cv(c,j) = cv_roof(l,j) * dz(c,j) else if (ctype(c) == icol_road_imperv .and. j >= 1 .and. j <= nlev_improad(l)) then cv(c,j) = cv_improad(l,j) * dz(c,j) elseif (ltype(l) /= istwet .AND. ltype(l) /= istice & .AND. ltype(l) /= istice_mec) then cv(c,j) = csol(c,j)*(1-watsat(c,j))*dz(c,j) + (h2osoi_ice(c,j)*cpice + h2osoi_liq(c,j)*cpliq) else if (ltype(l) == istwet) then cv(c,j) = (h2osoi_ice(c,j)*cpice + h2osoi_liq(c,j)*cpliq) if (j > nlevsoi) cv(c,j) = csol(c,j)*dz(c,j) else if (ltype(l) == istice .OR. ltype(l) == istice_mec) then cv(c,j) = (h2osoi_ice(c,j)*cpice + h2osoi_liq(c,j)*cpliq) endif if (j == 1) then if (snl(c)+1 == 1 .AND. h2osno(c) > 0._r8) then cv(c,j) = cv(c,j) + cpice*h2osno(c) end if end if enddo end do ! Snow heat capacity do j = -nlevsno+1,0 do fc = 1,num_nolakec c = filter_nolakec(fc) if (snl(c)+1 < 1 .and. j >= snl(c)+1) then cv(c,j) = cpliq*h2osoi_liq(c,j) + cpice*h2osoi_ice(c,j) end if end do end do end subroutine SoilThermProp !----------------------------------------------------------------------- !BOP ! ! !IROUTINE: PhaseChange ! ! !INTERFACE: subroutine PhaseChange (lbc, ubc, num_nolakec, filter_nolakec, fact, & brr, hs, dhsdT, xmf, hs_top, sabg_lyr_col) ! ! !DESCRIPTION: ! Calculation of the phase change within snow and soil layers: ! (1) Check the conditions for which the phase change may take place, ! i.e., the layer temperature is great than the freezing point ! and the ice mass is not equal to zero (i.e. melting), ! or the layer temperature is less than the freezing point ! and the liquid water mass is greater than the allowable supercooled ! liquid water calculated from freezing point depression (i.e. freezing). ! (2) Assess the rate of phase change from the energy excess (or deficit) ! after setting the layer temperature to freezing point. ! (3) Re-adjust the ice and liquid mass, and the layer temperature ! ! !USES: use shr_kind_mod , only : r8 => shr_kind_r8 use clmtype use clm_time_manager, only : get_step_size use clm_varcon , only : tfrz, hfus, grav, istsoil, istice_mec, isturb, icol_road_perv use clm_varcon , only : istcrop use clm_varpar , only : nlevsno, nlevgrnd ! ! !ARGUMENTS: implicit none integer , intent(in) :: lbc, ubc ! column bounds integer , intent(in) :: num_nolakec ! number of column non-lake points in column filter integer , intent(in) :: filter_nolakec(ubc-lbc+1) ! column filter for non-lake points real(r8), intent(in) :: brr (lbc:ubc, -nlevsno+1:nlevgrnd) ! temporary real(r8), intent(in) :: fact (lbc:ubc, -nlevsno+1:nlevgrnd) ! temporary real(r8), intent(in) :: hs (lbc:ubc) ! net ground heat flux into the surface real(r8), intent(in) :: dhsdT (lbc:ubc) ! temperature derivative of "hs" real(r8), intent(out):: xmf (lbc:ubc) ! total latent heat of phase change real(r8), intent(in) :: hs_top(lbc:ubc) ! net heat flux into the top snow layer [W/m2] real(r8), intent(in) :: sabg_lyr_col(lbc:ubc,-nlevsno+1:1) ! absorbed solar radiation (col,lyr) [W/m2] ! ! !CALLED FROM: ! subroutine SoilTemperature in this module ! ! !REVISION HISTORY: ! 15 September 1999: Yongjiu Dai; Initial code ! 15 December 1999: Paul Houser and Jon Radakovich; F90 Revision ! 2/14/02, Peter Thornton: Migrated to new data structures. ! 7/01/03, Mariana Vertenstein: Migrated to vector code ! 04/25/07 Keith Oleson: CLM3.5 Hydrology ! 03/28/08 Mark Flanner: accept new arguments and calculate freezing rate of h2o in snow ! ! !LOCAL VARIABLES: ! ! local pointers to original implicit in scalars ! integer , pointer :: snl(:) !number of snow layers real(r8), pointer :: h2osno(:) !snow water (mm H2O) integer , pointer :: ltype(:) !landunit type integer , pointer :: clandunit(:) !column's landunit integer , pointer :: ctype(:) !column type ! ! local pointers to original implicit inout scalars ! real(r8), pointer :: snowdp(:) !snow height (m) ! ! local pointers to original implicit out scalars ! real(r8), pointer :: qflx_snomelt(:) !snow melt (mm H2O /s) real(r8), pointer :: eflx_snomelt(:) !snow melt heat flux (W/m**2) real(r8), pointer :: eflx_snomelt_u(:)!urban snow melt heat flux (W/m**2) real(r8), pointer :: eflx_snomelt_r(:)!rural snow melt heat flux (W/m**2) real(r8), pointer :: qflx_snofrz_lyr(:,:) !snow freezing rate (positive definite) (col,lyr) [kg m-2 s-1] real(r8), pointer :: qflx_snofrz_col(:) !column-integrated snow freezing rate (positive definite) [kg m-2 s-1] real(r8), pointer :: qflx_glcice(:) !flux of new glacier ice (mm H2O/s) [+ = ice grows] real(r8), pointer :: qflx_glcice_melt(:) !ice melt (positive definite) (mm H2O/s) ! ! local pointers to original implicit in arrays ! real(r8), pointer :: h2osoi_liq(:,:) !liquid water (kg/m2) (new) real(r8), pointer :: h2osoi_ice(:,:) !ice lens (kg/m2) (new) real(r8), pointer :: tssbef(:,:) !temperature at previous time step [K] real(r8), pointer :: sucsat(:,:) !minimum soil suction (mm) real(r8), pointer :: watsat(:,:) !volumetric soil water at saturation (porosity) real(r8), pointer :: bsw(:,:) !Clapp and Hornberger "b" real(r8), pointer :: dz(:,:) !layer thickness (m) ! ! local pointers to original implicit inout arrays ! real(r8), pointer :: t_soisno(:,:) !soil temperature (Kelvin) ! ! local pointers to original implicit out arrays ! integer, pointer :: imelt(:,:) !flag for melting (=1), freezing (=2), Not=0 (new) ! ! ! !OTHER LOCAL VARIABLES: !EOP ! integer :: j,c,g,l !do loop index integer :: fc !lake filtered column indices real(r8) :: dtime !land model time step (sec) real(r8) :: heatr !energy residual or loss after melting or freezing real(r8) :: temp1 !temporary variables [kg/m2] real(r8) :: hm(lbc:ubc,-nlevsno+1:nlevgrnd) !energy residual [W/m2] real(r8) :: xm(lbc:ubc,-nlevsno+1:nlevgrnd) !melting or freezing within a time step [kg/m2] real(r8) :: wmass0(lbc:ubc,-nlevsno+1:nlevgrnd)!initial mass of ice and liquid (kg/m2) real(r8) :: wice0 (lbc:ubc,-nlevsno+1:nlevgrnd)!initial mass of ice (kg/m2) real(r8) :: wliq0 (lbc:ubc,-nlevsno+1:nlevgrnd)!initial mass of liquid (kg/m2) real(r8) :: supercool(lbc:ubc,nlevgrnd) !supercooled water in soil (kg/m2) real(r8) :: propor !proportionality constant (-) real(r8) :: tinc !t(n+1)-t(n) (K) real(r8) :: smp !frozen water potential (mm) !----------------------------------------------------------------------- ! Assign local pointers to derived subtypes components (column-level) snl => clm3%g%l%c%cps%snl h2osno => clm3%g%l%c%cws%h2osno snowdp => clm3%g%l%c%cps%snowdp qflx_snomelt => clm3%g%l%c%cwf%qflx_snomelt eflx_snomelt => clm3%g%l%c%cef%eflx_snomelt eflx_snomelt_u => clm3%g%l%c%cef%eflx_snomelt_u eflx_snomelt_r => clm3%g%l%c%cef%eflx_snomelt_r h2osoi_liq => clm3%g%l%c%cws%h2osoi_liq h2osoi_ice => clm3%g%l%c%cws%h2osoi_ice imelt => clm3%g%l%c%cps%imelt t_soisno => clm3%g%l%c%ces%t_soisno tssbef => clm3%g%l%c%ces%tssbef bsw => clm3%g%l%c%cps%bsw sucsat => clm3%g%l%c%cps%sucsat watsat => clm3%g%l%c%cps%watsat dz => clm3%g%l%c%cps%dz ctype => clm3%g%l%c%itype clandunit => clm3%g%l%c%landunit ltype => clm3%g%l%itype qflx_snofrz_lyr => clm3%g%l%c%cwf%qflx_snofrz_lyr qflx_snofrz_col => clm3%g%l%c%cwf%qflx_snofrz_col qflx_glcice => clm3%g%l%c%cwf%qflx_glcice qflx_glcice_melt => clm3%g%l%c%cwf%qflx_glcice_melt ! Get step size dtime = get_step_size() ! Initialization do fc = 1,num_nolakec c = filter_nolakec(fc) l = clandunit(c) qflx_snomelt(c) = 0._r8 xmf(c) = 0._r8 qflx_snofrz_lyr(c,-nlevsno+1:0) = 0._r8 qflx_snofrz_col(c) = 0._r8 if (ltype(l)==istice_mec) then ! only need to initialize qflx_glcice_melt over ice_mec landunits, because ! those are the only places where it is computed qflx_glcice_melt(c) = 0._r8 end if end do do j = -nlevsno+1,nlevgrnd ! all layers do fc = 1,num_nolakec c = filter_nolakec(fc) if (j >= snl(c)+1) then ! Initialization imelt(c,j) = 0 hm(c,j) = 0._r8 xm(c,j) = 0._r8 wice0(c,j) = h2osoi_ice(c,j) wliq0(c,j) = h2osoi_liq(c,j) wmass0(c,j) = h2osoi_ice(c,j) + h2osoi_liq(c,j) endif ! end of snow layer if-block end do ! end of column-loop enddo ! end of level-loop do j = -nlevsno+1,0 ! snow layers do fc = 1,num_nolakec c = filter_nolakec(fc) if (j >= snl(c)+1) then ! Melting identification ! If ice exists above melt point, melt some to liquid. if (h2osoi_ice(c,j) > 0._r8 .AND. t_soisno(c,j) > tfrz) then imelt(c,j) = 1 t_soisno(c,j) = tfrz endif ! Freezing identification ! If liquid exists below melt point, freeze some to ice. if (h2osoi_liq(c,j) > 0._r8 .AND. t_soisno(c,j) < tfrz) then imelt(c,j) = 2 t_soisno(c,j) = tfrz endif endif ! end of snow layer if-block end do ! end of column-loop enddo ! end of level-loop do j = 1,nlevgrnd ! soil layers do fc = 1,num_nolakec c = filter_nolakec(fc) l = clandunit(c) if (h2osoi_ice(c,j) > 0. .AND. t_soisno(c,j) > tfrz) then imelt(c,j) = 1 t_soisno(c,j) = tfrz endif ! from Zhao (1997) and Koren (1999) supercool(c,j) = 0.0_r8 if (ltype(l) == istsoil .or. ltype(l) == istcrop .or. ctype(c) == icol_road_perv) then if(t_soisno(c,j) < tfrz) then smp = hfus*(tfrz-t_soisno(c,j))/(grav*t_soisno(c,j)) * 1000._r8 !(mm) supercool(c,j) = watsat(c,j)*(smp/sucsat(c,j))**(-1._r8/bsw(c,j)) supercool(c,j) = supercool(c,j)*dz(c,j)*1000._r8 ! (mm) endif endif if (h2osoi_liq(c,j) > supercool(c,j) .AND. t_soisno(c,j) < tfrz) then imelt(c,j) = 2 t_soisno(c,j) = tfrz endif ! If snow exists, but its thickness is less than the critical value (0.01 m) if (snl(c)+1 == 1 .AND. h2osno(c) > 0._r8 .AND. j == 1) then if (t_soisno(c,j) > tfrz) then imelt(c,j) = 1 t_soisno(c,j) = tfrz endif endif end do enddo do j = -nlevsno+1,nlevgrnd ! all layers do fc = 1,num_nolakec c = filter_nolakec(fc) if (j >= snl(c)+1) then ! Calculate the energy surplus and loss for melting and freezing if (imelt(c,j) > 0) then tinc = t_soisno(c,j)-tssbef(c,j) ! added unique cases for this calculation, ! to account for absorbed solar radiation in each layer if (j == snl(c)+1) then ! top layer hm(c,j) = hs_top(c) + dhsdT(c)*tinc + brr(c,j) - tinc/fact(c,j) elseif (j <= 1) then ! snow layer or top soil layer (where sabg_lyr_col is defined) hm(c,j) = brr(c,j) - tinc/fact(c,j) + sabg_lyr_col(c,j) else ! soil layer hm(c,j) = brr(c,j) - tinc/fact(c,j) endif endif ! These two errors were checked carefully (Y. Dai). They result from the ! computed error of "Tridiagonal-Matrix" in subroutine "thermal". if (imelt(c,j) == 1 .AND. hm(c,j) < 0._r8) then hm(c,j) = 0._r8 imelt(c,j) = 0 endif if (imelt(c,j) == 2 .AND. hm(c,j) > 0._r8) then hm(c,j) = 0._r8 imelt(c,j) = 0 endif ! The rate of melting and freezing if (imelt(c,j) > 0 .and. abs(hm(c,j)) > 0._r8) then xm(c,j) = hm(c,j)*dtime/hfus ! kg/m2 ! If snow exists, but its thickness is less than the critical value ! (1 cm). Note: more work is needed to determine how to tune the ! snow depth for this case if (j == 1) then if (snl(c)+1 == 1 .AND. h2osno(c) > 0._r8 .AND. xm(c,j) > 0._r8) then temp1 = h2osno(c) ! kg/m2 h2osno(c) = max(0._r8,temp1-xm(c,j)) propor = h2osno(c)/temp1 snowdp(c) = propor * snowdp(c) heatr = hm(c,j) - hfus*(temp1-h2osno(c))/dtime ! W/m2 if (heatr > 0._r8) then xm(c,j) = heatr*dtime/hfus ! kg/m2 hm(c,j) = heatr ! W/m2 else xm(c,j) = 0._r8 hm(c,j) = 0._r8 endif qflx_snomelt(c) = max(0._r8,(temp1-h2osno(c)))/dtime ! kg/(m2 s) xmf(c) = hfus*qflx_snomelt(c) endif endif heatr = 0._r8 if (xm(c,j) > 0._r8) then h2osoi_ice(c,j) = max(0._r8, wice0(c,j)-xm(c,j)) heatr = hm(c,j) - hfus*(wice0(c,j)-h2osoi_ice(c,j))/dtime else if (xm(c,j) < 0._r8) then if (j <= 0) then h2osoi_ice(c,j) = min(wmass0(c,j), wice0(c,j)-xm(c,j)) ! snow else if (wmass0(c,j) < supercool(c,j)) then h2osoi_ice(c,j) = 0._r8 else h2osoi_ice(c,j) = min(wmass0(c,j) - supercool(c,j),wice0(c,j)-xm(c,j)) endif endif heatr = hm(c,j) - hfus*(wice0(c,j)-h2osoi_ice(c,j))/dtime endif h2osoi_liq(c,j) = max(0._r8,wmass0(c,j)-h2osoi_ice(c,j)) if (abs(heatr) > 0._r8) then if (j > snl(c)+1) then t_soisno(c,j) = t_soisno(c,j) + fact(c,j)*heatr else t_soisno(c,j) = t_soisno(c,j) + fact(c,j)*heatr/(1._r8-fact(c,j)*dhsdT(c)) endif if (j <= 0) then ! snow if (h2osoi_liq(c,j)*h2osoi_ice(c,j)>0._r8) t_soisno(c,j) = tfrz end if endif xmf(c) = xmf(c) + hfus * (wice0(c,j)-h2osoi_ice(c,j))/dtime if (imelt(c,j) == 1 .AND. j < 1) then qflx_snomelt(c) = qflx_snomelt(c) + max(0._r8,(wice0(c,j)-h2osoi_ice(c,j)))/dtime endif ! layer freezing mass flux (positive): if (imelt(c,j) == 2 .AND. j < 1) then qflx_snofrz_lyr(c,j) = max(0._r8,(h2osoi_ice(c,j)-wice0(c,j)))/dtime endif endif endif ! end of snow layer if-block ! For glacier_mec columns, compute negative ice flux from melted ice. ! Note that qflx_glcice can also include a positive component from excess snow, ! as computed in Hydrology2Mod.F90. l = clandunit(c) if (ltype(l)==istice_mec) then if (j>=1 .and. h2osoi_liq(c,j) > 0._r8) then ! ice layer with meltwater ! melting corresponds to a negative ice flux qflx_glcice_melt(c) = qflx_glcice_melt(c) + h2osoi_liq(c,j)/dtime qflx_glcice(c) = qflx_glcice(c) - h2osoi_liq(c,j)/dtime ! convert layer back to pure ice by "borrowing" ice from below the column h2osoi_ice(c,j) = h2osoi_ice(c,j) + h2osoi_liq(c,j) h2osoi_liq(c,j) = 0._r8 endif ! liquid water is present endif ! istice_mec end do ! end of column-loop enddo ! end of level-loop ! Needed for history file output do fc = 1,num_nolakec c = filter_nolakec(fc) eflx_snomelt(c) = qflx_snomelt(c) * hfus l = clandunit(c) if (ltype(l) == isturb) then eflx_snomelt_u(c) = eflx_snomelt(c) else if (ltype(l) == istsoil .or. ltype(l) == istcrop) then eflx_snomelt_r(c) = eflx_snomelt(c) end if end do do j = -nlevsno+1,0 do fc = 1,num_nolakec c = filter_nolakec(fc) qflx_snofrz_col(c) = qflx_snofrz_col(c) + qflx_snofrz_lyr(c,j) end do end do end subroutine PhaseChange end module SoilTemperatureMod