MODULE sbcblk_algo_ice_lu12 !!====================================================================== !! *** MODULE sbcblk_algo_ice_lu12 *** !! Computes turbulent components of surface fluxes over sea-ice !! !! Lüpkes, C., Gryanik, V. M., Hartmann, J., and Andreas, E. L. ( 2012), A parametrization, based on sea ice morphology, !! of the neutral atmospheric drag coefficients for weather prediction and climate models, J. Geophys. Res., 117, D13112, !! doi:10.1029/2012JD017630. !! !! => Despite the fact that the sea-ice concentration (frice) must be provided, !! only transfer coefficients, and air temp. + hum. height adjustement !! over ice are returned/performed. !! ==> 'frice' is only here to estimate the form drag caused by sea-ice... !! !! Routine turb_ice_lu12 maintained and developed in AeroBulk !! (https://github.com/brodeau/aerobulk/) !! !! Author: Laurent Brodeau, Summer 2020 !! !!---------------------------------------------------------------------- USE par_kind, ONLY: wp USE par_oce, ONLY: jpi, jpj USE phycst ! physical constants USE sbc_phy ! Catalog of functions for physical/meteorological parameters in the marine boundary layer USE sbcblk_algo_ice_cdn IMPLICIT NONE PRIVATE PUBLIC :: turb_ice_lu12 REAL(wp), PARAMETER :: rz0_i_s_0 = 0.69e-3_wp ! Eq.(43) of Lupkes & Gryanik (2015) [m] => to estimate CdN10 for skin drag! REAL(wp), PARAMETER :: rz0_i_f_0 = 4.54e-4_wp ! bottom p.562 MIZ [m] (LG15) !!---------------------------------------------------------------------- CONTAINS SUBROUTINE turb_ice_lu12( zt, zu, Ts_i, t_zt, qs_i, q_zt, U_zu, frice, & & Cd_i, Ch_i, Ce_i, t_zu_i, q_zu_i, & & CdN, ChN, CeN, xz0, xu_star, xL, xUN10 ) !!---------------------------------------------------------------------- !! *** ROUTINE turb_ice_lu12 *** !! !! ** Purpose : Computes turbulent transfert coefficients of surface !! fluxes according to: !! Lüpkes, C., Gryanik, V. M., Hartmann, J., and Andreas, E. L. ( 2012), !! A parametrization, based on sea ice morphology, of the neutral !! atmospheric drag coefficients for weather prediction and climate models, !! J. Geophys. Res., 117, D13112, doi:10.1029/2012JD017630. !! !! INPUT : !! ------- !! * zt : height for temperature and spec. hum. of air [m] !! * zu : height for wind speed (usually 10m) [m] !! * Ts_i : surface temperature of sea-ice [K] !! * t_zt : potential air temperature at zt [K] !! * qs_i : saturation specific humidity at temp. Ts_i over ice [kg/kg] !! * q_zt : specific humidity of air at zt [kg/kg] !! * U_zu : scalar wind speed at zu [m/s] !! * frice : sea-ice concentration (fraction) !! !! OUTPUT : !! -------- !! * Cd_i : drag coefficient over sea-ice !! * Ch_i : sensible heat coefficient over sea-ice !! * Ce_i : sublimation coefficient over sea-ice !! * t_zu_i : pot. air temp. adjusted at zu over sea-ice [K] !! * q_zu_i : spec. hum. of air adjusted at zu over sea-ice [kg/kg] !! !! OPTIONAL OUTPUT: !! ---------------- !! * CdN : neutral-stability drag coefficient !! * ChN : neutral-stability sensible heat coefficient !! * CeN : neutral-stability evaporation coefficient !! * xz0 : return the aerodynamic roughness length (integration constant for wind stress) [m] !! * xu_star : return u* the friction velocity [m/s] !! * xL : return the Obukhov length [m] !! * xUN10 : neutral wind speed at 10m [m/s] !! !! ** Author: L. Brodeau, January 2020 / AeroBulk (https://github.com/brodeau/aerobulk/) !!---------------------------------------------------------------------------------- REAL(wp), INTENT(in ) :: zt ! height for t_zt and q_zt [m] REAL(wp), INTENT(in ) :: zu ! height for U_zu [m] REAL(wp), INTENT(in ), DIMENSION(jpi,jpj) :: Ts_i ! ice surface temperature [Kelvin] REAL(wp), INTENT(in ), DIMENSION(jpi,jpj) :: t_zt ! potential air temperature [Kelvin] REAL(wp), INTENT(in ), DIMENSION(jpi,jpj) :: qs_i ! sat. spec. hum. at ice/air interface [kg/kg] REAL(wp), INTENT(in ), DIMENSION(jpi,jpj) :: q_zt ! spec. air humidity at zt [kg/kg] REAL(wp), INTENT(in ), DIMENSION(jpi,jpj) :: U_zu ! relative wind module at zu [m/s] REAL(wp), INTENT(in ), DIMENSION(jpi,jpj) :: frice ! sea-ice concentration (fraction) REAL(wp), INTENT(out), DIMENSION(jpi,jpj) :: Cd_i ! drag coefficient over sea-ice REAL(wp), INTENT(out), DIMENSION(jpi,jpj) :: Ch_i ! transfert coefficient for heat over ice REAL(wp), INTENT(out), DIMENSION(jpi,jpj) :: Ce_i ! transfert coefficient for sublimation over ice REAL(wp), INTENT(out), DIMENSION(jpi,jpj) :: t_zu_i ! pot. air temp. adjusted at zu [K] REAL(wp), INTENT(out), DIMENSION(jpi,jpj) :: q_zu_i ! spec. humidity adjusted at zu [kg/kg] !!---------------------------------------------------------------------------------- REAL(wp), INTENT(out), DIMENSION(jpi,jpj), OPTIONAL :: CdN REAL(wp), INTENT(out), DIMENSION(jpi,jpj), OPTIONAL :: ChN REAL(wp), INTENT(out), DIMENSION(jpi,jpj), OPTIONAL :: CeN REAL(wp), INTENT(out), DIMENSION(jpi,jpj), OPTIONAL :: xz0 ! Aerodynamic roughness length [m] REAL(wp), INTENT(out), DIMENSION(jpi,jpj), OPTIONAL :: xu_star ! u*, friction velocity REAL(wp), INTENT(out), DIMENSION(jpi,jpj), OPTIONAL :: xL ! zeta (zu/L) REAL(wp), INTENT(out), DIMENSION(jpi,jpj), OPTIONAL :: xUN10 ! Neutral wind at zu !!---------------------------------------------------------------------------------- REAL(wp), DIMENSION(:,:), ALLOCATABLE :: dt_zu, dq_zu, z0 REAL(wp), DIMENSION(:,:), ALLOCATABLE :: Ubzu !! LOGICAL :: lreturn_cdn=.FALSE., lreturn_chn=.FALSE., lreturn_cen=.FALSE. LOGICAL :: lreturn_z0=.FALSE., lreturn_ustar=.FALSE., lreturn_L=.FALSE., lreturn_UN10=.FALSE. !! CHARACTER(len=40), PARAMETER :: crtnm = 'turb_ice_lu12@sbcblk_algo_ice_lu12.f90' !!---------------------------------------------------------------------------------- ALLOCATE ( Ubzu(jpi,jpj) ) ALLOCATE ( dt_zu(jpi,jpj), dq_zu(jpi,jpj), z0(jpi,jpj) ) lreturn_cdn = PRESENT(CdN) lreturn_chn = PRESENT(ChN) lreturn_cen = PRESENT(CeN) lreturn_z0 = PRESENT(xz0) lreturn_ustar = PRESENT(xu_star) lreturn_L = PRESENT(xL) lreturn_UN10 = PRESENT(xUN10) !! Scalar wind speed cannot be below 0.2 m/s Ubzu = MAX( U_zu, wspd_thrshld_ice ) !! First guess of temperature and humidity at height zu: t_zu_i = MAX( t_zt , 100._wp ) ! who knows what's given on masked-continental regions... q_zu_i = MAX( q_zt , 0.1e-6_wp ) ! " !! Air-Ice & Air-Sea differences (and we don't want them to be 0!) dt_zu = t_zu_i - Ts_i ; dt_zu = SIGN( MAX(ABS(dt_zu),1.E-6_wp), dt_zu ) dq_zu = q_zu_i - qs_i ; dq_zu = SIGN( MAX(ABS(dq_zu),1.E-9_wp), dq_zu ) !! To estimate CDN10_skin: !! we use the method that comes in LG15, i.e. by starting from a default roughness length z0 for skin drag: Ce_i(:,:) = rz0_i_s_0 !! temporary array to contain roughness length for skin drag ! !! Method #1: !Cd_i(:,:) = Cd_from_z0( zu, Ce_i(:,:) ) + CdN10_f_LU13( frice(:,:) ) !IF( lreturn_cdfrm ) CdN_frm = CdN10_f_LU13( frice(:,:) ) !PRINT *, 'LOLO: estimate of Cd_f_i method #1 =>', CdN10_f_LU13( frice(:,:) ); PRINT *, '' !! Method #2: !! We need an estimate of z0 over water: !z0_w(:,:) = z0_from_Cd( zu, CD_N10_NCAR(Ubzu) ) !!PRINT *, 'LOLO: estimate of z0_w =>', z0_w !Cd_i(:,:) = Cd_from_z0( zu, Ce_i(:,:) ) + CdN10_f_LU12( frice(:,:), z0_w(:,:) ) !IF( lreturn_cdfrm ) CdN_frm = CdN10_f_LU12( frice(:,:), z0_w(:,:) ) !! N10 skin drag N10 form drag !! Method #3: !Cd_i(:,:) = Cd_from_z0( zu, Ce_i(:,:) ) + CdN10_f_LU12_eq36( frice(:,:) ) !IF( lreturn_cdfrm ) CdN_frm = CdN10_f_LU12_eq36( frice(:,:) ) !PRINT *, 'LOLO: estimate of Cd_f_i method #2 =>', CdN10_f_LU12( frice(:,:), z0_w(:,:) ) !! Method #4: !! using eq.21 of LG15 instead: z0(:,:) = rz0_i_f_0 !Cd_i(:,:) = Cd_from_z0( zu, Ce_i(:,:) ) + CdN_f_LG15( zu, frice(:,:), z0(:,:) ) / frice(:,:) Cd_i(:,:) = Cd_from_z0( zu, Ce_i(:,:) ) + CdN_f_LG15( zu, frice(:,:), z0(:,:) ) !/ frice(:,:) !IF( lreturn_cdfrm ) CdN_frm = CdN_f_LG15( zu, frice(:,:), z0(:,:) ) Ch_i(:,:) = Cd_i(:,:) Ce_i(:,:) = Cd_i(:,:) IF( lreturn_cdn ) CdN = Cd_i(:,:) IF( lreturn_chn ) ChN = Ch_i(:,:) IF( lreturn_cen ) CeN = Ce_i(:,:) IF( lreturn_z0 ) xz0 = z0_from_Cd( zu, Cd_i ) IF( lreturn_ustar ) xu_star = SQRT(Cd_i)*Ubzu IF( lreturn_L ) xL = 1./One_on_L(t_zu_i, q_zu_i, SQRT(Cd_i)*Ubzu, & & Cd_i/SQRT(Cd_i)*dt_zu, Cd_i/SQRT(Cd_i)*dq_zu) IF( lreturn_UN10 ) xUN10 = SQRT(Cd_i)*Ubzu/vkarmn * LOG( 10._wp / z0_from_Cd( zu, Cd_i ) ) DEALLOCATE ( dt_zu, dq_zu, z0 ) DEALLOCATE ( Ubzu ) END SUBROUTINE turb_ice_lu12 !!====================================================================== END MODULE sbcblk_algo_ice_lu12