! File %M% from Library %Q% ! Version %I% from %G% extracted: %H% !------------------------------------------------------------------------------ MODULE SfcFlx !------------------------------------------------------------------------------ ! ! Description: ! ! The main program unit of ! the atmospheric surface-layer parameterization scheme "SfcFlx". ! "SfcFlx" is used to compute fluxes ! of momentum and of sensible and latent heat over lakes. ! The surface-layer scheme developed by Mironov (1991) was used as the starting point. ! It was modified and further developed to incorporate new results as to ! the roughness lenghts for scalar quantities, ! heat and mass transfer in free convection, ! and the effect of limited fetch on the momentum transfer. ! Apart from the momentum flux and sensible and latent heat fluxes, ! the long-wave radiation flux from the water surface and ! the long-wave radiation flux from the atmosphere can also be computed. ! The atmospheric long-wave radiation flux is computed with simple empirical formulae, ! where the atmospheric emissivity is taken to be dependent on ! the water vapour pressure and cloud fraction. ! ! A description of SfcFlx is available from the author. ! Dmitrii Mironov ! German Weather Service, Kaiserleistr. 29/35, D-63067 Offenbach am Main, Germany. ! dmitrii.mironov@dwd.de ! ! Lines embraced with "!_tmp" contain temporary parts of the code. ! Lines embraced/marked with "!_dev" may be replaced ! as improved parameterizations are developed and tested. ! Lines embraced/marked with "!_dm" are DM's comments ! that may be helpful to a user. ! Lines embraced/marked with "!_dbg" are used ! for debugging purposes only. ! ! ! Current Code Owner: DWD, Dmitrii Mironov ! Phone: +49-69-8062 2705 ! Fax: +49-69-8062 3721 ! E-mail: dmitrii.mironov@dwd.de ! ! History: ! Version Date Name ! ---------- ---------- ---- ! 1.00 2005/11/17 Dmitrii Mironov ! Initial release ! !VERSION! !DATE! ! ! ! Code Description: ! Language: Fortran 90. ! Software Standards: "European Standards for Writing and ! Documenting Exchangeable Fortran 90 Code". !============================================================================== ! ! Declarations: ! ! Modules used: USE data_parameters , ONLY : & ireals , & ! KIND-type parameter for real variables iintegers ! KIND-type parameter for "normal" integer variables USE flake_parameters , ONLY : & tpl_grav , & ! Acceleration due to gravity [m s^{-2}] tpl_T_f , & ! Fresh water freezing point [K] tpl_rho_w_r , & ! Maximum density of fresh water [kg m^{-3}] tpl_c_w , & ! Specific heat of water [J kg^{-1} K^{-1}] tpl_L_f , & ! Latent heat of fusion [J kg^{-1}] h_Ice_min_flk ! Minimum ice thickness [m] !============================================================================== IMPLICIT NONE !============================================================================== ! ! Declarations ! Dimensionless constants in the Monin-Obukhov surface-layer ! similarity relations and in the expressions for the roughness lengths. REAL (KIND = ireals), PARAMETER :: & c_Karman = 0.40_ireals , & ! The von Karman constant Pr_neutral = 1.0_ireals , & ! Turbulent Prandtl number at neutral static stability Sc_neutral = 1.0_ireals , & ! Turbulent Schmidt number at neutral static stability c_MO_u_stab = 5.0_ireals , & ! Constant of the MO theory (wind, stable stratification) c_MO_t_stab = 5.0_ireals , & ! Constant of the MO theory (temperature, stable stratification) c_MO_q_stab = 5.0_ireals , & ! Constant of the MO theory (humidity, stable stratification) c_MO_u_conv = 15.0_ireals , & ! Constant of the MO theory (wind, convection) c_MO_t_conv = 15.0_ireals , & ! Constant of the MO theory (temperature, convection) c_MO_q_conv = 15.0_ireals , & ! Constant of the MO theory (humidity, convection) c_MO_u_exp = 0.25_ireals , & ! Constant of the MO theory (wind, exponent) c_MO_t_exp = 0.5_ireals , & ! Constant of the MO theory (temperature, exponent) c_MO_q_exp = 0.5_ireals , & ! Constant of the MO theory (humidity, exponent) z0u_ice_rough = 1.0E-03_ireals , & ! Aerodynamic roughness of the ice surface [m] (rough flow) c_z0u_smooth = 0.1_ireals , & ! Constant in the expression for z0u (smooth flow) c_z0u_rough = 1.23E-02_ireals , & ! The Charnock constant in the expression for z0u (rough flow) c_z0u_rough_L = 1.00E-01_ireals , & ! An increased Charnock constant (used as the upper limit) c_z0u_ftch_f = 0.70_ireals , & ! Factor in the expression for fetch-dependent Charnock parameter c_z0u_ftch_ex = 0.3333333_ireals , & ! Exponent in the expression for fetch-dependent Charnock parameter c_z0t_rough_1 = 4.0_ireals , & ! Constant in the expression for z0t (factor) c_z0t_rough_2 = 3.2_ireals , & ! Constant in the expression for z0t (factor) c_z0t_rough_3 = 0.5_ireals , & ! Constant in the expression for z0t (exponent) c_z0q_rough_1 = 4.0_ireals , & ! Constant in the expression for z0q (factor) c_z0q_rough_2 = 4.2_ireals , & ! Constant in the expression for z0q (factor) c_z0q_rough_3 = 0.5_ireals , & ! Constant in the expression for z0q (exponent) c_z0t_ice_b0s = 1.250_ireals , & ! Constant in the expression for z0t over ice c_z0t_ice_b0t = 0.149_ireals , & ! Constant in the expression for z0t over ice c_z0t_ice_b1t = -0.550_ireals , & ! Constant in the expression for z0t over ice c_z0t_ice_b0r = 0.317_ireals , & ! Constant in the expression for z0t over ice c_z0t_ice_b1r = -0.565_ireals , & ! Constant in the expression for z0t over ice c_z0t_ice_b2r = -0.183_ireals , & ! Constant in the expression for z0t over ice c_z0q_ice_b0s = 1.610_ireals , & ! Constant in the expression for z0q over ice c_z0q_ice_b0t = 0.351_ireals , & ! Constant in the expression for z0q over ice c_z0q_ice_b1t = -0.628_ireals , & ! Constant in the expression for z0q over ice c_z0q_ice_b0r = 0.396_ireals , & ! Constant in the expression for z0q over ice c_z0q_ice_b1r = -0.512_ireals , & ! Constant in the expression for z0q over ice c_z0q_ice_b2r = -0.180_ireals , & ! Constant in the expression for z0q over ice Re_z0s_ice_t = 2.5_ireals , & ! Threshold value of the surface Reynolds number ! used to compute z0t and z0q over ice (Andreas 2002) Re_z0u_thresh = 0.1_ireals ! Threshold value of the roughness Reynolds number ! [value from Zilitinkevich, Grachev, and Fairall (200), ! currently not used] ! Dimensionless constants REAL (KIND = ireals), PARAMETER :: & c_free_conv = 0.14_ireals ! Constant in the expressions for fluxes in free convection ! Dimensionless constants REAL (KIND = ireals), PARAMETER :: & c_lwrad_emis = 0.99_ireals ! Surface emissivity with respect to the long-wave radiation ! Thermodynamic parameters REAL (KIND = ireals), PARAMETER :: & tpsf_C_StefBoltz = 5.67E-08_ireals , & ! The Stefan-Boltzmann constant [W m^{-2} K^{-4}] tpsf_R_dryair = 2.8705E+02_ireals , & ! Gas constant for dry air [J kg^{-1} K^{-1}] tpsf_R_watvap = 4.6151E+02_ireals , & ! Gas constant for water vapour [J kg^{-1} K^{-1}] tpsf_c_a_p = 1.005E+03_ireals , & ! Specific heat of air at constant pressure [J kg^{-1} K^{-1}] tpsf_L_evap = 2.501E+06_ireals , & ! Specific heat of evaporation [J kg^{-1}] tpsf_nu_u_a = 1.50E-05_ireals , & ! Kinematic molecular viscosity of air [m^{2} s^{-1}] tpsf_kappa_t_a = 2.20E-05_ireals , & ! Molecular temperature conductivity of air [m^{2} s^{-1}] tpsf_kappa_q_a = 2.40E-05_ireals ! Molecular diffusivity of air for water vapour [m^{2} s^{-1}] ! Derived thermodynamic parameters REAL (KIND = ireals), PARAMETER :: & tpsf_Rd_o_Rv = tpsf_R_dryair/tpsf_R_watvap , & ! Ratio of gas constants (Rd/Rv) tpsf_alpha_q = (1._ireals-tpsf_Rd_o_Rv)/tpsf_Rd_o_Rv ! Diemsnionless ratio ! Thermodynamic parameters REAL (KIND = ireals), PARAMETER :: & P_a_ref = 1.0E+05_ireals ! Reference pressure [N m^{-2} = kg m^{-1} s^{-2}] ! The variables declared below ! are accessible to all program units of the MODULE "SfcFlx" ! and to the driving routines that use "SfcFlx". ! These are basically the quantities computed by SfcFlx. ! Apart from these quantities, there a few local scalars ! used by SfcFlx routines mainly for security reasons. ! All variables declared below have a suffix "sf". ! SfcFlx variables of type REAL ! Roughness lengths REAL (KIND = ireals) :: & z0u_sf , & ! Roughness length with respect to wind velocity [m] z0t_sf , & ! Roughness length with respect to potential temperature [m] z0q_sf ! Roughness length with respect to specific humidity [m] ! Fluxes in the surface air layer REAL (KIND = ireals) :: & u_star_a_sf , & ! Friction velocity [m s^{-1}] Q_mom_a_sf , & ! Momentum flux [N m^{-2}] Q_sens_a_sf , & ! Sensible heat flux [W m^{-2}] Q_lat_a_sf , & ! Laten heat flux [W m^{-2}] Q_watvap_a_sf ! Flux of water vapout [kg m^{-2} s^{-1}] ! Security constants REAL (KIND = ireals), PARAMETER :: & u_wind_min_sf = 1.0E-02_ireals , & ! Minimum wind speed [m s^{-1}] u_star_min_sf = 1.0E-04_ireals , & ! Minimum value of friction velocity [m s^{-1}] c_accur_sf = 1.0E-07_ireals , & ! A small number (accuracy) c_small_sf = 1.0E-04_ireals ! A small number (used to compute fluxes) ! Useful constants REAL (KIND = ireals), PARAMETER :: & num_1o3_sf = 1._ireals/3._ireals ! 1/3 !============================================================================== ! Procedures !============================================================================== CONTAINS !============================================================================== ! The codes of the SfcFlx procedures are stored in separate "*.incf" files ! and are included below. !------------------------------------------------------------------------------ !============================================================================== include 'SfcFlx_lwradatm.incf' !============================================================================== !============================================================================== include 'SfcFlx_lwradwsfc.incf' !============================================================================== !============================================================================== include 'SfcFlx_momsenlat.incf' !============================================================================== !============================================================================== include 'SfcFlx_rhoair.incf' !============================================================================== !============================================================================== include 'SfcFlx_roughness.incf' !============================================================================== !============================================================================== include 'SfcFlx_satwvpres.incf' !============================================================================== !============================================================================== include 'SfcFlx_spechum.incf' !============================================================================== !============================================================================== include 'SfcFlx_wvpreswetbulb.incf' !============================================================================== END MODULE SfcFlx