!> @file diagnostic_quantities_mod.f90 !------------------------------------------------------------------------------! ! This file is part of the PALM model system. ! ! PALM is free software: you can redistribute it and/or modify it under the ! terms of the GNU General Public License as published by the Free Software ! Foundation, either version 3 of the License, or (at your option) any later ! version. ! ! PALM is distributed in the hope that it will be useful, but WITHOUT ANY ! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR ! A PARTICULAR PURPOSE. See the GNU General Public License for more details. ! ! You should have received a copy of the GNU General Public License along with ! PALM. If not, see . ! ! Copyright 1997-2018 Leibniz Universitaet Hannover !------------------------------------------------------------------------------! ! ! Current revisions: ! ----------------- ! ! ! Former revisions: ! -----------------! ! $Id: diagnostic_quantities_mod.f90 2718 2018-01-02 08:49:38Z raasch $ ! Corrected "Former revisions" section ! ! 2696 2017-12-14 17:12:51Z kanani ! Change in file header (GPL part) ! ! 2608 2017-11-13 14:04:26Z schwenkel ! Initial revision ! ! ! Description: ! ------------ !> This module contains subroutines and functions for the calculation of !> diagnostic quantities. Especially moisture quantities such as the saturation !> mixining ratio is calculated !------------------------------------------------------------------------------! MODULE diagnostic_quantities_mod USE kinds IMPLICIT NONE REAL(wp) :: alpha !< correction factor REAL(wp) :: e_s !< saturation water vapor pressure REAL(wp) :: q_s !< saturation mixing ratio REAL(wp) :: sat !< supersaturation REAL(wp) :: t_l !< actual temperature PRIVATE PUBLIC e_s, magnus, q_s, sat, supersaturation, t_l INTERFACE supersaturation MODULE PROCEDURE supersaturation END INTERFACE supersaturation CONTAINS !------------------------------------------------------------------------------! ! Description: ! ------------ !> Computation of the diagnostic supersaturation sat, actual temperature t_l !< and saturation water vapor mixing ratio q_ !------------------------------------------------------------------------------! SUBROUTINE supersaturation ( i,j,k ) USE arrays_3d, & ONLY: hyp, pt, q, qc, qr USE cloud_parameters, & ONLY: l_d_cp, l_d_r, t_d_pt IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< ! !-- Actual liquid water temperature: t_l = t_d_pt(k) * pt(k,j,i) ! !-- Calculate water vapor saturation pressure e_s = magnus( t_l ) ! !-- Computation of saturation humidity: q_s = 0.622_wp * e_s / ( hyp(k) - e_s ) ! !-- Correction factor alpha = 0.622_wp * l_d_r * l_d_cp / ( t_l * t_l ) ! !-- Correction of the approximated value !-- (see: Cuijpers + Duynkerke, 1993, JAS, 23) q_s = q_s * ( 1.0_wp + alpha * q(k,j,i) ) / ( 1.0_wp + alpha * q_s ) ! !-- Supersaturation: sat = ( q(k,j,i) - qr(k,j,i) - qc(k,j,i) ) / q_s - 1.0_wp END SUBROUTINE supersaturation !------------------------------------------------------------------------------! ! Description: ! ------------ !> This function computes the magnus function (Press et al., 1992). !> The magnus formula is needed to calculate the saturation vapor pressure !------------------------------------------------------------------------------! FUNCTION magnus( temperature ) IMPLICIT NONE REAL(wp) :: magnus !< REAL(wp) :: temperature !< ! !-- Saturation vapor pressure at t_l: magnus = 611.2_wp * EXP( 17.62_wp * ( temperature - 273.15_wp ) / & ( temperature - 29.65_wp ) ) ! magnus = 610.78_wp * EXP( 17.269_wp * ( temperature - 273.16_wp ) / & ! ( temperature - 35.86_wp ) & ! ) END FUNCTION magnus END MODULE diagnostic_quantities_mod