minor update

obl_common_phys.f90

@@ -2,6 +2,8 @@ module obl_common_phys
     !< @brief common physical parameters and constants
     ! --------------------------------------------------------------------------------
 
+    ! directives list
+    ! --------------------------------------------------------------------------------
     implicit none
     private
 
@@ -22,23 +24,35 @@ module obl_common_phys
     real, public, parameter :: R_v = 461.0              !< water vapor gas constant [J / (K * kg)]
     ! --------------------------------------------------------------------------------
 
+
     contains 
 
+    ! --------------------------------------------------------------------------------
     subroutine get_specific_humidity(Q, e, P, R_d, R_v)
-        real, intent(out) :: Q
+        !> @brief calculate specific humidity
+        ! --------------------------------------------------------------------------------
+        real, intent(out) :: Q                  !< specific humidity [kg/kg]
         
-        real, intent(in) :: e, P, R_d, R_v
+        real, intent(in) :: e, P                !< vapor pressure & pressure [*]
+        real, intent(in) :: R_d, R_v
         real :: gamma
+        ! --------------------------------------------------------------------------------
 
         gamma = R_d / R_v
         Q = gamma * e / (p - (1.0 - gamma) * e) 
     end subroutine
 
+    ! --------------------------------------------------------------------------------
     subroutine get_water_saturation_vapor_pressure_in_kPa(e, TinK)
-        real, intent(out) :: e
+        !> @brief water saturation vapor pressure [Alduchov & Eskridge, 1996. J. Appl. Meteor. 35. 601-609]
+        !> @brief *: see also [Ambaum, 2020. Q.J.R.Met.Soc. 146(733). 4252-4258]
+        !> @brief *: moist air corrections are neglected currently
+        ! --------------------------------------------------------------------------------
+        real, intent(out) :: e                  !< vapor pressure, [kPa]
 
         real, intent(in) :: TinK
         real :: TinC
+        ! --------------------------------------------------------------------------------
         
         TinC = TinK - zero_celsius
         e = 0.61094 * exp((17.625 * TinC) / (TinC + 243.04))