Calculate the humidity (Source File: humidity.F90)

INTERFACE:

    subroutine humidity(hum_method,hum,airp,tw,ta)

DESCRIPTION:

This routine calculated the saturation vapour pressure at SST and at air temperature, as well as the saturation specific humidty and the specific humidity. For the latter, four methods are implemented, and the method has to be chosen in the namelist file airsea.nml as parameter hum_method, see section 5.2.1 for details.

USES:

    use airsea_variables, only: kelvin,const06,rgas
    use airsea_variables, only: es,ea,qs,qa,rhoa
    IMPLICIT NONE

INPUT PARAMETERS:

    integer, intent(in)                 :: hum_method
    REALTYPE, intent(in)                :: hum,airp,tw,ta

OUTPUT PARAMETERS:

REVISION HISTORY:

    Original author(s): Adolf Stips, Hans Burchard & Karsten Bolding

DEFINED PARAMETERS:

    REALTYPE, parameter       :: a1=6.107799961
    REALTYPE, parameter       :: a2=4.436518521e-1
    REALTYPE, parameter       :: a3=1.428945805e-2
    REALTYPE, parameter       :: a4=2.650648471e-4
    REALTYPE, parameter       :: a5=3.031240396e-6
    REALTYPE, parameter       :: a6=2.034080948e-8
    REALTYPE, parameter       :: a7=6.136820929e-11

LOCAL VARIABLES:

    REALTYPE        :: rh,twet,twet_k,dew,dew_k