The Jackett et al. (2005) equation of state

INTERFACE:

    REALTYPE function rho_feistel(s,th,p,UNPress)

DESCRIPTION:

Computes the in-situ density in (242) according to the Jackett et al. (2005) equation of state for sea water, which is based on the Gibbs potential developed by Feistel (2003). The pressure dependence can be switched on (UNPress=.true.) or off (UNPress=.false.). s is salinity $S$ in psu, th is potential temperature $\theta$ in $^{\circ}$C (ITS-90), p is gauge pressure (absolute pressure - 10.1325 dbar) and rho_feistel is the in-situ density in kgm$^{-3}$. The check value is rho_feistel(20,20,1000) = 1017.728868019642 .

USES:

    IMPLICIT NONE

INPUT PARAMETERS:

    REALTYPE, intent(in)                :: s,th,p
    LOGICAL, intent(in)                 :: UNPress

REVISION HISTORY:

    Original author(s): Hans Burchard & Karsten Bolding