do_advection - 2D advection schemes

INTERFACE:

    subroutine do_advection(dt,f,U,V,DU,DV,Do,Dn,split,scheme,AH,tag, &
                            Dires,advres)

DESCRIPTION:

Laterally advects a 2D quantity. The location of the quantity on the grid (either T-, U- or V-points) must be specified by the argument tag. The transports through the interfaces of the corresponding Finite-Volumes and their different height information (all relative to the given quantity) must be provided as well. Depending on split and scheme several fractional steps (Strang splitting) with different options for the calculation of the interfacial fluxes are carried out.

The options for split are:

split = NOSPLIT:	no split (one 2D uv step)
split = FULLSPLIT:	full step splitting (u + v)
split = HALFSPLIT:	half step splitting (u/2 + v + u/2)

The options for scheme are:

scheme = NOADV:	advection disabled
scheme = UPSTREAM:	first-order upstream (monotone)
scheme = UPSTREAM_2DH:	2DH upstream with forced monotonicity
scheme = P2:	third-order polynomial (non-monotone)
scheme = SUPERBEE:	second-order TVD (monotone)
scheme = MUSCL:	second-order TVD (monotone)
scheme = P2_PDM:	third-order ULTIMATE-QUICKEST (monotone)
scheme = J7:	2DH Arakawa J7
scheme = FCT:	2DH FCT with forced monotonicity
scheme = P2_2DH:	2DH P2 with forced monotonicity

With the compiler option SLICE_MODEL, the advection in meridional direction is not executed.

USES:

    use halo_zones, only: update_2d_halo,wait_halo,D_TAG,H_TAG,U_TAG,V_TAG
    use getm_timers, only: tic,toc,TIM_ADV,TIM_ADVH
    IMPLICIT NONE

INPUT PARAMETERS:

    REALTYPE,intent(in)                               :: dt,AH
    REALTYPE,dimension(E2DFIELD),intent(in)           :: U,V,Do,Dn,DU,DV
    integer,intent(in)                                :: split,scheme,tag

INPUT/OUTPUT PARAMETERS:

    REALTYPE,dimension(E2DFIELD),intent(inout)        :: f

OUTPUT PARAMETERS:

    REALTYPE,dimension(E2DFIELD),target,intent(out),optional :: Dires,advres

LOCAL VARIABLES:

    type(t_adv_grid),pointer                   :: adv_grid
    REALTYPE,dimension(E2DFIELD),target        :: fi,Di,adv
    REALTYPE,dimension(:,:),pointer,contiguous :: p_Di,p_adv
    integer                                    :: i,j