1 |
jmc |
1.4 |
C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_dst2u1_adv_y.F,v 1.3 2006/06/12 16:06:28 jmc Exp $ |
2 |
jmc |
1.1 |
C $Name: $ |
3 |
|
|
|
4 |
|
|
#include "GAD_OPTIONS.h" |
5 |
|
|
|
6 |
|
|
CBOP |
7 |
|
|
C !ROUTINE: GAD_DST2U1_ADV_Y |
8 |
|
|
|
9 |
|
|
C !INTERFACE: ========================================================== |
10 |
jmc |
1.3 |
SUBROUTINE GAD_DST2U1_ADV_Y( |
11 |
jmc |
1.1 |
I bi,bj,k, advectionScheme, deltaTloc, |
12 |
jmc |
1.4 |
I vTrans, vFld, |
13 |
jmc |
1.1 |
I tracer, |
14 |
|
|
O vT, |
15 |
|
|
I myThid ) |
16 |
|
|
|
17 |
|
|
C !DESCRIPTION: |
18 |
|
|
C Calculates the area integrated meridional flux due to advection |
19 |
jmc |
1.3 |
C of a tracer using second-order Direct Space and Time (DST-2) |
20 |
jmc |
1.1 |
C interpolation (=Lax-Wendroff) or simple 1rst order upwind scheme. |
21 |
|
|
|
22 |
|
|
C !USES: =============================================================== |
23 |
|
|
IMPLICIT NONE |
24 |
|
|
#include "SIZE.h" |
25 |
|
|
#include "GRID.h" |
26 |
|
|
#include "GAD.h" |
27 |
|
|
|
28 |
|
|
C !INPUT PARAMETERS: =================================================== |
29 |
|
|
C bi,bj :: tile indices |
30 |
|
|
C k :: vertical level |
31 |
|
|
C advectionScheme :: advection scheme to use: either 2nd Order DST |
32 |
|
|
C or 1rst Order Upwind |
33 |
|
|
C vTrans :: meridional volume transport |
34 |
jmc |
1.4 |
C vFld :: meridional flow |
35 |
jmc |
1.1 |
C tracer :: tracer field |
36 |
|
|
C myThid :: thread number |
37 |
|
|
INTEGER bi,bj, k, advectionScheme |
38 |
|
|
_RL deltaTloc |
39 |
|
|
_RL vTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
40 |
jmc |
1.4 |
_RL vFld (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
41 |
jmc |
1.1 |
_RL tracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
42 |
|
|
INTEGER myThid |
43 |
|
|
|
44 |
|
|
C !OUTPUT PARAMETERS: ================================================== |
45 |
|
|
C vT :: meridional advective flux |
46 |
|
|
_RL vT (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
47 |
|
|
|
48 |
|
|
C !LOCAL VARIABLES: ==================================================== |
49 |
|
|
C i,j :: loop indices |
50 |
|
|
C yLimit :: centered (vs upwind) fraction |
51 |
jmc |
1.4 |
C vLoc :: velocity [m/s], meridional component |
52 |
jmc |
1.1 |
C vCFL :: Courant-Friedrich-Levy number |
53 |
|
|
INTEGER i,j |
54 |
jmc |
1.4 |
_RL vLoc, vCFL, yLimit, vAbs |
55 |
jmc |
1.1 |
CEOP |
56 |
|
|
|
57 |
|
|
yLimit = 0. _d 0 |
58 |
|
|
IF ( advectionScheme.EQ.ENUM_DST2 ) yLimit = 1. _d 0 |
59 |
|
|
|
60 |
|
|
DO i=1-Olx,sNx+Olx |
61 |
|
|
vT(i,1-Oly)=0. |
62 |
|
|
ENDDO |
63 |
|
|
DO j=1-Oly+1,sNy+Oly |
64 |
|
|
DO i=1-Olx,sNx+Olx |
65 |
|
|
|
66 |
jmc |
1.4 |
c vLoc = vFld(i,j) |
67 |
|
|
vLoc = vTrans(i,j)*recip_dxG(i,j,bi,bj) |
68 |
heimbach |
1.2 |
& *recip_drF(k)*_recip_hFacS(i,j,k,bi,bj) |
69 |
jmc |
1.4 |
vCFL = ABS(vLoc*deltaTloc*recip_dyC(i,j,bi,bj)) |
70 |
jmc |
1.1 |
|
71 |
jmc |
1.3 |
c vT(i,j) = |
72 |
|
|
c & vTrans(i,j)*(tracer(i,j-1)+tracer(i,j))*0.5 _d 0 |
73 |
|
|
c & + ( 1. _d 0 - yLimit*(1. _d 0 - vCFL) )*ABS(vTrans(i,j)) |
74 |
|
|
c & *(tracer(i,j-1)-tracer(i,j))*0.5 _d 0 |
75 |
|
|
C-- above formulation produces large truncation error when: |
76 |
|
|
C 1rst.O upWind and v > 0 & |tracer(i,j-1)| << |tracer(i,j)| |
77 |
|
|
C or v < 0 & |tracer(i,j-1)| >> |tracer(i,j)| |
78 |
|
|
C-- change to a more robust expression: |
79 |
|
|
vAbs = ABS(vTrans(i,j)) |
80 |
|
|
& *( 1. _d 0 - yLimit*(1. _d 0 - vCFL) ) |
81 |
|
|
vT(i,j) = ( vTrans(i,j)+vAbs )* 0.5 _d 0 * tracer(i,j-1) |
82 |
|
|
& + ( vTrans(i,j)-vAbs )* 0.5 _d 0 * tracer(i,j) |
83 |
|
|
|
84 |
jmc |
1.1 |
ENDDO |
85 |
|
|
ENDDO |
86 |
|
|
|
87 |
|
|
RETURN |
88 |
|
|
END |