/[MITgcm]/MITgcm/pkg/obcs/orlanski_north.F
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Revision 1.2 - (hide annotations) (download)
Fri Feb 2 21:36:30 2001 UTC (23 years, 4 months ago) by adcroft
Branch: MAIN
CVS Tags: checkpoint40pre3, checkpoint40pre1, checkpoint40pre7, checkpoint40pre6, checkpoint40pre9, checkpoint40pre8, checkpoint38, checkpoint40pre2, checkpoint40pre4, pre38tag1, c37_adj, pre38-close, checkpoint39, checkpoint37, checkpoint36, checkpoint35, checkpoint40pre5, checkpoint40, checkpoint41
Branch point for: pre38
Changes since 1.1: +249 -0 lines
Merged changes from branch "branch-atmos-merge" into MAIN (checkpoint34)
 - substantial modifications to algorithm sequence (dynamics.F)
 - packaged OBCS, Shapiro filter, Zonal filter, Atmospheric Physics

1 adcroft 1.2 C $Header: /u/gcmpack/models/MITgcmUV/pkg/obcs/Attic/orlanski_north.F,v 1.1.2.1 2001/01/30 21:03:00 adcroft Exp $
2     C $Name: branch-atmos-merge-freeze $
3    
4     #include "OBCS_OPTIONS.h"
5    
6     SUBROUTINE ORLANSKI_NORTH( bi, bj, futureTime,
7     I uVel, vVel, wVel, theta, salt,
8     I myThid )
9     C /==========================================================\
10     C | SUBROUTINE OBCS_RADIATE |
11     C | o Calculate future boundary data at open boundaries |
12     C | at time = futureTime by applying Orlanski radiation |
13     C | conditions. |
14     C |==========================================================|
15     C | |
16     C \==========================================================/
17     IMPLICIT NONE
18    
19     C === Global variables ===
20     #include "SIZE.h"
21     #include "EEPARAMS.h"
22     #include "PARAMS.h"
23     #include "GRID.h"
24     #include "OBCS.h"
25     #include "ORLANSKI.h"
26    
27     C SPK 6/2/00: Added radiative OBC's for salinity.
28     C SPK 6/6/00: Changed calculation of OB*w. When K=1, the
29     C upstream value is used. For example on the eastern OB:
30     C IF (K.EQ.1) THEN
31     C OBEw(J,K,bi,bj)=wVel(I_obc-1,J,K,bi,bj)
32     C ENDIF
33     C
34     C SPK 7/7/00: 1) Removed OB*w fix (see above).
35     C 2) Added variable CMAX. Maximum diagnosed phase speed is now
36     C clamped to CMAX. For stability of AB-II scheme (CFL) the
37     C (non-dimensional) phase speed must be <0.5
38     C 3) (Sonya Legg) Changed application of uVel and vVel.
39     C uVel on the western OB is actually applied at I_obc+1
40     C while vVel on the southern OB is applied at J_obc+1.
41     C 4) (Sonya Legg) Added templates for forced OB's.
42     C
43     C SPK 7/17/00: Non-uniform resolution is now taken into account in diagnosing
44     C phase speeds and time-stepping OB values. CL is still the
45     C non-dimensional phase speed; CVEL is the dimensional phase
46     C speed: CVEL = CL*(dx or dy)/dt, where dx and dy is the
47     C appropriate grid spacings. Note that CMAX (with which CL
48     C is compared) remains non-dimensional.
49     C
50     C SPK 7/18/00: Added code to allow filtering of phase speed following
51     C Blumberg and Kantha. There is now a separate array
52     C CVEL_**, where **=Variable(U,V,T,S,W)Boundary(E,W,N,S) for
53     C the dimensional phase speed. These arrays are initialized to
54     C zero in ini_obcs.F. CVEL_** is filtered according to
55     C CVEL_** = fracCVEL*CVEL(new) + (1-fracCVEL)*CVEL_**(old).
56     C fracCVEL=1.0 turns off filtering.
57     C
58     C SPK 7/26/00: Changed code to average phase speed. A new variable
59     C 'cvelTimeScale' was created. This variable must now be
60     C specified. Then, fracCVEL=deltaT/cvelTimeScale.
61     C Since the goal is to smooth out the 'singularities' in the
62     C diagnosed phase speed, cvelTimeScale could be picked as the
63     C duration of the singular period in the unfiltered case. Thus,
64     C for a plane wave cvelTimeScale might be the time take for the
65     C wave to travel a distance DX, where DX is the width of the region
66     C near which d(phi)/dx is small.
67    
68     C == Routine arguments ==
69     INTEGER bi, bj
70     _RL futureTime
71     _RL uVel (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy)
72     _RL vVel (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy)
73     _RL wVel (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy)
74     _RL theta(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy)
75     _RL salt (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy)
76     INTEGER myThid
77    
78     #ifdef ALLOW_ORLANSKI
79    
80     C == Local variables ==
81     INTEGER I, K, J_obc
82     _RL CL, ab1, ab2, fracCVEL, f1, f2
83    
84     ab1 = 1.5 _d 0 + abEps /* Adams-Bashforth coefficients */
85     ab2 = -0.5 _d 0 - abEps
86     /* CMAX is maximum allowable phase speed-CFL for AB-II */
87     /* cvelTimeScale is averaging period for phase speed in sec. */
88    
89     fracCVEL = deltaT/cvelTimeScale /* fraction of new phase speed used*/
90     f1 = fracCVEL /* don't change this. Set cvelTimeScale */
91     f2 = 1.0-fracCVEL /* don't change this. set cvelTimeScale */
92    
93     C Northern OB (Orlanski Radiation Condition)
94     DO K=1,Nr
95     DO I=1-Olx,sNx+Olx
96     J_obc=OB_Jn(I,bi,bj)
97     IF (J_obc.ne.0) THEN
98     C uVel
99     IF ((UN_STORE_2(I,K,bi,bj).eq.0.).and.
100     & (UN_STORE_3(I,K,bi,bj).eq.0.)) THEN
101     CL=0.
102     ELSE
103     CL=-(uVel(I,J_obc-1,K,bi,bj)-UN_STORE_1(I,K,bi,bj))/
104     & (ab1*UN_STORE_2(I,K,bi,bj) + ab2*UN_STORE_3(I,K,bi,bj))
105     ENDIF
106     IF (CL.lt.0.) THEN
107     CL=0.
108     ELSEIF (CL.gt.CMAX) THEN
109     CL=CMAX
110     ENDIF
111     CVEL_UN(I,K,bi,bj) = f1*(CL*dyU(I,J_obc-1,bi,bj)/deltaT)+
112     & f2*CVEL_UN(I,K,bi,bj)
113     C update OBC to next timestep
114     OBNu(I,K,bi,bj)=uVel(I,J_obc,K,bi,bj)-
115     & CVEL_UN(I,K,bi,bj)*(deltaT/dyU(I,J_obc,bi,bj))*
116     & (ab1*(uVel(I,J_obc,K,bi,bj)-uVel(I,J_obc-1,K,bi,bj)) +
117     & ab2*(UN_STORE_4(I,K,bi,bj)-UN_STORE_1(I,K,bi,bj)))
118     C vVel
119     IF ((VN_STORE_2(I,K,bi,bj).eq.0.).and.
120     & (VN_STORE_3(I,K,bi,bj).eq.0.)) THEN
121     CL=0.
122     ELSE
123     CL=-(vVel(I,J_obc-1,K,bi,bj)-VN_STORE_1(I,K,bi,bj))/
124     & (ab1*VN_STORE_2(I,K,bi,bj) + ab2*VN_STORE_3(I,K,bi,bj))
125     ENDIF
126     IF (CL.lt.0.) THEN
127     CL=0.
128     ELSEIF (CL.gt.CMAX) THEN
129     CL=CMAX
130     ENDIF
131     CVEL_VN(I,K,bi,bj) = f1*(CL*dyF(I,J_obc-2,bi,bj)/deltaT)+
132     & f2*CVEL_VN(I,K,bi,bj)
133     C update OBC to next timestep
134     OBNv(I,K,bi,bj)=vVel(I,J_obc,K,bi,bj)-
135     & CVEL_VN(I,K,bi,bj)*(deltaT/dyF(I,J_obc-1,bi,bj))*
136     & (ab1*(vVel(I,J_obc,K,bi,bj)-vVel(I,J_obc-1,K,bi,bj)) +
137     & ab2*(VN_STORE_4(I,K,bi,bj)-VN_STORE_1(I,K,bi,bj)))
138     C Temperature
139     IF ((TN_STORE_2(I,K,bi,bj).eq.0.).and.
140     & (TN_STORE_3(I,K,bi,bj).eq.0.)) THEN
141     CL=0.
142     ELSE
143     CL=-(theta(I,J_obc-1,K,bi,bj)-TN_STORE_1(I,K,bi,bj))/
144     & (ab1*TN_STORE_2(I,K,bi,bj) + ab2*TN_STORE_3(I,K,bi,bj))
145     ENDIF
146     IF (CL.lt.0.) THEN
147     CL=0.
148     ELSEIF (CL.gt.CMAX) THEN
149     CL=CMAX
150     ENDIF
151     CVEL_TN(I,K,bi,bj) = f1*(CL*dyC(I,J_obc-1,bi,bj)/deltaT)+
152     & f2*CVEL_TN(I,K,bi,bj)
153     C update OBC to next timestep
154     OBNt(I,K,bi,bj)=theta(I,J_obc,K,bi,bj)-
155     & CVEL_TN(I,K,bi,bj)*(deltaT/dyC(I,J_obc,bi,bj))*
156     & (ab1*(theta(I,J_obc,K,bi,bj)-theta(I,J_obc-1,K,bi,bj))+
157     & ab2*(TN_STORE_4(I,K,bi,bj)-TN_STORE_1(I,K,bi,bj)))
158     C Salinity
159     IF ((SN_STORE_2(I,K,bi,bj).eq.0.).and.
160     & (SN_STORE_3(I,K,bi,bj).eq.0.)) THEN
161     CL=0.
162     ELSE
163     CL=-(salt(I,J_obc-1,K,bi,bj)-SN_STORE_1(I,K,bi,bj))/
164     & (ab1*SN_STORE_2(I,K,bi,bj) + ab2*SN_STORE_3(I,K,bi,bj))
165     ENDIF
166     IF (CL.lt.0.) THEN
167     CL=0.
168     ELSEIF (CL.gt.CMAX) THEN
169     CL=CMAX
170     ENDIF
171     CVEL_SN(I,K,bi,bj) = f1*(CL*dyC(I,J_obc-1,bi,bj)/deltaT)+
172     & f2*CVEL_SN(I,K,bi,bj)
173     C update OBC to next timestep
174     OBNs(I,K,bi,bj)=salt(I,J_obc,K,bi,bj)-
175     & CVEL_SN(I,K,bi,bj)*(deltaT/dyC(I,J_obc,bi,bj))*
176     & (ab1*(salt(I,J_obc,K,bi,bj)-salt(I,J_obc-1,K,bi,bj)) +
177     & ab2*(SN_STORE_4(I,K,bi,bj)-SN_STORE_1(I,K,bi,bj)))
178     C wVel
179     #ifdef ALLOW_NONHYDROSTATIC
180     IF ((WN_STORE_2(I,K,bi,bj).eq.0.).and.
181     & (WN_STORE_3(I,K,bi,bj).eq.0.)) THEN
182     CL=0.
183     ELSE
184     CL=-(wVel(I,J_obc-1,K,bi,bj)-WN_STORE_1(I,K,bi,bj))/
185     & (ab1*WN_STORE_2(I,K,bi,bj)+ab2*WN_STORE_3(I,K,bi,bj))
186     ENDIF
187     IF (CL.lt.0.) THEN
188     CL=0.
189     ELSEIF (CL.gt.CMAX) THEN
190     CL=CMAX
191     ENDIF
192     CVEL_WN(I,K,bi,bj)=f1*(CL*dyC(I,J_obc-1,bi,bj)/deltaT)
193     & + f2*CVEL_WN(I,K,bi,bj)
194     C update OBC to next timestep
195     OBNw(I,K,bi,bj)=wVel(I,J_obc,K,bi,bj)-
196     & CVEL_WN(I,K,bi,bj)*(deltaT/dyC(I,J_obc,bi,bj))*
197     & (ab1*(wVel(I,J_obc,K,bi,bj)-wVel(I,J_obc-1,K,bi,bj))+
198     & ab2*(WN_STORE_4(I,K,bi,bj)-WN_STORE_1(I,K,bi,bj)))
199     #endif
200     C update/save storage arrays
201     C uVel
202     C copy t-1 to t-2 array
203     UN_STORE_3(I,K,bi,bj)=UN_STORE_2(I,K,bi,bj)
204     C copy (current time) t to t-1 arrays
205     UN_STORE_2(I,K,bi,bj)=uVel(I,J_obc-1,K,bi,bj) -
206     & uVel(I,J_obc-2,K,bi,bj)
207     UN_STORE_1(I,K,bi,bj)=uVel(I,J_obc-1,K,bi,bj)
208     UN_STORE_4(I,K,bi,bj)=uVel(I,J_obc,K,bi,bj)
209     C vVel
210     C copy t-1 to t-2 array
211     VN_STORE_3(I,K,bi,bj)=VN_STORE_2(I,K,bi,bj)
212     C copy (current time) t to t-1 arrays
213     VN_STORE_2(I,K,bi,bj)=vVel(I,J_obc-1,K,bi,bj) -
214     & vVel(I,J_obc-2,K,bi,bj)
215     VN_STORE_1(I,K,bi,bj)=vVel(I,J_obc-1,K,bi,bj)
216     VN_STORE_4(I,K,bi,bj)=vVel(I,J_obc,K,bi,bj)
217     C Temperature
218     C copy t-1 to t-2 array
219     TN_STORE_3(I,K,bi,bj)=TN_STORE_2(I,K,bi,bj)
220     C copy (current time) t to t-1 arrays
221     TN_STORE_2(I,K,bi,bj)=theta(I,J_obc-1,K,bi,bj) -
222     & theta(I,J_obc-2,K,bi,bj)
223     TN_STORE_1(I,K,bi,bj)=theta(I,J_obc-1,K,bi,bj)
224     TN_STORE_4(I,K,bi,bj)=theta(I,J_obc,K,bi,bj)
225     C Salinity
226     C copy t-1 to t-2 array
227     SN_STORE_3(I,K,bi,bj)=SN_STORE_2(I,K,bi,bj)
228     C copy (current time) t to t-1 arrays
229     SN_STORE_2(I,K,bi,bj)=salt(I,J_obc-1,K,bi,bj) -
230     & salt(I,J_obc-2,K,bi,bj)
231     SN_STORE_1(I,K,bi,bj)=salt(I,J_obc-1,K,bi,bj)
232     SN_STORE_4(I,K,bi,bj)=salt(I,J_obc,K,bi,bj)
233     C wVel
234     #ifdef ALLOW_NONHYDROSTATIC
235     C copy t-1 to t-2 array
236     WN_STORE_3(I,K,bi,bj)=WN_STORE_2(I,K,bi,bj)
237     C copy (current time) t to t-1 arrays
238     WN_STORE_2(I,K,bi,bj)=wVel(I,J_obc-1,K,bi,bj) -
239     & wVel(I,J_obc-2,K,bi,bj)
240     WN_STORE_1(I,K,bi,bj)=wVel(I,J_obc-1,K,bi,bj)
241     WN_STORE_4(I,K,bi,bj)=wVel(I,J_obc,K,bi,bj)
242     #endif
243     ENDIF
244     ENDDO
245     ENDDO
246    
247     #endif /* ALLOW_ORLANSKI */
248     RETURN
249     END

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