/[MITgcm]/MITgcm/pkg/seaice/seaice_ocean_stress.F
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Contents of /MITgcm/pkg/seaice/seaice_ocean_stress.F

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Revision 1.8 - (show annotations) (download)
Mon Mar 20 21:36:11 2006 UTC (18 years, 2 months ago) by mlosch
Branch: MAIN
CVS Tags: checkpoint58e_post, checkpoint58h_post, checkpoint58f_post, checkpoint58d_post, checkpoint58c_post, checkpoint58g_post
Changes since 1.7: +4 -1 lines
  seaice: add an EVP solver following Hunke and Dukowicz (1997) and the
  documentation of CICE. Turn on by defining SEAICE_ALLOW_EVP in
  SEAICE_OPTIONS.h and SEAICEuseEVP=.true. in data.seaice. Works only
  with SEAICE_CGRID defined.
  Use at own risk.

1 C $Header: /u/gcmpack/MITgcm/pkg/seaice/seaice_ocean_stress.F,v 1.7 2006/03/17 15:53:38 mlosch Exp $
2 C $Name: $
3
4 #include "SEAICE_OPTIONS.h"
5
6 CStartOfInterface
7 SUBROUTINE SEAICE_OCEAN_STRESS(
8 I myTime, myIter, myThid )
9 C /==========================================================\
10 C | SUBROUTINE SEAICE_OCEAN_STRESS |
11 C | o Calculate ocean surface stresses |
12 C | - C-grid version |
13 C |==========================================================|
14 C \==========================================================/
15 IMPLICIT NONE
16
17 C === Global variables ===
18 #include "SIZE.h"
19 #include "EEPARAMS.h"
20 #include "PARAMS.h"
21 #include "GRID.h"
22 #include "FFIELDS.h"
23 #include "SEAICE.h"
24 #include "SEAICE_PARAMS.h"
25 #include "SEAICE_FFIELDS.h"
26
27 C === Routine arguments ===
28 C myTime - Simulation time
29 C myIter - Simulation timestep number
30 C myThid - Thread no. that called this routine.
31 _RL myTime
32 INTEGER myIter
33 INTEGER myThid
34 CEndOfInterface
35
36 #ifdef SEAICE_CGRID
37 C === Local variables ===
38 C i,j,bi,bj - Loop counters
39
40 INTEGER i, j, bi, bj
41 _RL SINWAT, COSWAT, SINWIN, COSWIN
42 _RL fuIce, fvIce, FX, FY
43 _RL areaW, areaS
44
45 _RL press (1-Olx:sNx+Olx,1-Oly:sNy+Oly,nSx,nSy)
46 _RL etaPlusZeta (1-Olx:sNx+Olx,1-Oly:sNy+Oly)
47 _RL zetaMinusEta(1-Olx:sNx+Olx,1-Oly:sNy+Oly)
48 _RL etaMeanZ (1-Olx:sNx+Olx,1-Oly:sNy+Oly)
49 _RL etaMeanU (1-Olx:sNx+Olx,1-Oly:sNy+Oly)
50 _RL etaMeanV (1-Olx:sNx+Olx,1-Oly:sNy+Oly)
51 _RL dVdx (1-Olx:sNx+Olx,1-Oly:sNy+Oly)
52 _RL dVdy (1-Olx:sNx+Olx,1-Oly:sNy+Oly)
53 _RL dUdx (1-Olx:sNx+Olx,1-Oly:sNy+Oly)
54 _RL dUdy (1-Olx:sNx+Olx,1-Oly:sNy+Oly)
55
56 c introduce turning angle (default is zero)
57 SINWAT=SIN(SEAICE_waterTurnAngle*deg2rad)
58 COSWAT=COS(SEAICE_waterTurnAngle*deg2rad)
59 SINWIN=SIN(SEAICE_airTurnAngle*deg2rad)
60 COSWIN=COS(SEAICE_airTurnAngle*deg2rad)
61
62 C-- Update overlap regions
63 CALL EXCH_UV_XY_RL(WINDX, WINDY, .TRUE., myThid)
64
65 #ifndef SEAICE_EXTERNAL_FLUXES
66 C-- Interpolate wind stress (N/m^2) from C-points of C-grid
67 C to U and V points of C-grid for forcing the ocean model.
68 DO bj=myByLo(myThid),myByHi(myThid)
69 DO bi=myBxLo(myThid),myBxHi(myThid)
70 DO j=1,sNy
71 DO i=1,sNx
72 fu(I,J,bi,bj)=0.5*(WINDX(I,J,bi,bj) + WINDX(I-1,J,bi,bj))
73 fv(I,J,bi,bj)=0.5*(WINDY(I,J,bi,bj) + WINDY(I,J-1,bi,bj))
74 ENDDO
75 ENDDO
76 ENDDO
77 ENDDO
78 #endif /* ifndef SEAICE_EXTERNAL_FLUXES */
79
80 IF ( useHB87StressCoupling ) THEN
81 C
82 C use an intergral over ice and ocean surface layer to define
83 C surface stresses on ocean following Hibler and Bryan (1987, JPO)
84 C
85 C recompute viscosities from updated ice velocities
86 CALL SEAICE_CALC_VISCOSITIES(
87 I uIce(1-Olx,1-Oly,1,1,1), vIce(1-Olx,1-Oly,1,1,1),
88 I zMin, zMax, hEffM, press0,
89 O eta, zeta, press,
90 #ifdef SEAICE_ALLOW_EVP
91 O seaice_div, seaice_tension, seaice_shear,
92 #endif /* SEAICE_ALLOW_EVP */
93 I myThid )
94 C re-compute internal stresses with updated ice velocities
95 DO bj=myByLo(myThid),myByHi(myThid)
96 DO bi=myBxLo(myThid),myBxHi(myThid)
97 DO j=1-Oly+1,sNy+Oly-1
98 DO i=1-Olx+1,sNx+Olx-1
99 etaPlusZeta (I,J) = eta(I,J,bi,bj) + zeta(I,J,bi,bj)
100 zetaMinusEta(I,J) = zeta(I,J,bi,bj) - eta(I,J,bi,bj)
101 etaMeanU (I,J) =
102 & HALF*(ETA (I,J,bi,bj) + ETA (I-1,J ,bi,bj))
103 etaMeanV (I,J) =
104 & HALF*(ETA (I,J,bi,bj) + ETA (I ,J-1,bi,bj))
105 etaMeanZ (I,J) = QUART *
106 & ( eta(I ,J,bi,bj) + eta(I ,J-1,bi,bj)
107 & + eta(I-1,J,bi,bj) + eta(I-1,J-1,bi,bj) )
108 dUdx(I,J) = ( uIce(I+1,J,1,bi,bj) - uIce(I,J,1,bi,bj) )
109 & * _recip_dxF(I,J,bi,bj)
110 dUdy(I,J) = ( uIce(I,J+1,1,bi,bj) - uIce(I,J,1,bi,bj) )
111 & * _recip_dyU(I,J+1,bi,bj)
112 dVdx(I,J) = ( vIce(I+1,J,1,bi,bj) - vIce(I,J,1,bi,bj) )
113 & * _recip_dxV(I+1,J,bi,bj)
114 dVdy(I,J) = ( vIce(I,J+1,1,bi,bj) - vIce(I,J,1,bi,bj) )
115 & * _recip_dyF(I,J,bi,bj)
116 ENDDO
117 ENDDO
118 DO J = 1,sNy
119 DO I = 1,sNx
120 C First FX = (d/dx)*sigma
121 C + d/dx[ eta+zeta d/dx ] U
122 FX = _recip_dxC(I,J,bi,bj) *
123 & ( etaPlusZeta(I ,J) * dUdx(I ,J)
124 & - etaPlusZeta(I-1,J) * dUdx(I-1,J) )
125 C + (d/dy)[eta*(d/dy + tanphi/a)] U (also on UVRT1/2)
126 FX = FX + _recip_dyG(I,J,bi,bj) * (
127 & ( etaMeanZ(I,J+1) * dUdy(I,J+1)
128 & - etaMeanZ(I,J ) * dUdy(I,J )
129 & )
130 & - ( etaMeanZ(I,J+1)
131 & * ( uIce(I,J+1,1,bi,bj)+uIce(I,J,1,bi,bj) )
132 & - etaMeanZ(I,J )
133 & * ( uIce(I,J-1,1,bi,bj)+uIce(I,J,1,bi,bj) ) )
134 & * 0.5 _d 0 * _tanPhiAtU(I,J,bi,bj)
135 & * recip_rSphere )
136 C - 2*eta*(tanphi/a) * ( tanphi/a ) U
137 FX = FX - TWO * uIce(I,J,1,bi,bj)
138 & * etaMeanU(I,J)*recip_rSphere*recip_rSphere
139 & * _tanPhiAtU(I,J,bi,bj) * _tanPhiAtU(I,J,bi,bj)
140 C + d/dx[ (zeta-eta) dV/dy]
141 FX = FX +
142 & ( zetaMinusEta(I ,J ) * dVdy(I ,J )
143 & - zetaMinusEta(I-1,J ) * dVdy(I-1,J )
144 & ) * _recip_dxC(I,J,bi,bj)
145 C + d/dy[ eta dV/x ]
146 FX = FX + (
147 & etaMeanZ(I,J+1)
148 & * ( vIce(I ,J+1,1,bi,bj) - vIce(I-1,J+1,1,bi,bj) )
149 & * _recip_dxV(I,J+1,bi,bj)
150 & - etaMeanZ(I,J )
151 & * ( vIce(I ,J,1,bi,bj) - vIce(I-1,J,1,bi,bj) )
152 & * _recip_dxV(I,J,bi,bj)
153 & ) * _recip_dyG(I,J,bi,bj)
154 C - d/dx[ (eta+zeta) * v * (tanphi/a) ]
155 FX = FX - (
156 & etaPlusZeta(I ,J)
157 & * 0.5 * (vIce(I ,J,1,bi,bj)+vIce(I ,J+1,1,bi,bj))
158 & * 0.5 * ( _tanPhiAtU(I ,J,bi,bj)
159 & + _tanPhiAtU(I+1,J,bi,bj) )
160 & - etaPlusZeta(I-1,J) *
161 & * 0.5 * (vIce(I-1,J,1,bi,bj)+vIce(I-1,J+1,1,bi,bj))
162 & * 0.5 * ( _tanPhiAtU(I-1,J,bi,bj)
163 & + _tanPhiAtU(I ,J,bi,bj) )
164 & )* _recip_dxC(I,J,bi,bj)*recip_rSphere
165 C - 2*eta*(tanphi/a) * dV/dx
166 FX = FX
167 & -TWO * etaMeanU(I,J) * _tanPhiAtV(I,J,bi,bj)
168 & *recip_rSphere
169 & *(vIce(I ,J,1,bi,bj) + vIce(I ,J+1,1,bi,bj)
170 & - vIce(I-1,J,1,bi,bj) - vIce(I-1,J+1,1,bi,bj))
171 & * _recip_dxC(I,J,bi,bj)
172 C - (d/dx) P/2
173 FX = _maskW(I,J,1,bi,bj) * ( FX - _recip_dxC(I,J,bi,bj)
174 & * ( press(I,J,bi,bj) - press(I-1,J,bi,bj) ) )
175 C
176 C then FY = (d/dy)*sigma
177 C + d/dy [(eta+zeta) d/dy] V
178 FY = _recip_dyC(I,J,bi,bj) *
179 & ( dVdy(I,J ) * etaPlusZeta(I,J )
180 & - dVdy(I,J-1) * etaPlusZeta(I,J-1) )
181 C + d/dx [eta d/dx] V
182 FY = FY + _recip_dxC(I,J,bi,bj) *
183 & ( eta(I ,J,bi,bj) * dVdx(I ,J)
184 & - eta(I-1,J,bi,bj) * dVdx(I-1,J) )
185 C - d/dy [(zeta-eta) tanphi/a] V
186 FY = FY - _recip_dyC(I,J,bi,bj) * recip_rSphere * (
187 & zetaMinusEta(I,J ) * tanPhiAtU(I,J ,bi,bj)
188 & * 0.5 * ( vIce(I,J,1,bi,bj) + vIce(I,J+1,1,bi,bj))
189 & - zetaMinusEta(I,J-1) * tanPhiAtU(I,J-1,bi,bj)
190 & * 0.5 * ( vIce(I,J,1,bi,bj) + vIce(I,J-1,1,bi,bj)) )
191 C 2*eta tanphi/a ( - tanphi/a - d/dy) V
192 FY = FY - TWO*etaMeanV(I,J) * recip_rSphere
193 & * _tanPhiAtV(I,J,bi,bj) * (
194 & _tanPhiAtV(I,J,bi,bj) * recip_rSphere
195 & + _recip_dyC(I,J,bi,bj) *
196 & ( 0.5 * ( vIce(I,J,1,bi,bj) + vIce(I,J+1,1,bi,bj))
197 & - 0.5 * ( vIce(I,J,1,bi,bj) + vIce(I,J-1,1,bi,bj)) ) )
198 C + d/dy[ (zeta-eta) dU/dx ]
199 FY = FY +
200 & ( zetaMinusEta(I,J )*dUdx(I,J )
201 & - zetaMinusEta(I,J-1)*dUdx(I,J-1) )
202 & * _recip_dyC(I,J,bi,bj)
203 C + d/dx[ eta dU/dy ]
204 FY = FY + _recip_dxG(I,J,bi,bj) *
205 & ( etaMeanZ(I+1,J) * dUdy(I+1,J)
206 & - etaMeanZ(I ,J) * dUdy(I ,J) )
207 C + d/dx[ eta * (tanphi/a) * U ]
208 FY = FY + (
209 & etaMeanZ(I+1,J) * 0.5 *
210 & ( uIce(I+1,J ,1,bi,bj) * _tanPhiAtU(I+1,J ,bi,bj)
211 & + uIce(I+1,J-1,1,bi,bj) * _tanPhiAtU(I+1,J-1,bi,bj) )
212 & - etaMeanZ(I ,J) * 0.5 *
213 & ( uIce(I ,J ,1,bi,bj) * _tanPhiAtU(I ,J ,bi,bj)
214 & + uIce(I ,J-1,1,bi,bj) * _tanPhiAtU(I ,J ,bi,bj) )
215 & ) * _recip_dxG(I,J,bi,bj)*recip_rSphere
216 C + 2*eta*(tanphi/a) dU/dx
217 FY = FY +
218 & TWO * etaMeanV(I,J)*TWO * _tanPhiAtV(I,J,bi,bj)
219 & * ( uIce(I+1,J,1,bi,bj)+uIce(I+1,J-1,1,bi,bj)
220 & - uIce(I ,J,1,bi,bj)-uIce(I ,J-1,1,bi,bj) )
221 & * _recip_dxG(I,J,bi,bj) * recip_rSphere
222 C - (d/dy) P/2
223 FY = _maskS(I,J,1,bi,bj) * ( FY - _recip_dyC(I,J,bi,bj)
224 & * ( press(I,J,bi,bj) - press(I,J-1,bi,bj) ) )
225 C
226 C recompute wind stress over ice (done already in seaice_dynsolver,
227 C but not saved)
228 fuIce = 0.5 _d 0 *
229 & ( DAIRN(I ,J,bi,bj)*(
230 & COSWIN*uWind(I ,J,bi,bj)
231 & -SIGN(SINWIN, _fCori(I ,J,bi,bj))*vWind(I ,J,bi,bj) )
232 & + DAIRN(I-1,J,bi,bj)*(
233 & COSWIN*uWind(I-1,J,bi,bj)
234 & -SIGN(SINWIN, _fCori(I-1,J,bi,bj))*vWind(I-1,J,bi,bj) )
235 & )
236 fvIce = 0.5 _d 0 *
237 & ( DAIRN(I,J ,bi,bj)*(
238 & SIGN(SINWIN, _fCori(I ,J,bi,bj))*uWind(I,J ,bi,bj)
239 & +COSWIN*vWind(I,J ,bi,bj) )
240 & + DAIRN(I,J-1,bi,bj)*(
241 & SIGN(SINWIN, _fCori(I,J-1,bi,bj))*uWind(I,J-1,bi,bj)
242 & +COSWIN*vWind(I,J-1,bi,bj) )
243 & )
244 C average wind stress over ice and ocean and apply averaged wind
245 C stress and internal ice stresses to surface layer of ocean
246 areaW = 0.5 * (AREA(I,J,1,bi,bj) + AREA(I-1,J,1,bi,bj))
247 areaS = 0.5 * (AREA(I,J,1,bi,bj) + AREA(I,J-1,1,bi,bj))
248 fu(I,J,bi,bj)=(ONE-areaW)*fu(I,J,bi,bj)+areaW*fuIce + FX
249 fv(I,J,bi,bj)=(ONE-areaS)*fv(I,J,bi,bj)+areaS*fvIce + FY
250 END DO
251 END DO
252 ENDDO
253 ENDDO
254 ELSE
255
256 C-- Compute ice-affected wind stress (interpolate to U/V-points)
257 C by averaging wind stress and ice-ocean stress according to
258 C ice cover
259 DO bj=myByLo(myThid),myByHi(myThid)
260 DO bi=myBxLo(myThid),myBxHi(myThid)
261 DO j=1,sNy
262 DO i=1,sNx
263 fuIce=HALF*( DWATN(I,J,bi,bj)+DWATN(I,J+1,bi,bj) )*
264 & COSWAT *
265 & ( UICE(I,J,1,bi,bj)-GWATX(I,J,bi,bj) )
266 & - SIGN(SINWAT, _fCori(I,J,bi,bj)) * 0.5 _d 0 *
267 & ( DWATN(I ,J,bi,bj) *
268 & 0.5 _d 0*(vIce(I ,J ,1,bi,bj)-GWATY(I ,J ,bi,bj)
269 & +vIce(I ,J+1,1,bi,bj)-GWATY(I ,J+1,bi,bj))
270 & + DWATN(I-1,J,bi,bj) *
271 & 0.5 _d 0*(vIce(I-1,J ,1,bi,bj)-GWATY(I-1,J ,bi,bj)
272 & +vIce(I-1,J+1,1,bi,bj)-GWATY(I-1,J+1,bi,bj))
273 & )
274 fvIce=HALF*( DWATN(I,J,bi,bj)+DWATN(I+1,J,bi,bj) )*
275 & COSWAT *
276 & ( VICE(I,J,1,bi,bj)-GWATY(I,J,bi,bj) )
277 & + SIGN(SINWAT, _fCori(I,J,bi,bj)) * 0.5 _d 0 *
278 & ( DWATN(I,J ,bi,bj) *
279 & 0.5 _d 0*(uIce(I ,J ,1,bi,bj)-GWATX(I ,J ,bi,bj)
280 & +uIce(I+1,J ,1,bi,bj)-GWATX(I+1,J ,bi,bj))
281 & + DWATN(I,J-1,bi,bj) *
282 & 0.5 _d 0*(uIce(I ,J-1,1,bi,bj)-GWATX(I ,J-1,bi,bj)
283 & +uIce(I+1,J-1,1,bi,bj)-GWATX(I+1,J-1,bi,bj))
284 & )
285 areaW = 0.5 _d 0 * (AREA(I,J,1,bi,bj) + AREA(I-1,J,1,bi,bj))
286 areaS = 0.5 _d 0 * (AREA(I,J,1,bi,bj) + AREA(I,J-1,1,bi,bj))
287 fu(I,J,bi,bj)=(ONE-areaW)*fu(I,J,bi,bj)+areaW*fuIce
288 fv(I,J,bi,bj)=(ONE-areaS)*fv(I,J,bi,bj)+areaS*fvIce
289 ENDDO
290 ENDDO
291 ENDDO
292 ENDDO
293 ENDIF
294 CALL EXCH_UV_XY_RS(fu, fv, .TRUE., myThid)
295
296 #endif /* not SEAICE_CGRID */
297
298 RETURN
299 END

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