/[MITgcm]/MITgcm/pkg/dic/dic_surfforcing.F
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Contents of /MITgcm/pkg/dic/dic_surfforcing.F

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Revision 1.2 - (show annotations) (download)
Wed Jul 9 19:59:18 2003 UTC (22 years ago) by stephd
Branch: MAIN
CVS Tags: checkpoint51e_post, checkpoint51f_pre, checkpoint51f_post, branchpoint-genmake2, checkpoint51g_post, checkpoint51d_post
Branch point for: branch-genmake2
Changes since 1.1: +7 -6 lines
add variable Si; fix bugs in dic_diags, dic_fields_load

1 #include "CPP_OPTIONS.h"
2 #include "PTRACERS_OPTIONS.h"
3 #include "GCHEM_OPTIONS.h"
4
5 CStartOfInterFace
6 SUBROUTINE DIC_SURFFORCING( PTR_CO2 , GDC,
7 I bi,bj,imin,imax,jmin,jmax,
8 I myIter,myTime,myThid)
9
10 C /==========================================================\
11 C | SUBROUTINE DIC_SURFFORCING |
12 C | o Calculate the carbon air-sea flux terms |
13 C | o following external_forcing_dic.F from Mick |
14 C |==========================================================|
15 IMPLICIT NONE
16
17 C == GLobal variables ==
18 #include "SIZE.h"
19 #include "DYNVARS.h"
20 #include "EEPARAMS.h"
21 #include "PARAMS.h"
22 #include "GRID.h"
23 #include "FFIELDS.h"
24 #include "DIC_ABIOTIC.h"
25 #ifdef DIC_BIOTIC
26 #include "PTRACERS.h"
27 #endif
28
29 C == Routine arguments ==
30 INTEGER myIter, myThid
31 _RL myTime
32 _RL PTR_CO2(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
33 _RL GDC(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
34 INTEGER iMin,iMax,jMin,jMax, bi, bj
35
36 #ifdef ALLOW_PTRACERS
37 #ifdef DIC_ABIOTIC
38 C == Local variables ==
39 INTEGER I,J, kLev, it
40 C Number of iterations for pCO2 solvers...
41 INTEGER inewtonmax
42 INTEGER ibrackmax
43 INTEGER donewt
44 C Solubility relation coefficients
45 _RL SchmidtNoDIC(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
46 _RL pCO2sat(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
47 _RL Kwexch(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
48 C local variables for carbon chem
49 _RL surfalk(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
50 _RL surfphos(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
51 _RL surfsi(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
52 _RL VirtualFlux(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
53
54 cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
55
56 kLev=1
57
58 C PRE-INDUSTRIAL STEADY STATE pCO2 = 278.0 ppmv
59 DO j=1-OLy,sNy+OLy
60 DO i=1-OLx,sNx+OLx
61 AtmospCO2(i,j,bi,bj)=278.0d-6
62 ENDDO
63 ENDDO
64
65
66 C =================================================================
67 C determine inorganic carbon chem coefficients
68 DO j=1-OLy,sNy+OLy
69 DO i=1-OLx,sNx+OLx
70
71 #ifdef DIC_BIOTIC
72 cQQQQ check ptracer numbers
73 surfalk(i,j) = PTRACER(i,j,klev,bi,bj,2)
74 & * maskC(i,j,kLev,bi,bj)
75 surfphos(i,j) = PTRACER(i,j,klev,bi,bj,3)
76 & * maskC(i,j,kLev,bi,bj)
77 #else
78 surfalk(i,j) = 2.366595 * salt(i,j,kLev,bi,bj)/gsm_s
79 & * maskC(i,j,kLev,bi,bj)
80 surfphos(i,j) = 5.1225e-4 * maskC(i,j,kLev,bi,bj)
81 #endif
82 C FOR NON-INTERACTIVE Si
83 surfsi(i,j) = 7.6838e-3 * maskC(i,j,kLev,bi,bj)
84 ENDDO
85 ENDDO
86
87 CALL CARBON_COEFFS(
88 I theta,salt,
89 I bi,bj,iMin,iMax,jMin,jMax)
90 C====================================================================
91
92 #define PH_APPROX
93 c set number of iterations for [H+] solvers
94 #ifdef PH_APPROX
95 inewtonmax = 1
96 #else
97 inewtonmax = 10
98 #endif
99 ibrackmax = 30
100 C determine pCO2 in surface ocean
101 C set guess of pH for first step here
102 C IF first step THEN use bracket-bisection for first step,
103 C and determine carbon coefficients for safety
104 C ELSE use newton-raphson with previous H+(x,y) as first guess
105
106 donewt=1
107
108 c for first few timesteps
109 IF(myIter .le. (nIter0+inewtonmax) )then
110 donewt=0
111 DO j=1-OLy,sNy+OLy
112 DO i=1-OLx,sNx+OLx
113 pH(i,j,bi,bj) = 8.0
114 ENDDO
115 ENDDO
116 #ifdef PH_APPROX
117 print*,'QQ: pCO2 approximation method'
118 c first approxmation
119 DO j=1-OLy,sNy+OLy
120 DO i=1-OLx,sNx+OLx
121 do it=1,10
122 CALL CALC_PCO2_APPROX(
123 I theta(i,j,kLev,bi,bj),salt(i,j,kLev,bi,bj),
124 I PTR_CO2(i,j,kLev), surfphos(i,j),
125 I surfsi(i,j),surfalk(i,j),
126 I ak1(i,j,bi,bj),ak2(i,j,bi,bj),
127 I ak1p(i,j,bi,bj),ak2p(i,j,bi,bj),ak3p(i,j,bi,bj),
128 I aks(i,j,bi,bj),akb(i,j,bi,bj),akw(i,j,bi,bj),
129 I aksi(i,j,bi,bj),akf(i,j,bi,bj),ff(i,j,bi,bj),
130 I bt(i,j,bi,bj),st(i,j,bi,bj),ft(i,j,bi,bj),
131 U pH(i,j,bi,bj),pCO2(i,j,bi,bj) )
132 enddo
133 ENDDO
134 ENDDO
135 #else
136 print*,'QQ: pCO2 full method'
137 #endif
138 ENDIF
139
140
141 c pCO2 solver...
142 DO j=1-OLy,sNy+OLy
143 DO i=1-OLx,sNx+OLx
144
145 IF(maskC(i,j,kLev,bi,bj) .NE. 0.)THEN
146 #ifdef PH_APPROX
147 CALL CALC_PCO2_APPROX(
148 I theta(i,j,kLev,bi,bj),salt(i,j,kLev,bi,bj),
149 I PTR_CO2(i,j,kLev), surfphos(i,j),
150 I surfsi(i,j),surfalk(i,j),
151 I ak1(i,j,bi,bj),ak2(i,j,bi,bj),
152 I ak1p(i,j,bi,bj),ak2p(i,j,bi,bj),ak3p(i,j,bi,bj),
153 I aks(i,j,bi,bj),akb(i,j,bi,bj),akw(i,j,bi,bj),
154 I aksi(i,j,bi,bj),akf(i,j,bi,bj),ff(i,j,bi,bj),
155 I bt(i,j,bi,bj),st(i,j,bi,bj),ft(i,j,bi,bj),
156 U pH(i,j,bi,bj),pCO2(i,j,bi,bj) )
157 #else
158 CALL CALC_PCO2(donewt,inewtonmax,ibrackmax,
159 I theta(i,j,kLev,bi,bj),salt(i,j,kLev,bi,bj),
160 I PTR_CO2(i,j,kLev), surfphos(i,j),
161 I surfsi(i,j),surfalk(i,j),
162 I ak1(i,j,bi,bj),ak2(i,j,bi,bj),
163 I ak1p(i,j,bi,bj),ak2p(i,j,bi,bj),ak3p(i,j,bi,bj),
164 I aks(i,j,bi,bj),akb(i,j,bi,bj),akw(i,j,bi,bj),
165 I aksi(i,j,bi,bj),akf(i,j,bi,bj),ff(i,j,bi,bj),
166 I bt(i,j,bi,bj),st(i,j,bi,bj),ft(i,j,bi,bj),
167 U pH(i,j,bi,bj),pCO2(i,j,bi,bj) )
168 #endif
169 ELSE
170 pCO2(i,j,bi,bj)=0. _d 0
171 END IF
172 ENDDO
173 ENDDO
174
175 DO j=1-OLy,sNy+OLy
176 DO i=1-OLx,sNx+OLx
177
178 IF (maskC(i,j,kLev,bi,bj).NE.0.) THEN
179 C calculate SCHMIDT NO. for CO2
180 SchmidtNoDIC(i,j) =
181 & sca1
182 & + sca2 * theta(i,j,kLev,bi,bj)
183 & + sca3 * theta(i,j,kLev,bi,bj)*theta(i,j,kLev,bi,bj)
184 & + sca4 * theta(i,j,kLev,bi,bj)*theta(i,j,kLev,bi,bj)
185 & *theta(i,j,kLev,bi,bj)
186
187 C Determine surface flux (FDIC)
188 C first correct pCO2at for surface atmos pressure
189 pCO2sat(i,j) =
190 & AtmosP(i,j,bi,bj)*AtmospCO2(i,j,bi,bj)
191 c find exchange coefficient
192 c account for schmidt number and and varible piston velocity
193 Kwexch(i,j) =
194 & pisvel(i,j,bi,bj)
195 & / sqrt(SchmidtNoDIC(i,j)/660.0)
196 c OR use a constant coeff
197 c Kwexch(i,j) = 5e-5
198 c ice influence
199 cQQ Kwexch(i,j) =(1.d0-Fice(i,j,bi,bj))*Kwexch(i,j)
200
201
202 C Calculate flux in terms of DIC units using K0, solubility
203 C Flux = Vp * ([CO2sat] - [CO2])
204 C CO2sat = K0*pCO2atmos*P/P0
205 C Converting pCO2 to [CO2] using ff, as in CALC_PCO2
206 FluxCO2(i,j,bi,bj) =
207 & maskC(i,j,kLev,bi,bj)*Kwexch(i,j)*(
208 & ak0(i,j,bi,bj)*pCO2sat(i,j) -
209 & ff(i,j,bi,bj)*pCO2(i,j,bi,bj)
210 & )
211 ELSE
212 FluxCO2(i,j,bi,bj) = 0.
213 ENDIF
214 C convert flux (mol kg-1 m s-1) to (mol m-2 s-1)
215 FluxCO2(i,j,bi,bj) = FluxCO2(i,j,bi,bj)/permil
216
217 IF (maskC(i,j,kLev,bi,bj).NE.0.) THEN
218 c calculate virtual flux
219 c EminusPforV = dS/dt*(1/Sglob)
220 C NOTE: Be very careful with signs here!
221 C Positive EminusPforV => loss of water to atmos and increase
222 C in salinity. Thus, also increase in other surface tracers
223 C (i.e. positive virtual flux into surface layer)
224 C ...so here, VirtualFLux = dC/dt!
225 VirtualFlux(i,j)=gsm_DIC*surfaceTendencyS(i,j,bi,bj)/gsm_s
226 c OR
227 c let virtual flux be zero
228 c VirtualFlux(i,j)=0.d0
229 c
230 ELSE
231 VirtualFlux(i,j)=0. _d 0
232 ENDIF
233 ENDDO
234 ENDDO
235
236 C update tendency
237 DO j=1-OLy,sNy+OLy
238 DO i=1-OLx,sNx+OLx
239 GDC(i,j)= maskC(i,j,kLev,bi,bj)*(
240 & FluxCO2(i,j,bi,bj)*recip_drF(kLev)
241 & + VirtualFlux(i,j)
242 & )
243 ENDDO
244 ENDDO
245
246 #endif
247 #endif
248 RETURN
249 END

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