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

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Revision 1.16 - (show annotations) (download)
Mon Aug 27 19:44:13 2007 UTC (17 years, 10 months ago) by dfer
Branch: MAIN
Changes since 1.15: +11 -4 lines
CPP option to do virtual flux of dic and alkalinity as coded in dic package

1 C $Header: /u/gcmpack/MITgcm/pkg/dic/dic_surfforcing.F,v 1.15 2007/08/14 19:32:40 dfer Exp $
2 C $Name: $
3
4 #include "DIC_OPTIONS.h"
5 #include "PTRACERS_OPTIONS.h"
6 #include "GCHEM_OPTIONS.h"
7
8 CBOP
9 C !ROUTINE: DIC_SURFFORCING
10
11 C !INTERFACE: ==========================================================
12 SUBROUTINE DIC_SURFFORCING( PTR_CO2 , PTR_ALK, PTR_PO4, GDC,
13 I bi,bj,imin,imax,jmin,jmax,
14 I myIter,myTime,myThid)
15
16 C !DESCRIPTION:
17 C Calculate the carbon air-sea flux terms
18 C following external_forcing_dic.F (OCMIP run) from Mick
19
20 C !USES: ===============================================================
21 IMPLICIT NONE
22 #include "SIZE.h"
23 #include "DYNVARS.h"
24 #include "EEPARAMS.h"
25 #include "PARAMS.h"
26 #include "GRID.h"
27 #include "FFIELDS.h"
28 #include "DIC_ABIOTIC.h"
29
30 C !INPUT PARAMETERS: ===================================================
31 C myThid :: thread number
32 C myIter :: current timestep
33 C myTime :: current time
34 c PTR_CO2 :: DIC tracer field
35 INTEGER myIter, myThid
36 _RL myTime
37 _RL PTR_CO2(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
38 _RL PTR_ALK(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
39 _RL PTR_PO4(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
40 INTEGER iMin,iMax,jMin,jMax, bi, bj
41
42 C !OUTPUT PARAMETERS: ===================================================
43 c GDC :: tendency due to air-sea exchange
44 _RL GDC(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
45
46 #ifdef ALLOW_PTRACERS
47
48 C !LOCAL VARIABLES: ====================================================
49 INTEGER I,J, kLev, it
50 C Number of iterations for pCO2 solvers...
51 C Solubility relation coefficients
52 _RL SchmidtNoDIC(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
53 _RL pCO2sat(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
54 _RL Kwexch(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
55 C local variables for carbon chem
56 _RL surfalk(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
57 _RL surfphos(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
58 _RL surfsi(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
59 #ifdef ALLOW_OLD_VIRTUALFLUX
60 _RL VirtualFlux(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
61 #endif
62 CEOP
63
64 cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
65
66 kLev=1
67
68 c if coupled to atmsopheric model, use the
69 c Co2 value passed from the coupler
70 #ifndef USE_ATMOSCO2
71 C PRE-INDUSTRIAL STEADY STATE pCO2 = 278.0 ppmv
72 DO j=1-OLy,sNy+OLy
73 DO i=1-OLx,sNx+OLx
74 AtmospCO2(i,j,bi,bj)=278.0 _d -6
75 ENDDO
76 ENDDO
77 #endif
78
79
80 C =================================================================
81 C determine inorganic carbon chem coefficients
82 DO j=jmin,jmax
83 DO i=imin,imax
84
85 #ifdef DIC_BIOTIC
86 cQQQQ check ptracer numbers
87 surfalk(i,j) = PTR_ALK(i,j,klev)
88 & * maskC(i,j,kLev,bi,bj)
89 surfphos(i,j) = PTR_PO4(i,j,klev)
90 & * maskC(i,j,kLev,bi,bj)
91 #else
92 surfalk(i,j) = 2.366595 _d 0 * salt(i,j,kLev,bi,bj)/gsm_s
93 & * maskC(i,j,kLev,bi,bj)
94 surfphos(i,j) = 5.1225 _d -4 * maskC(i,j,kLev,bi,bj)
95 #endif
96 C FOR NON-INTERACTIVE Si
97 surfsi(i,j) = SILICA(i,j,bi,bj) * maskC(i,j,kLev,bi,bj)
98 ENDDO
99 ENDDO
100
101 CALL CARBON_COEFFS(
102 I theta,salt,
103 I bi,bj,iMin,iMax,jMin,jMax)
104 C====================================================================
105
106 c pCO2 solver...
107 C$TAF LOOP = parallel
108 DO j=jmin,jmax
109 C$TAF LOOP = parallel
110 DO i=imin,imax
111
112 IF(maskC(i,j,kLev,bi,bj) .NE. 0.)THEN
113 CALL CALC_PCO2_APPROX(
114 I theta(i,j,kLev,bi,bj),salt(i,j,kLev,bi,bj),
115 I PTR_CO2(i,j,kLev), surfphos(i,j),
116 I surfsi(i,j),surfalk(i,j),
117 I ak1(i,j,bi,bj),ak2(i,j,bi,bj),
118 I ak1p(i,j,bi,bj),ak2p(i,j,bi,bj),ak3p(i,j,bi,bj),
119 I aks(i,j,bi,bj),akb(i,j,bi,bj),akw(i,j,bi,bj),
120 I aksi(i,j,bi,bj),akf(i,j,bi,bj),ff(i,j,bi,bj),
121 I bt(i,j,bi,bj),st(i,j,bi,bj),ft(i,j,bi,bj),
122 U pH(i,j,bi,bj),pCO2(i,j,bi,bj) )
123 ELSE
124 pCO2(i,j,bi,bj)=0. _d 0
125 END IF
126 ENDDO
127 ENDDO
128
129 DO j=jmin,jmax
130 DO i=imin,imax
131
132 IF (maskC(i,j,kLev,bi,bj).NE.0.) THEN
133 C calculate SCHMIDT NO. for CO2
134 SchmidtNoDIC(i,j) =
135 & sca1
136 & + sca2 * theta(i,j,kLev,bi,bj)
137 & + sca3 * theta(i,j,kLev,bi,bj)*theta(i,j,kLev,bi,bj)
138 & + sca4 * theta(i,j,kLev,bi,bj)*theta(i,j,kLev,bi,bj)
139 & *theta(i,j,kLev,bi,bj)
140
141 c
142 #ifdef USE_PLOAD
143 C Convert anomalous pressure pLoad (in Pa) from atmospheric model
144 C to total pressure (in Atm)
145 C Note: it is assumed the reference atmospheric pressure is 1Atm=1013mb
146 C rather than the actual ref. pressure from Atm. model so that on
147 C average AtmosP is about 1 Atm.
148 AtmosP(i,j,bi,bj)= 1. _d 0 + pLoad(i,j,bi,bj)/Pa2Atm
149 #endif
150
151 C Determine surface flux (FDIC)
152 C first correct pCO2at for surface atmos pressure
153 pCO2sat(i,j) =
154 & AtmosP(i,j,bi,bj)*AtmospCO2(i,j,bi,bj)
155 c find exchange coefficient
156 c account for schmidt number and and varible piston velocity
157 pisvel(i,j,bi,bj)=0.337 _d 0 *wind(i,j,bi,bj)**2/3.6 _d 5
158 Kwexch(i,j) =
159 & pisvel(i,j,bi,bj)
160 & / sqrt(SchmidtNoDIC(i,j)/660.0 _d 0)
161 c OR use a constant coeff
162 c Kwexch(i,j) = 5e-5
163 c ice influence
164 Kwexch(i,j) =(1. _d 0 - FIce(i,j,bi,bj))*Kwexch(i,j)
165
166
167 C Calculate flux in terms of DIC units using K0, solubility
168 C Flux = Vp * ([CO2sat] - [CO2])
169 C CO2sat = K0*pCO2atmos*P/P0
170 C Converting pCO2 to [CO2] using ff, as in CALC_PCO2
171 FluxCO2(i,j,bi,bj) =
172 & maskC(i,j,kLev,bi,bj)*Kwexch(i,j)*(
173 & ak0(i,j,bi,bj)*pCO2sat(i,j) -
174 & ff(i,j,bi,bj)*pCO2(i,j,bi,bj)
175 & )
176 ELSE
177 FluxCO2(i,j,bi,bj) = 0. _d 0
178 ENDIF
179 C convert flux (mol kg-1 m s-1) to (mol m-2 s-1)
180 FluxCO2(i,j,bi,bj) = FluxCO2(i,j,bi,bj)/permil
181
182 #ifdef ALLOW_OLD_VIRTUALFLUX
183 IF (maskC(i,j,kLev,bi,bj).NE.0.) THEN
184 c calculate virtual flux
185 c EminusPforV = dS/dt*(1/Sglob)
186 C NOTE: Be very careful with signs here!
187 C Positive EminusPforV => loss of water to atmos and increase
188 C in salinity. Thus, also increase in other surface tracers
189 C (i.e. positive virtual flux into surface layer)
190 C ...so here, VirtualFLux = dC/dt!
191 VirtualFlux(i,j)=gsm_DIC*surfaceForcingS(i,j,bi,bj)/gsm_s
192 c OR
193 c let virtual flux be zero
194 c VirtualFlux(i,j)=0.d0
195 c
196 ELSE
197 VirtualFlux(i,j)=0. _d 0
198 ENDIF
199 #endif /* ALLOW_OLD_VIRTUALFLUX */
200 ENDDO
201 ENDDO
202
203 C update tendency
204 DO j=jmin,jmax
205 DO i=imin,imax
206 GDC(i,j)= maskC(i,j,kLev,bi,bj)*recip_drF(kLev)*
207 & recip_hFacC(i,j,kLev,bi,bj)
208 & *(FluxCO2(i,j,bi,bj)
209 #ifdef ALLOW_OLD_VIRTUALFLUX
210 & + VirtualFlux(i,j)
211 #endif
212 & )
213 ENDDO
214 ENDDO
215
216 #endif
217 RETURN
218 END

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