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

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Revision 1.13 - (show annotations) (download)
Mon May 7 15:58:20 2007 UTC (17 years, 1 month ago) by stephd
Branch: MAIN
CVS Tags: checkpoint59e, checkpoint59d, checkpoint59c, checkpoint59b
Changes since 1.12: +11 -1 lines
o add (and change) flags so that pkg/dic can uses Qsw, Pload from FFIELDS.
  also ATMOSCO2 from the coupler (for times when coupled to an atmospheric
  model.

1 C $Header: /u/gcmpack/MITgcm/pkg/dic/dic_surfforcing.F,v 1.12 2006/11/28 21:16:03 stephd 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 _RL VirtualFlux(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
60 CEOP
61
62 cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
63
64 kLev=1
65
66 c if coupled to atmsopheric model, use the
67 c Co2 value passed from the coupler
68 #ifndef USE_ATMOSCO2
69 C PRE-INDUSTRIAL STEADY STATE pCO2 = 278.0 ppmv
70 DO j=1-OLy,sNy+OLy
71 DO i=1-OLx,sNx+OLx
72 AtmospCO2(i,j,bi,bj)=278.0d-6
73 ENDDO
74 ENDDO
75 #endif
76
77
78 C =================================================================
79 C determine inorganic carbon chem coefficients
80 DO j=jmin,jmax
81 DO i=imin,imax
82
83 #ifdef DIC_BIOTIC
84 cQQQQ check ptracer numbers
85 surfalk(i,j) = PTR_ALK(i,j,klev)
86 & * maskC(i,j,kLev,bi,bj)
87 surfphos(i,j) = PTR_PO4(i,j,klev)
88 & * maskC(i,j,kLev,bi,bj)
89 #else
90 surfalk(i,j) = 2.366595 * salt(i,j,kLev,bi,bj)/gsm_s
91 & * maskC(i,j,kLev,bi,bj)
92 surfphos(i,j) = 5.1225e-4 * maskC(i,j,kLev,bi,bj)
93 #endif
94 C FOR NON-INTERACTIVE Si
95 surfsi(i,j) = SILICA(i,j,bi,bj) * maskC(i,j,kLev,bi,bj)
96 ENDDO
97 ENDDO
98
99 CALL CARBON_COEFFS(
100 I theta,salt,
101 I bi,bj,iMin,iMax,jMin,jMax)
102 C====================================================================
103
104 c pCO2 solver...
105 C$TAF LOOP = parallel
106 DO j=jmin,jmax
107 C$TAF LOOP = parallel
108 DO i=imin,imax
109
110 IF(maskC(i,j,kLev,bi,bj) .NE. 0.)THEN
111 CALL CALC_PCO2_APPROX(
112 I theta(i,j,kLev,bi,bj),salt(i,j,kLev,bi,bj),
113 I PTR_CO2(i,j,kLev), surfphos(i,j),
114 I surfsi(i,j),surfalk(i,j),
115 I ak1(i,j,bi,bj),ak2(i,j,bi,bj),
116 I ak1p(i,j,bi,bj),ak2p(i,j,bi,bj),ak3p(i,j,bi,bj),
117 I aks(i,j,bi,bj),akb(i,j,bi,bj),akw(i,j,bi,bj),
118 I aksi(i,j,bi,bj),akf(i,j,bi,bj),ff(i,j,bi,bj),
119 I bt(i,j,bi,bj),st(i,j,bi,bj),ft(i,j,bi,bj),
120 U pH(i,j,bi,bj),pCO2(i,j,bi,bj) )
121 ELSE
122 pCO2(i,j,bi,bj)=0. _d 0
123 END IF
124 ENDDO
125 ENDDO
126
127 DO j=jmin,jmax
128 DO i=imin,imax
129
130 IF (maskC(i,j,kLev,bi,bj).NE.0.) THEN
131 C calculate SCHMIDT NO. for CO2
132 SchmidtNoDIC(i,j) =
133 & sca1
134 & + sca2 * theta(i,j,kLev,bi,bj)
135 & + sca3 * theta(i,j,kLev,bi,bj)*theta(i,j,kLev,bi,bj)
136 & + sca4 * theta(i,j,kLev,bi,bj)*theta(i,j,kLev,bi,bj)
137 & *theta(i,j,kLev,bi,bj)
138
139 c
140 #ifdef USE_PLOAD
141 c convert from Pa to atmos
142 AtmosP(i,j,bi,bj)=pLoad(i,j,bi,bj)/1.01295e5
143 #endif
144
145 C Determine surface flux (FDIC)
146 C first correct pCO2at for surface atmos pressure
147 pCO2sat(i,j) =
148 & AtmosP(i,j,bi,bj)*AtmospCO2(i,j,bi,bj)
149 c find exchange coefficient
150 c account for schmidt number and and varible piston velocity
151 pisvel(i,j,bi,bj) =0.337*wind(i,j,bi,bj)**2/3.6d5
152 Kwexch(i,j) =
153 & pisvel(i,j,bi,bj)
154 & / sqrt(SchmidtNoDIC(i,j)/660.0)
155 c OR use a constant coeff
156 c Kwexch(i,j) = 5e-5
157 c ice influence
158 Kwexch(i,j) =(1.d0-Fice(i,j,bi,bj))*Kwexch(i,j)
159
160
161 C Calculate flux in terms of DIC units using K0, solubility
162 C Flux = Vp * ([CO2sat] - [CO2])
163 C CO2sat = K0*pCO2atmos*P/P0
164 C Converting pCO2 to [CO2] using ff, as in CALC_PCO2
165 FluxCO2(i,j,bi,bj) =
166 & maskC(i,j,kLev,bi,bj)*Kwexch(i,j)*(
167 & ak0(i,j,bi,bj)*pCO2sat(i,j) -
168 & ff(i,j,bi,bj)*pCO2(i,j,bi,bj)
169 & )
170 ELSE
171 FluxCO2(i,j,bi,bj) = 0.
172 ENDIF
173 C convert flux (mol kg-1 m s-1) to (mol m-2 s-1)
174 FluxCO2(i,j,bi,bj) = FluxCO2(i,j,bi,bj)/permil
175
176 IF (maskC(i,j,kLev,bi,bj).NE.0.) THEN
177 c calculate virtual flux
178 c EminusPforV = dS/dt*(1/Sglob)
179 C NOTE: Be very careful with signs here!
180 C Positive EminusPforV => loss of water to atmos and increase
181 C in salinity. Thus, also increase in other surface tracers
182 C (i.e. positive virtual flux into surface layer)
183 C ...so here, VirtualFLux = dC/dt!
184 VirtualFlux(i,j)=gsm_DIC*surfaceForcingS(i,j,bi,bj)/gsm_s
185 c OR
186 c let virtual flux be zero
187 c VirtualFlux(i,j)=0.d0
188 c
189 ELSE
190 VirtualFlux(i,j)=0. _d 0
191 ENDIF
192 ENDDO
193 ENDDO
194
195 C update tendency
196 DO j=jmin,jmax
197 DO i=imin,imax
198 GDC(i,j)= maskC(i,j,kLev,bi,bj)*recip_drF(kLev)*
199 & recip_hFacC(i,j,kLev,bi,bj)*(
200 & FluxCO2(i,j,bi,bj) + VirtualFlux(i,j)
201 & )
202 ENDDO
203 ENDDO
204
205 #endif
206 RETURN
207 END

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