/[MITgcm]/MITgcm/doc/diags_changes.txt
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Contents of /MITgcm/doc/diags_changes.txt

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Revision 1.5 - (show annotations) (download)
Sat Aug 13 13:34:22 2011 UTC (10 years, 10 months ago) by heimbach
Branch: MAIN
CVS Tags: checkpoint64y, checkpoint64x, checkpoint64z, checkpoint64q, checkpoint64p, checkpoint64s, checkpoint64r, checkpoint64u, checkpoint64t, checkpoint64w, checkpoint64v, checkpoint64i, checkpoint64h, checkpoint64k, checkpoint64j, checkpoint64m, checkpoint64l, checkpoint64o, checkpoint64n, checkpoint64a, checkpoint64c, checkpoint64b, checkpoint64e, checkpoint64d, checkpoint64g, checkpoint64f, checkpoint63p, checkpoint63q, checkpoint63r, checkpoint63s, checkpoint63l, checkpoint63m, checkpoint63n, checkpoint63o, checkpoint63h, checkpoint63i, checkpoint63j, checkpoint63k, checkpoint63d, checkpoint63e, checkpoint63f, checkpoint63g, checkpoint63b, checkpoint63c, checkpoint64, checkpoint65, checkpoint66g, checkpoint66f, checkpoint66e, checkpoint66d, checkpoint66c, checkpoint66b, checkpoint66a, checkpoint66o, checkpoint66n, checkpoint66m, checkpoint66l, checkpoint66k, checkpoint66j, checkpoint66i, checkpoint66h, checkpoint65z, checkpoint65x, checkpoint65y, checkpoint65r, checkpoint65s, checkpoint65p, checkpoint65q, checkpoint65v, checkpoint65w, checkpoint65t, checkpoint65u, checkpoint65j, checkpoint65k, checkpoint65h, checkpoint65i, checkpoint65n, checkpoint65o, checkpoint65l, checkpoint65m, checkpoint65b, checkpoint65c, checkpoint65a, checkpoint65f, checkpoint65g, checkpoint65d, checkpoint65e, HEAD
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1 ================================================================
2 Apr 03, 2010
3 1) add diagnostics for KPP non-local flux of Temp, Salt and pTracers
4 (respectively: KPPg_TH, KPPg_SLT and KPPgTrXX for tracer number XX)
5 This allows to close the tracer budget when using KPP.
6
7 2) Change the diagnostic for KPP non-local term:
8 name: description:
9 KPPghat Nonlocal transport coefficient (s/m^2)
10 (correspond to KPP ghat field, from which the non-local
11 flux of tracer (T,S,pTr) is computed, as the product of
12 ghat , KPPdiffKz and surface flux.)
13 replaced by:
14 KPPghatK ratio of KPP non-local (salt) flux relative to surface-flux
15 (correspond to the product: KPP_ghat * KPPdiffKzS
16 which gives the fraction of the the surface flux of Salt
17 that KPP return as non local flux; also valid for any passive
18 tracer, but could be different for Temp., see comment below)
19
20 comments (from mitgcm-devel list):
21 I was also tempted to replace the KPPghat diagnostics
22 with something more useful which incorporates the KPPdiffKz:
23 Since it is the product KPPghat*KPPdiffKz which matters,
24 and given that short time variations of both (which have no
25 reason not to be correlated) can be significant,
26 the product of the 2 time-ave is very likely to be quiet
27 far from the time-ave of the product.
28 It has also the advantage of a simpler interpretation:
29 the product is just the fraction of the surface flux which is
30 treated as non local (no unit, instead of this funny s/m^2
31 for KPPghat).
32
33 Then I would propose to just pick one KPPdiffKz (for instance,
34 KPPdiffKzS for salinity, since it's also used for Ptracers),
35 and have only 1 diag: "KPPghatK" for KPPghat*KPPdiffKzS (no unit).
36
37 For temperature (KPPghat*KPPdiffKzT), it's probably not too different
38 from the one computed for salinity (might be in fact a better
39 time-ave value that what we have now, for the reason above).
40 And to get a precise diagnostic of KPP-non-local effect
41 on temperature, there would be this new diagnostic directly from
42 kpp_transport_t.F (which can be used to close a Temp. budget).
43
44 ================================================================
45 Jun 21, 2009
46 Some redundancies and relations for model diagnostics:
47
48 1) Qnet = QNETtave = - oceQnet = SIqnet
49
50 2) For open-ocean, i.e., when there is no sea ice:
51 Qnet = QNETtave = - oceQnet = SIqnet = EXFqnet = SIqneto = SIatmQnt
52
53 3) EXFqnet = EXFlwnet + EXFswnet - EXFhl - EXFhs
54
55 4) Qsw = QSWtave = - oceQsw = SIqsw
56
57 5) For open-ocean, i.e., when there is no sea ice:
58 Qsw = QSWtave = - oceQsw = SIqsw = EXFswnet
59
60 6) EmPmR = EmPmRtave = -oceFWflx = SIempmr
61
62 ================================================================
63
64 Nov 19, 2006 (after tag checkpoint58r_post)
65
66 I) Some diagnostics have been renamed (essentially, to better
67 match the content):
68
69 1) name: description (oceanic set-up):
70 PRESSURE Cell-Center Height
71 replaced by:
72 RCENTER Cell-Center Height
73
74 2) name: description (oceanic set-up):
75 TICE heat from melt/freeze of sea-ice, >0 increases theta
76 replaced by:
77 oceFreez heating from freezing of sea-water (allowFreezing=T)
78
79 3) name: description (oceanic set-up):
80 TAUX zonal surface wind stress, >0 increases uVel
81 TAUY meridional surf. wind stress, >0 increases vVel
82 replaced by:
83 oceTAUX zonal surface wind stress, >0 increases uVel
84 oceTAUY meridional surf. wind stress, >0 increases vVel
85
86 4) name: description (oceanic set-up):
87 SWFLUX net upward SW radiation, >0 increases theta
88 replaced by:
89 oceQsw net Short-Wave radiation (+=down), >0 increases theta
90
91 5) name: description (oceanic set-up):
92 DIFx_TH Zonal Diffusive Flux of Pot.Temperature
93 DIFy_TH Meridional Diffusive Flux of Pot.Temperature
94 replaced by:
95 DFxE_TH Zonal Diffusive Flux of Pot.Temperature
96 DFyE_TH Meridional Diffusive Flux of Pot.Temperature
97
98 6) name: description (oceanic set-up):
99 DIFx_SLT Zonal Diffusive Flux of Salinity
100 DIFy_SLT Meridional Diffusive Flux of Salinity
101 replaced by:
102 DFxE_SLT Zonal Diffusive Flux of Salinity
103 DFyE_SLT Meridional Diffusive Flux of Salinity
104
105 -----------------------------------------------
106 II) Change description of existing diagnostics:
107
108 name: old description (oceanic set-up):
109 TFLUX net surface heat flux, >0 increases theta
110 SFLUX net surface salt flux, >0 increases salt
111 name: new description (oceanic set-up):
112 TFLUX total heat flux (match heat-content variations), >0 increases theta
113 SFLUX total salt flux (match salt-content variations), >0 increases salt
114
115 -----------------------------------------------
116 III) New diagnostics have been added:
117
118 name: description (oceanic set-up):
119 atmPload Atmospheric pressure loading
120 sIceLoad sea-ice loading (in Mass of ice+snow / area unit)
121 oceQnet net surface heat flux into the ocean (+=down), >0 increases theta
122 oceFWflx net surface Fresh-Water flux into the ocean (+=down), >0 decreases salinity
123 oceSflux net surface Salt flux into the ocean (+=down), >0 increases salinity
124 surForcT model surface forcing for Temperature, >0 increases theta
125 surForcS model surface forcing for Salinity, >0 increases salinity
126
127 --------------------------------------------------------------------------
128 Relation between surForcT,surForcS and others surface forcing diagnostics:
129 [x] = average of model variable "x" over the diagnostic time interval
130
131 a) if useRealFreshWaterFlux=F or (nonlinFreeSurf=0 & usingZCoords=T)
132 surForcT = oceQnet + TRELAX - oceQsw
133 surForcS = oceSflux + SRELAX - [PmEpR*So]
134 (with So = local Sea-Surface Salinity (SSS) if convertFW2Salt=-1
135 and So = convertFW2Salt otherwise)
136 oceFWflx = [PmEpR]
137 TFLUX = surForcT + oceQsw + oceFreez
138 SFLUX = surForcS
139
140 b) if useRealFreshWaterFlux=T & (nonlinFreeSurf>0 or usingPCoords=T),
141 In general:
142 surForcT = oceQnet + TRELAX - oceQsw + [T_dilution_effect]*Cp
143 surForcS = oceSflux + SRELAX + [S_dilution_effect]
144 where T_dilution_effect = PmEpR*( temp_EvPrRn - SST )
145 and S_dilution_effect = PmEpR*( salt_EvPrRn - SSS )
146 oceFWflx = [PmEpR]
147 TFLUX = surForcT + oceQsw + oceFreez + [PmEpR*SST]*Cp
148 SFLUX = surForcS + [PmEpR*SSS]
149
150 And with the default value: salt_EvPrRn=0. & temp_EvPrRn=UNSET_RL
151 (=> no dilution effect on Temp.):
152 surForcT = oceQnet + TRELAX - oceQsw
153 surForcS = oceSflux + SRELAX - [PmEpR*SSS]
154
155 Notes:
156 1) Here PmEpR is assumed to be the fresh-water mass flux
157 per surface area [units: kg/m^2/s] whereas the model variable
158 EmPmR is still a volume flux per surface area [units: m/s].
159 2) With Linear FreeSurf, there is a small loss of heat/salt/tracer at the
160 surface (d/dt(Eta) inconsistent with fixed surf grid cell thickness:
161 a) if linFSConserveTr is set to true (file "data"), then the model
162 corrects for this (see S/R calc_wsurf_tr.F).
163 b) if linFSConserveTr=False (=the default), the term corresponding
164 to w_surface*SST,SSS is missing in TFLUX,SFLUX to match exactly the
165 Heat and Salt budget evolution so need to account for this term in
166 the budget, which can be obtained from the 1rst level
167 of WTHMASS / WSLTMASS diagnostics (diagnostics ADVr_TH / ADVr_SLT
168 is not the right one for this purpose, it's just zero at k=1).
169 3) There is just one more undocumented/hidden case
170 (nonlinFreeSurf=0 & select_rStar=-1) which is not covered.
171 4) For extended diagnostics in the presence of sea-ice and using
172 pkg/seaice/ (in particular atmosphere-ice and ice-ocean fluxes)
173 see online documentation, section 6.6.2.6 "SEAICE diagnostics"
174

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