/[MITgcm]/MITgcm/doc/diags_changes.txt
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Revision 1.5 - (hide annotations) (download)
Sat Aug 13 13:34:22 2011 UTC (11 years 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 jmc 1.3 ================================================================
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 dimitri 1.1 Jun 21, 2009
46     Some redundancies and relations for model diagnostics:
47    
48     1) Qnet = QNETtave = - oceQnet = SIqnet
49    
50 dimitri 1.2 2) For open-ocean, i.e., when there is no sea ice:
51     Qnet = QNETtave = - oceQnet = SIqnet = EXFqnet = SIqneto = SIatmQnt
52 dimitri 1.1
53 dimitri 1.2 3) EXFqnet = EXFlwnet + EXFswnet - EXFhl - EXFhs
54 dimitri 1.1
55 dimitri 1.2 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 dimitri 1.1
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 dimitri 1.4 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 heimbach 1.5 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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