MITgcm/doc/diags_changes.txt

================================================================
Apr 03, 2010
1) add diagnostics for KPP non-local flux of Temp, Salt and pTracers
 (respectively: KPPg_TH, KPPg_SLT and KPPgTrXX for tracer number XX)
This allows to close the tracer budget when using KPP.

2) Change the diagnostic for KPP non-local term:
 name:          description:
KPPghat         Nonlocal transport coefficient (s/m^2)
                (correspond to KPP ghat field, from which the non-local
                flux of tracer (T,S,pTr) is computed, as the product of
                ghat , KPPdiffKz and surface flux.)
replaced by:
KPPghatK        ratio of KPP non-local (salt) flux relative to surface-flux
                (correspond to the product: KPP_ghat * KPPdiffKzS
                 which gives the fraction of the the surface flux of Salt
                 that KPP return as non local flux; also valid for any passive
                 tracer, but could be different for Temp., see comment below)

comments (from mitgcm-devel list):
 I was also tempted to replace the KPPghat diagnostics
 with something more useful which incorporates the KPPdiffKz:
 Since it is the product KPPghat*KPPdiffKz which matters,
 and given that short time variations of both (which have no
 reason not to be correlated) can be significant,
 the product of the 2 time-ave is very likely to be quiet
 far from the time-ave of the product.
 It has also the advantage of a simpler interpretation:
 the product is just the fraction of the surface flux which is
 treated as non local (no unit, instead of this funny s/m^2
 for KPPghat).

 Then I would propose to just pick one KPPdiffKz (for instance,
 KPPdiffKzS for salinity, since it's also used for Ptracers),
 and have only 1 diag: "KPPghatK" for KPPghat*KPPdiffKzS (no unit).

 For temperature (KPPghat*KPPdiffKzT), it's probably not too different
 from the one computed for salinity (might be in fact a better
 time-ave value that what we have now, for the reason above).
 And to get a precise diagnostic of KPP-non-local effect
 on temperature, there would be this new diagnostic directly from
 kpp_transport_t.F (which can be used to close a Temp. budget).

================================================================
Jun 21, 2009
Some redundancies and relations for model diagnostics:

1) Qnet = QNETtave = - oceQnet = SIqnet

2) For open-ocean, i.e., when there is no sea ice:
   Qnet = QNETtave = - oceQnet = SIqnet = EXFqnet = SIqneto = SIatmQnt

3) EXFqnet = EXFlwnet + EXFswnet - EXFhl - EXFhs

4) Qsw = QSWtave = - oceQsw = SIqsw

5) For open-ocean, i.e., when there is no sea ice:
   Qsw = QSWtave = - oceQsw = SIqsw = EXFswnet

6) EmPmR = EmPmRtave = -oceFWflx = SIempmr

================================================================

Nov 19, 2006 (after tag checkpoint58r_post)

I) Some diagnostics have been renamed (essentially, to better
match the content):

1) name:        description (oceanic set-up):
PRESSURE        Cell-Center Height
replaced by:
RCENTER         Cell-Center Height

2) name:        description (oceanic set-up):
TICE            heat from melt/freeze of sea-ice, >0 increases theta
replaced by:
oceFreez        heating from freezing of sea-water (allowFreezing=T)

3) name:        description (oceanic set-up):
TAUX            zonal surface wind stress, >0 increases uVel
TAUY            meridional surf. wind stress, >0 increases vVel
replaced by:
oceTAUX         zonal surface wind stress, >0 increases uVel
oceTAUY         meridional surf. wind stress, >0 increases vVel

4) name:        description (oceanic set-up):
SWFLUX          net upward SW radiation, >0 increases theta
replaced by:
oceQsw          net Short-Wave radiation (+=down), >0 increases theta

5) name:        description (oceanic set-up):
DIFx_TH         Zonal      Diffusive Flux of Pot.Temperature
DIFy_TH         Meridional Diffusive Flux of Pot.Temperature
replaced by:
DFxE_TH         Zonal      Diffusive Flux of Pot.Temperature
DFyE_TH         Meridional Diffusive Flux of Pot.Temperature

6) name:        description (oceanic set-up):
DIFx_SLT        Zonal      Diffusive Flux of Salinity
DIFy_SLT        Meridional Diffusive Flux of Salinity
replaced by:
DFxE_SLT        Zonal      Diffusive Flux of Salinity
DFyE_SLT        Meridional Diffusive Flux of Salinity

-----------------------------------------------
II) Change description of existing diagnostics:

name:           old description (oceanic set-up):
TFLUX           net surface heat flux, >0 increases theta
SFLUX           net surface salt flux, >0 increases salt
name:           new description (oceanic set-up):
TFLUX           total heat flux (match heat-content variations), >0 increases theta
SFLUX           total salt flux (match salt-content variations), >0 increases salt

-----------------------------------------------
III) New diagnostics have been added:

name:           description (oceanic set-up):
atmPload        Atmospheric pressure loading
sIceLoad        sea-ice loading (in Mass of ice+snow / area unit)
oceQnet         net surface heat flux into the ocean (+=down), >0 increases theta
oceFWflx        net surface Fresh-Water flux into the ocean (+=down), >0 decreases salinity
oceSflux        net surface Salt flux into the ocean (+=down), >0 increases salinity
surForcT        model surface forcing for Temperature, >0 increases theta
surForcS        model surface forcing for Salinity, >0 increases salinity

--------------------------------------------------------------------------
Relation between surForcT,surForcS and others surface forcing diagnostics:
 [x] = average of model variable "x" over the diagnostic time interval

a) if useRealFreshWaterFlux=F or (nonlinFreeSurf=0 & usingZCoords=T)
 surForcT = oceQnet  + TRELAX - oceQsw
 surForcS = oceSflux + SRELAX - [PmEpR*So]
  (with So = local Sea-Surface Salinity (SSS) if convertFW2Salt=-1
    and So = convertFW2Salt otherwise)
 oceFWflx = [PmEpR]
 TFLUX = surForcT + oceQsw + oceFreez
 SFLUX = surForcS

b) if useRealFreshWaterFlux=T & (nonlinFreeSurf>0 or usingPCoords=T),
In general:
 surForcT = oceQnet  + TRELAX - oceQsw + [T_dilution_effect]*Cp
 surForcS = oceSflux + SRELAX          + [S_dilution_effect]
    where T_dilution_effect = PmEpR*( temp_EvPrRn - SST )
      and S_dilution_effect = PmEpR*( salt_EvPrRn - SSS )
 oceFWflx = [PmEpR]
 TFLUX = surForcT + oceQsw + oceFreez + [PmEpR*SST]*Cp
 SFLUX = surForcS + [PmEpR*SSS]

And with the default value: salt_EvPrRn=0. & temp_EvPrRn=UNSET_RL
 (=> no dilution effect on Temp.):
 surForcT = oceQnet  + TRELAX - oceQsw
 surForcS = oceSflux + SRELAX - [PmEpR*SSS]

Notes:
1) here PmEpR is assumed to be the fresh-water mass flux
 per surface area [units: kg/m^2/s] whereas the model variable
 EmPmR is still a volume flux per surface area [units: m/s].
2) with Linear Free surface (nonlinFreeSurf=0), the term
corresponding to w_surface*SST,SSS is missing in TFLUX,SFLUX
[might be added later ?] to match exactly the Heat and Salt
budget evolution.
--------------------------------------------------------------------------
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 + [PmEpRSST]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 Free surface (nonlinFreeSurf=0), the term
160	corresponding to w_surface*SST,SSS is missing in TFLUX,SFLUX
161	[might be added later ?] to match exactly the Heat and Salt
162	budget evolution.
163	--------------------------------------------------------------------------