GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 1
Temperature, Salinity and Sea Level:
climate variability from ocean reanalyses
(Intercomparison Items 3 & 4)
Magdalena A. BalmasedaAnthony Weaver
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 2
Outline
Defining the variability: signal and noise
- Seasonal cycle removed: Anomalies with respect to the common period (1994-2000)
- 12-month/3-month running mean
- Focus on the upper ocean (upper 300m): Equator, Mid latitudes
Temperature and salinity:
- What can we say about climate variability?
- Time variation of uncertainty
- Outliers?
Source of uncertainty (forcing, model, assimilation method)?
Sea Level variations: volume or mass changes?
Summary and conclusions
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 3
Focus Regions for Items 3 & 4
Focus regionsFocus regionsFocus regions
100E 160W 60WLongitude
50S
0
50N
Latitu
de
EQPAC
TRPAC
NPAC
EQATL
TRATL
NATL
EQIND
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 4
Uncertainty in the Mean24m-rm EQPAC Averaged temperature over the top 300m
1950 1960 1970 1980 1990 2000Time
16
17
18
19
20
21
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.260s/n ensm = 0.544
sdv all = 0.448s/n all = 0.939
spread = 0.478
•Ambiguity in the definitionclosest level, interpolated values…?
•Real Uncertainty?
We will use anomalies…
24m-rm EQIND Averaged salinity over the top 300m
1950 1960 1970 1980 1990 2000Time
34.5
35.0
35.5
36.0
36.5
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.079s/n ensm = 0.365
sdv all = 0.260s/n all = 1.201
spread = 0.216
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 5
T300: Equatorial regions
Eq Pac: Uncertainty decreases with time.
Relatively robust interannual variability.
Increased uncertainty after 2000. Why?
12m-rm seasonal anom: EQPAC Averaged temperature over the top 300m
1950 1960 1970 1980 1990 2000Time
-1.0
-0.5
0.0
0.5
1.0
1.5
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.272s/n ensm = 1.139
sdv all = 0.337s/n all = 1.411
spread = 0.239
12m-rm seasonal anom: EQIND Averaged temperature over the top 300m
1950 1960 1970 1980 1990 2000Time
-1.5
-1.0
-0.5
0.0
0.5ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.136s/n ensm = 0.619
sdv all = 0.220s/n all = 0.998
spread = 0.220
Eq Indian: Uncertainty remains large throughout the record.
Signal to noise <1. Outliers
This is also the case for the Eq Atlantic
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 6
What can we say about Tropical variability?
12m-rm seasonal anom: TRATL Averaged temperature over the top 300m
1950 1960 1970 1980 1990 2000Time
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.113s/n ensm = 0.916
sdv all = 0.144s/n all = 1.172
spread = 0.123
12m-rm seasonal anom: TRIND Averaged temperature over the top 300m
1950 1960 1970 1980 1990 2000Time
-0.6
-0.4
-0.2
0.0
0.2
0.4
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.078s/n ensm = 0.674
sdv all = 0.131s/n all = 1.137
spread = 0.115
12m-rm seasonal anom: TRPAC Averaged temperature over the top 300m
1950 1960 1970 1980 1990 2000Time
-0.4
-0.2
0.0
0.2
0.4
0.6
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.071s/n ensm = 0.532
sdv all = 0.108s/n all = 0.803
spread = 0.134
How should we interpret the outliers?
Need to understand the reasons
An outlier for the good reason is very valuable
An outlier for the wrong reason is damaging
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 7
T300: Mid latitudes (northern)12m-rm seasonal anom: NATL Averaged temperature over the top 300m
1950 1960 1970 1980 1990 2000Time
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.164s/n ensm = 1.620
sdv all = 0.206s/n all = 2.028
spread = 0.101
•The North Atlantic is dominated by a warming trend, especially post 1997
•Large uncertainty after 2000.
•Phase/amplitude of decadal variability is poorly resolved.
12m-rm seasonal anom: NPAC Averaged temperature over the top 300m
1950 1960 1970 1980 1990 2000Time
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.117s/n ensm = 0.780
sdv all = 0.156s/n all = 1.040
spread = 0.150
•The North Pacific does not show a warming trend, but more of a rapid shift in the early 90’s
•Large uncertainty after 2000
•Phase/amplitude of decadal signal is poorly resolved. Outliers.
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 8
GLOBAL SIGNALS
12m-rm seasonal anom: GLOBAL Averaged temperature over the top 300m
1950 1960 1970 1980 1990 2000Time
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.054s/n ensm = 0.850
sdv all = 0.078s/n all = 1.233
spread = 0.063
GLOBAL: Upper T-300m
12m-rm seasonal anom: GLOBAL 264
1950 1960 1970 1980 1990 2000Time
-0.3
-0.2
-0.1
0.0
0.1
0.2
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.041s/n ensm = 0.855
sdv all = 0.058s/n all = 1.220
spread = 0.048
GLOBAL Upper T-750m
12m-rm seasonal anom: GLOBAL 364
1950 1960 1970 1980 1990 2000Time
-0.10
-0.05
0.00
0.05
0.10
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMIT
sdv ensm = 0.017s/n ensm = 0.863
sdv all = 0.023s/n all = 1.168
spread = 0.020
GLOBAL Upper T-3000m
Warming occurs ~ in first 750m
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 9
Salinity Variability
Salinity variability dominated by spin-up effects in several cases.
There is no consistency among reanalyes
12m-rm seasonal anom: NPAC Averaged salinity over the top 300m
1950 1960 1970 1980 1990 2000Time
-0.10
-0.05
0.00
0.05
0.10
0.15
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.010s/n ensm = 0.423
sdv all = 0.024s/n all = 1.015
spread = 0.023
12m-rm seasonal anom: NPAC 375
1950 1960 1970 1980 1990 2000Time
-0.02
-0.01
0.00
0.01
0.02
0.03ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMIT
sdv ensm = 0.004s/n ensm = 0.478
sdv all = 0.007s/n all = 0.843
spread = 0.008
12m-rm seasonal anom: TRATL Averaged salinity over the top 300m
1950 1960 1970 1980 1990 2000Time
-0.2
0.0
0.2
0.4
0.6
ukdpukoicfcs2cfas2ecco50y
gfdlsodaecmfaecmfcukgs
ingvmri-eccoSIOcfasamct2
mct3eccoJPLaeccoJPLceccoMITGMAO
sdv ensm = 0.014s/n ensm = 0.246
sdv all = 0.051s/n all = 0.912
spread = 0.056
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 10
Signal/Noise Ratio (long period)s_gsop_12rm_anom_164
0.0
0.5
1.0
1.5
2.0
2.5
s/n
s_gsop_12rm_anom_264
0.0
0.5
1.0
1.5
2.0
2.5
s/n
s_gsop_12rm_anom_364
0.0
0.5
1.0
1.5
2.0
2.5
s/n
s_gsop_12rm_anom_175
0.0
0.5
1.0
1.5
2.0
2.5
s/n
s_gsop_12rm_anom_275
0.0
0.5
1.0
1.5
2.0
2.5
s/n
s_gsop_12rm_anom_375
0.0
0.5
1.0
1.5
2.0
2.5
s/n
EQPAC
EQATL
EQINDTRPAC
TRATL
NPAC
NATL
GLOBAL
T300-12m-rm T750-12m-rm T3000-12m-rm
S300-12m-rm S750-12m-rm S3000-12m-rm
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 11
sc_gsop_3rm_anom_164
0.0
0.5
1.0
1.5
2.0
2.5
s/n
sc_gsop_3rm_anom_264
0.0
0.5
1.0
1.5
2.0
2.5
s/n
sc_gsop_3rm_anom_364
0.0
0.5
1.0
1.5
2.0
2.5
s/n
sc_gsop_3rm_anom_175
0.0
0.5
1.0
1.5
2.0
2.5
s/n
sc_gsop_3rm_anom_275
0.0
0.5
1.0
1.5
2.0
2.5
s/n
sc_gsop_3rm_anom_375
0.0
0.5
1.0
1.5
2.0
2.5
s/n
Signal/Noise Ratio (Short period, interannual)
EQPAC
EQATL
EQINDTRPAC
TRATL
NPAC
NATL
GLOBAL
T300-3m-rm T750-3m-rm T3000-3m-rm
S300-3m-rm S750-3m-rm S3000-3m-rm
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 12
Sources of Uncertainty
EQPAC
0.00
0.05
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0.15
0.20
spre
ad
EQATL
0.00
0.05
0.10
0.15
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EQIND
0.00
0.05
0.10
0.15
0.20
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NINO3
0.00
0.05
0.10
0.15
0.20
0.25
0.30
spre
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DTRATL
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
spre
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INDPL
0.0
0.1
0.2
0.3
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ad
All
ERA40
ERA40-No data
ERA40-Assim
12m-rm seasonal anom: EQPAC Averaged temperature over the top 300m
1950 1960 1970 1980 1990 2000Time
-1.0
-0.5
0.0
0.5
1.0
1.5
allsdv_ensm= 0.269spread= 0.239s/n_ensm = 1.127
era40sdv_ensm= 0.278spread= 0.145s/n_ensm = 1.912
era40-ctrlsdv_ensm= 0.338spread= 0.117s/n_ensm = 2.887
era40-assmsdv_ensm= 0.332spread= 0.085s/n_ensm = 3.910
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 13
Equatorial Atlantic: Assimilation increases spread
EQPAC
0.00
0.02
0.04
0.06
0.08
0.10
0.12
spre
ad
EQATL
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
spre
ad
EQIND
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
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ad
NINO3
0.00
0.05
0.10
0.15sp
rea
d
DTRATL
0.00
0.02
0.04
0.06
0.08
0.10
spre
ad
INDPL
0.0
0.1
0.2
0.3
0.4
spre
ad
3m-rm seasonal anom: EQATL Averaged temperature over the top 300m
1994 1996 1998 2000 2002 2004 2006Time
-1.0
-0.5
0.0
0.5
1.0
allsdv_ensm= 0.118spread= 0.145s/n_ensm = 0.811
era40sdv_ensm= 0.101spread= 0.084s/n_ensm = 1.197
era40-ctrlsdv_ensm= 0.094spread= 0.018s/n_ensm = 5.218
era40-assmsdv_ensm= 0.126spread= 0.067s/n_ensm = 1.862
All
ERA40
ERA40-No data
ERA40-Assim
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 14
Assimilation and Uncertainty T300
Long period 1956-2005:
Assimilation decreases uncertainty
everywhere
EQPAC
0.00
0.05
0.10
0.15
0.20
spre
ad
EQATL
0.00
0.05
0.10
0.15
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ad
EQIND
0.00
0.05
0.10
0.15
0.20
spre
ad
TRPAC
0.00
0.02
0.04
0.06
0.08
0.10
0.12
spre
ad
TRATL
0.00
0.02
0.04
0.06
0.08
0.10
0.12
spre
ad
NPAC
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
spre
ad
NATL
0.00
0.02
0.04
0.06
0.08
0.10
spre
ad
GLOBAL
0.00
0.01
0.02
0.03
0.04
0.05
0.06
spre
ad
EQPAC
0.00
0.02
0.04
0.06
0.08
0.10
spre
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EQATL
0.00
0.02
0.04
0.06
0.08
0.10
0.12
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EQIND
0.00
0.02
0.04
0.06
0.08
0.10
0.12
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TRPAC
0.00
0.01
0.02
0.03
0.04
0.05
0.06
spre
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TRATL
0.00
0.01
0.02
0.03
0.04
0.05
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NPAC
0.00
0.02
0.04
0.06
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NATL
0.00
0.02
0.04
0.06
0.08
0.10
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GLOBAL
0.00
0.01
0.02
0.03
0.04
spre
ad
Latest period 1993-2005
Only in EQPAC the assimilation reduces uncertainty
1956-2005
1993-2005EQPAC EQATL EQIND TRPAC
EQPAC EQATL EQIND TRPAC
TRATL NPAC NATL GLOBAL
TRATL NPAC NATL GLOBAL
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 15
Assimilation and Uncertainty S300
Long period 1956-2005:
Assimilation increases uncertainty
everywhere
Latest period 1993-2005
Assimilation increases uncertainty
1956-2005
1993-2005
EQPAC
0.000
0.005
0.010
0.015
0.020
0.025
spre
ad
EQATL
0.00
0.02
0.04
0.06
spre
ad
EQIND
0.00
0.01
0.02
0.03
0.04
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TRPAC
0.000
0.005
0.010
0.015
0.020
0.025
0.030
spre
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TRATL
0.00
0.01
0.02
0.03
0.04
0.05
spre
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NPAC
0.000
0.005
0.010
0.015
0.020
0.025
0.030
spre
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NATL
0.00
0.01
0.02
0.03
0.04
0.05
spre
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GLOBAL
0.000
0.005
0.010
0.015
0.020
0.025
spre
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EQPAC
0.000
0.005
0.010
0.015
spre
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EQATL
0.00
0.01
0.02
0.03
0.04
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EQIND
0.00
0.01
0.02
0.03
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TRPAC
0.000
0.002
0.004
0.006
0.008
0.010
0.012
spre
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TRATL
0.000
0.005
0.010
0.015
0.020
0.025
0.030
spre
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NPAC
0.000
0.005
0.010
0.015
0.020
0.025
0.030
spre
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NATL
0.00
0.01
0.02
0.03
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GLOBAL
0.000
0.002
0.004
0.006
0.008
0.010
0.012
spre
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TRATL NPAC NATL GLOBAL
TRATL NPAC NATL GLOBALEQPAC EQATL EQIND TRPAC
EQPAC EQATL EQIND TRPAC
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 16
GLOBAL SEA LEVEL VARIATIONS I
•Prior to 2002, changes in sea level and steric height are correlated:
Volume rather than mass
•Changes in bottom pressure are not consistent amont analyses?
eccoMIT 12m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.02
-0.01
0.00
0.01
0.02
0.03
0.04
altimetersea levelbpress
eccJPLa 12m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.01
0.00
0.01
0.02
0.03
0.04
altimetersea levelbpress
eccJPLc 12m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.01
0.00
0.01
0.02
0.03
0.04
altimetersea levelbpress
ecmfa 12m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.01
0.00
0.01
0.02
0.03
0.04
0.05
altimetersea levelbpresssheight
ecmfc 12m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.02
-0.01
0.00
0.01
0.02
0.03
0.04
altimetersea levelbpresssheight
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 17
GLOBAL SEA LEVEL VARIATIONS II
Temperature contribution to dynamic height dominates the trend
cfcs2 12m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.02
-0.01
0.00
0.01
0.02
0.03
0.04
altimetersea leveldynhdynh-tdynh-h
cfas2 12m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.04
-0.02
0.00
0.02
0.04
altimetersea leveldynhdynh-tdynh-h
cfasa 12m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.01
0.00
0.01
0.02
0.03
0.04
altimetersea leveldynhdynh-tdynh-h
mct2 12m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.04
-0.02
0.00
0.02
0.04
altimetersea leveldynhdynh-tdynh-h
mct3 12m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.01
0.00
0.01
0.02
0.03
0.04
altimetersea leveldynhdynh-tdynh-h
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 18
Sea level variations: Seasonal cycleecmfa 3m-rm annual anom: GLOBAL
1994 1996 1998 2000 2002 2004 2006Time
-0.02
0.00
0.02
0.04
0.06
altimetersea levelbpresssheight
Seasonal variations in global sea level are attributed to mass variations that affect the bottom pressure.
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 19
Summary and Conclusions
There is large uncertainty in climate signals
- Signal to noise ratio > 1 in the Eastern Pacific for Temperature
- Signal to noise ratio <1 for salinity in most regions- Warming trend in the 90’s is consistently reproduced
- What is happening now? There is not consistent picture
Forcing fluxes and analysis methods are largest source of uncertainty
- Data Assimilation does not always collapse the spread: We need to pay more attention to the assimilation methods.
Global Sea level trends- 1993-2002: Consistently attributed to temperature rise.- 2002-present: It is not clear. Mass increase?- Seasonal variations related to mass variations.
GSOP Workshop, Reading, 31 Agust-1 September 2006
Slide 20
NEXT
Web page to collect. WHERE? GSOP web page?
Maps of signal to noise ratio, and so on
Need to define the variables so there are not “so” dependent on the vertical model grid.
There are currently 20 analysis… are there more there?
Agreement on colour coding and naming convention?
Other?