Slide 1 GSOP Workshop, Reading, 31 Agust-1 September 2006 Temperature, Salinity and Sea Level: climate variability from ocean reanalyses (Intercomparison

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


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


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


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






sdv all = 0.260s/n all = 1.201

spread = 0.216


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






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





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


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






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






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






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


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






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






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.


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






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






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




mct3eccoJPLaeccoJPLceccoMIT


sdv all = 0.023s/n all = 1.168

spread = 0.020

GLOBAL Upper T-3000m

Warming occurs ~ in first 750m


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






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



mct3eccoJPLaeccoJPLceccoMIT


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






sdv all = 0.051s/n all = 0.912

spread = 0.056


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


0.0

0.5

1.0

1.5

2.0

2.5

s/n


0.0

0.5

1.0

1.5

2.0

2.5

s/n


0.0

0.5

1.0

1.5

2.0

2.5

s/n


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


Slide 11

sc_gsop_3rm_anom_164

0.0

0.5

1.0

1.5

2.0

2.5

s/n


0.0

0.5

1.0

1.5

2.0

2.5

s/n


0.0

0.5

1.0

1.5

2.0

2.5

s/n


0.0

0.5

1.0

1.5

2.0

2.5

s/n


0.0

0.5

1.0

1.5

2.0

2.5

s/n


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


Slide 12

Sources of Uncertainty

EQPAC

0.00

0.05

0.10

0.15

0.20

spre

ad

EQATL

0.00

0.05

0.10

0.15

spre

ad

EQIND

0.00

0.05

0.10

0.15

0.20

spre

ad

NINO3

0.00

0.05

0.10

0.15

0.20

0.25

0.30

spre

ad

DTRATL

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

spre

ad

INDPL

0.0

0.1

0.2

0.3

spre

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


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

spre

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


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

spre

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

ad

EQATL

0.00

0.02

0.04

0.06

0.08

0.10

0.12

spre

ad

EQIND

0.00

0.02

0.04

0.06

0.08

0.10

0.12

spre

ad

TRPAC

0.00

0.01

0.02

0.03

0.04

0.05

0.06

spre

ad

TRATL

0.00

0.01

0.02

0.03

0.04

0.05

spre

ad

NPAC

0.00

0.02

0.04

0.06

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

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



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

spre

ad

TRPAC

0.000

0.005

0.010

0.015

0.020

0.025

0.030

spre

ad

TRATL

0.00

0.01

0.02

0.03

0.04

0.05

spre

ad

NPAC

0.000

0.005

0.010

0.015

0.020

0.025

0.030

spre

ad

NATL

0.00

0.01

0.02

0.03

0.04

0.05

spre

ad

GLOBAL

0.000

0.005

0.010

0.015

0.020

0.025

spre

ad

EQPAC

0.000

0.005

0.010

0.015

spre

ad

EQATL

0.00

0.01

0.02

0.03

0.04

spre

ad

EQIND

0.00

0.01

0.02

0.03

spre

ad

TRPAC

0.000

0.002

0.004

0.006

0.008

0.010

0.012

spre

ad

TRATL

0.000

0.005

0.010

0.015

0.020

0.025

0.030

spre

ad

NPAC

0.000

0.005

0.010

0.015

0.020

0.025

0.030

spre

ad

NATL

0.00

0.01

0.02

0.03

spre

ad

GLOBAL

0.000

0.002

0.004

0.006

0.008

0.010

0.012

spre

ad


TRATL NPAC NATL GLOBALEQPAC EQATL EQIND TRPAC

EQPAC EQATL EQIND TRPAC


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


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


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



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


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


mct2 12m-rm annual anom: GLOBAL

1994 1996 1998 2000 2002 2004 2006Time

-0.04

-0.02

0.00

0.02

0.04


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



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


Seasonal variations in global sea level are attributed to mass variations that affect the bottom pressure.


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.


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?

Documents

Slide 1 GSOP Workshop, Reading, 31 Agust-1 September 2006 Temperature, Salinity and Sea Level: climate variability from ocean reanalyses (Intercomparison