Land-ocean surface temperature contrast and radiative forcing    

Hugo LambertUniversity of Exeter

thanks to Mark Webb and Manoj Joshi

1955-2003

Lambert and Chiang, (2007)

OLS regression for 1955-2003

Model Φ

GFDL CM 2 0 1.4 +/- 0.2

GFDL CM 2 1 1.5 +/- 0.2

GISS E-R 1.5 +/- 0.1

MIROC 1.5 +/- 0.2

MRI 0.9 +/- 0.2

Observations 1.6 +/- 0.1

OLS regression for 1955-2003: residual

varianceModel r

GFDL CM 2 0 0.020

GFDL CM 2 1 0.021

GISS E-R 0.013

MIROC 0.016

MRI 0.029

Observations 0.009

Into the future

Some references

Hansen et al., (1983)

Manabe et al., (1991)

Huntingford and Cox, (2000)

Sutton et al., (2007)

Joshi et al., (2008)

Structure of talk

• Motivation

• Simple model of land-sea contrast.

• Comparison with complex models.

• Some stuff that I don't really understand.

∆N = ∆Q, ∆T = 0

∆N = 0, ∆T = ∆Teq

∆T = 3K, ∆N = ∆T / λ

∆Ain some idealised 2xCO2

and prescribedSST experiments.

And ∆TL against∆TO

Structure of talk

• Motivation

• Simple model of land-sea contrast.

• Comparison with complex models.

• Some stuff that I don't really understand.

© Crown copyright Met Office

CRUTEM3

vs

HadISST2

1900-1954 1955-2008

© Crown copyright Met Office

CRUTEM3

vs

HadISST2

(masked to 1900)

1900-1954 1955-2008

© Crown copyright Met Office

1900-1954 1955-2008

CRUTEM3

vs

HadISST2

(masked to 1900)

1.5 +/- 0.4

0.7 +/- 0.3

© Crown copyright Met Office

1900-1954 1955-2008

HadISST2

(masked to 1900)

© Crown copyright Met Office

1900-1954 1955-2008

1900-1954, constant Φ

HadISST2

(masked to 1900)

Conclusions

Annual mean ∆TL / ∆TO is remarkably constant – especially in observations.

Simple model and GCM study suggests powerful land-ocean heat transport.

Early 20th century behaviour is different / problematic.