Inter-annual to decadal climate predictionMojib Latif, Leibniz Institute of Marine Sciences at Kiel University

Outline1. Some general remarks2. Inter-annual predictability3. Decadal predictability4. Limitations

The last three decades

annual global SAT

Uncertainties in climate change projections

Hawkins and Sutton 2009

internal variability

model

scenario

annual global SAT, derived from CMIP3 models

Uncertainty due to internal variability increases at regional scales

Hawkins and Sutton 2009

internal variability internal variability

Unpredictable external factors enhance the uncertainty

Potential predictability at inter-annual and decadal time scales

Outline1. Some general remarks2. Inter-annual predictability3. Decadal predictability4. Limitations

El Niño/Southern Oscillation

The role of air-sea interactions and upper ocean heat content

A simple theoretical concept has been developed

The ocean observing system

Three days (24-26 March 2010) of real-time in situ data from moorings (red squares), Argo floats (inverted yellow triangles), drifters (blue circles), shore and bottom stations (blue triangles), and ships (green symbols).

The TOGA TAO array, the basis for ENSO prediction

El Niño prediction, November starts predicting winter (DJF)

r = 0.96

NAO prediction, November starts predicting winter (DJF)

r = 0.27

What’s next?

Outline1. Some general remarks2. Inter-annual predictability3. Decadal predictability4. Limitations

Multidecadal climate variability

Is some of the multidecadal variability in NH-SAT linked to MOC variations, and if so, are they predictable?

Societal relevance of multidecadal variability

Latif et al. 2009

The North Atlantic Oscillation (NAO)NAO-related SAT pattern (°C), +1σ

The NAO can affect Labrador Sea convection

The NAOI spectrum is almost white, but there is multidecadal variability

MOC may respond to the multidecadal changes

Forced ocean model MOC and Northern Hemisphere temperature

ORCA (0.5°) forced by “observations”, courtesy F. Alvarez and A. Biastoch

MOC may have contributed to the accelerated NH warming in the recent decades

MOC since 1950 in different analyses

The analyses are all over the place

Jin Ba, IFM-GEOMAR

Initialized forecasts for the next decades are highly uncertain

Outline1. Some general remarks2. Inter-annual predictability3. Decadal predictability4. Limitations

Climate models suffer from large biases

Errors can amount to several degrees in certain regions

IPCC 2007

We lack understanding of the mechanisms underlying decadal variability

There is a large spread in the model results, which was expected given the large biases. Convection sites, for instance, are misplaced in several models.

NAO tends to lead MOC

MOC tends to lead SST

Do we understand abrupt climate change?

Summary•A predictability potential exists at inter-annual and decadal time scales•Inter-annual predictability is restricted mostly to the Tropics, decadal predictability to mid and high latitudes•Inter-annual prediction is much more advanced•This is mostly due to a suitable observing system•The (inter-annual) skill, however, is mostly limited to the Tropics•Decadal predictability seems to exist mostly in the mid and high latitudes•It is likely related to variations of the AMOC (in the Atlantic)•We are, however, strongly limited by the lack of data and our understanding of the physical mechanisms, and by rather large model biases

Thank you for your attention