inter-annual to decadal climate prediction mojib latif, leibniz institute of marine sciences at kiel...
TRANSCRIPT
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