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Inter-annual to decadal climate prediction. Mojib Latif, Leibniz Institute of Marine Sciences at Kiel University . Outline. Some general remarks Inter-annual predictability Decadal predictability Limitations. The last three decades. annual global SAT.
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Inter-annual to decadal climate prediction Mojib Latif, Leibniz Institute of Marine Sciences at Kiel University
Outline Some general remarks Inter-annual predictability Decadal predictability Limitations
The last three decades annual global SAT
Uncertainties in climate change projections annual global SAT, derived from CMIP3 models internal variability scenario model Hawkins and Sutton 2009
Uncertainty due to internal variability increases at regional scales internal variability internal variability Hawkins and Sutton 2009 Unpredictable external factors enhance the uncertainty
Potential predictability at inter-annual and decadal time scales
Outline Some general remarks Inter-annual predictability Decadal predictability Limitations
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
Outline Some general remarks Inter-annual predictability Decadal predictability 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 Jin Ba, IFM-GEOMAR The analyses are all over the place
Initialized forecasts for the next decades are highly uncertain
Outline Some general remarks Inter-annual predictability Decadal predictability Limitations
Climate models suffer from large biases IPCC 2007 Errors can amount to several degrees in certain regions
We lack understanding of the mechanisms underlying decadal variability NAO tends to lead MOC MOC tends to lead SST 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.
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