Arctic predictability

After attending a recent workshop on Arctic predictability, I thought a brief discussion on sea-ice variability and potential predictability might be of interest.

The simplest measure of predictability on multi-annual timescales is “potential predictability” (PP), which is the ratio of the standard deviation in decadal means to the standard deviation of annual means. This is essentially a crude measure of the fraction of the variability which has a decadal timescale and is therefore potentially predictable.

Below is the PP for Arctic sea-ice and SSTs (below the ice) in two different GCMs (HadCM3 and Bergen CM) and shows that there is considerable decadal variability in sea-ice extent in both models. Interestingly, often this variability is found co-incident with decadal variability in SSTs under the sea-ice, suggesting that the underlying SSTs are responsible. This provides some evidence that decadal variability in sea-ice might be predictable.

Potential predictability in HadCM3
Potential predictability of Arctic sea-ice concentration and SSTs in HadCM3
Potential predictability in the BCM
Potential predictability of Arctic sea-ice and SSTs in the Bergen Climate Model

About Ed Hawkins

Climate scientist in the National Centre for Atmospheric Science (NCAS) at the University of Reading. IPCC AR5 Contributing Author. Can be found on twitter too: @ed_hawkins

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