06 October, 2006

Worship the awesome geo-nerd!

So says Kevin Vranes over at No Se Nada (OK, so I paraphrase a little...). Anyway, welcome to those who have got here from there - the highlights of my last year's ramblings are handily summarised here.

If you haven't, go and read his account of an interesting new paper by Latif et al., which tries to estimate the amount of multidecadal variability in the meridional overturning circulation (MOC). This is poorly known, which makes interpreting the results of Bryden et al.'s Nature paper rather difficult (Kevin's just reposted his take on this, which is similar to mine).

Their estimate is indirect: they've taken the fact that in climate models changes in the MOC are expressed as specific changes in sea surface temperature (SST) patterns, looked for this signal in actual SST records, and used that to estimate that the strength of the MOC might vary by 1.5–3 Sv (106 m3/s) over multi-decadal timescales. For reference, the reduction estimated by Bryden et al. was about 8 +/- 6 Sv.

What I'm still waiting for is the results from the moorings Harry Bryden deployed in 2004, which have been recording real-time data on the short-term (annual, monthly, daily?) variability of the MOC. As I commented over at No Se Nada, I've heard rumours that they've found some and it's significant; I'll revisit the issue when this paper is published (thanks to Steve Bloom for knowing his way around the NOC webpages better than me).

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