cc: Keith Briffa date: Tue, 14 Jun 2005 14:10:25 +0100 from: Gerard van der Schrier subject: fingerprinting to: Tim Osborn Hi Tim, Before leaving for the Netherlands, I wanted to have shown you some results of the fingerprinting work. It turns out to be a bit of a headache, I'm afraid. Following your suggestion, I use decadal averaged for the MOC/NAO and PDSI data. The amplitude of the MOC and the NAO-related signal is then estimated on the change in PDSI between consecutive decades. To get better statistics on the performance of the method, I used the trick to combine each decade with all other decades (rather than only the next in line). So the impact of MOC & NAO on the change in PDSI between e.g. decade 1700-1709 and e.g. decade 1810-1819 is then estimated. This gives 1250 different testcases. It seems that the percentage of getting the sign of the MOC right is about 50%...... Also other tests indicate that I'm not doing much better than guessing randomly. It works better for the NAO though. Tricks like regressing out the (known) NAO-signal or smoothing the response patterns (hoping to further reduce the noise) don't help much. I expected this to work better, so I may have to look at this again. There is a strong signal of the MOC on (summer) sea-ice concentration. But is mainly east of Greenland (and not near northern Scandinavia as I had hoped). Sea-ice has a strong impact on temperatures, so maybe we can use that link between terrestrial climate and MOC. Any ideas? [[[retracted 3 paragraphs: personal, family]]] I'll be back wednesday morning 22st June. Cheers, Gerard