Polar Urals “Grass Plot”

Here’s another look at Polar Urals using a “grass plot” showing cumulative ring width for individual trees against time. The trees plotted in black are from the original archive (russ021) and the ones plotted in red are form the 1998 update (russ176). This gives a little different viewpoint on variance stabilization issues. First, one of the resaons for the change in the update is simply the addition of several very large medieval trees – remember that Shiyatov said that the medieval period was especially favorable. Also you see the much increased relication in the eleventh century where I’ve argued that Briffa et al 1995 misdated 3 cores – and that their “cold” 11th century was an artifact of incorrect crossdating.


5 Comments

  1. John A
    Posted Feb 23, 2006 at 8:16 AM | Permalink

    Hold on a second…

    How many trees are involved in the original series for the year 1032?

    Two, would you say?

    Is the "coldest year of the Millenium" based on the ring widths of two trees?

  2. Steve McIntyre
    Posted Feb 23, 2006 at 8:54 AM | Permalink

    John A – look back at my posts on Polar Urals last May or so. Category Jones et al. It was actually only 3 trees – but 2 of them are almost certainly misdated. I’ll have to re-visit the dating in light of the updated info.

  3. beng
    Posted Feb 23, 2006 at 9:37 AM | Permalink

    This is a Polar Ural series — Russia. Of course it could be an artefact of lack of sample #s, selection, etc, but there are “events” ~1000 BP & ~500 BP.

    Now look at the Sargasso Sea proxy from an earlier J. Daly reference (scroll down):

    http://www.john-daly.com/hockey/hockey.htm

    Note similar “events” at the same periods. Looks to me like the same distinct signal between two widely separate NH sites. Interesting if the Polar Ural site tree-growth is mostly cold-limited…

  4. beng
    Posted Feb 23, 2006 at 12:44 PM | Permalink

    Sorry, OT, but after reading Daly’s page (again), and seeing these fairly distinct “pulses” occur worldwide in many various proxies, it dawned on me that the sun looks like it’s controlling the climate with ~500 yr periods and relatively abrupt peaks & declines (flickering in extremely slow-motion). How else could there be such distinct & closely synchronized global events, other than, say, massive volcanism or glacial melt?

    It couldn’t have been CO2, since that was static in the Holocene at the PC level of 280 ppm until recently. :)

  5. jae
    Posted Feb 24, 2006 at 10:55 AM | Permalink

    There is irrefutable proof that the sun causes climate changes. There is no clear proof that CO2 does–yet. The Hockey Stick Team sure has not demonstrated it, IMHO. The models can’t be verified or trusted. What is there to convince anyone that the warming, if there is indeed warming, is not caused by the sun, alone?

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