Comments on: Noise in Multiproxy Studies

By: TCO

TCO — Mon, 26 Sep 2005 21:10:19 +0000

1 is moberg? Isn’t that the one that shows the most variation, least stickishness?

P.s. Where is the comment from someone else’s blog about “mann, you lose” because of him refusing to divulge his algorithm?

By: TCO

TCO — Mon, 26 Sep 2005 20:31:37 +0000

well…if I buy some of your blabla about autocorrelation and ARMA and such, shouldn’t that explain some of the failure of the high freq comparisons? Maybe looking at low freq is a way to deal with that effect (of course if significance is lowered thereby, need to square up on that). Are you trying to have it both ways?

By: Steve McIntyre

Steve McIntyre — Mon, 26 Sep 2005 20:29:00 +0000

The whole multiproxy project, from at least Hughes and Diaz 1994 and Bradley and Jones 1993, has been that they can achieve “high-resolution” results. That’s how they sold tree rings in the first place.

If there is no high-frequency relation between the “proxies” and temperature, then you’re into very precarious calibration for low frequency. You might have as few as 3 degrees of freedom for decadal averages.

By: TCO

TCO — Mon, 26 Sep 2005 20:21:34 +0000

He looked at the match of overall trends (proxy to instrument) versus the year to year matching? Low freq versus high freq?

Regardless, what would one get from doing it my way?

By: Steve McIntyre

Steve McIntyre — Mon, 26 Sep 2005 20:14:03 +0000

No, what MBH did was to look for the series that had a trend in the 20th century and assign them big weights. I’ve drafted a note showing how this ties into a multiple regression of a series with 79 measurements on 22-112 predictors i.e. you can achieve a representation, but no confidence.

By: TCO

TCO — Mon, 26 Sep 2005 20:08:50 +0000

What do you get if you consolidate them (either brute force or the independant parts) and then do some exercise to look at how well they correlate to instrumented changes during the iunstrumented period and then based on the efficacy of that relationship extrapolate backwards what happend during pre-instrument days?

Oh..wait…that’s what MBH did. It sounds pretty logical when you phrase it that way…

By: Steve McIntyre

Steve McIntyre — Mon, 26 Sep 2005 19:31:42 +0000

The blue reflect the square root of the number of series. Jones decreases to only 3 series as you go back. So with only 3 series, for the variance in the mean of 3 series is bigger than the variance in the mean of say 10 series. The other data sets tend to have the same number of series (Mann is stepwise, but I’ve kept the proxy set frozen )

By: TCO

TCO — Mon, 26 Sep 2005 18:40:24 +0000

1. Dat somebedy were?

2. Why do blue envelopes in these series not open up as you go back, as in Jones?

3. Why the level set not at 1.96 (same as Jones)?

By: Steve McIntyre

Steve McIntyre — Mon, 26 Sep 2005 14:32:46 +0000

Re #1. No. The MBH99 data here are the 14 proxies used in the MWP reconstruction carried through. I shuold have made that clear (I’m editing now).

By: Dave Dardinger

Dave Dardinger — Mon, 26 Sep 2005 14:30:06 +0000

Well, I don’t know about the rest but surely #4 is MBH99. The Hockey Stick is obvious a mile away.