Comments on: Age Models at Quelccaya and Kilimanjaro http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/ by Steve McIntyre Sat, 25 May 2013 16:04:22 +0000 hourly 1 http://wordpress.com/ By: Goodbye, Quelccaya Glacier, Hellow Hell | elcidharth http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/#comment-410390 Sat, 06 Apr 2013 21:16:39 +0000 http://www.climateaudit.org/?p=412#comment-410390 [...] 24, 2005 at 9:10 AM, filed under Proxies, Thompson and tagged kilimanjaro, quelccaya. Bookmark the permalink. Follow any comments here with the RSS feed for this post. Post a comment or leave a trackback: [...]

]]> By: Willis Eschenbach http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/#comment-39088 Wed, 30 Aug 2006 06:04:36 +0000 http://www.climateaudit.org/?p=412#comment-39088 Re 13, thanks, John. Now I just have to figure out how it relates to the other equation above …

w.

]]> By: John A http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/#comment-39087 Tue, 29 Aug 2006 17:03:24 +0000 http://www.climateaudit.org/?p=412#comment-39087 re #12

Fixed.

It’s just easier to read in LaTeX than trying to guess from text.

]]> By: Willis Eschenbach http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/#comment-39086 Tue, 29 Aug 2006 16:36:46 +0000 http://www.climateaudit.org/?p=412#comment-39086 Steve, I think there’s an error in the latex version of the formula in #9, the quantity in parentheses should be to the minus p, not to the p …

w.

]]> By: Steve McIntyre http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/#comment-39085 Tue, 29 Aug 2006 13:03:54 +0000 http://www.climateaudit.org/?p=412#comment-39085 #10. Yes, that graphic is fun. That was one of the first ones that I noticed in the Mann data set. I corresponded with Hans Erren about it in spring 2003. Hans Erren explained the odd pattern as due to aliasing from rounding. None of this is directly “observed” data. It has all been transformed through an age model to create an observation. At the left end, the layers are squished togethre so that the linear slope represents the inflation of the same measured thickness back to a calculated “accumulation”.

]]> By: Willis Eschenbach http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/#comment-39084 Tue, 29 Aug 2006 08:34:50 +0000 http://www.climateaudit.org/?p=412#comment-39084 Steve, you should appreciate this one. It’s the accumulation rates by year for the two cores at Quelccaya …

w.

]]> By: Willis Eschenbach http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/#comment-39083 Tue, 29 Aug 2006 08:28:13 +0000 http://www.climateaudit.org/?p=412#comment-39083 Further thoughts. In the Sajama info I found this:

If changes in ice thickness are ignored, the average accumulation rate a(ij) between the dated depth horizons zi and zj (where i, and j, are any two dated horizons) is given by:

Aij = {1/dt(ij)} * (Integral from zi to zj) (1 – z/H)^-p dz

A_{ij} = {\frac{1}{dt_{ij}} \int_{z_i}^{z_j} (1-{\frac{z}{H}})^{-p} dz

where H is the ice thickness, z is the ice-equivalent depth, p is a constant, and dt(ij) is the
number of years between zi and zj.

I’m too tired right now to do the math to see how that relates to your formula above.

w.

]]> By: Willis Eschenbach http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/#comment-39082 Tue, 29 Aug 2006 08:26:56 +0000 http://www.climateaudit.org/?p=412#comment-39082 Steve, just started looking at this … one possibility is that there are several values for “accumulation” “¢’‚¬? snow accumulation, ice equivalent accumulation, and water equivalent accumulation. For Huarascaran, Thompson gives accumulation figures of:

snow “¢’‚¬? 3.3m
ice equiv. “¢’‚¬? 1.4m
h2o equiv. “¢’‚¬? 1.3m

Unfortunately, neither your formula above nor the Quelccaya text file you link to above say what kind of accumulation they’re talking about … I suspect the desired figure is h2o equivalent, but Quelccaya doesn’t say what they’re using … OK, I found it, they do say it’s h20 equivalent.

I just looked up the Sajama core information. No accumulation information, but I did a Solver solution and got a value of 0.02 to match with their dates/depths … doesn’t make sense. Likely this is because the accumulation rates change over time, as described in TROPICAL GLACIER AND ICE CORE EVIDENCE OF CLIMATE CHANGE ON ANNUAL TO MILLENNIAL TIME SCALES.

Unfortunately, they do not give absolute accumulation rates for the various dates, just deviations in sigma from zero … I’ll have to read more to figure out why.

w.

]]> By: Steve McIntyre http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/#comment-39081 Tue, 29 Aug 2006 04:33:08 +0000 http://www.climateaudit.org/?p=412#comment-39081 Bump.

]]> By: beng http://climateaudit.org/2005/10/24/age-models-at-quelccaya-and-kilimanjaro/#comment-39080 Wed, 26 Oct 2005 13:19:56 +0000 http://www.climateaudit.org/?p=412#comment-39080 And if Kilimanjaro is much younger than touted, then it’s prb’ly quite transient, geologically, and any time that it’s growing, or melting & close to disappearing or even gone, won’t necessarily be “unusual”.

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