Posts Tagged ‘hockey stick’

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Super-simple hockey stick explanation.

January 31, 2010

I have been reading over the blog posts of Steve McIntryre and Jeff Id and others about the nuances of various constructions of the hockey stick.  I’ve been examining the archived Mann08 data at the NCDC.  This is my attempt to boil down hockey stick construction to its bare-bones, expressed as five essential steps:

Step 1. Gather time series.
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Step 2. Select those time series that fit the instrumental (measured) temperature record of choice. Assume that since these time series match the instrumental temperature record in some way, then they are, in fact, temperature proxies.
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Step 3. Combine the chosen proxies in some fashion and note, not surprisingly, that the combined proxies match the temperature record (duh!).
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Step 4. Call this thing made from the combined proxies your temperature reconstruction, and therefore assume that the combined proxies are also a match for the temperature that occurred prior to the temperature measurement records.
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Step 5.  Note that the reconstruction shows that the temperature prior to the instrumental data is relatively flat.  Make the important conclusion that the temperature prior to the instrumental record changed very little.

Defenders of hockey stick constructions will point out my naïvety with an endless list of nuances and subtleties involved in each of these steps.  But keep your eye on the puck.  The following picture illustrates the difference between my simple steps and their more nuanced approaches…

It’s important to examine those details and nuances at some time and place.  But sometimes they are simply a smokescreen.  Keep your eye on the hockey puck.

Coming soon to ClimateSanity: the Amazing Multiplying Proxies.

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Mann’s 1209 temperature proxies

January 21, 2010

I believe that data used temperature reconstructions, which are in turn used to push for re-structuring the economy of the world, should be easily accessible to everybody.

You can view the plots of all 1,209 proxies used by Michael Mann for his 2008 hockey stick temperature reconstruction joined together into one giant image. Amazingly, the images are relatively small (less than one megabyte) and will download quite quickly. The proxies are arranged in alphabetical order, right to left and up to down.

Steve McIntyre, Jeff Id, and others have done a vast amount of work analyzing how Mann, et. al., used this data in hockey stick construction.  I am just starting to look at it in my own ignorant fashion, and expect to have a lot a fun

1000AD to 2000AD

Click on the graph at the left to see the 1209 proxies from which Michael Mann created his 2008 hockey stick.  This graph plots the data from 1000AD to 2000AD.  Note that most of these proxies cover only part of that year range.  There are some proxies that extend back further that 1000AD, but the pre 1000AD portion of the data has been truncated in these plots.

1500AD to 2000AD

Click on the graph on the left to see plots the data from 1500AD to 2000AD.  This shows the last 500 year a little closer up.

Download data

If you see a proxy of particular interest, note the name at the top of the graph.  Then go here to download the corresponding text file.  The file is tab delimited and will open nicely  in any spreadsheet.  The first column is the year, the second column is the proxy value.

Banners

Finally, you can get banner type versions of the graphical data.   The following banners are each 3 feet by 6 feet, each showing half of the proxy data (1000AD to 2000AD).   These versions will print out on a large format printer at Fedex-Kinko’s stores for about $14 each.  They  might make interesting conversation pieces in the classroom or office.  Left click on the links to see the banners, right-click on the links to download the files (only about 300 kilobytes each).

Part 1

Part 2

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Mohib Ebrahim’s Climategate poster at NREL

December 31, 2009

I downloaded the large version of Mohib Ebrahim’s very nicely made climategate timeline from Jo Nova’s blog.  The local FedEx Kinko’s copy store printed out the 8 foot by 3 foot work of art in black and white for a mere $17.   This poster is now hanging on the wall of my office cubicle at the National Renewable Energy Laboratory.  It will be interesting to see how this goes over with my colleagues.  Here is a picture of the poster….

The cheapest way that I could find to make a color version in the US is to print out the 18 page version (825 kBytes, courtesy of Jo Nova and Mohib Ebrahim) on 11″ x 17″ paper at about $2 a page, then paste them together.   If money is no object, you can print out the 8 foot by 3 foot color version on a single sheet for about $180.

By the way, does anybody have more information about Mohib Ebrahim?  He deserves a lot of publicity for this timeline.

Click on this image to get to Jo Nova's site and links to several different versions of the timeline.