Tag Archives: kaufman

Overpeck’s Enigmatic Tuq(?)

In fairness to Kaufman, he and his students actually did useful field work. Elsewhere I’ve noted that their MSc theses contain many helpful details on the Alaskan lakes. The situation is entirely different with the Greenland lakes, where Jonathan Overpeck was the point man for the ARCUS2k lake project collection. Kaufman et al 2009 contains […]

Kaufman's "Classical" Log Regression

I observed yesterday that I had been unable to replicate the archived version of Kaufman’s Hallet Lake series – something that I thought was due to a change in the archived version (since the NCDC archive noted that a new version had been archived in Nov 2008.) This turns out not to be what happened. […]

Five Alaskan BSi Series

At the second meeting of Kaufman’s PIs, one of the scientists plaintively asked: But shouldn’t we aim to do a synthesis that is only lake seds (at least as first step)? This logical building block was pushed aside (thereby allowing Briffa’s Yamal series to be recycled for the nth time) on the following grounds: some […]

Kaufman's BSi Selection

Below is a plot comparing sediment BSi (biological silica) to depth (cm) from two of Kaufman’s lakes (done by different students). I’ve shown it by depth (rather than ascribed age) since the dating of these sediment series is not without some hairiness. I’ve shown equal lengths for each lake, both covering at least 800AD-present on […]

Is Kaufman 'Robust'?

A common meme in Team-world these days is that any issues or errors are minor and that none of them “matter”. As we peel back the layers of Kaufman et al, this is the first line of Team defence. The rhetorical impact of Team reconstructions largely derives from the modern-medieval differential: is it in the […]

Invalid Calibration in Kaufman 2009

Darrell S. Kaufman, David P. Schneider, Nicholas P. McKay, Caspar M. Ammann, Raymond S. Bradley, Keith R. Briffa, Gifford H. Miller, Bette L. Otto-Bliesner, Jonthan T. Overpeck, and Bo M. Vinther (Science 9/4/2009) propose a reconstruction of Arctic summer land temperatures for the last 2000 years, using 23 diverse proxies. Decadal averages of each proxy […]

The Kaufman Backstory

The backstory to the development of the Kaufman et al 2009 reconstruction is pretty interesting. A few years ago (after the MM criticisms of paleoclimate reconstructions), the US National Science Foundation sponsored the sampling of 30 Arctic lakes in a standardized way. It’s remarkable to compare the original population to the data sets used in […]

Kaufman et al: Obstructed by Thompson and Jacoby

A CA reader sent me an email, noting the following entry in minutes of a meeting. M Loso inquired about Lonnie Thompson’s ice core data. These data are not presently available but will be investigated by Caspar. This comment is minuted in a meeting of PIs leading up to Kaufman et al 2009 – a […]

Kaufman's Stick: Iceberg Lake Varves

In the first post on Kaufman et al, I observed that, like other Team multiproxy studies, its HS-ness is contributed by only a few series. As shown below, a composite of 19 out of 23 Kaufman proxies does not yield an “unprecedented” late 20th century (tho it yields an elevated late 20th century.) A composite […]

Kaufman and Upside-Down Mann

Kaufman et al (2009), published at 2 pm today, is a multiproxy study involving the following regular Team authors: Bradley, Briffa (the AR4 millennial reconstruction lead author), Overpeck, Caspar Ammann, David Schneider (of Steig et al 2009), Bradley as well as Otto-Bleisner (Ammann’s supervisor and conflicted NAS Panel member) and “JOPL-SI authors” who are various […]

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