Search Results for: Marcott

Gergis and Law Dome

In today’s post, I’m going to examine Gergis’ dubious screening out of the Law Dome d18O series, a series that has been of long-standing interest at Climate Audit (tag). Gergis et al 2016 stated that they screened proxies according to significance of the correlation to local gridcell temperature. Law Dome d18O not only had a significant […]

The “Blade” of Ocean2K

I’ve had a longstanding interest in high-resolution ocean proxies (with posts as early as 2005 – see Ocean Sediment tag) and had already written detailed reviews of many of the individual high-resolution series used in Ocean2K (e.g. here here here here here here). In these prior discussions, the divergence between the 20th century proxy data and 20th century instrumental […]

Important New North American East Coast Proxy Data

One of my long-standing interests is the location of ocean sediment series that enable apples-to-apples comparison of the 20th century to the mid-Holocene.   These are not nearly as common as one would think.   Ocean sediment series covering the Holocene typically stop prior to the 20th century due to core recovery problems and, on […]

SH Proxies: Peru d18O

One of the hidden assumptions of proxy reconstructions, as carried out by IPCC authors, is that each “proxy” has a linear relationship to temperature plus relatively low-order red noise. Under such circumstances, the noise will cancel out in a linear combination of proxies (reconstruction) and a “signal” will emerge. However, I’ve never seen any author […]

Rosenthal et al 2013

There has been considerable recent attention to Rosenthal et al 2013 (pdfpdf SI) :WUWT here, Judy Curry here, Andy Revkin here. The article itself presents a Holocene temperature reconstruction that is very much at odds both with Marcott et al 2013 and Mann et al 2008. And, only a few weeks after IPCC expressed great confidence in […]

The Impact of TN05-17

TN05-17 is by far the most influential Southern Hemisphere core in Marcott et al 2013- it’s Marcott’s YAD061, so to speak. Its influence is much enhanced by the interaction of short-segment centering in the mid-Holocene and non-robustness in the modern period. Marcott’s SHX reconstruction becomes worthless well before the 20th century, a point that they […]

Alkenone Divergence offshore Iceland

The longest very high-resolution alkenone core that I’m aware of is Sicre et al’s MD99-2275 (plus splices) from offshore Iceland (67N 18W). It is 4550 years long, its most recent value is 2001AD and its resolution is 4 years. Marcott used nearby core JR51GC-35 (also at 67N 18W), also an alkenone record, which had a […]

Alkenone Divergence in Peru

Gutierrez et al (GRL 2011) pdf here; data here is another very high resolution alkenone series that is well-dated in the 20th century. It was taken in an upwelling zone offshore Peru at a similar latitude to Quelccaya. Like the high-resolution series offshore Morocco and Namibia, it shows a sharp decline in alkenone-estimated SST in […]

Alkenone Divergence

While there are disappointingly few high-resolution alkenone ocean cores with 20th century resolution, there are a few. Given the importance of this class of proxy in Marcott et al, one would have thought the performance of high-resolution alkenones in the 20th century would have been of interest to Marcott et al, but they were silent […]

The Quelccaya Update

Lonnie Thompson has done a much better job of archiving data for his recent update Quelccaya – see NOAA here – both in terms of information and promptness. Quelccaya is familiar territory for Thompson as it was the location of his first tropical ice cores (1983) and his first publication of this type. Thompson published […]