Climate Audit

Date: 16 Nov 1999, Phil

I’ve just completed Mike’s Nature trick of adding in the real temps
to each series for the last 20 years (ie from 1981 onwards) amd from
1961 for Keith’s to hide the decline.

Date: 22 Dec 2004, mike

No researchers in this field have ever, to our knowledge, “grafted the thermometer record onto” any reconstruction. It is somewhat disappointing to find this specious claim (which we usually find originating from industry-funded climate disinformation websites) appearing in this forum. Most proxy reconstructions end somewhere around 1980, for the reasons discussed above. Often, as in the comparisons we show on this site, the instrumental record (which extends to present) is shown along with the reconstructions, and clearly distinguished from them (e.g. highlighted in red as here).

Date: 21 Nov 2005, Steve

The MBH versions illustrated also splice reconstruction and instrumental values. Thus, Crowley made two different splices of the temperature record into the proxy record. One splice is made in 1965, with proxy values for the 13-site composite (see below) before 1965 and instrumental values from 1965 to 1998 (with the 11-point smooth version ending in 1993). A second version is spliced in 1870, with proxy values from the 13-site composite before 1870 and instrumental records after wards.

Date: 6 May 2009, UC

Let’s see; I think this is made by padding with zeros, but 1981-1998 instrumental is grafted onto reconstruction:

(larger image here )

I used Mann’s lowpass.m , modified to pad with zeros instead of mean of the data,

out=lowpass0(data,1/40,0,0);

Original CA link

Backup

Date: 20 Nov 2009, UC

“I’ve just completed Mike’s Nature trick of adding in the real temps
to each series for the last 20 years (ie from 1981 onwards) amd from
1961 for Keith’s to hide the decline”

Is this about the MBH99 smooth ?

http://www.climateaudit.org/?p=1553#comment-340175

http://www.climateaudit.org/?p=1553#comment-340207

Date: 20 Nov 2009, gavin

[Response: This has nothing to do with Mann’s Nature article. The 50-year smooth in figure 5b is only of the reconstruction, not the instrumental data. – gavin]

Date: 21 Nov 2009, gavin

And it remains unclear why this was described as Mann’s Nature trick since no such effect is seen in Mike’s paper in any case. – gavin]

Date: 22 Nov 2009, mike

In some earlier work though (Mann et al, 1999), the boundary condition for the smoothed curve (at 1980) was determined by padding with the mean of the subsequent data (taken from the instrumental record).

Date: 24 Nov 2009, CRU

To produce temperature series that were completely up-to-date (i.e. through to 1999) it was necessary to combine the temperature reconstructions with the instrumental record, because the temperature reconstructions from proxy data ended many years earlier whereas the instrumental record is updated every month. The use of the word “trick” was not intended to imply any deception.

Date: 25 Nov 2009, Jean S

UC has corrected me on the fact that adding the instrumental series to the proxy data prior smoothing was used already in MBH98 (Figure 5b), so, unlike I claimed in #66, “Mike’s Nature trick” is NOT a misnomer.

Date: 25 Nov 2009, UC

..and here’s instrumental (81-95)+zero padded Fig 5b smooth (red):

Original CA link

Backup

Date: 1 Apr 2010, UC

April Fools, here’s the turn-key(*) code

(*) after you download the two files , http://www.climateaudit.info/wp-content/uploads/2009/11/mbhsmooths1.txt and http://uc00.files.wordpress.com/2010/05/mbh985b.png

Date: Aug 29 2014, Jean S

nails it,

MBH98 has 50-year smoothing with padding of 1981-1995 instrumental. Additionally, the smoothing is cut back 25 samples (half of the “filter length”) from both ends. MBH99 used 40-year filtering with 1981-1997 (not 1998!) instrumental padding. The smooth is cut back 20 samples from the end but not from the beginning.