[Stephen Wilde]

Not sure how seriously to take this.

Any opinions ?

http://www.jennifermarohasy.com/blog...es/003303.html

[andykn]

A very brief look; it seem that "base period bias" is an invention of the poster; both people whose work has been misused have stated this lower down.

[Stephen Wilde]

I was hoping for an independent viewpoint from a statistician.

The comments on the link seem to be pretty varied but not conclusive either way.

The question is whether the 'step up' in the charts which has concerned you and I for so long could really be a statistical artifact. I really don't know and at this point I don't think you can be entirely sure either.

[Stephen Wilde]

As I interpret it the choice of base period is such that the effect of the two positive spells and one negative spell of ENSO during the 20th Century are causing the upward progression of the temperature line. Two spells of positive are bound to outweigh one spell of negative and the length of each episode will also be a factor.

Mr. Tisdale seems to have adjusted it by removing the ENSO signal which appears to leave the temperature line pretty much flat.

If there had been a CO2 background influence masked by the ENSO signal then the line should still have been upwards albeit less so.

Provided Mr. Tisdale's exercise is accurate then there would seem to be no CO2 warming signal.

Of course I have no idea whether his adjustment is correct but no doubt others will be looking into it.

[nickbat]

I agree with your logic, Stephen. As you say, others will no doubt be looking into it.

[andykn]

Originally Posted by Stephen Wilde

As I interpret it the choice of base period is such that the effect of the two positive spells and one negative spell of ENSO during the 20th Century are causing the upward progression of the temperature line. Two spells of positive are bound to outweigh one spell of negative and the length of each episode will also be a factor.

Mr. Tisdale seems to have adjusted it by removing the ENSO signal which appears to leave the temperature line pretty much flat.

If there had been a CO2 background influence masked by the ENSO signal then the line should still have been upwards albeit less so.

Provided Mr. Tisdale's exercise is accurate then there would seem to be no CO2 warming signal.

Of course I have no idea whether his adjustment is correct but no doubt others will be looking into it.

It looks like you've posted the work of another blogger who does not understand science at all.

Rather than try and explain myself I'll quote the author of the graphs used (my emphasis):

"Paul: It appears I should comment since my name and graphs are being used as reference. Temperatures over the term of the instrument temperature record have risen. I'm confused as to why Cohenite doesn't like the use of a reference temperature to calculate anomaly, because the same curves result when absolute temperatures are examined.

The following graphs are from my series on "NCDC Absolute Temperature."
http://bobtisdale.blogspot.com/2008/...mperature.html
http://bobtisdale.blogspot.com/2008/...e-part-ii.html
http://bobtisdale.blogspot.com/2008/...te-part-3.html

Absolute Land, Ocean, and Land+Ocean Surface Temperatures:
http://i29.tinypic.com/iozy2h.jpg

Annual Maximum, Minimum and Average Land+Ocean Surface Temperatures:
http://i29.tinypic.com/10f2rr9.jpg

The graph of average Land+Ocean Surface Temperatures has the same shape as an anomaly curve. The difference is that the absolute data hasn't been shifted by a reference temperature. That's all anomaly data is, data that's been shifted by a reference temperature.
http://i25.tinypic.com/2igbzgl.jpg

Now for the discussion of the PDO: I don't understand how the data sets and graphs I created for a discussion on "Annual and Long-Term Effects of El Nino/Southern Oscillation" have now become my work on the PDO. Refer to Figures 1 through 3 in the following.
http://bobtisdale.blogspot.com/2008/...cts-of-el.html
I don't believe I used those graphs in another post.

Additionally, my most recent post on the PDO, "The Common Misunderstanding About the PDO", was intended to illustrate that the PDO is a function of ENSO. It is not a simple residual like the AMO.
http://bobtisdale.blogspot.com/2008/...about-pdo.html

Sorry if I'm somehow responsible for the confusion.

Regards.

Posted by: Bob Tisdale at August 6, 2008 03:08 AM"