the Air Vent

Because the world needs another opinion

John Christy and Roy Spencer on UAH

Posted by Jeff Id on December 21, 2011

I have written often that the UAH dataset is the most accurate data available on the market.  Unfortunately its trend runs lower than other datasets excepting RSS in recent years.  This does not indicate that there are no problems with it but I do make that statement after a considerable amount of time examining the papers and documentation behind the data.  Unfortunately, the low trend makes it a  denier dataset in the eyes of the IPCC, a fact evident both in the AR documents as well as the disparaging comments in the climategate emails.  Please note, UAH has a statistically significant positive trend which is in agreement with AGW (or natural warming), just not with extreme AGW as presented by the models.

Anyway, Roy Spencer and Anthony Watts are carrying a post which replies to some of the often uninformed advocate critique of their data as well as where it differs from the AGW extremist message.   It is very much worth a read.   –JEFF


Addressing Criticisms of the UAH Temperature Dataset at 1/3 Century

December 21st, 2011

The UAH satellite-based global temperature dataset has reached 1/3 of a century in length, a milestone we marked with a press release in the last week (e.g. covered here).

As a result of that press release, a Capital Weather Gang blog post by Andrew Freedman was dutifully dispatched as damage control, since we had inconveniently noted the continuing disagreement between climate models used to predict global warming and the satellite observations.

What follows is a response by John Christy, who has been producing these datasets with me for the last 20 years:

Many of you are aware that as a matter of preference I do not use the blogosphere to report information about climate or to correct the considerable amount of misinformation that appears out there related to our work. My general rule is never to get in a fight with someone who owns an obnoxious website, because you are simply a tool of the gatekeeper at that point.

However, I thought I would do so here because a number of folks have requested an explanation about a blog post connected to the Washington Post that appeared on 20 Dec. Unfortunately, some of the issues are complicated, so the comments here will probably not satisfy those who want the details and I don’t have time to address all of its errors.

Click here for the rest.

12 Responses to “John Christy and Roy Spencer on UAH”

  1. kim said

    Yep, attribution.

  2. steveta_uk said

    In the Andrew Freeman article that Christy and Spencer are responding to is this:

    Santer, along with several coauthors, recently published a study in the Journal of Geophysical Research, Atmospheres that found there are many independent observations showing that temperatures at the surface and lower atmosphere are warming in a way that is consistent with expectations, although surface warming has outpaced atmospheric warming. The paper found the lower troposphere has warmed by 0.5 degrees C, or 0.9 degrees F, during the past 32 years.

    This is apparently proof that Christy and Spenser are completely wrong as they said

    “Globally averaged, Earth’s atmosphere has warmed about 0.45 Celsius (about 0.82° F) during the almost one-third of a century.”

    So exactly what is Freeman complaining about?

  3. AJStrata said


    But wait – there’s more! Went back to Climategate 1 code and guess what I found – what looks like nearly a decade of code ‘hiding the decline’ across a bunch of supposedly independent studies.

  4. Spen said

    Please will someone tell me what the range of errors is with all these quoted temperature anomalies. Are temperatures measured within an accuracy of 0.5 degC. If not how can we quote a figure of 0.65 or 0.45 etc?

  5. kim said

    Gad, AJ, I leap to the same conclusion that you do. What could be an innocent explanation for that stuff you’ve found?

  6. kim said

    Show it to Steve.

  7. AJStrata said


    Were you asking me to show it to McIntyre?


  8. kim said


  9. kim said

    If this is from CG1, how come no one’s spotted it sooner?

  10. AJStrata said

    I missed it too! It never occurred to be to search for ‘decline’ in the code and then cross check file dates.

  11. Jeff Id said


    This was covered in CG1 by a blogger whom I can’t remember. It doesn’t hurt to revisit it though.

  12. Mark F said

    AJ: Steve on CA long ago hosted an article with the code with the string of values to be added to the respective years’ data. I have been surprised that the topic hasn’t come up many times in the interim. Good work!

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