Thursday, December 17, 2009

Weather Station Selection

The Russian Institute of Economic Analysis (IEA) claims that the Climate Research Unit (CRU) used only one in four available weather stations in Russia over the past fifty years (see here for the IEA report in Russian). CRU uses their selection of stations to generate their global surface trend. According to the president of the IEA, "The IEA authors calculated that the scale of actual warming for the Russian territory in 1877-1998 was probably exaggerated by 0.64°C." He claims that the stations selected by CRU are mostly urban, and that the rural Russian stations show no warming in the past fifty years.

Some climatologists appear to have suspected the Russian stations were being selected based upon their warming trends, and tried to publish academic papers on the subject back in 2004. Unfortunately for them, their papers were reviewed by the director of the very same institute they were criticizing. In this e-mail, we see Phil Jones, the director at that time, telling Michael Mann that he rejected the papers.

The station data we obtained from CRU via NCDC may be incomplete. The trend we obtained ourselves may contain an erroneous 0.64°C rise in Russia, which represents 12% of the world's land mass. We do not know how much pre-selection of stations has been done in other parts of the world. We see no evidence of such selection being performed upon US data.

The US data appears to be subjected to corrections instead of selections. For example, according to a NASA Paper, rural stations in the US show a cooling of −0.05°C from 1990 to 1999, but after NASA applies its correction, rural stations show a warming of 0.35°C. Most of this warming is due to what the authors call the "time of observation debiasing" correction. (We did our best to wade our way through this paper and all its corrections, if we have made a mistake, we welcome correction.)


  1. Thank you for all the work you do on this topic. I am really excited to have found your blog and website where you document your analysis.

    Strange thought...How come the corrections inevitably arrive at higher temperatures? Surely some correction somewhere found even lower temperatures than demonstrated by the raw data?

  2. I'm glad our work has provided satisfaction.

    IIt does appear that the majority of corrections are positive. In the case of the NASA corrections, they have three: one for urban heating, which is negative, and two others that are positive, but the three of them added together is positive.

    Why are they always positive? Well, I don't really know. All I can do is make a guess based upon my personal experience. When I plan an experiment, I find myself excited at the prospect of putting a theory of mine to the test. I think I'm right. So I do the experiment. The result is not what I expected. I look for errors. I repeat the experiment. I find some errors. Suppose I now get the result I expected. Do I keep looking for errors? No, I stop. I'm satisfied. But if I don't get the result I want, I keep working for the whole day. I might find more errors.

    In the case of global warming, most climatologists believe that the world is getting warmer. They are incredulous that anyone could doubt the truth of their belief. It's not something they question any more. If any measurement suggests that the world is not getting warmer, they believe firmly that the measurement to be wrong. They they look for errors. And they find errors. There are always errors when you first take a measurement. They keep looking until they get the answer they believe in.

    So, one possible explanation for the positive corrections is that the world is not getting warmer, and in order to adjust the data to match our belief in warming, the majority of corrections must be positive.