More on the UAH Change

I hope this won’t get too boring, but since the UAH is provides the best source of global temperature I find myself crunching the data in a variety of ways.  The readers of this site tend to get stuck with whatever it is I am working on.  🙂

My initial review of the data showed that on average the change lowered the value of the anomaly by month and the full review is linked here.

I use the UAH data for breaking down what is happening in the different regions of the world.  Since the polar regions are of particular interest I wanted to know what the impact of the new UAH data would show for those regions of the world.  I must admit that I am finding some really interesting things.  I have also found parts of the backlash against the adjustment as I expected to find.  Many of the warmist sites are dismissing the whole thing as a scam.  None of them have actually analyzed the data.  While I am not one to shy away from strong opinions, I prefer to base opinions on the data.

What is clear from my increasingly in depth review is that the shift is very much what would be expected from a simple shift in the baseline normal.  That shift did happen in the different regions of the world as well.  Since the North Pole region has experienced the most warming, it also saw the biggest change in the normal temperature.  The two versions of the data are shown here for the North Pole of the UAH data.

The Inconvenient Skeptic

The 20yr and 30yr data for the North Pole in comparison

Interestingly enough the shift resulted in an increased rate of warming by 0.0002 °C per year.  Once again that happened because each month received a different new average temperature.  The average drop in anomaly was larger for the North Pole than for the Earth as a whole at -0.364 °C.  June-September showed the least shift while December showed the most.  This is very much in line with what was seen for the Earth as a whole.

Far more interesting was what the South Pole showed.  According to the UAH data it has been cooling over the past 40 years.  If the past 10 years had been cooler than the previous 30 years, then the change should have actually made the average baseline temperature decrease which would increase the anomaly.  Not surprisingly that is exactly what happened.  The average monthly increase in the baseline was 0.041 °C.  This is more evidence that the South Pole continues to cool.  Not every month showed the cooling, but most did.  Here is the monthly breakdown of the change.

The Inconvenient Skeptic

The monthly shift in anomaly.

This causes some very interesting results for the anomaly data itself.  Many months are now warmer using the new 30 year average of the UAH data.  This is when the monthly data for the South Pole is shown.

The Inconvenient Skeptic

The monthly data for the South Pole shows that some months are warmer than before as most months in the South Pole have been cooling in the past 10 years.

This was a re-assuring find as it is what should be expected from the shift to a 30 year average.  It is clear that the adjustment is precisely what it is stated to be.

Finally I would like to show the results of the change to the temperature in the Tropics.  They are generally not very interesting and very tightly correlated to the ENSO.  In fact without the ENSO there would be almost no temperature variation year to year in the Tropics.  They are just that stable.  Unless there is another El Nino to match 1998 in the near future the trend will go neutral in the future and drop once it is in the early portion of the data.  Since the Tropics are so stable there was almost no change in the monthly baseline.  In fact 2 months showed no change in baseline and 1 month showed an increase in the average.  The change in the others was very small.  Anyone worried about warming in the Tropics is not paying attention to the data.  Without the 1998 El Nino there simply is no warming in the tropics.  The two versions of the UAH data are shown here for the Tropics.

The Inconvenient Skeptic

The Tropics show their typical temperature stability in both versions of the UAH data.

Overall there is little to be concerned about in the version change from 20 to 30 year average.  It does reduce anomaly data in the regions that have shown warming, but it also reduces the average in the times and places that are cooling.  The results are pretty clear that the change is exactly what it was stated to be.  Considering the difficulty in determining the change for sets like the GHCN or the GISS this is an easy one to work with.

This does not remove the fact that warmists will call foul on this, but they will on anyone who is skeptical of global warming.  I know I seen plenty of that first hand.  My review of the data sets does make me feel comfortable with the new data as I have not found any surprises.  I don’t know how much more I will spend comparing the data, but I will keep both sets handy for a while in case I do find something interesting.

Posted in Anomaly by inconvenientskeptic on January 12th, 2011 at 5:05 am.


This post has 6 comments

  1. Green Sand Jan 12th 2011

    Thanks, not boring, clears up any “confusion” that might be “raised” by the change. Just need them to get the channels fixed asap, not good having problems right now.

  2. The whole point of the switch is to use a similar baseline as GISS and the other surface based data sets, right?

    If we were to take one of those data sets and switch it to a 20-year baseline, would it not show more warming as well? That would pretty well show the alarmist side that their “argument” is flawed.

  3. inconvenientskeptic Jan 12th 2011

    There are valid reasons for the switch. Understanding the change is important. I am just making sure I understand it.

  4. T.G.Watkins Jan 12th 2011

    Hi John,
    I was under the impression that satellites do not cover beyond 82 degreesN and 70+ degrees S. which partly explains the difficulty in refuting Hansen’s 1200km grid guesses.
    I enjoy your blog and no doubt you will explain my confusion.

  5. inconvenientskeptic Jan 12th 2011


    The AMSU provides more coverage. RSS stops the analysis at 70S, the data is there for more. I am not sure why more extensive analysis is not done.

    Since the RSS stops at 70S and the UAH does not, the cooling in Antarctica is not picked up by the RSS, but is by the UAH.

    It is obscene that the stations project into those regions when the satellite data is available.

  6. Thank you for the interesting article.

    What strikes me as interesting is:

    Given Dr. Lindzen’s observations that Arctic average temperature has increased, but maximum and minimum temperatures have not changed (i.e. the shift is solely due to increased transition temperatures)

    Combined with your observation of tropic temperatures not changing.

    I wonder if in fact what is happening worldwide is similar to what is happening specifically in the Arctic – that is the transition temperatures are changing (for whatever reason) but the mins/maxs will remain the same.

    Note this isn’t Miskolczi per se – rather that the climate system has preferred ‘target’ temperatures for each season and the only shift is how quickly these targets are achieved.

    If true, this would be a very different proposition from either situation as normal or the sky is falling.

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