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Roy Spencer On Satellite v Surface Temperature Data

August 30, 2015

By Paul Homewood  


With the ever increasing divergence of surface temperatures from satellite ones, it is worth republishing this post from Roy Spencer last October:


Why 2014 Won’t Be the Warmest Year on Record


October 21st, 2014 by Roy W. Spencer, Ph. D.


Much is being made of the “global” surface thermometer data, which three-quarters the way through 2014 is now suggesting the global average this year will be the warmest in the modern instrumental record.

I claim 2014 won’t be the warmest global-average year on record.

..if for no other reason than this: thermometers cannot measure global averages — only satellites can. The satellite instruments measure nearly every cubic kilometer – hell, every cubic inch — of the lower atmosphere on a daily basis. You can travel hundreds if not thousands of kilometers without finding a thermometer nearby.

(And even if 2014 or 2015 turns out to be the warmest, this is not a cause for concern…more about that later).

The two main research groups tracking global lower-tropospheric temperatures (our UAH group, and the Remote Sensing Systems [RSS] group) show 2014 lagging significantly behind 2010 and especially 1998:



With only 3 months left in the year, there is no realistic way for 2014 to set a record in the satellite data.


Granted, the satellites are less good at sampling right near the poles, but compared to the very sparse data from the thermometer network we are in fat city coverage-wise with the satellite data.

In my opinion, though, a bigger problem than the spotty sampling of the thermometer data is the endless adjustment game applied to the thermometer data. The thermometer network is made up of a patchwork of non-research quality instruments that were never made to monitor long-term temperature changes to tenths or hundredths of a degree, and the huge data voids around the world are either ignored or in-filled with fictitious data.

Furthermore, land-based thermometers are placed where people live, and people build stuff, often replacing cooling vegetation with manmade structures that cause an artificial warming (urban heat island, UHI) effect right around the thermometer. The data adjustment processes in place cannot reliably remove the UHI effect because it can’t be distinguished from real global warming.

Satellite microwave radiometers, however, are equipped with laboratory-calibrated platinum resistance thermometers, which have demonstrated stability to thousandths of a degree over many years, and which are used to continuously calibrate the satellite instruments once every 8 seconds. The satellite measurements still have residual calibration effects that must be adjusted for, but these are usually on the order of hundredths of a degree, rather than tenths or whole degrees in the case of ground-based thermometers.

And, it is of continuing amusement to us that the global warming skeptic community now tracks the RSS satellite product rather than our UAH dataset. RSS was originally supposed to provide a quality check on our product (a worthy and necessary goal) and was heralded by the global warming alarmist community. But since RSS shows a slight cooling trend since the 1998 super El Nino, and the UAH dataset doesn’t, it is more referenced by the skeptic community now. Too funny.

In the meantime, the alarmists will continue to use the outdated, spotty, and heavily-massaged thermometer data to support their case. For a group that trumpets the high-tech climate modeling effort used to guide energy policy — models which have failed to forecast (or even hindcast!) the lack of warming in recent years — they sure do cling bitterly to whatever will support their case.

As British economist Ronald Coase once said, “If you torture the data long enough, it will confess to anything.”

So, why are the surface thermometer data used to the exclusion of our best technology — satellites — when tracking global temperatures? Because they better support the narrative of a dangerously warming planet.

Except, as the public can tell, the changes in global temperature aren’t even on their radar screen (sorry for the metaphor).



Roy’s point about adjustments made to the thermometer data is readily borne out by a comparison of HADCRUT3 and HADCRUT4. The latter was introduced in 2012, but the Hadley Centre still produced data for HADCRUT3 until May 2014. Using Woodfortrees, we can compare trends up to the end of 2013.




On the older version, the trend was effectively flat, 0.03C/C, but this has now increased to 0.49C/C on HADCRUT4.

On HADCRUT3, 1998 still remains the hottest year, at least until May 2014, when it was discontinued. On the new version, it has been relegated to 4th place.



Finally, it is worth remembering what the Met Office had to say in October 2013:




“Changes in temperature observed in surface data records are corroborated by records of temperatures in the troposphere recorded by satellites”

  1. August 30, 2015 3:54 pm

    Thanks to Dr. Roy W. Spencer and a few other brave souls, the modern-day Wizard of Oz may be unmasked before the complete demise of We the People.

  2. August 30, 2015 4:01 pm

    Reblogged this on WeatherAction News.

  3. August 30, 2015 4:42 pm

    Reblogged this on Climatism and commented:
    Satellite temperature data was all the rage in the nineties, when it was warming. Now it’s scoffed at.

  4. August 30, 2015 6:58 pm

    Thanks, Paul.
    There is no way we are going to keep looking at homogenized thermometers when we have satellites.

  5. John F. Hultquist permalink
    August 30, 2015 7:06 pm


    C° per Century

  6. Bruce of Newcastle permalink
    August 30, 2015 9:55 pm

    Related to Dr Spencer’s analysis is this useful site from RSS.

    RSS – MSU Data Images – Monthly

    Using it you can visually check the claims. For example when NOAA recently claimed that July was the hottest month ever I looked at this pair of images:

    July 1998
    July 2015

    Even by eye you can see that July 1998 was significantly warmer than July 2015. The difference of course is the AMSU data is global and unbiased by the location of thermometers at airports etc.

  7. September 8, 2015 1:47 pm

    Reblogged this on Climate Collections.


  1. 2016 allegedly ‘hottest year’ by immeasurable 1/100 of a degree – Iowa Climate Science Education

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