See also: RSS data: 2010 not the warmest year in satellite record, but a close second
Dec. 2010 UAH Global Temperature Update: +0.18 deg. C
By Dr. Roy Spencer, PhD.
NEW 30-YEAR BASE PERIOD IMPLEMENTED!
Sorry for yelling like that, but if you have been following our global tropospheric temperature updates every month, you will have to re-calibrate your brains because we have just switched from a 20 year base period (1979 – 1998) to a more traditional 30 year base period (1981-2010) like that NOAA uses for climate “normals”.
This change from a 20 to a 30 year base period has 2 main impacts:
1) because the most recent decade averaged somewhat warmer than the previous two decades, the anomaly values will be about 0.1 deg. C lower than they used to be. This does NOT affect the long-term trend of the data…it only reflects a change in the zero-level, which is somewhat arbitrary.
2) the 30-year average annual cycle shape will be somewhat different, and more representative of “normal” of the satellite record than with 20 years; as a result, the month-to-month changes in the anomalies might be slightly less “erratic” in appearance. (Some enterprising person should check into that with the old versus new anomaly datasets).
Note that the tropics continue to cool as a result of the La Nina still in progress, and the Northern Hemisphere also cooled in December, more consistent with the anecdotal evidence. 
I will provide a global sea surface temperature update later today.
YR MON GLOBE NH SH TROPICS
2010 1 0.542 0.675 0.410 0.635
2010 2 0.510 0.553 0.466 0.759
2010 3 0.554 0.665 0.443 0.721
2010 4 0.400 0.606 0.193 0.633
2010 5 0.454 0.642 0.265 0.706
2010 6 0.385 0.482 0.287 0.485
2010 7 0.419 0.558 0.280 0.370
2010 8 0.441 0.579 0.304 0.321
2010 9 0.477 0.410 0.545 0.237
2010 10 0.306 0.257 0.356 0.106
2010 11 0.273 0.372 0.173 -0.117
2010 12 0.180 0.213 0.147 -0.221
WHO WINS THE RACE FOR WARMEST YEAR?
As far as the race for warmest year goes, 1998 (+0.424 deg. C) barely edged out 2010 (+0.411 deg. C), but the difference (0.01 deg. C) is nowhere near statistically significant. So feel free to use or misuse those statistics to your heart’s content.
THE DISCOVER WEBSITE: NOAA-15 PROBLEMS STARTING IN MID-DECEMBER
For those tracking our daily updates of global temperatures at the Discover website, remember that only 2 “channels” can be trusted for comparing different years to each other, both being the only ones posted there from NASA’s Aqua satellite:
1) only ch. 5 data should be used for tracking tropospheric temperatures,
2) the global-average “sea surface” temperatures are from AMSR-E on Aqua, and should be accurate.
The rest of the channels come from the AMSU on the 12 year old NOAA-15 satellite, WHICH IS NOW EXPERIENCING LARGE AMOUNTS OF MISSING DATA AS OF AROUND DECEMBER 20, 2010. This is why some of you have noted exceptionally large temperature changes in late December. While we wait for NOAA to investigate, it seems like more than coincidence that the NOAA-15 AMSU status report had a December 17 notice that the AMSU scan motor position was being reported incorrectly due to a bit error.
The notice says that problem has been sporadic, but increasing over time as has the amount of missing data I have seen during my processing. At this early stage, I am guessing that the processing software cannot determine which direction the instrument is pointing when making its measurements, and so the data from the radiometer are not being processed.
The daily NOAA-15 AMSU imagery available at the Discover website shows that the data loss is much more in the Northern Hemisphere than the Southern Hemisphere, which suggests that the temperature of the instrument is probably involved in the bit error rate. But at this point, this is all my speculation, based upon my past experience studying how the temperature of these instruments vary throughout the orbit as the solar illumination of the spacecraft varies.
UPDATE from Dr. Spencer(1/3/10, 2:50 p.m. CDT): Graph fixed…it was missing Dec. 2010.
Thank you for posting the data sets, but it surprises me that it did not occur to you that these are monitored here constantly. What you must think of us, … shame.
@Honeycut
Sorry, the motives of some of the scientists you mention may be pure. But, Hansen has demonstrated that he has an agenda and if truth inconveniently interferes with his agenda, he will remake the truth to fit his agenda. He hasn’t been a scientist for a long time.
Rob Honeycutt 8:42:
“He had 100+ years of temperature reconstructions…..”
So he would have been making a fuss about global warming ten years earlier when he had 90+ years of data to go on. Right?
Rob Honeycutt says: January 4, 2011 at 4:41 pm
Rob, you do realize that the ‘adjustments’ Hansen makes are more than changing a baseline reference, he actually changes the data from the past, as well as adjusting current temperatures the wrong direction to compensate for UHI?!
http://i42.tinypic.com/vpx303.jpg
http://i42.tinypic.com/2luqma8.jpg
Putting Hansen in the same class of scientific integrity as Spencer and Cristy is a joke, I am not familiar enough with Santer’s work to make a relative assessment.
@Steve Keohane
You do realize that Spencer and Cristy defended their inaccurate satellite temp data for almost a decade before they were finally persuaded it was wrong and that the past data all had to be “adjusted” … don’t you?
mike g… Honestly, it doesn’t matter if Hansen is evil incarnate itself. If he is wrong, even if he manipulates the data all day long, then ultimately his results will be falsified. That is how the process works. Same goes for Spencer, Lindzen and others. Ultimately what matters is the BIG picture that results from all the work that ALL the scientists do collectively. Irrespective of any political bias, that is where the physical reality of this issue lay.
Steve Keohane… I think you should ask Dr Spencer if he is ever required to adjust his data. Go ask the folks at the CRU or RSS. As with anything, if you spot errors they have to be corrected.
David Ball says:
“Thank you for posting the data sets, but it surprises me that it did not occur to you that these are monitored here constantly. What you must think of us, … shame.”
Well then, if you are watching the data so closely you should be able to point to me the bias in Hansen’s data. I’m still not seeing it.
Steve Keohane says:
“Putting Hansen in the same class of scientific integrity as Spencer and Cristy is a joke.”
Again, every scientist is human. All humans have their biases. That is why the scientific process works. Whether you think that Spencer and Christy have more integrity or I think Hansen has more integrity does not matter. Physical processes do not care one wit about our who we like better.
The truth is not in our political inclinations. The truth will be in the collective data.
Werner Brozek says:
January 3, 2011 at 9:32 pm
Thank you, I don’t disagree with what you are saying and only used one data set because this thread is about that one. Of course it is 0.013c, just using 0.014c with reference to the post I replied too previously, so this person couldn’t mistake the value I was referring too.
Actually both these values are very likely to be lower because the warmth from the Pacific where El Nino originates is circulated towards the pole, eventually warming other ocean regions too.
Rob Honeycutt says:
January 4, 2011 at 2:04 pm
http://woodfortrees.org/plot/uah/from:1970/to:2011/plot/uah/from:1970/to:2011/trend/plot/rss/from:1970/to:2011/plot/hadcrut3vgl/from:1970/to:2011/offset:-0.15/plot/gistemp/from:1970/to:2011/offset:-0.23
Rob,
Look at that carefully, the GISS in the earlier period was often one of the coolest, over the last decade it is easily the warmest. The baseline has changed between the GISS and all the rest. The reason being is because it makes up more data only over the past decade compared with the rest. Especially the GISS has no control to compare with other decades, so the 2001-2010 decade was the warmest of the only data set that exists for that decade. Similar for Hadley too with changing data sources for different time periods, but it doesn’t show the errors as bad.
Matt G…
The only thing the baseline does is change the zero axis. It doesn’t affect the data in any way. What we have with this composite chart is, overall, four data sets showing virtually exactly the same thing. There is little divergence between the data sets. The satellite sets tend to show higher highs and lower lows I suspect because they are more sensitive to short term fluctuations.
If you add in all the trend lines for the data sets what you see is that GISS and CRU are showing almost identical warming over the total series. RSS shows slightly less warming than those two and then UAH shows less cooling than RSS.
Now, I’m not going to speculate on who is right. Potentially the ALL are correct in that they are all tracking and parsing the data differently.
What we see, though, is that these data all agree in general on warming over the past 30 years. Squint as hard as you want at tiny nuances, it won’t change the overall trend.
My most fervent hope is there will be no raising of the debt ceiling in congress and that NASA/GISS will be one of the resulting casualties.
mike g says:
“My most fervent hope is there will be no raising of the debt ceiling in congress and that NASA/GISS will be one of the resulting casualties.”
Sounds like you are more in this as a vendetta than for scientific discovery. If Hansen is cooking the books then let him die on his own sword. If he’s not, then it will become obvious as the cards play out over the next decade.
Rob Honeycutt says:
January 5, 2011 at 6:40 pm
Changing the baseline doesn’t do much to the recent data, but when this changes every decade it makes a significant difference when comparing with much earlier data in the series. The problem has never been so much how they compare with other data sets of recent times, but longer periods that the satellites don’t cover. Still over recent data that little change is only needed to produce records when the others don’t show it. That is simply why it is done to get as much warming from the data as it is possible. With the temperature changes involved just in the tenths of a degree, this change makes a difference.