July UAH Global Temperature Anomaly: up a bit and in general agreement with RSS

UAH (University of Alabama, Huntsville) Microwave Sounder Unit (MSU) lower troposphere global temperature anomaly data for July 2008 was published today and has moved a bit above the zero anomaly line, with a value of 0.048, up from -0.114 in June 2008

The global UAH ∆T from June to July 2008 was .162°C

2008 1 -0.046
2008 2 0.020
2008 3 0.094
2008 4 0.015
2008 5 -0.180
2008 6 -0.114
2008 7  0.048  

Click for a larger image
Reference: UAH lower troposphere data

Just like with the RSS global temperature anomaly data, I rather expected it to go up a bit, given that La Nina has diminished, plus the NH has a greater landmass than the SH, and we are in summer.

Click for a large image

Steve McIntyre of Climate Audit did an interesting graph that shows the difference between the NH and SH using the RSS data:

Figure 1. TLT3 20-80N minus TLT3 20-70S.

He writes:

In general terms, the relative warming of the NH relative to the SH is something that we’re aware of, but isn’t the strength of the trend in the 30 years of satellite record astonishing? And this is nothing to do with UHI.

In comments, he proposes a some hints on a possible mechanism:

The N-S delta is very interesting in terms of historical fluctuations. The earth has small but interesting asymmetries in its poleward heat transfer, with a slight bias towards the north. In entropy terms, if the energy can find a pathway to be slightly biased north, then that’s a more efficient solution. With the same T^4 average and somewhat more efficient poleward distribution, you can increase the T^1 average, which is what we measure. A line of reasoning suggests that the ITCZ was further north in the MWP and south in the LIA.

See the complete article on Climate Audit here

Roger Pielke Sr. writes to me:

With respect to your posting on [RSS July Data]

Don’t forget that the effect of land mass and time of year is included in  creating the annual variation of average tropospheric temperature, such that the anomalies are from the average for a given month. This means that  in the RSS data, the increase in temperature was faster than average  between June and July.

See my weblog on this subject at



27 thoughts on “July UAH Global Temperature Anomaly: up a bit and in general agreement with RSS

  1. It appears that, as well as the global temperature, the differential is flattening in the 21st century. Given the post you had on the CO2 distribution, could we be seeing a saturation of the CO2 warming effect or negative feedbacks kicking in?

  2. Hmm.

    Jan. ’08…which caused the massive shift in grass watching from warming to cooling…seems to have ‘stepped’ down from several years previous. I have a feeling it will remain down…at ~1995-1999 levels before dropping ever so slightly heading towards 2010-2015. But hey, I could be way off! Guess we’ll see. It could also do the opposite.

  3. I’m wondering as to the difference in the data between the link provided beneath the UAH graphic –


    and that cited above by Fred –


    I just checked the first link and it doesn’t show July data. Has it, or is it, being changed?

    I followed the link to the analysis by Roger Pielke Sr. I don’t doubt the need for more detailed analysis as espoused by Roger, but sometimes (such as on this blog) I think the broad brushstroke look is adequate. Any individual who desires can pursue a more in depth analysis available at the appropriate source (RSS or UAH).

  4. Surely this up anomoly is just the result of the La Nina effect finishing and normal summer resuming, in terms of, “Hey, it’s summer so expect a warmer temperature”??

  5. Anthony,

    Since these are temperature *anomalies*, they are seasonally adjusted by definition. That is, the fact that “the NH has a greater landmass than the SH, and we are in summer” has no effect on temperature anomalies. (Only on absolute temperatures).

  6. Wow that extra .048 of a degree above normal is killing me… Turning up thermontat extra .048 degrees…

  7. They say it is the 30th. warmest july recorded
    Can anyone say how many years since we last had a July as cool as this?

  8. Tropics:
    >2007 -10 ……….. -0.129
    >2007- 11………… -0.052
    >2007- 12………… -0.179
    >2008- 01………….-0.212
    >2008- 02………….-0.325
    >2008- 03………….-0.489
    >2008- 04………….-0.532
    >2008- 05………….-0.581
    >2008- 06………….-0.333
    >2008- 07………….-0.118
    This seems consistent with the number of sunspot. It also seems consistent with the Pinatubo.

  9. This just in:

    UAH reports that July 2008 was the second coldest July in this century! It was also the 11th coldest month of the 21st century.

  10. Ya know ….

    I hear people talk about Pinatubo all the time, but in a recent discussion, I went to Woodfortrees, and plotted the hadsst2 against RSS, Hadcrut, and GISS from 1980. Two things JUMPED out fo the page at me.

    1) Surface temp remarkably follows SST. (consistent with D’Aleo’s recent article)

    2) Pinatubo was nothing remarkable at all.

    When I say this, the downward drop in temp after Pinatubo was consistent with the cycling of SST, and the magnitude was unremarkable compared to natural variation that one would have expected. I know it is standard to believe that the aeresols of volcanoes cool the earth, but once again, that is modeling. Looking at the graph, I wonder.

    I found this other paper that was I’m guessing an abstract at the Cosmic Ray conference:

    It shows that SST correlates (R2=0.93) with long term solar fluctuations. His conclusion was that solar output would at some time return to 1906 values, and that temperature would likely follow. My thoughts are if you add a negative PDO to it, will likely be relatively rapid. If you add yet again La Nina .. you have the massive drop we saw for 2007-2008.

    It sets up a relationship, that I know some of you are all too aware of, and that is a solar-ocean-temperature relationship. One thing is for sure, I just don’t see how CO2 figures into the graph at WFT. And it dern sure doesn’t figure into the graph of the Cosmic Flux paper.

  11. After a very warm winter in NYC (while the RoW was freezing), we have had a rather cool July.

    It would seem the La Nina has gone on neutral. It will be interesting to see how well the current downtick holds.

  12. UAH reports that July 2008 was the second coldest July in this century! It was also the 11th coldest month of the 21st century.

    Huh? Say, what?

    Does july have an anomalous curse on it?

    (If it does, I suppose we may expect the anomaly to be reported and the ranking to be ignored.)

  13. Evan,

    I was just being sarcastic, but from Jan 1 2001 (start of the 21st century) till now those are the rankings for this century.

  14. Deanster…

    I am afraid you are wrong about Pinatubo being insignificant. When the eruption occurred, there was an El Nino happening and solar activity was just descending from max peak. Global temps were running quite warm when it occurred, and then plunged dramatically following the eruption. There is no way to explain this sudden drop in temps other than Pinatubo.

  15. Anthony: Several of us pointed out this issue with about NH/SH summer not being relevant in comments on the RSS item; the same applies here. Seasonal differences have already been subtracted to create the monthly anomaly data.

    BTW, is WordPress now shortening (eliding) URLs? That’s going to make an awful mess of WFT links like Deanster’s above.

    Testing: latest data for all four series with baselines adjusted:


  16. Thanks Dee, I’ve used TinyURL myself but I didn’t want other people to have to use it to link here, particularly because WFT URLs are designed to be somewhat self-explanatory. Actually I was just now pondering whether to provide a shortened URL service on WFT itself, maybe one day…

    But actually it seems to be fine; I guess something in the way ‘Deanster’ wrote his post did the shortening.

  17. Thanks Jarod .. I was aware of this.

    This brings up an interesting problem that I’m trying to reconcile. Judith Lean and others suggests a Lag Time between solar effects and surface temperatures. The Pinatubo event “seems” to fly in the face of this assertion.

    The only thoughts I can come up with are that the effects of aeresol induced clouds within the context of decreasing solar input are magnitudes more powerful than the solar signal itself. Thus, while temperature shows a 5-10 year lag behind a pure solar signal, the affect of clouds has the potential to decrease solar input to the point that temps fall immediately.

    Maybe some of you guys who are more informed than I can suggests something.

    BTW … everyone .. I apologize for the truncated WFT link. I cut and paste that from a post I made on a different blog site that automatically puts it in that format. Sorry .. didn’t mean to cause a stink :D


  18. The trend of temperature difference between the NH and SH is always a source of frustration, their is obviously a transfer of heat between the poles, and the fact that the Earth is about a million miles closer to the sun during the SH summer and receives about 90 W/M^2 more energy than during the SH winter has to play a part. This naive assumption in climatology that the NH and SH seasonal differences cancel each other every year has got to stop, then perhaps we will understand the various Pacific and Atlantic interdecadal cirrculation anomalies, and possibly make real progress in understanding climate.

  19. Oh, and for some reason, they changed Dec 2007 from 39 last month back to June’s 40. Their number for June was also increased by one as well. — John M Reynolds

  20. HadCRUT is in at 0.403 for July. Several past temps changed including 2007/08. Here are the data since last August. The second column has today’s figures. The third column has the figures they had on their site as of 2007/07/16. The last column has the small differences.

    2007/08 0.370 0.362 +0.008
    2007/09 0.412 0.410 +0.002
    2007/10 0.370 0.367 +0.003
    2007/11 0.266 0.266
    2007/12 0.220 0.212 +0.008
    2008/01 0.050 0.054 -0.004
    2008/02 0.192 0.192
    2008/03 0.445 0.445
    2008/04 0.267 0.254 +0.013
    2008/05 0.278 0.278
    2008/06 0.312 0.314 +0.002
    2008/07 0.403

    John M Reynolds

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