Thursday, February 9, 2017

Not the hottest January in the troposphere, but way hotter than normal in the Arctic

Sou | 11:52 PM Go to the first of 4 comments. Add a comment
The troposphere temperatures for January 2017 were released earlier this month. The lower troposphere is recorded in UAH v6 and RSS TLT v3.3. This report also covers RSS TTT for the troposphere (without the "lower") and follows pretty much the same format as previous monthly updates.

For RSS TTT (troposphere), the 12 months to January 2017 remain the hottest 12 months in the record (comparing similar Feb-Jan periods). January itself was the just the fifth hottest January, with January 2016 the hottest.

The lower troposphere (UAH v6) also showed the 12 months to January as the hottest on record. However, January was only the seventh hottest January on record, with January 2016 the hottest.

Troposphere temperature (RSS TTT v4) chart

First here is RSS TTT with the latest dataset, version 4. TTT seems to measure more of the troposphere than TLT (that is, it has a greater vertical profile) with less of the stratosphere than the mid-troposphere data (TMT). It shows a higher rate of warming than RSS v3.3 and higher than UAH. Hover the cursor (arrow) over the plots to see the data points, trend etc.

The chart below is the average of the 12 months to January each year from 1979 through to 2017. The annual averaged anomaly was 0.77 °C, which is 0.20 °C higher than the previous hottest 12 month Feb-Jan period that ended in January 1998. The rate of warming is 0.18 °C/decade or 1.8 °C/century.
Figure 1 | Troposphere temperature for 12 months to January (TTT). Anomaly is from the 1979-1998 mean. Data source: RSS

From the RSS website, TTT is derived from TMT and TLS with the formula:

TTT = 1.1*TMT - 0.1*TLS. 

This combination reduces the influence of the lower stratosphere, which is cooling at most locations. TLT gives most weight to the temperatures closer to the surface. TTT gives more weight to the troposhere and less to the stratosphere than TMT does, but not as much to the lowest levels of the troposphere as TLT does. However TTT has version 4, while TLT is still only provided as version 3.3. For a fuller explanation see the RSS website or the July 16 report here.

Below is the TTT chart just for the month of January. The anomaly for January was 0.6 °C, which is 0.193 °C cooler than January 2016. The rate of warming just for January is quite high at 0.19 °C/decade.
Figure 2 | Troposphere temperature for the month of January only (TTT). Anomaly is from the 1979-1998 mean. Data source: RSS

Lower troposphere

The rest of the charts are from UAH v6. This is almost identical to the old version of RSS, which is v3.3, so is likely to be updated at some time. (Other RSS data sets, like TTT are now at version 4.)

The chart below is the average for each 12 month period ending in January each year (1979 to 2017). The 12 months to January 2017 is the hottest Feb-Jan period on record by 0.03 C.
Figure 3 | Lower troposphere temperature for 12 months to January. Anomaly is from the 1981-2010 mean. Data source: UAH

Below is the UAH chart for the month of January only for each year going back to 1979. The anomaly was 0.3 °C above the 1981-2010 mean, which was only the seventh warmest January in the record, and 0.24 C cooler than the hottest January in 2016.

Figure 4 | Lower troposphere temperature for the month of January only. Anomaly is from the 1981-2010 mean. Data source: UAH

Comparing recent ENSO years

Below is a chart comparing the strongest El Niño years since 1979, which were followed by a La Niña, just for UAH v6. I've included the 2015/16 period for comparison, though its more likely there'd be an El Niño this year now, than a La Niña. (It's even more likely to remain ENSO neutral.)

Figure 5 | Global mean lower troposphere temperature for strong or moderate/strong El Nino years that were followed by a La Nina. Data source: UAH

Even though La Nina hasn't emerged, the UAH December and January temperatures aren't that different from 1998/99, when there was a La Nina, at least not in the UAH record.

Roy Spencer and John Christy expect big swings in troposphere temperature

They haven't said so outright, however looking at the UAH chart put up at WUWT, Roy Spencer and John Christy are expecting a sudden change of massive proportions in lower troposphere temperature. You can tell by looking at the chart below.

The arrow down the bottom is the usual range of temperature anomalies in the upper air (to around 8 km up:- between +/- 3.5 C.  Going by the legend at the bottom, they reckon there could be parts of the world soon that have a monthly anomaly of +/- 9.5 C.

Very high temperatures for the Arctic

Now that's not as silly as it sounds. It could be Roy and John have been watching surface temperatures and thinking that their satellites might detect the record surface warmth. At Svalbard in the Arctic, the last 30 days have averaged 7.2 C above normal (h/t Zach Labe).  I don't know what years "normal" is measured over but it can't be all that long ago. The weather station was only installed in 1964.

Jason Samenow wrote about the incredible warmth in the Arctic (which doesn't show up in the UAH record). Here's a chart showing the anomalies for the month of January, from NCEP via The Washington Post.

I don't know how much of an impact that will have on global surface temperatures. The weather in the USA has been weird (cold and hot). It's been rather warm in northern Europe - and large parts of Australia.

From the WUWT comments

The thoughts below are from Anthony Watts' blog WUWT, under the UAH report (archived here).

Mark hasn't learnt how to read a temperature chart. Hope he's not in a dangerous occupation.
February 1, 2017 at 3:59 pm
So it’s basically the same temperatures now as it was in the 1980’s…. After it cooled from 1935 to 1975. Can someone please explain what the problem is?

mib8 has a lot of questions but doesn't believe the answers, which aren't very hard to find, except at WUWT.
February 1, 2017 at 6:15 pm
I have been sending the occasional url to a watermelon acquaintance of mine, with a bit of grumping about lack of the base data and precise methods used to homogenize, interpolate, extrapolate, not-so-arbitrarily choose base times or time periods for the “anomalies”, aggregate and then publish only the resulting few numbers. Why don’t we get the whole story? Why do they fight so hard against the FOIA law-suits? If they are, as they claim to be, scientists, applying the scientific method, all of this shoul be out in the open. (Why not choose the hottest previous inter-glacial? Or the coldest previous ice age? Or the worst year of the Little Ice Age? Why not 1900, or 1910, or 1915 as the anomaly base?) “is what it is” but we do not know what it actually is, because all we get are the results of what seems to be chicanery.
But, if they are merely power-mad watermelons 🍉 wanting to punish the average citizens of developed economies, to engage in more “redistribution”, while they jet-set around on the tax-victim dime, then it all makes perfect sense.
I confess that between this and the dysfunctional STEM job markets, I am quite frustrated and annoyed.

 There is "base data" all over the internet. All mib8 has to do is learn how to use Google. If he wanted to find out the precise methods used to homogenise, interpolate, extrapolate, not-so-arbitrarily choose base times or time periods for the “anomalies”, aggregate and then publish only the resulting few numbers - he's not looking in the right place. There are very big numbers of numbers available, if he wants lots of numbers. However given that mib8 hasn't even learnt how to do an internet search, I doubt he'd have heard of a tar.gz file, let alone know what to do with one. There are also very detailed explanations of how the numbers are crunched (eg for HadCRUT4 and for GISTemp and for RSS, but not yet for UAH). There are simpler explanations as well for the less technically inclined, like the excellent articles written by Victor Venema. There's even code that he could analyse and use himself, should he choose to. And while I say that WUWT isn't known for encouraging people to learn about such matters, it does have a resident expert who explores temperature data as his post-career passion (for love, not money, though he doesn't get much love at WUWT. Nick Stokes is currently under moderation at WUWT, for spoiling Anthony's efforts to disinform the world.)

rishrac doesn't understand ENSO events, and is talking through his hat. He or she is a regular at WUWT and you'd think information would have been absorbed. It's as if knowledge hits the heads of WUWT-ers and bounces right off again, as if it's repelled by what it sees or doesn't see inside their skulls. Even in the flawed UAH record, the highest monthly anomaly of all was just last February, at 0.83 C above the 1981-2010 baseline. Eight years ago, in 2008, the highest monthly anomaly for the whole year was only 0.06 C above the baseline. The most recent 12 months (and 2016) have been the "hottest ever" in the troposphere:
February 1, 2017 at 6:51 pm
Doesn’t really matter does it Nick, AGW theory is an epic fail. Therefore, most of your support of global warming is wrong. 8 years ago the global temperature was sited at being 1.2 C above normal. And now we are talking about 0.3 C ?

Some people at WUWT are most impolite. kuhnkat, quoting the ever patient, always courteous Nick Stokes, wrote:
February 2, 2017 at 9:55 pm
But no-one thinks the problem is in the troposphere. What matters for us is what happens down here.”
So you are now telling us that the models are shit and we don’t look to the Hot Spot in the troposphere?? You are an F’ing moron racehorse.
I don't know how kuhnkat got his interpretation out of that statement of Nick's, which was pointing out that we live on the surface, not 8 kilometres up in the cold thin air. Nor do I understand why those two sentences upset him so much. (I'll assume it's a him.)

You get the picture. Anthony's getting a lot more comments these days. It's like the old days when times seemed good to fake sceptics. Maybe they are all enthused about all the anti-science people who they've elected. They are probably jumping for joy that they've also got someone in charge of schools, whose aim in life is to wreck the education system in the USA, treating everyone like mushrooms (just as WUWT-ers like it).

Note: Made some light edits to clarify ambiguous points, thanks D - Sou 10 Feb 2016


  1. "Roy Spencer and John Christy expect big swings in troposphere temperature"

    I could be missing the sarcasm, but it seems more likely they're using a large scale to minimize the anomalies in the visual.

    1. I thought I'd be kind for a change, and take the line that they really wanted to inform for a change and had stopped doing deceptive charts.

      Thing is, it probably won't be long before they or their successors will find they need all that extra legend. What will they do then? Change the colours to shades of white or aqua (to look cold)?

  2. Musing on the graphs above I was thinking about how 'on average' the bisectors of the peaks and troughs are essentially perpendicular to the x-axis (as one would expect, given the way that time series data manifests). I wonder if there's a cognitive glitch occurring in the minds of 'pause' perceptors, where they anticipate that these bisectors should be perpendicular to the linear regression trajectory, and whether this causes/enhances their perception of said 'pause' when eyeballing such graphs?

    Such a cognitive bias does not exclude the existence of other phenomena, such as motivated reasoning, but if real it opens up the possibility that lack of training/appreciation for data properties may predispose people to incorrect interpretation of visual data. it may suggest an extra avenue of response (in addition to statistical training) when attempting to educate people in understanding what the data really imply.

    1. That's an interesting thought, Bernard. It occurs to me that although many deniers are innumerate, quite a few are engineers of one kind or another, so they should be competent in dealing with numbers and charts. It's a puzzle.

      The thought has also just occurred to me that I've yet to come across an accountant at WUWT (that I know of). Accountants are also used to dealing with numbers and charts, but perhaps lack the scientist envy of engineers. So the motivated reasoning is missing, which could explain why deniers don't attract a lot of accountants to their ranks. Oh, as well as the fact that accountants understand money (and risk) a lot better than deniers - so that motivation is missing in their case as well :)


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