Troposphere temperatures for October 2016 - another hottest on record

The troposphere temperatures for October 2016 have been released. The lower troposphere is recorded in UAH v6 beta 5 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), last month was the hottest October on record. For 2016 to be colder than the previous hottest year (1998), the troposphere would have to average a negative anomaly:- less than -0.41 °C for the remaining months.

The lower troposphere (UAH beta v6.05) was the equal hottest October on record with 2015. For 1998 to remain the hottest year in the UAH lower troposphere record, the average for the next two months would need to be below 0.21 °C.

Troposphere temperature (RSS TTT v4) chart

First here is RSS TTT with the latest dataset, version 4. TTT seems to be 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 October, from November 1979 to October 1980, through to November 2015 to October 2016. The 12 month averaged anomaly was 0.78 °C, which is 0.16 °C higher than the previous hottest 12 month period in 1998. The rate of warming is 0.18 °C/decade.

Figure 1 | Troposphere temperature for 12 months to October (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 October. The anomaly for October was 0.763 °C, which is 0.04 °C warmer than October 2015. The rate of warming just for Octobers is 0.21 °C/decade.

Figure 3 | Troposphere temperature for the month of October only (TTT). Anomaly is from the 1979-1998 mean. Data source: RSS

Lower troposphere

The rest of the charts are from UAH beta v6.5. 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 of the 12 months to October, from November 1979 to October 1980, through to November 2015 to October 2016. The past 12 months is the hottest on record by 0.03 C.

Figure 4 | Lower troposphere temperature for 12 months to October. Anomaly is from the 1981-2010 mean. Data source: UAH

Below is the UAH chart for the month of October only for each year going back to 1979. The anomaly was 0.41 °C above the 1981-2010 mean, which was the same as October last year.

Figure 5 | Lower troposphere temperature for the month of October 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 v6beta. I've included the 2015/16 period for comparison.

Figure 7 | Global mean surface temperature for strong or moderate/strong El Nino years that were followed by a La Nina. Data source: UAH

La Nina is not very likely to appear this year according to BoM. One thing you'll notice is that the last couple of months in the UAH data are similar to 1998. I think the result would be different if satellite drift were better accounted for - going by comparison with RSS data.

From the WUWT comments

The comments below are from the WUWT copy and paste of Roy Spencer's latest article about the UAH lower troposphere record (archived here, latest here).

ChadB wonders when the temperatures are going to stop increasing, and asked:

November 1, 2016 at 9:33 am
Curious, what would the trend need to look like in 2017 for “the Pause” to return?

There were a few responses. Nick Stokes was the only person who helped, though, and wrote:

November 1, 2016 at 8:32 pm
“Curious, what would the trend need to look like in 2017 for “the Pause” to return?”
There is simple arithmetic you can do. UAH did show a near zero trend from about May 1997 to Feb 2016, and the intercept was about 0.25°C. As long as the mean since Feb 2016 is greater than 0.25, the trend since 1997 will be positive, else not. This is an approx good for a year or two at least. The average since Feb is now way higher, and continued monthly values of around 0.4 are adding to the task. The trend won’t stop rising until months are below 0.25 °C, and no pause until a sequence of months have been below 0.25 by as much cumulatively as 2016 has been above. That’s very unlikely.

Kristian wanted to know why it was unlikely:

November 2, 2016 at 11:04 am
Why is that “very unlikely”?

Nick Stokes explained the arithmetic:

November 2, 2016 at 2:17 pm
Why unlikely? I looked up details. From Jul 1997 to Jan 2016, there was zero trend, and the average was 0.14C (I had V5.6 above). From Feb to Sep, the average was 0.55. For pause return, the average since Feb 2016 has to be 0.14. So what would it take? Either:

1. Eight months averaging -0.26C. But such months individually are very rare in the record.
2. 24 months averaging 0C. That did happen once, around 2008. But it didn’t start from temps of 0.4C.

And yet, UAH seems to be running along at about 0.4. Each extra month which is 0.26 above the .14 level requires another balancing month 0.26 below, or -0.12C. 

Kiwibok thinks that temperatures rise by magic and will keep rising for ever more. I don't know if she or he is planning a move to the poles any time soon. Kiwibok is also wrong about "new highs every month for 400 years".

November 1, 2016 at 12:31 pm
Don’t forget everyone that as temps have been rising since the LIA that any year that does NOT make a new record should make news .
A new high does not mean it’s anything to do with humans – there have been new highs every few moths for 400 years .
It’s only in “Hoaxworld ” a “record ” temp is big news .