Sunday, August 7, 2016

Troposphere temperatures for July 2016

Sou | 6:34 PM Go to the first of 4 comments. Add a comment
The troposphere temperatures are out for July 2016. 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"). This report follows pretty much the same format as previous monthly updates. It's my fault that it's a bit later than usual. (I was away most of last week.)

In all records, the July global anomaly was a bit higher than it was in June but lower than earlier this year as El Niño is now over. In the lower troposphere (UAH beta v6.05) last month is the second hottest July on record, lower than it was in 1998. For RSS TTT (troposphere), last month was the hottest July on record.

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 July, from August 1979 to July 1980, through to August 2015 to July 2016.
Figure 1 | Troposphere temperature for 12 months to July (TTT). Anomaly is from the 1979-1998 mean. Data source: RSS
TTT is a multi-channel combined product made by calculating a linear combination of TMT and TLS. TTT = 1.1*TMT - 0.1*TLS. This combination has the effect of reducing the influence of the lower stratosphere, as shown Figure 3. In the simpler TMT product, about 10% of the weight is from the lower stratosphere. Because the lower stratosphere is cooling at most locations, this causes the decadal trends in TMT to be less than the trends in the mid and upper troposphere. TTT was proposed by Fu and Johanson, 2005.

Figure 2 below shows the differences between TTT, TLT and other measures. The vertical axis is the height above sea level.
Figure 2 | Weighting function for each RSS product. The vertical weighting function describes the relative contribution that microwave radiation emitted by a layer in the atmosphere makes to the total intensity measured above the atmosphere by the satellite. Source: RSS

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. The weightings given to the measures taken by the (currently two) satellites are complicated and described on this website.

Below is the TTT chart just for the month of July. The anomaly for July was 0.66 °C, which is just 0.03 °C warmer than July 1998. For 2016 to be colder than the previous hottest year (1998), the troposphere would have to average 0.29 °C or less for the remaining months:
Figure 3 | Troposphere temperature for the month of July 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 July, from August 1979 to July 1980, through to August 2015 to July 2016.

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

Below is the UAH chart for the month of July only for each year going back to 1979. The anomaly was 0.39 °C above the 1981-2010 mean, which was 0.12 °C lower than the previously hottest July in 1998 (0.51 °C). For 1998 to remain the hottest year in the UAH lower troposphere record, the average for the next six months would need to be below 0.34 °C.

Figure 5 | Lower troposphere temperature for the month of July 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 6 | Global mean surface temperature for strong or moderate/strong El Nino years that were followed by a La Nina. Data source: UAH

It's still too soon to tell if there will be a La Nina this year.

From the WUWT comments

This is a selection of comments from the WUWT copy and paste of Roy Spencer's latest article about the UAH lower troposphere record (archived here). His sub-headline was: "July Temperature Recovers Slightly from Previous Free-Fall", which was much more muted than last month's headline: "Spectacular Drop In Global Average Satellite Temperatures". The WUWT "thoughts" were also more muted than they were last month.

Stephen Greene is funny. He doesn't know that Roy Spencer and John Christy are under contract to NASA for their work estimating atmospheric temperature changes, and that his "research has been entirely supported by U.S. government agencies: NASA, NOAA, and DOE." Doesn't he know that the satellites used are NASA satellites? NOAA provides a list of satellites and the data available.
August 1, 2016 at 6:44 pm
I finally got it. After spending weeks auditing land source data and seeing how much NOAA / NASA changes it and how much alarmist ACTUALLY ENJOY saying …. 333 strait months of record (FRAUD) whatever,… I finally got it. NASA can’t get on board with a better system of temp monitoring, satellite, because the main source of global warming is NASA. Almost 0.7 C in my now pretty F-in enlightened opinion.

Joe Bastardi says something about a "shoo in" for the warmest year:
August 1, 2016 at 7:35 pm
wow, NCEP CFSR and Dr Roy both the same. Was warmest July in NCEP 35 year model initialization . On that record, Year is shoo in for warmest ever

John Leggett has a question. Well, we're already hotter than at any time in the Holocene, and we're on track to warm ten times faster than at any time in the past 65 million years.
August 2, 2016 at 4:23 am
I do not think that it would be unexpected that after the end of the Little Ice Age. During the first two hundred years of The Modern Warm Period. It would be unexpected for the climatic to grow warmer. What I want to know is how it is significantly different than during the first two hundred years of previous warm periods. 

spaatch got in a cheeky question about this wrong comment from Denier Don:
August 2, 2016 at 12:27 am
But, how can 2016 be another record hot year – the third in a row – when Don Easterbrook said yesterday:
I predicted that global cooling would set in sometime after about 2000 and that is happening
So Don Easterbrook is wrong?

wallensworth might be a greenhouse effect denier:
August 2, 2016 at 7:45 am
Temperature also correlates well with the price of Apple stock.
Repeat after me: Correlation is not causation. 

KLohrn has a question too. He or she isn't familiar with UAH lower troposphere temperatures. The last time the monthly anomaly was less than minus 0.3 was in September 1993, almost twenty three years ago. There has not been a year with an annual anomaly less than -0.26 C. The only time the annual anomaly was lower than -0.3 C was around thirty years ago in 1985, when it was -0.36 C. (In 1982 it was -0.3 C).
August 2, 2016 at 9:07 pm
What happens when it reaches -0.3 again, as it has so many times in the past?
Do 97% of scientists go back to school on grants?


  1. Does anyone know if Spencer has published information on his - now not so recent- revision to the UAH dataset?

    1. He claims "the paper describing the methodology is still in peer review." He's been claiming that for around six months. I wonder how slow Spencer's "peers" read?

    2. I wonder how many peers there are for this sort of review? Be interesting if Karl Mears of RSS is one of the reviewers.

  2. One of the most curious features of UAH6.0b5 is just how well it now tracks RSS 3.3 TLT, yet Mears et al recently pointed out (in the peer reviewed literature) problems with the latter, hence their revision to V4.0 (with the updated TLT yet to appear, as Sou points out above). They now advise caution using TLT 3.3 on their own web site, so I guess given the near identical trajectory that it follows to UAH 6.0b5, we should apply the same caution to the latter. See http://www.remss.com/node/5166


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