RSS MSU TLT Anomalies February 2011 Update and A Look At Version 3.3
RSS TLT anomalies continue to drop in response to the 2010/2011 La Niña. RSS MSU TLT anomalies are now at 0.051 deg C, Figure 1.
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Figure 1
RECENT VERSION UPDATE
RSS recently updated their MSU Lower Troposphere Temperature (TLT) anomaly data with a new version, v3.3. This was discussed last month at Watts Up With That? in the post RSS global temp drops, version change adjusts cooler post 1998. At that time, RSS had not described the changes. They now have at their website on their data description webpage.
http://www.remss.com/msu/msu_data_description.html
Refer to the Version Notes. Here’s what RSS has to say:
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Version Notes
RSS Version 3.3 Channel TLT, TMT, TTS, and TLS – January, 2011
Change from 3.2 to 3.3:
* Additional satellites are now included in the merge. Version 3.2 only used data from one AMSU instrument, NOAA-15. For TLT, TMT, and TLS, Version 3.3 includes data from the AMSU instruments on NOAA-15, AQUA, NOAA-18, and METOP-A. AMSU channel 7 exhibits unexplained drifts in METOP-A, so for TTS, data from METOP-A is not used.
* Comparisons with other AMSU satellites are now used to detemine [sic] the AMSU merging coefficients.
* When merging MSU and AMSU together, the data for each generation of satellites is weighted by the number of satellites with valid data for that month. This has the effect of de-emphasizing MSU data after the advent of the AQUA satellite in June 2002. Since the 2002-2004 period is when there is an unexplained warming drift in MSU channel 2 data from NOAA-14 relative to AMSU data, this change has the effect of lowering the overall warming in TMT and TLT during the post 2002 period.
* The changes also result in a reduction of sampling noise and “orbital striping” for periods when data from more satellites is used.
* Data from NOAA-16 is not used because all 3 channels show unexplained drift throughout it’s [sic] lifetime. NOAA-17 was only operational for a short period of time, thus it’s [sic] data is of little use for climate studies. We plan to begin including data from NOAA-19 after 3 years of operation.
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VERSION COMPARISON
Figure 2 compares the anomaly data and linear trends of the new RSS TLT Version 3.3 to the obsolete Version 3.2. The update lowered the linear trend since 1979 from approximately 1.6 deg C to 1.5 deg C per Century, Figure 2.
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Figure 2
The difference between the two datasets is shown in Figure 3.
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Figure 3
Figure 4 is a .gif animation that compares the2010 anomaly maps for the new and old versions when using 1979-1980 as the base years. Basically both maps are showing the change in TLT anomalies from the average of the years 1979 and 1980 to the year 2010. The patterns for both datasets are similar, but there are minor changes in the variations.
http://i54.tinypic.com/261bxja.jpg
Figure 4
COMPARISON TO UAH MSU TLT DATA
The linear trends of the RSS version 3.4 and the most recent version of UAH TLT anomaly data (v5.4) are basically the same: 1.47 versus 1.44 deg C per Century. Refer to Figure 5. Note that I’ve switched to KNMI climate Explorer as the source for both datasets, so that I could limit the UAH latitudes to those used by RSS, 70S-82.5N.
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Figure 5
Figure 6 shows the difference between the two datasets.
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Figure 6
And Figure 7 is a gif animation similar to Figure 4, but this compares RSS (v3.3) to UAH (v5.4) TLT anomaly data.
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Figure 7
THE ENSO-INDUCED STEP CHANGES
I illustrated and discussed the ENSO-induced rises in the RSS MSU TLT anomalies for the data north of 20N in the post RSS MSU TLT Time-Latitude Plots… Show Climate Responses That Cannot Be Easily Illustrated With Time-Series Graphs Alone. I further discussed the likely cause for the upward steps in the post The ENSO-Related Variations In Kuroshio-Oyashio Extension (KOE) SST Anomalies And Their Impact On Northern Hemisphere Temperatures.
Figure 8 illustrates Volcano-adjusted RSS TLT anomalies north of 20N in “raw” form and smoothed with a 13-month running-average filter. Also included are the period average temperature anomalies of -0.187 for 1979 to 1987, -0.016 for 1988 to 1997, and 0.268 for 1998 to present.
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Figure 8
I adjusted the data for the linear effects of the two major volcanic eruptions, El Chichon and Mount Pinatubo. To determine the scaling factor for the volcanic aerosol proxy, I used a linear regression software tool (Analyse-it for Excel) with global RSS TLT anomalies (v3.3) as the dependent variable and GISS Stratospheric Aerosol Optical Thickness data (ASCII data) as the independent variable. The scaling factor determined was 2.9.
And in Figure 9 the “raw” data has been deleted to help show the ENSO-induced upward steps in this dataset. So the revisions have not changed these to any great extent, so I won’t go back and update the earlier posts.
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Figure 9
SOURCES
The following are links to the data use to create Figures 1, 2, and 3.
RSS_Monthly_MSU_AMSU_Channel_TLT_Anomalies_Land_and_Ocean_v03_2.txt
RSS_Monthly_MSU_AMSU_Channel_TLT_Anomalies_Land_and_Ocean_v03_3.txt
All other data were downloaded, and the maps were created, using the KNMI Climate Explorer Monthly observations webpage.
(Many thanks to Dr. Geert Jan van Oldenborgh of KNMI for the quick update to RSS TLT version 3.3.)
Posted by Bob Tisdale at 12:01 PM
Sorry Bob, I just don’t understand. It appears to me that the data is being adjusted to fit a pre-ordained result. Kind of like adding UHI corrections to cool rural stations. The results even look fake. But then I am just a dirt farmer. pg
vukcevic says:
March 11, 2011 at 12:19 pm
I am not certain, but sensors may be affected by solar wind (proton and electron flux) […] We need Dr. Svalgaard’s comment on this one.
I don’t comment on things I don’t know anything about.
Leif Svalgaard says: March 11, 2011 at 11:30 pm
…..
Not knowing, even more reason to find out; essentially drive for the scientific progress!
Walter Dnes says: “I don’t agree with Hansen’s statistical gymnastics, but the far north does contribute to global temps. ”
RSS reaches as far north as 82.5N. Isn’t it the coverage of the Antarctic where RSS and UAH differ the most, with RSS only reaching as far south as 70S?
http://i52.tinypic.com/mtm3xs.jpg
Arno Arrak says: “Bob – you are dead wrong with your volcano adjustments. Neither Pinatubo nor El Chichon had any global cooling effect on tropospheric temperature. It did have both warming and cooling effects in the stratosphere but this never descended to ground level. The tropospheric cooling attributed to Pinatubo is nothing more than a normal La Nina cooling that follows an El Nino. Pinatubo just happened to erupt at the exact time that an El Nino peaked, Self et al. appropriated the deep La Nina valley that followed to Pinatubo cooling, and everybody else just blindly copied him.”
Arno: Are you at this again? There was no La Nina after the 1991/92 El Nino. The following is a graph of detrended Global RSS TLT anomalies versus detrended and scaled NINO3.4 SST anomalies. Show me the La Nina in 1992/93 that was capable of explaining the divergence between Global TLT anomalies and the scaled NINO3.4 SST anomalies from 1991 to 1995.
http://i54.tinypic.com/2jb3ypw.jpg
Again, there was no La Nina at that time. In fact, there are papers that describe the period from 1991 through 1995 as one long El Nino–Trenberth and Hoar (1996) for example:
http://www.agu.org/journals/ABS/1996/95GL03602.shtml
Over the past six months (year, whatever it was), you have repeatedly claimed that volcanic aerosols have no impact on global surface temperatures, yet you have never backed your claims with data. Please provide an ENSO index that shows a La Nina that was capable of explaining the divergence between the NINO3.4 SST anomalies and Global TLT anomalies from 1991 to 1995.
Phil’s Dad: Thanks for finding the typo. You’re right. It should read RSS version 3.3, not 3.4. I’ve fixed the original at my website.
The step changes are caused by the solar cycle, not ENSO.
Bob, is there any instance over the recorded period of the reverse – a down-step in global temperature caused by (for instance) a La Nina? What are the chances of such a down-step if we move from an el Nino dominated to a La Nina dominated phase of the ENSO?
The ’88 step is a figment of your imagination. This period could be simplified as a linear ramp but not a step.
You chose not to respond to my earlier comment to that effect, so I guess you accept the point.
The ’85 to ’98 ramp is what got everyone panicking. The post ’98 flat is what has got the warmists panicking.
I don’t think you’ll get very far with trying to persuade anyone that there was a step change in climate in 1988.
onion2 says: “The step changes are caused by the solar cycle, not ENSO.”
Please support this with data.
P. Solar says: “You chose not to respond to my earlier comment to that effect, so I guess you accept the point.”
I didn’t see your earlier comment because I was searched only for my name on this thread. I’ll read it and reply later.
phlogiston says: “Bob, is there any instance over the recorded period of the reverse – a down-step in global temperature caused by (for instance) a La Nina?”
I have not run across an instance.
Bob Tisdale says:
March 11, 2011 at 3:19 pm
IF (big if), after the 2009/10 El Nino & 2010/11 La Nina ENSO episode, the TLT anomalies north of 20N were to drop and remain at a lower average for a number of years, I, like many others, would be investigating the reason for the change.
Hi Bob, I would think that if OHC continues to fall, this is what we’ll see.
phlogiston says: “Bob, is there any instance over the recorded period of the reverse – a down-step in global temperature caused by (for instance) a La Nina?”
I have not run across an instance.
If my cumulative solar energy model is near the mark, I thnk you’ll see a drop to a lower baseline starting this year. By 2015 it will have settled around 0.2C lower than now I would expect from my model Unless the Sun does something spectacular. Always possible.
Try removing ENSO and the longterm trend from the temperature record and see what’s left, looks very much like an 11 year cycle. An oscillation over a linear upward trend will resemble a series of plateaus and step changes upward. And of course those step changes upward will be most eye-catching at the point of the first significant el nino in the upward phase of the solar cycle.
As both AQUA and MSU estimate the same “real” temp and errors in AQUA and MSU should be distributed around the same mean “real” temp. If changing the weighting between AQUA and MSU between versions changes smouthed temp as suggested, then blending is unsatisfactory. If MSU has a spurious trend, we need to adjust it out over the whole MSU measurement period before blending. If that had been done, you would expect slope over the 1979 to 1999. Of course the problem can be in AQUA. Either way splicing sensors showing diffrent trends during the overlap period is unsatisfactory.
P. Solar and onion2: Regarding P. Solar’s disagreement about the upward steps in the Volcano-adjusted TLT anomalies north of 20N, and onion2’s solar suggestion, refer first to the following comparison of the that dataset to NINO3.4 SST anomalies (Kaplan, scaled (0.25), lagged 9 months, and a shift of -0.2 deg C). The scaling factor for the GISS Aerosol Optical Thickness data is 2.9. The adjusted TLT anomalies mimic NINO3.4 SST anomalies from the start of the dataset until the peak of the 1986/87/88 El Niño. Then they fail to respond to the La Niña that follows. That’s step one:
http://i55.tinypic.com/2wox5ye.jpg
The next graph is of the same two datasets with the NINO3.4 SST anomalies shifted +0.07. The adjusted TLT anomalies mimic NINO3.4 SST anomalies from the start 1995 until the peak of the 1977/98 El Niño. And then they don’t respond to the La Niña. That’s step two:
http://i53.tinypic.com/2cn3iv.jpg
Tallbloke says: “Hi Bob, I would think that if OHC continues to fall, this is what we’ll see.”
Hi Tallbloke. The drop in OHC is only in a few basins: North Atlantic, South Pacific, Arctic… I’ll be updating the NODC OHC graphs per basin through Dec 2010 hopefully on Monday.
You wrote, “If my cumulative solar energy model is near the mark, I thnk you’ll see a drop to a lower baseline starting this year. By 2015 it will have settled around 0.2C lower than now I would expect from my model Unless the Sun does something spectacular. Always possible.”
I’ll hope for the success of your model. I would like the opportunity to explain a 0.2 deg C downward shift.
Regards
Thanks, Anthony.