Tisdale on ENSO step changes in RSS global temperature data

The sensors are calibrated before flight and compared to a onboard reference. So why do the sensors not agree about surface temp straight out of the box?
Is the uncertaintly in the orbit or a limit in our knowledge of modelling temp from the reading?
At least with satellites the revision of the past are limited and documented.

The step changes are even more apparent in the TLS channel, where the temperature level drops abruptly following the large spikes caused by the El Chichon and Mt. Pinatubo eruptions, but then is flat or even slightly upward. I find the use of a linear trend line unreasonable when there’s almost no trend since 1994 (which is over half the total period).

Dear Bob,
I respect and appreciate your fine work and analysis, and I am not qualified to criticize it. However, two questions jump out:
1. Are there other equally valid smoothed lines that fit the data other than your 3-step summary (especially if other, earlier, starting points were considered)?
2. How sensitive is your model to possible future states? That is, what if by the end of the year 2011 data shows a drop to -0.2°C anomaly? Would that change your conclusions?

What are the “standard deviations” of this data over this period.
How “significant” are the changes?
Max

Mike D. says: “Are there other equally valid smoothed lines that fit the data other than your 3-step summary (especially if other, earlier, starting points were considered)?”
The thought that TLT anomalies north of 20N were rising in steps in response to significant ENSO events came from the RSS Hovmoller plots. Refer to…
http://bobtisdale.blogspot.com/2009/06/rss-msu-tlt-time-latitude-plots.html
With respect to earlier TLT data, the satellite-based TLT anomaly data starts in 1979, so there’s no way to consider earlier starting points
You asked, “How sensitive is your model to possible future states? That is, what if by the end of the year 2011 data shows a drop to -0.2°C anomaly? Would that change your conclusions?”
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.

Max Hugoson says: “What are the ‘standard deviations’ of this data over this period.”
For the global RSS TLT anomalies version 3.2, the standard deviation is 0.23 deg C and for version 3.3, it’s 0.22 deg C.

@Sean: From the RSS site “The brightness temperature for each channel corresponds to an average temperature of the atmosphere averaged over that channel’s weighting function.” This appears to confirm that they have done an inversion step. Since frequency drift in the radiometers would shift the weighting functions either up or down in altitude, going back and using a time varying weighting function to re-invert the temperature data would be logical. Something that we ignored way back when, but something that causes a drift in the retrieved temperature profile with time. As I stated, you are trying to pull 15 temperatures from 3 or 4 channels of data and an estimated reflectivity. 15 numbers from 5 numbers leaves 10 degrees of freedom that you have to pull out of something. The adiabatic lapse rate of the atmosphere helps you under the assumption of no vertical mixing. Again, I do not know what inversion scheme they use these days. If anyone knows, I would be interested to hear what it is.

Actually, I doubt that because its dipping so low now and comparing with 2008, at this rate 2011 looking very like 2008 or cooler, ie: no warming again

Should we act on the climate change information we have been fed?
I think this little post of mine illustrates that dilemma very well.
http://globalwarmingsupporter.wordpress.com/2011/03/07/what%e2%80%99s-up-there-and-how-we-know/
Cheers
Roger

Stephan says: “What is this then?”
AMSU Channel 5 with different base years than the data being presented in this post

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. They go on and babble about the cooling effect of Pinatubo overriding the warming effect of an El Nino which is utter nonsense because the El Nino that did coincide with the eruption is there as big as life. As to El Chichon, it erupted when a La Nina had just bottomed out and an El Nino was starting. If a volcano can override an El Nino this was a golden opportunity for El Chichon to demonstrate that but it never happened. This volcano had no cooling effect whatsoever at ground level and even Self et al. admit that as an unexplained mystery. It is not a mystery if you understand that tyis volcanic cooling effect is a myth. El Chichon aerosols did their stuff in the stratosphere and that is where its influence remained. For this reason there is no justification whatsoever to use any kind of volcanic adjustment because there is no way you can show any ground level cooling from it. And this goes for all volcanoes of the twentieth century. As I have pointed out in my book there is just one step change in the entire satellite record and that is the one that raises global temperature by a third of a degree between 1998 and 2002. There was no temperature rise before or after it. It started with the super El Nino of 1998 which itself does not belong to ENSO and should not be included in any sort of averaging like you have done in figures 2 and 5. You need to redraw these figures and show two horizontal lines on both sides of the step rise initiated by the super El Nino and its aftermath. It is best accomplished by using the full monthly resolution temperature chart and applying the magic marker method to fully articulate the temperature trend. Check out my figure 15 in the book to see how it is done. Better yet, spring for my book to avoid future embarrassments like this.

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

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.

The step changes are caused by the solar cycle, not 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.

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.

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.

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