They create an adjustment for the way the Alabama scientists handled data from NOAA-9, a satellite that collected temperature data in the mid-1980s.
From the University of Washington comes this press release:
New research brings satellite measurements and global climate models closer
By Nancy Gohring News and Information For more information: Po-Chedley, pochedls@atmos.uw.edu Trenberth, trenbert@ucar.edu, 303.497.1318
One popular climate record that shows a slower atmospheric warming trend than other studies contains a data calibration problem, and when the problem is corrected the results fall in line with other records and climate models, according to a new University of Washington study.
The finding is important because it helps confirm that models that simulate global warming agree with observations, said Stephen Po-Chedley, a UW graduate student in atmospheric sciences who wrote the paper with Qiang Fu, a UW professor of atmospheric sciences.
They identified a problem with the satellite temperature record put together by the University of Alabama in Huntsville. Researchers there were the first to release such a record, in 1989, and it has often been cited by climate change skeptics to cast doubt on models that show the impact of greenhouse gases on global warming.
In their paper, appearing this month in the American Meteorological Society’s Journal of Atmospheric and Oceanic Technology, Po-Chedley and Fu examined the record from the researchers in Alabama along with satellite temperature records that were subsequently developed by the National Oceanic and Atmospheric Administration and Remote Sensing Systems.
The UW researchers are the first to come up with an adjustment for the way the Alabama scientists handled data from NOAA-9, a satellite that collected temperature data in the mid-1980s.
Scientists like Po-Chedley and Fu have been studying the three records because each comes to a different conclusion.
“There’s been a debate for many, many years about the different results but we didn’t know which had a problem,” Fu said. “This discovery reduces uncertainty, which is very important.”
When they applied their correction to the Alabama-Huntsville climate record for a UW-derived tropospheric temperature measurement, it effectively eliminated differences with the other studies.
Scientists already had noticed that there were issues with the way the Alabama researchers handled data from NOAA-9, one satellite that collected temperature data for a short time in the mid-1980s. But Po-Chedley and Fu are the first to offer a calculation related to the NOAA-9 data for adjusting the Alabama findings, said Kevin Trenberth, a distinguished senior scientist at the National Center for Atmospheric Research.
“It should therefore make for a better record, as long as UAH accepts it,” he said.
To come up with the correction, Po-Chedley and Fu closely examined the way the three teams interpreted readings from NOAA-9 and compared it to data collected from weather balloons about the temperature of the troposphere.
They found that the Alabama research incorrectly factors in the changing temperature of the NOAA-9 satellite itself and devised a method to estimate the impact on the Alabama trend.
Like how a baker might use an oven thermometer to gauge the true temperature of an oven and then adjust the oven dial accordingly, the researchers must adjust the temperature data collected by the satellites.
That’s because the calibration of the instruments used to measure the Earth’s temperature is different after the satellites are launched, and because the satellite readings are calibrated by the temperature of the satellite itself. The groups have each separately made their adjustments in part by comparing the satellite’s data to that of other satellites in service at the same time.
Once Po-Chedley and Fu apply the correction, the Alabama-Huntsville record shows 0.21 F warming per decade in the tropics since 1979, instead of its previous finding of 0.13 F warming. Surface measurements show the temperature of Earth in the tropics has increased by about 0.21 F per decade.
The Remote Sensing Systems and NOAA reports continue to reflect warming of the troposphere that’s close to the surface measurements, with warming of 0.26 F per decade and 0.33 F respectively.
The discrepancy among the records stems from challenges climate researchers face when using weather satellites to measure the temperature of the atmosphere. The records are a composite of over a dozen satellites launched since late 1978 that use microwaves to determine atmospheric temperature.
However, stitching together data collected by those satellites to discover how the climate has changed over time is a complicated matter. Other factors scientists must take into account include the satellite’s drift over time and differences in the instruments used to measure atmospheric temperature on board each satellite.
The temperature reports look largely at the troposphere, which stretches from the surface of the earth to around 10 miles above it, where most weather occurs. Climate models show that this region of the atmosphere will warm considerably due to greenhouse gas emissions. In fact, scientists expect that in some areas, such as over the tropics, the troposphere will warm faster than the surface of the Earth.
The paper does not resolve all the discrepancies among the records, and researchers will continue to look at ways to reconcile those conflicts.
“It will be interesting to see how these differences are resolved in the coming years,” Po-Chedley said.
The research was supported by the National Science Foundation and NOAA.
I am afraid Po and Fu sound like Teletubbies. Hence I must ask my granddaughter whether to believe them. She probably already knows more about climate than them anyway, after all there is a big smiley Sun in the Teletubbies which totally controls their climate.
DR says:
May 7, 2012 at 7:52 pm
Note how these “scientists” never consult Spencer and Christy, they just lob grenades. Fu is the same guy who smeared UAH for stratospheric measurements. Christy and Spencer gobsmacked him then, and I suspect will do the same now.
Whether they ‘gobsmacked’ him or not there was a subsequent upwards adjustment to the UAH trend which was almost exactly the same as the stratospheric cooling influence estimated by Fu.
Until Drs Spencer and Christy have assessed and commented on the data in this paper it seems premature for posters here to comment disparagingly on the alterations. Judging without reading the paper or checking the processes used to or the scientific rationale for making the adjustments is hardly a scientific approach. Responding in this vein gives those such as Gavin Schmidt and Grant Foster more ammunition with which to lambast “CAGW deniers”.
Trenbeth fixes the data.
jorgekafkazar says @ur momisugly May 7, 2012 at 5:59 pm
It’s hard to uncreate data where some exists.
CRU have been quite successful at it 🙂
There are problems with UAH data, particularly evident in the Tropics. I don’t know if this proposed fix is the right fix or not, but they do need to fix it. This issue is why a lot of people have been turning from UAH to RSS for data lately. Dr Spencer even admits this in his blog when he says:
“But, until the discrepancy is resolved to everyone’s satisfaction, those of you who REALLY REALLY need the global temperature record to show as little warming as possible might want to consider jumping ship, and switch from the UAH to RSS dataset.
It’s OK, we’ve developed thick skin over the years. You can always come home later.”
You can read the whole blog here…
http://www.drroyspencer.com/2011/07/on-the-divergence-between-the-uah-and-rss-global-temperature-records/
As a skeptic, I think the most important thing is to get the differences in satellite datasets sorted out as quickly as possible. We need a completely valid dataset which everyone can believe in and put their trust in.
A telling statement from RSS at: http://www.ssmi.com/msu/msu_data_description.html
The MSU and AMSU instruments were intended for day to day operational use in weather forecasting and thus are not calibrated to the precision needed for climate studies. A climate quality dataset can be extracted from their measurements only by careful intercalibration of the distinct MSU and AMSU instruments.
The above page also describes some of the ‘adjustments’ made to data showing just how difficult it is to rely upon satellite measurements for temperature.
And: http://www.star.nesdis.noaa.gov/smcd/spb/calibration/msu/msucal.pdf contains a good description of how the MSU is calibrated.
The abstract for this paper reports in degrees K, not F. It is reasonable to assume the paper will use K.
“The University of Alabama at Huntsville (UAH), Remote Sensing Systems (RSS), and the National Oceanic and Atmospheric Administration (NOAA) have constructed long-term temperature records for deep atmospheric layers using satellite microwave sounding unit (MSU) and advanced microwave sounding unit (AMSU) observations. However, these groups disagree on the magnitude of global temperature trends since 1979, including the trend for the mid-tropospheric layer (TMT). This study evaluates the selection of the MSU TMT warm target factor for the NOAA-9 satellite using five homogenized radiosonde products as references. The analysis reveals that the UAH TMT product has a positive bias of 0.062 ± 0.040 in the warm target factor that artificially reduces the global TMT trend by 0.050 K decade−1 for 1979 – 2009. Accounting for this bias increases the global UAH TMT trend from 0.038 K decade−1 to 0.088 K decade−1, effectively eliminating the trend difference between UAH and RSS and decreasing the trend difference between UAH and NOAA by 56%. This warm target factor bias directly affects the UAH lower tropospheric (TLT) product and tropospheric temperature trends derived from a combination of TMT and lower stratospheric (TLS) channels.
@ur momisugly Skeptikal on May 8, 2012 at 4:38 am:
Your comment and reasoning seems most confused. As mentioned at the start of the original post above, stated as a conclusion of the paper:
One popular climate record that shows a slower atmospheric warming trend than other studies contains a data calibration problem, and when the problem is corrected the results fall in line with other records and climate models, according to a new University of Washington study.
So the identified problem is UAH is not showing enough warming.
You say of assorted “problems” with the UAH dataset, noting specifically the Tropics: “This issue is why a lot of people have been turning from UAH to RSS for data lately.”
Yet the Dr. Spencer post you linked to and quoted from says (bold added), backed with data and graphs:
But, until the discrepancy is resolved to everyone’s satisfaction, those of you who REALLY REALLY need the global temperature record to show as little warming as possible might want to consider jumping ship, and switch from the UAH to RSS dataset.
Thus Dr. Spencer identified in that post that UAH shows more warming than RSS.
So this new paper argues UAH needs more warming to bring it in line with RSS and other datasets. Dr. Spencer identified that UAH needs less warming to line up with RSS, or RSS needs more to align with UAH.
Got that?
Paper: UAH needs more warmth to match RSS
Spencer: UAH needs less warmth to match RSS
Now how can that paper possibly be right, and that proposed fix be a good one, when they don’t even know what direction to move UAH?
@ur momisugly kadaka (KD Knoebel),
If you read the article, you’ll notice that the problem being addressed in this article relates to data from NOAA-9. This was a satellite used in the 1980’s. Back then, UAH was LOWER than RSS. The numbers being punched out by UAH for the latest observations are HIGHER than RSS.
UAH: LOW in the 1980’s
UAH: HIGH now.
So, UAH data has more than one problem when compared to RSS or any other dataset. That’s not to say that all the problems are with UAH data, but I’d be surprised to find no problems with UAH data.
Got it?
Hmm. I am no expert but their approach sounds like it assumes that the UAH data is the data that needs recalibration. Is there a rationale given for why the RSS and NOAA data do not need recalibration to match the UAH data? They seem to assume there is “something wrong with” the UAH data, so we need to adjust it to fit their models. Is there a rationale given for why the models should not be adjusted to fit the data?
Reading J. Gleick’s Chaos book would indicate that modeling non-normal, nonlinear systems such as climate should be done with great humility. Minor differences in the beginning conditions can cause dramatically different results. Misunderstanding processes (which is easy to do) leads GIGO. In climate research, it seems rational to ALWAYS start with the hypothesis that the model is wrong and needs changing to reflect the data. Am I missing something?
Probably time to trot out this email.
http://www.ecowho.com/foia.php?file=1939.txt&search=wealth+of+others
@ur momisugly kellyhaughton,
“They seem to assume there is “something wrong with” the UAH data, so we need to adjust it to fit their models.”
This has nothing to do with models. It’s all about datasets being in agreement with other datasets.
what have these temperature-anomalies to do with the definition of the climate?. These values are in my opinion absolutly useless numbers. Accordung to Prof. Kramm, university of Alaska, Fairbanks, none of the global mean energyfluxes depends on the mean tempeature value of the earth surface.
I was buying a particular model of thermometer in Walmart the other day and noticed they didn’t all show the same temperature. So I lined them all up and chose one based on how many others gave the same reading.
I went with the consensus opinion.
It was quite clear when the “CO2 leads temperature” paper that the team is systematically attacking some of the core points skeptics use. They are just making stuff up for AR5. It doesn’t matter if it won’t hold up to scrutiny. They have the money and the will to tell lies and stand behind them forever.
Kadaka, Spencer is referring to the TLT product whereas this paper is talking about the discrepancy in the TMT products.
SM touched upon this subject ~3yrs ago:
http://climateaudit.org/2009/07/18/rss-versus-uah-battles-over-tropical-land-and-ocean/
http://climateaudit.org/2009/07/21/more-tropical-troposphere-uah-versus-noaa/
I don’t think Steve is interested in updating this analysis, but maybe Willis is?
The true definition of Manmade Global Warming is men fiddeling with empirical data to make all temperature graphs go from lower left to upper right….
It’s funny, I was joking with a friend yesterday that the IPCC will have to increase UAH and RSS satellite temperatures as their huge disparities currently invalidate the “new and improved” HadCRUT4 and CRUTEM4 monstrosities….
Right on cue…..
I’d like to say I can’t believe they’re actually considering increasing the satellite temperatures, but That would be naive.
CAGW *sigh*ence at its best…. It’s disgusting.
nutso fasst says:
May 8, 2012 at 7:25 am
I was buying a particular model of thermometer in Walmart the other day and noticed they didn’t all show the same temperature. So I lined them all up and chose one based on how many others gave the same reading.
I went with the consensus opinion.
=================================================================
I would’ve gone and bought a drink with ice in it….. and done it scientifically.
I’d buy whichever thermometer said my melting ice was 0 degrees celsius.
Now to adjust that pesky historical record so it shows the AGW predictions regarding extreme weather……
This ‘adjustment’ reeks of ex-post facto diddling to achieve the desired result.
Perhaps it is the current data the needs adjusting- down?
@ur momisugly Skeptikal on May 8, 2012 at 6:20 am:
Had read it, wasn’t impressed. For example:
Yet as has long been mentioned by Spencer, as it says at this writing on the UAH Monthly Global Anomaly Update page here:
I have read they used to calibrate by referencing an onboard “hot target”, and temperature of the satellite was something to consider, but not currently. Thus the more recent UAH vs RSS divergence, which Spencer’s post identified as growing over the last ten years, remains unresolved.
The arguing is over the trends, with the UAH warming trends since 1979 not matching RSS. As it says above:
By applying their correction to the NOAA-9 changeover near the oldest end of the record, lowering the trend line on that end, they get the tropic trends to match.
But Spencer said in his post about the global average lower tropospheric temperature anomalies (1979 through June 2011):
So the paper basically argues for a correction that lowers one end of UAH’s tropic trend line until it matches the RSS tropic trend line. But how can you make such a correction that affects all of the relevant satellite readings to bring the tropics into agreement, without screwing up the already-existing great agreement with the global trend lines?
I will admit you got me on the timeline, I should have caught that, and I shouldn’t allow my current sleep-deprived state to be an excuse. But please explain to me, if you can, how this adjustment to rectify the “tropic problem” won’t screw up the global trends. Looks like another fine example of “cutting off the nose to spite the face” at this point.
From J.Hansford on May 8, 2012 at 8:22 am:
Ethanol depresses the freezing point. Its cousin methanol was used in the early days of automobiles as engine antifreeze. If you were watching your flavored ethanol/water solution as it cooled to see when ice started to form, I definitely would not pick a thermometer which said it happened at 0°C. But I’m not certain what would happen with an above-freezing solution that had ice added, if you’re actually directly checking the temperature of the solution rather than the ice.
Research is indicated.
So there’s a calibration error. That implies, to me, that they’ve found a systematic, constant error to the satellite temperature measurements. So how does this affect the temperature slope over time?
ROFLMAO.
So how are they (Po-Chedley & Fu) going to justify their results when the .21 F warming per decade gets re-adjusted after the surface temp data is “corrected” later by their cohorts?
What we’ve got is not the dog chasing its tail, but the tail chasing its tail. My prediction, based on the CAGW history of adjustments is that they’ll want this paper to quietly fade when more NOAA adjustments make this paper false.