NOAA and NASA "versions" of average US temperature

[marchesarosa]

I've already posted this graph somewhere else but I can't find it. So I'll start a new thread.

It shows that the 2009 annual US temperature, according to NOAA, returned to the 20th century average. That's a bit of a surprise, isn't it, what with all those hockeysticks we are so accustomed to seeing?

A bit of background.

There are three institutions that collate global temperature datasets, CRU, NOAA and NASA/GISS. They are all based on the Global Historical Climate Network that has been described in detail by the Chiefio here thesequal.proboards.com/index.cgi?board=climate&action=display&thread=20

The GHCN is deeply flawed. It was savagely reduced in about 1990 from 6,000 to about 1,500 surface stations, its raw data are subject to SERIOUS Urban Heat Island Effect and other non-climatic distortions and some of the data has already been fiddled with by the National Metorological Bureaux before it even gets o the GHCN!

THEN the IPCC favoured sons (NASA/GISS, NOAA and CRU) get to fiddle with it even more (adjustments and homogenisation) to produce their idea of what the global average temperature is. This thread is about the difference between the NASA/GISS and NOAA figures for the United States.




Steve McIntyre cautions:

Readers need to keep in mind that there is a substantial “divergence” between NOAA US and NASA US temperatures as shown in the graphic below. Since 1940, NOAA’s US has increased relative to NASA’s US at a rate of 0.39 deg C/century, thus 0.27 deg C since 1940.



Figure 2. Difference (deg C) between NOAA US and NASA US temperature anomalies.


At present, we don’t know very much about the NOAA calculation. To my knowledge, they make no effort to make a UHI adjustment along the lines of NASA GISS. As I’ve mentioned before, in my opinion, the moral of the surfacestations.org project www.surfacestations.org/ in the US is mainly that it gives a relatively objective means of deciding between these two discrepant series. As others have observed, the drift in the GISS results looks like it’s going to be relatively small compared to results from CRN1-2 stations – a result that has caused some cackling in the blogosphere. IMO, such cackling is misplaced.

The surfacestations results give an objective reason to view the the NOAA result as biased. It also confirms that adjustments for UHI are required. Outside the US, the GISS meta-data on population and rural-ness is so screwed up and obsolete that their UHI “adjustment” is essentially random and its effectiveness in the ROW is very doubtful. Neither NOAA nor CRU even bother with such adjustments as they rely on various hokey “proofs” that UHI changes over the 20th century do not “matter”.

Steve then tetchily points out that though we layfolk may be surprised that there should be a difference between the findings of NOAA and NASA that is based on a wrong assumption. He says "you’re assuming that there is “data” that gives you a straightforward answer; there isn’t. Measurement systems and environments have changed. Having said that, there are better and worse data sets and better and worse ways of handling data. There are dozens of threads on this."

So, we've been told!

It take it that this means until the data are settled the science is not settled, either. Good! Glad we've got that sorted.

[sciencebiker]

But this is, once again, wrong in important details which invalidate the whole line of argument.
You say that Chiefio claims the major datasets all come from the same source data? Just wrong, completely wrong. HadCRU certainly doesn't even take data from GHCN. This takes approximately 5 minutes to check, so why don't you?
]
You ask what about the hockey-stick...did you look at the graphs? I see a hockey-stick quite clearly.

The IPCC do NOT get the modellers or the data-suppliers to change the source data or model treatment of that data, so I'm not sure where that particular piece of nonsense comes from.

Remove these and the rest of it falls apart under the weight of its own misconceptions.

[marchesarosa]

I'm afraid I do NOT see a hockey stick in the graph in question, biker. (You are surely not referring to the second "differences" NOAA minus NASA graph?)

I see, in the top graph, a cyclical oscillation around a slightly rising trend. (with the latest observation DEAD on the century average.)

Nothing there points to an anthropogenic signal rather than natural variation.

We KNOW the world's temperature has been on an overall rising trend since the last ice-age, don't we, that's not controversial, is it?

[marchesarosa]

I found the original graph which I obtained from Pat Michaels' blog entitled

"Another normal year in the US"

www.worldclimatereport.com/index.php/2010/01/08/update-2009-another-normal-year-in-the-us/








Figure 1. U.S. annual average temperature, 1895-2009 (source: National Climatic Data Center)

[sciencebiker]

Jan 17, 2010 14:25:57 GMT marchesarosa said:

We KNOW the world's temperature has been on an overall rising trend since the last ice-age, don't we, that's not controversial, is it?

Of course not (not amongst the scientists anyway). The thing that the sceptics always forget to add - in order to prevent YET MORE misinformation, is that those rising trends are gradual and last for thousands of years, not sudden and obvious over a 30 year average.
All the graphs you have provided show the same thing - warming consistent with the basic observation that CO2 and temperature correlate pretty strongly.

[marchesarosa]

Although we are discussing just the American record I would be surprised if the rest of the Northern hemisphere departed much from this trend over the 20th century.

[sciencebiker]

Jan 17, 2010 15:15:40 GMT marchesarosa said:

Although we are discussing just the American record I would be surprised if the rest of the Northern hemisphere departed much from this trend over the 20th century.

Why? Local climate variations can display different periodicities.
We already know about el and la nino effects, the global conveyor, the two known solar cycles (which obviously produce different effects depending on latitude and other variables.
Some local climate trends may be completely opposite for a while to the global temp trend.
When, however, you 'fiddle' with the moving average these local effects begin to smooth into the overall trend. This is one reason to fiddle with the data - but of course sceptics immediately cry dishonest.

[marchesarosa]

Ah, now you are bringing CO2 into the debate, biker.

I remain unpersuaded that we have got to the bottom of that particular phenomenon either.

But the fact that atmospheric CO2 from fossil fuels has increased does not mean it is the CAUSE of the slight upward temp trend we observe. We are still largely ignorant of the other climatic elements that could serve as an effective "thermostat" mitigating the predicted ruanaway/catastrophic impact of extra CO2.

Assertion is only assertion and even though it be asserted a million times that does not make it true.

Constant reference to the "greenhouse effect" and "settled science" begs the question of how CO2 ACTUALLY works since it but a single element in the climate system which, as you know, is VERY complicated indeed. Just because the big picture is not yet understood is no reason to over-hype the importance of the one piece of the jigsaw which, it is claimed by some, is perfectly conceptualised.

It isn't. Even I, as a complete amateur, can perceive the almost total lack of evidence concerning the role of CO2 in the climate system. I do not deny it is a GHG. I deny its influence is understood. And so do plenty of others whose scientific credentials are unassailable.

And please, don't try to denigrate "contrarian" scientists by claiming they are "creationists" or believe in Martians or some such imagined slur. If the science stands up to criticism it doesn't matter who is conducting it or what motivation YOU may impute to them.

Motivation or interest is irrelevant to the actual development of science. Does it stand up to criticism is the only thing that's important.

[sciencebiker]

Conrtarians dengrate themselves by their constant untrue claims and attacks on the integrity of scientists with not a scrap of evidence.

a) The mechanism of the Greenhouse effect is very well known and have been for over a century. There a thousands of papers on this in the literature.

b) The cause-effect relationship is disputed by contrarians because of an apparent lag between the start of warming and the concentration of CO2 in some ice core data. There are two points which climate scientists keep repeating and contrarians keep choosing to ignore:
i. The recordings are very difficult to match exactly - we are overlaying data from two or more different sources on a long timescale. The lag COULD be measurement inaccuracy.
ii. Even if the graphs are aligned correctly, a slight lag was predicted ages age (17 years) by climate scientists. The reasons are a little technical but not beyond the comprehension of a lay-person willing to devote a little effort.
I can provide links to the papers, but it is explained for the non scientist here:
www.realclimate.org/index.php/archives/2007/04/the-lag-between-temp-and-co2/
So there IS a correlation between Co2 and temp and a very strong and obvious one.

I can give a basic lecture in how CO2 effects temperature, because it really isn't as complex as you think. I'll post a link to the wiki which explains it pretty well, but if you want better sources from the literature I can do that too:
en.wikipedia.org/wiki/Greenhouse_effect

[marchesarosa]

You may be able to discuss how CO2 works in isolation absorbing and emiting radation of certain wavelengths but you certainly cannot explain how it works on a planetary scale, and no-one else can - YET.

Hubris!