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Post by helen on Feb 6, 2011 20:19:26 GMT 1
Ok, but how's the general trend?
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Post by marchesarosa on Feb 7, 2011 10:11:57 GMT 1
Helen, dear, you cannot talk about a "trend" when the stations providing the 1960s temperatures are a different set from the ones providing the 2000s data.
At its peak the number of stations selected by GHCN to calculate the average was more than 6,000. Today the stations from which the average is derived is just in excess of 1000. (Hence the joke in reply#25 about 'reinstating' the Canadian and Siberian stations as a cheap way to "cool" the planet, which presumably you didn't "get"!)
I'm REALLY surprised you did not know this well known fact. How do YOU think such a sampling change would affect mean temperature comparability over time especially in view of the fact that the vast majority of surface stations included in the GHCN set today are located in airports and urban areas whereas the ones used to calculate the temperatures of periods prior to the 1990s are much more geographically spread including many more pristine rural surface stations?
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Post by louise on Feb 7, 2011 10:23:36 GMT 1
Perhaps one of the reasons that they do not use as many stations as previously is that those that have been discarded are now too close to urban areas whereas they weren't originally?
Removing them may help to counter any effect of UHI - that is the title of this thread after all.
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Post by marchesarosa on Feb 7, 2011 10:31:51 GMT 1
Ingenious idea, Louise! Or did I mean ingenuous?
It is the pristine rural areas which have been culled, alas.
The selection of stations (as also the adjustments and homogenisation) always has the effect of increasing the calculated global mean temperature. In other words, UHI is being passed off as CO2-induced warming.
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Post by marchesarosa on Feb 7, 2011 10:40:24 GMT 1
Jo Nova adds
"... people might not realize that many thermometers haven’t actually disappeared — they are often still collecting data — it’s just that their records are not being included in the “global” compilations. Though, as Watts and D’Aleo point out, sometimes these forgotten thermometers are still used to calculate the baseline averages."
Now there's a thought, thelma and louise! Had you considered the implication of the base-line including a much wider spread of data than the most recently culled selection? How would that affect the comparisons, do you think? Would it be a comparison of like with like?
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Post by marchesarosa on Feb 7, 2011 10:47:41 GMT 1
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Post by louise on Feb 7, 2011 11:26:19 GMT 1
Entirely off topic, sorry.
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Post by jonjel on Feb 7, 2011 11:59:07 GMT 1
Entirely off topic, sorry.
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Post by helen on Feb 7, 2011 12:59:59 GMT 1
Entirely off topic and disingenuous too.
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Post by helen on Feb 7, 2011 13:04:47 GMT 1
Just looked at your links marchesarosa. How come no one takes any notice of this stuff? Ever ask yourself this?
Helen, if you cannot respond to substantive posts with substantive answers find another board.
If I have to mention this again you will be suspended again.
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Post by helen on Feb 7, 2011 13:44:08 GMT 1
That's a weird post, Joanne and me together? So I'm called for disagreeing with marchesarosa, again.....so suspend me. We don't seem to have a very level playing field here.
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Post by helen on Feb 7, 2011 13:50:21 GMT 1
Can I add that if you suspend me, can you allow me to visit the site? It's interesting stuff here on the whole. Being denied access to even view was bit harsh last time. Don't get the rules Joanne, some folk seem to get away with metaphorical murder and others get called from pillar to post. There are rules here, what are they?
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Post by marchesarosa on Feb 7, 2011 14:14:55 GMT 1
Back on topic! Here's a post from October 2009 when Chiefio had just started deconstructing the diminishing GHCN network. He is discussing Canada here. chiefio.wordpress.com/2009/10/27/ghcn-up-north-blame-canada-comrade/" There are now NO thermometers (as of 2009) in the 65-70, 70-75, and 80-85 bands. 1992 saw the 80-85 band die. 2009, the others. Due to the general slaughter of thermometers, that 75-80 band is ONE thermometer. (the bands Chiefio refers to are bands of latitude) That’s right. ONE thermometer for everything north of LAT 65. Who needs Northwest Territories, The Yukon Territories, or Baffin Island anyway… GIStemp can just estimate it from the satellite ice map projection synthesis interpolation estimates. (Yes, it does that…). Oh, wait, you say there have been sensor issues with the polar ice satellites?
EUREKA,N.W.T. 79.98 -85.93 10 222R -9MVxxCO 1A-9WATER A 0
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Post by louise on Feb 7, 2011 14:26:35 GMT 1
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Post by Joanne Byers on Feb 7, 2011 14:30:22 GMT 1
Helen, write substantive posts on scientific subjects if you wish to participate here. Persistent needling will not be tolerated. If you think the board is worth reading try to contribute something worthwhile to it, please.
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