lol

aTTP, what part of you running your blog as you see fit do you not understand? That is what I had said. You are so efficient at it that you do not generate much discussion, and have to come here instead.

Clearly you consider your site to be perfection which is why you want this site to adopt your standards.

Yes I know you have been snipped at this site, ironically, so have I, responding to your posts.

Radical Rodent, satellite data has been one of the most expensive and accurate means of measuring global warming. Except when climate scientists decide it isn't.

You would have thought it would be easy to program the satellites to produce data in accordance with the computer generated models. It is hardly rocket science for NASA

That's an interesting paper. It's only valid though if the data points are representative of the areas that they cover.

So, how many spatial degrees of freedom do you believe the climate field has? That paper came up with an estimate of 50-90, others have calculated it as 60. So I was indeed wrong to say 60 thermometers were sufficient to provide a good estimate of global temperature.

I should have said 60 well placed thermometers.

We do, of course, have rather more than 60.

http://rankexploits.com/musings/2011/a-monte-carlo-approach-to-estimating-sampling-error/
https://noconsensus.wordpress.com/2011/07/15/subsampled-confidence-intervals-zeke/
http://moyhu.blogspot.co.uk/2010/05/just-60-stations.html

Most of the signatories to the Oregon Petition are engineers. Go figure.

Just for clarification, is this Phil Clarke, who claims that 60 thermometers are sufficient to measure the global temperature, the same person who, on another thread, debunked the CET record because it incorporates readings taken in Utrecht (or so he claims, no doubt because someone on SkS made it up)?

The thermometers have to be where they say they are. Not a difficult idea, surely?

And re: CET I was also concerned with indoor readings and the fact the mercury in glass thermometer was not invented until 1714 ish. Here's what Parker et al - not me or SkS- say about their data

Manley (1953) published a time series of monthly mean temperatures representative of central England for 1698-1952, followed (Manley 1974) by an extended and revised series for 1659-1973. Up to 1814 his data are based mainly on overlapping sequences of observations from a variety of carefully chosen and documented locations. Up to 1722, available instrumental records fail to overlap and Manley needs to use non-instrumental series for Utrecht compiled by Labrijn (1945), in order to mate the monthly central England temperature (CET) series complete. Between 1723 and the 1760s there are no gaps in the composite instrumental record, but the observations generally were taken in unheated rooms rather than with a truly outdoor exposure. Manley (1952) used a few outdoor temperatures, observations of snow or sleet, and likely temperatures given the wind direction, to establish relationships between the unheated room and outdoor temperatures: these relationships were used to adjust the monthly unheated room data. Daily temperatures in unheated rooms are, however, not not reliably convertible to daily outdoor values, because of the slow thermal response of the rooms. For this reason, no daily series truly representative of CET can begin before about 1770.

Remember the noise the Wattites make around badly-sited stations?

LOL

And again it is not me who calculated the 60 degrees of freedom, I rely on Sam Shen et al:

Another example is the question of how many stations are needed to measure the global average annual mean surface temperature. Researchers previously believed that an accurate estimate required a large number of observations. Jones et al. (1986a,b),Hansen and Lebedeff (1987), and Vinnikov et al. (1990) used more than 500 stations. However, researchers gradually realized that the global surface temperature field has a very low dof. For observed seasonal average temperature, the dof are around 40 (Jones et al. 1997), and one estimate for GCM output is 135 (Madden et al.1993). Jones (1994) showed that the average temperature of the Northern (Southern) Hemisphere estimated with 109 (63) stations was satisfactorily accurate when compared to the results from more than 2000 stations.Shen et al. (1994) showed that the global average annual mean surface temperature can be accurately estimated by using around 60 stations, well distributed on the globe, with an optimal weight for each station.

Estimation of Spatial Degrees of Freedom of a Climate Field

The 1994 paper is here

You say the funniest things, Phil:

"The thermometers have to be where they say they are. Not a difficult idea, surely?" Does it matter so much when 60 theremometers can tell you the global temperature?

Also, what is the real relevance of taking the temperature inside a dwelling in an era where central heating did not exist and internal temperatures would have probably followed the same trends as external ones? Stevenson screens were invented to protect thermometers from undue influence of extraneous factors. An 18thc house was probably akin to a Stevenson screen. But, in any case, it would probably allow a reliable anomaly to be calculated since internal temperatures probably track external ones, once the stevenson screen convention is established and there is not central heating and little in the way of draught exlusion, ill-fitting windows etc.

Given the track record of climate science, surely you can permit these assumptions. So much of climate science is just assumptions piled on assunmptions backed by scientific papers without any real proof, eg the under-sampling of global temperatures. How many thermometers used in compiling the global indices are sited in Central Asia, the Himalayas, Hindu Kush, South America. Africa etc? If the resulting index is good enough for your purposes, then the CET qualifies as an outstandingly good case.

Martin A

You estimate that 60 thermometers is too small a sample to calculate a global average.

How many do you estimate are necessary? Please show your calculation.