They can analyze the data 100 more times if they want to; it's still worthless. For all intents and purposes, a truly accurate and reliable long term temperature data set doesn't even exist.
Urbanization effects could, in principle, be tracked.
They know that. The Met office just wants to announce that the unfortunate (but minor) problems with their data have been resolved. Everything is fine now. Please stop pestering us to support our claims with verifiable evidence.
I believe the conspirators must have recognized that years ago which is why they set about creating a "proxy" data set using reports from "standard weather stations" located around the world.
Depending on which story you read there were up to 1800 such stations outside the United States, and maybe up to 1200 stations inside the United States.
For the last 25 years most of them have had "auto-logging" capability ~ which means that they have a device that automatically records the readings on the various instruments that make up a "standard weather station".
Before that the typical standard weather station was non-automated. We've had articles with analysis appear in FR over the last few years that discuss the utility of the non-automated standard weather stations. A review of what the stations are about and how measurements have been made in the past is available at http://www.nws.noaa.gov/om/coop/standard.htm (for what it's worth).
The deal with these stations is that someone has to stop by and record what the instruments are saying on some sort of regular basis. The idea of having a standard station suitible for placement anywhere is that it doesn't matter if you make these measurements in Antarctica or the Khalihari desert, as long as you have the same instruments, the same protective housing and adhere to the guidelines in siting the station, there should be some resultant and meaningful relationship between what you report to have been measured and what actually went on at a global scale, e.g. Hot at Equator, Cold at Poles.
The fundamental problem with the standard weather station as used in the "cooperative program" is called MAINTENANCE, and not just maintenance of the measurement devices, but also of the siting of the station. Many stations have not been "fixed" in decades, and others have ended up located next to air conditioners (as urbanization has moved out to their locations).
In yet other cases the standard weather station has simply been replaced with a much more expensive manned radio sonde operation with 24/7 minute by minute reporting of all relevant factors.
BTW, it is my impression that the weather guys want folks to believe that the standard weather station is the radio sonde type of device array rather than some passive unpowered bulbs housed in a wooden box out in the middle of a farmer's field!
The "data set" the climatologists are referring to is the century of measurements made AT, not by, unmanned, unpowered standard weather stations (bulb type thermometers, et al inside a vented wooden box). Again, these things are all over the world with the largest number in a single country called The United States.
Some very large areas, e.g. the Congo, have only 3 such stations! For the most part only 1 station (an advanced radio sonde operation) has been "open" over the last half century. The other 2 are sometimes open, somtimes closed, and sometimes the parts are stolen for scrap. One difficulty has been finding trained personnel to take the measurements ~ most notoriously in an outbreak of war nearly 15 years go the folks responsible for taking and reporting measurements appear to have been captured and eaten by rebel troops.
Data from Congolese stations has been used in the "data base". Obviously its reliability should be open to question.
Two years ago even Dr. Hansen became sufficiently alarmed at the maintenance and reliability issues surrounding the standard weather stations in Africa and South America he simply deleted it all from his climatological models. He said it really didn't matter much to the model anyway.
Other researchers did a phenomenal job evaluating the reliability of the American data. Yes, even in America maintenance has been a serious problem. Hansen has trimmed things down to just 600 out of the 1200 standard weather stations. That, alas, has the effect of increasing the influence of the radio sonde stations in the data flow ~ making things toastier since most of those operations take place at airfields in or near urban areas. At the same time Hansen has rejected data from older standard weather stations that've ended up in the middle of interstate highways (like one between Richmond Indiana and Dayton Ohio), next to air conditioners, at the end of runways at jet capable airports, and so on.
I do not believe he made an attempt to reject station data where white wash paint on the roof of the standard weather stations had been replaced with acrylic paint. Seems white wash (Portland cement based) STOPS ultraviolet in its tracks, but acrylic lets ultraviolet get through to the delicate instruments inside. The heat curve reported by the stations has, BTW, paralleled the replacement of white wash paint by acrylic paint in outdoor applications.
For whatever reason, Hansen DROPPED the data from half the standard weather stations in the United States.
There is a very good chance that all of the data reported in the first 50 years after the invention of the thermometer will prove inadequate to world wide reporting needs. After all, the standard weather station didn't exist. There was no control on siting. Africa and South America, to say nothing of North America, Siberia and other farflung places weren't even fully mapped at the time! Western China (the Himalayan plateau and Tibet) appears to have been covered by about 30 standard weather stations.
The next 100 years of reporting runs smack into the problem with maintenance, or technological change.
I really don't think these guys can get past the problem of the data generated by use of standard weather stations being functionally incompatible with radio sonde data, and neither being functionally compatible with more recent satellite data.
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NEXT ~ an extended discussion of how you take data reported twice a day and turn that into an AVERAGE DAILY TEMPERATURE.
No, adding the results and dividing by 2 doesn't cut it ~ the problem is far, far more complex!