****************************************EXCERPT****************************************
Mike Haseler says:
I once designed a precision temperature “oven” which had a display showing the temperature to 0.01C. In practice the controller for device was only accurate to 0.1C at best and with a typical lab thermometer there was at least another 0.1C error. Then the was the fact you were not measuring the temperature at the centre of the oven and drift and even mains supply variation had a significant effect!
All in all the error of this device which might appear to be accurate to 0.01C could have been as bad as the total so called “global warming signal”.
I’ve also set up commercial weather stations using good commercial equipment which I believe is also used by many meteorological stations and the total error is above +/-1C even on this “good” equipment.
As for your bulk standard thermometer from a DIY shop. Go to one and take a reading from them all and see how much they vary … it’s normally as much as 2C or even 3C from highest to lowest.
Basically, the kind of temperature error being quoted by the climategate team is only possible in a lab with regularly calibrated equipment.
Good Stuff at the link:
******************************EXCERPT***************************************
boballab says:
I actually ran a spreadsheet back in December showing how just 3 instrument changes, with each instrument having better resolution, over a long term historical record changes the trend of the data (over 1° F in change to the USCHN data)
http://boballab.wordpress.com/2010/12/06/do-we-really-know-what-the-temperature-is/