Captain Nemo wrote on Dec 13
th, 2018 at 11:07am:
That's why they constantly strive to improve the accuracy of the data.
Which of course does not say it is good.
Captain Nemo wrote on Dec 13
th, 2018 at 11:07am:
There is no doubt that the GISS data is the best and most thoroughly wide ranging data to provide the best long term climate change picture that is available.
Actually HadCRUt4 is alleged to be the best. And even that is not saying it is good.
"In this research report, the most important surface data adjustment issues are identified and past changes in the previously reported historical data are quantified. It was found that each new version of GAST has nearly always exhibited a steeper warming linear trend over its entire history. And, it was nearly always accomplished by
systematically removing the previously existing cyclical temperature pattern. This was true for all three entities providing GAST data measurement, NOAA, NASA and Hadley CRU. "
https://thsresearch.files.wordpress.com/2017/05/ef-gast-data-research-report-062... "For station data to be useful for such studies, it is essential that the time series of observations are consistent, and that any non-climatic temperature jumps, introduced by station moves or equipment updates, are eliminated. In adjusted data the effect of such non-climatic influences is eliminated whenever possible. Originally, only documented cases were adjusted, however the current procedure used by NOAA/NCEI
applies an automated system that uses systematic comparisons with neighboring stations to deal with undocumented instances of artificial changes."
So how do they know there were actual changes? Neighbouring stations don't necessarily reflect what is happening elsewhere. Eg. A thunderstorm is a local event. It causes cooling. How would a neighbouring station know that?