Did Federal Climate Scientists Fudge Temperature Data to Make It Warmer? - Reason.com

Great read to be reminded how hard it is to even answer the question "what temperature was the world yesterday?"

Answer:  We think we know because we correct for measurement bias.

This is a must read - it makes crystal clear that it is entirely within the power of these NCDC folks to invent temperatures.

http://reason.com/archives/2014/07/03/did-federal-climate-scientists-fudge-tem

In contrast, the researchers at the NCDC have spent years combing through U.S. temperature data records trying to figure out ways to adjust for confounders. In 2009, the NCDC researchers detailed how they go about adjusting the temperature data from the 1,218 stations in the Historical Climatology Network (HCN). They look for changes in the time of observation, station moves, instrument changes, and changes in conditions near the station sites (e.g., expanding cities). They filter the data through various algorithms to detect such problems as implausibly high or low temperatures or artifacts produced by lazy observers who just keep marking down the same daily temperatures for long periods.