Approximately 92% (or 99%) of USHCN surface temperature data consists of estimated values
Conclusion
The US accounts for 6.62% of the land area on Earth, but accounts for 39% of the data in the GHCN network. Overall, from 1880 to the present, approximately 99% of the temperature data in the USHCN homogenized output has been estimated (differs from the original raw data). Approximately 92% of the temperature data in the USHCN TOB output has been estimated. The GHCN adjustment models estimate approximately 92% of the US temperatures, but those estimates do not match either the USHCN TOB or homogenized estimates.
The homogenization estimate introduces a positive temperature trend of approximately 0.34 C per century relative to the USHCN raw data. The TOBs estimate introduces a positive temperature trend of approximately 0.16 C per century. These are not additive. The homogenization trend already accounts for the TOBs trend.
http://wattsupwiththat.com/2015/09/27/approximately-92-or-99-of-ushcn-surface-temperature-data-consists-of-estimated-values/
The US accounts for 6.62% of the land area on Earth, but accounts for 39% of the data in the GHCN network. Overall, from 1880 to the present, approximately 99% of the temperature data in the USHCN homogenized output has been estimated (differs from the original raw data). Approximately 92% of the temperature data in the USHCN TOB output has been estimated. The GHCN adjustment models estimate approximately 92% of the US temperatures, but those estimates do not match either the USHCN TOB or homogenized estimates.
The homogenization estimate introduces a positive temperature trend of approximately 0.34 C per century relative to the USHCN raw data. The TOBs estimate introduces a positive temperature trend of approximately 0.16 C per century. These are not additive. The homogenization trend already accounts for the TOBs trend.
http://wattsupwiththat.com/2015/09/27/approximately-92-or-99-of-ushcn-surface-temperature-data-consists-of-estimated-values/