On the reliability of the U.S. surface temperature record

Recent photographic documentation of stations that comprise the U.S. Historical Climatology Network (HCN) has lead to questions regarding the reliability of surface temperature trends over the continental U.S. (CONUS). In order to evaluate the potential impact of exposure on CONUS temperature trends, we compare trends derived from poor and well sited HCN stations. In addition, annual CONUS temperatures from the HCN are compared to values derived from the U.S. Climate Reference Network. The role that data homogenization plays in reducing uncertainty in U.S. temperature trends is also discussed.