Surface Solar Radiation in North America: A Comparison of Observations, Reanalyses, Satellite, and Derived Products*

AbstractObservations of daily surface solar or shortwave radiation data from over 4000 stations have been gathered, covering much of the continental United States as well as portions of Alberta and British Columbia, Canada. The quantity of data increases almost linearly from 1998, when only several hundred stations had data. A quality-control procedure utilizing threshold values along with computing the clear-sky radiation envelope for individual stations was implemented to both screen bad data and rescue informative data. Over two-thirds of the observations are seen as acceptable. There are 15 different surface solar radiation products assessed relative to observations, including reanalyses [Twentieth-Century Reanalysis (20CR), CFS Reanalysis and Reforecast (CFSRR), ERA-Interim, Japanese 55-year Reanalysis Project (JRA-55), MERRA, NARR, and NCEP–NCAR Reanalysis 1 (NCEP-1)], derived products [observations from the CRU and NCEP-1 (CRU–NCEP); Daily Surface Weather and Climatological Summaries (Daymet); Glob...