Hourly Solar Radiation and Meteorological Data

Hourly Solar Radiation Data is historical data set DSI-9725 archived at the National Climatic Data Center (NCDC). Elements included are total solar radiation measured in Langleys per hour, solar elevation, extraterrestrial radiation and various surface observations ranging from temperature and dew point to type of precipitation, snow cover and cloud layer parameters. This data set covers approximately 50 stations in the United States and in the Pacific area. A few stations have records beginning in December 1951. The remaining stations began observations in July 1952. Hourly surface observations were recorded in Local Standard Time. Prior to June 1, 1957, the surface observations were taken 20-30 minutes past the hour. From June 1, 1957 through December 31, 1964, the surface observations were taken a few minutes before the hour. From July 1, 1958 to the end of this observation period the solar data are for the hour ending on the hour punched. This change made the hourly data compatible with the times of the surface observation on Form WBAN 10. Hourly observed solar radiation data is combined with hourly surface meteorological data. Variables included: Radiation (Langleys per hour), sunshine, snow cover, opaque sky cover, percent of possible radiation, visibility, occurrence of precipitation/precipitation type, present weather/obstructions to vision, dry bulb temperature, dew point temperature, cloud cover (total cloud amount, layered cloud data)