These are supporting meteorological measurements for selectable sites. The surface reflaction is the upwelling visible irradiance measured by a downward looking pyranometer and is used primarily to indicate the presence of snow.
Graphs of the data are available for a time selection of two months or less. Also provided, is a feature to export the data to a file on your local computer in several different formats(excel, csv, xml). Keep in mind a year's worth of data is about 25 megabytes, and will take almost 2 minutes to generate.
Valid date range for location Alaska, Fairbanks, AK01 is from Sat Aug 26 00:00:00 GMT+00:00 2000 to Sat Feb 16 00:00:34 GMT+00:00 2019