Table C-3. Solar Radiation Source Flags
FlagDefinition
APost-1976 measured solar radiation data as received from NCDC or other sources
BSame as 'A' except the global horizontal data underwent a calibration correction
CPre-1976 measured global horizontal data (direct and diffuse were not measured before 1976), adjusted from solar to local time, usually with a calibration correction
DData derived from the other two elements of solar radiation using the relation, Kt = Kn + Kd (see Part 2, Section 8.1 for more information)
EModeled solar radiation data using inputs of observed sky cover (cloud amount) and aerosol optical depths derived from direct normal data collected at the same location
FModeled solar radiation using interpolated sky cover and aerosol optical depths derived from direct normal data collected at the same location
GModeled solar radiation data using observed sky cover and aerosol optical depths estimated from geographical relationships
HModeled solar radiation data using interpolated sky cover and estimated aerosol optical depths
?Source does not fit any of the above categories. Used for nighttime values, calculated extraterrestrial values, and missing data


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