Daily/Hourly Sums represent an integration over time. Basically by summing the readings over the number of seconds in the measurement period, the units of radiant power are converted to radiant energy and are useful for studying effects related to exposure. Current available values are Caldwell biological spectral weighting function, Flint biological spectral weighting function, erythemally weighted irradiance, UV-A irradiance, and UV-B irradiance and spectral weighting function Vitamin D. To insure quality data, the Sums data is available through the previous month.
The data is downloaded in CSV format. Each set of data has a header. The header lines begin wth the # sign, and contains a description of location and data, along with possible data issues. The nighttime data is set to -9999 and data that are not currently available or associated with instrument errors are set to -9998.