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Daylight availability data for San Francisco

Conference ·
OSTI ID:6477807

This paper analyzes solar radiation and daylight measurements taken during a four-year period in San Francisco, California. Horizontal and vertical surface measurements were taken by nine sensors at 15-minute intervals under all sun and sky conditions. The data base from which results were derived exceeds 400,000 measurements. Equations are derived for clear sky global, direct, and diffuse illuminance and irradiance on a horizontal surface as a function of solar altitude, and for overcast sky horizontal illuminance and irradiance. The standard deviations for all parameters in the equations are presented to show the scatter in the data. The average illuminance on horizontal and vertical surfaces by hour and by month are presented as isolux contour plots. These data are also displayed as probability distributions, showing the percent of time in a year that a given irradiance or illuminance value will be exceeded. Monthly average values of sunshine probability are determined and compared to long-term NOAA data.

Research Organization:
Lawrence Berkeley Lab., CA (USA)
DOE Contract Number:
AC03-76SF00098
OSTI ID:
6477807
Report Number(s):
LBL-15623; CONF-830229-3; ON: DE84016896
Country of Publication:
United States
Language:
English