Instruments
Golden, Colorado (39.740, -105.168)
PREDE POM 01
The SRRL was established at the Solar Energy Research Institute (now NREL) in 1981 to provide continuous
measurements of the solar resources, outdoor calibrations of pyranometers and pyrheliometers, and to
characterize commercially available instrumentation. The SRRL is an outdoor laboratory located on South Table
Mountain, a mesa providing excellent solar access throughout the year, overlooking Denver.
Beginning with the basic measurements of global horizontal irradiance, direct normal irradiance
and diffuse horizontal irradiance at 5-minute intervals, the SRRL Baseline Measurement System now
produces more than 130 data elements at 1-min intervals that are available from the
Measurement & Instrumentation Data Center Web site. Data sources include global horizontal, direct normal,
diffuse horizontal (from shadowband and tracking disk), global on tilted surfaces, reflected solar irradiance,
ultraviolet, infrared (upwelling and downwelling), photometric and spectral radiometers, sky imagery,
and surface meteorological conditions (temperature, relative humidity, barometric pressure, precipitation,
snow cover, wind speed and direction at multiple levels). Data quality control and assessment
include daily instrument maintenance (M-F) with automated data quality control based on real-time examinations
of redundant instrumentation and internal consistency checks using NREL's SERI-QC methodology.
Operators are notified of equipment problems by automatic e-mail messages generated by the data
acquisition and processing system. Radiometers are recalibrated at least annually with reference
instruments traceable to the World Radiometric Reference (WRR).
December 2012
Afshin Andreas , NREL, USA
email: afshin.andreas@nrel.gov