Improved Methods for Broadband Outdoor Radiometer Calibration (BORCAL)
Wilcox, S.M., Andreas, A.M., Reda, I., and Myers, D.R., National Renewable Energy Laboratory
Twelfth Atmospheric Radiation Measurement (ARM) Science Team Meeting
The ARM Program deploys approximately 100 radiometers to measure broadband solar radiation at stations in the North Slope of Alaska (NSA), Southern Great Plains (SGP), and Tropical Western Pacific (TWP) Cloud and Radiation Testbed (CART) sites. Two calibration events performed at the SGP Radiometer Calibration Facility (RCF) each year maintain radiometer calibration traceability to the World Radiometric Reference and assure reliable and uniform measurements at each CART site. Calibrations are performed using the Radiometer Calibration and Characterization (RCC) software developed by the National Renewable Energy Laboratory, allowing simultaneous calibrations of up to 200 instruments. The first generation RCC installed in 1996 was developed and implemented on a DOS computing platform. Subsequent advances in operating systems and connectivity technology outdated the system's computing environment, and the system became difficult to maintain. That and recent improvements in radiometer calibration knowledge lead to the upgrade of RCC to a Windows-based product with improved functionality and a more flexible user interface. This poster describes changes and functional improvements in the new system: a more comprehensive basis for calculating calibration uncertainty, accommodation of new state-of-the-art cavity radiometer reference instruments at the RCF, implementation of improved diffuse reference measurements, improved reporting of calibration results, the ability to perform tilt calibrations for increasing pyranometer angular response measurements, improved event configuration, and the capability to correct and document data acquisition or configuration errors.
Note: This is the poster abstract presented at the meeting; an extended version was not provided by the author(s).
