The ULTRAVIOLET MULTI-FILTER ROTATING SHADOWBAND RADIOMETER

The Ultraviolet Multi-Filter Rotating Shadowband Radiometer

The Yankee Environmental Systems UV Multifilter Rotating Shadowband Radiometer (UV-MFRSR) uses 7 independent interference filter photodiode detector combinations to make total horizontal solar irradiance measurements at 300, 305.5, 311.4, 317.6, 325.4, 332.4 and 368 nm (nominal 2 nm FWHM bandwidth) through a single Lambertian detector. A computer-controlled, automatic rotating shadow band permits the near simultaneous determination of total horizontal, direct normal and diffuse radiation at each filtered passband.

Measurements are made sequentially at each wavelength every 20 seconds and integrated into 3-minute averages by an on-board computer. The computer also serves as the data logger for the UV-MFRSR. The UV-MFRSR is polled daily via a dedicated telephone line.

As with other multifilter rotating shadowband radiometers the choice of wavelengths permits a Langley analysis for the direct determination of optical depth. The 332.4nm wavelength serves as a reference to Dobson instruments and the 311.5 is designed to be a reference point to a relatively unstructured (flat) portion of the UV spectra.

Lamp Calibrations are performed by the NOAA Central UV Calibrations Facility(CUCF).

Representativeness

Bias

Precision

Comparability

Additional Manufacturer's Specifications

Overall Radiometric Accuracy: 2-3% with angle corrections

References

Harrison, L., J. Michalsky, J. Bernt, Automated multi-filter rotating shadow-band radiometer: an instrument for optical depth and radiation measurements, Appl. Opt. 33(22) 1994.

Bigelow, D.S. and J.R. Slusser, 1999, Establishing the Stability of Multi-filter UV Rotating Shadowband Radiometers, J. Geophys. Res. (In press).

Slusser, J.R., J.H. Gibson, D.S. Bigelow, D. Kolinski, P. Disterhoft, K. Lantz and A. Beaubien, 1999, Langley Method of Calibrating UV Filter Radiometers, J. Geophys. Res. (In press).