Yankee Environmental Systems, Inc. Pyranometer UVB-1 / UVA-1

Model UVB-1 and UVA-1 Pyranometers are precision meteorological instruments for the measurement of biologically effective solar ultraviolet-B (UV-B) and UV-A radiation, respectively. The measurement technique employed in both instruments utilizes colored glass filters and a highly stable UV-sensitive fluorescent phosphor to stop all of the sun's visible light and convert UV photons into visible light, which, in turn, is measured by a solid-state photodetector. UVB-1 and UVA-1 pyranometers are rugged instruments, designed to ensure stability of operation during long term, unattended operation in remote field stations. Both instruments measure global solar irradiance, the radiation received by a horizontal surface from the entire hemisphere of the sky. Global radiation includes both light transmitted directly through the atmosphere and light scattered by atmospheric gases and particulate matter in the atmosphere. Unlike the case of visible light, scattered UV-B light is a major and, under some conditions, a dominant component of the global radiation. The design of the UVB-1 Pyranometer ensures the proper measurement of both components. The Model UVA-1 is nearly identical to a UVB-1 but utilizes a phosphor that is sensitive out to 400 nm. Although the UVA-1 measures both UV-B (280-320 nm) and UV-A (320-400 nm), because the solar spectrum's UV-A irradiance component is approximately 100 times greater than the UV-B portion, the output is essentially UV-A.