The Austrian UVA-Network.

The ultraviolet-A (UVA) part of the solar spectrum at the Earth's surface is an essential environmental factor but continuous long-time monitoring of UVA radiation is rarely done. In Austria, three existing stations of the UV monitoring network have been upgraded with UVA broadband instruments. At each station, one instrument measures global UVA irradiance and-in parallel-a second instrument measures diffuse irradiance.

Portable device for characterizing the angular response of UV spectroradiometers.

This paper introduces a device that was developed to measure the angular response of UV spectroradiometers in the field. This device is designed to be used at the operating position of spectroradiometers; thus the derived angular response also includes any effects from imperfect leveling of the diffuser and corresponds to the actual operational angular response. The design and characterization of the device and the results from its application on 11 different spectroradiometers that operate at different European UV stations are presented.

Traveling reference spectroradiometer for routine quality assurance of spectral solar ultraviolet irradiance measurements.

A transportable reference spectroradiometer for measuring spectral solar ultraviolet irradiance has been developed and validated. The expanded uncertainty of solar irradiance measurements with this reference spectroradiometer, based on the described methodology, is 8.8% to 4.

Intercomparison of monochromatic source facilities for the determination of the relative spectral response of erythemal broadband filter radiometers.

The relative spectral responses of erythemally weighted broadband radiometers determined at three different laboratories are compared, and the systems are described. The results of measurements of four different broadband radiometers are discussed. Although the common dynamic range of the measured relative spectral responses is approximately 10(4), the differences in the relative spectral response functions are lower than 20%.

Multichannel moderate-bandwidth filter instrument for measurement of the ozone-column amount, cloud transmittance, and ultraviolet dose rates.

A six-channel moderate-bandwidth filter instrument for measurement of UV and visible radiation has been developed. The characteristic of the instrument are described, including the spectral and the angular responses. Furthermore the calibration procedure is outlined.

Effect of ambient temperature on Robertson-Berger-type erythemal dosimeters.

To quantify the effect of ambient temperature on the voltage signal of Solar Light UV-Biometers, spectral response functions of two instruments were determined in the laboratory under various external temperature conditions. Despite the biometer's internal temperature stabilization, a temperature increase of 20 degrees C at the outside of an instrument's housing resulted in a reduction of the instrument's spectral response by as much as 10% in the UVB range and by as much as a factor of 2 in the UVA range, depending on the individual instrument and on its internal relative humidity. The significance of this effect for outdoor measurements is demonstrated by data from an intercomparison campaign of erythemal radiometers in Thessaloniki, Greece, organized by the Laboratory of Atmospheric Physics (Aristotle University of Thessaloniki), the Cooperation in Science and Technology (European Commission), and the World Meteorological Organization.