Study of suitability of AvaSpec array spectrometer for solar UV field measurements

Abstract

Abstract.A system to record the ultraviolet (UV) spectra of atmospheric global irradiance with the miniature fiber optic spectrometer AvaSpec-256 was developed for continuous computer-aided spectrometry at Tartu Observatory in 2005. As a result, the database of spectra recorded with 15-mininterval round 24 h over 300-400 nm, has been developed. The quantities retrieved from the spectra have been compared with those measured by the Scintec erythemal UV-SET sensor and the Kipp & Zonen narrowband 306 nm sensor. Almost clear and overcast days were selected for comparison. Reliable results on the spectral distribution of the UV global irradiance as well as the integrated daily spectral doses could be obtained at least during the bright half-year. The results were compared with the calculations performed by means of the LibRadtran package. The biases in irradiance were significant at SZA above 70-75 • . At dominating larger SZA the recorded values need sophisticated corrections and remain less reliable. At lower latitudes than that of the study site (58.3 • ), the reliability of the spectrometer is expected to increase due to a smaller contribution of data measured at large SZA.The variations of the ratio of UV-A/UV-B irradiance, retrieved from the spectra, were investigated. Also the covariation of the narrowband 306 nm irradiance and the irradiance integrated over the whole UV-B range was studied. The biases between the UV-A/UV-B irradiances calculated by means of the LibRadtran package and measured with the AvaSpec were small at SZA below 70 • . At larger SZA the values of the ratio as well as the biases increased, significantly depending on total ozone.

Validation of spectral sky radiance derived from all-sky camera images – a case study

“…A CCD spectroradiometer system based on a CCD array spectrometer (S2000, Ocean Optics Inc., Dunedin, USA) and a positioning unit (SkyScanner, Czibula and Grundmann, Berlin, Germany) (Czibula and Grundmann, 2002) is used for measuring the spectral sky radiance distribution. Similar spectrometers have been used to measure solar and artificial radiation in Ansko et al (2008); Kouremeti et al (2008); Kreuter and Blumthaler (2009). The system is capable of measuring spectral sky radiance with a spectral resolution of 2 nm between 300 and 800 nm covering the visible part of the spectrum.…”

“…The variation of the sky radiance has been observed and analysed under different sky conditions by using several types of instruments (Dorno, 1911;Bener, 1963;Blumthaler et al, 1996;Ricchiazzi et al, 2000;Huber et al, 2004). and performed spectral sky radiance measurements over the snowcovered surface in Antarctic environments in order to investigate the impact of high snow albedo on the sky radiance.…”

Glass transmitted solar irradiances on horizontal and sun-normal planes evaluated with a smartphone camera

“…Traditionally, UVR is measured using three main types of devices, specifically radiometers, spectrometers, and spectroradiometers [6], each of which has specific measurement qualities and output formats [7,8]. These devices have varying degrees of portability but are often too expensive for many research and occupational health and safety research groups.…”

Noise analysis for CCD-based ultraviolet and visible spectrophotometry

“…In this study a characterisation is made of an AvaSpec-3648 CCD UV spectrometer and a Ocean Optics S2000 UV-Vis spectrometer. To the best of the author's knowledge noise performance of these spectrometers has not been reported before, but studies have been made of the similar AvaSpec-256 [12], Ocean Optics USB 4000 [11] and USB 2000 [9].…”