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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 113, D14310, doi:10.1029/2007JD009489, 2008

Comparison of ultraviolet spectroradiometers in Antarctica

Germar Bernhard

Biospherical Instruments Inc., San Diego, California, USA


Richard L. McKenzie

National Institute of Water and Atmospheric Research (NIWA), Lauder, Central Otago, New Zealand


Michael Kotkamp

National Institute of Water and Atmospheric Research (NIWA), Lauder, Central Otago, New Zealand


Stephen Wood

National Institute of Water and Atmospheric Research (NIWA), Lauder, Central Otago, New Zealand


Charles R. Booth

Biospherical Instruments Inc., San Diego, California, USA


James C. Ehramjian

Biospherical Instruments Inc., San Diego, California, USA


Paul Johnston

National Institute of Water and Atmospheric Research (NIWA), Lauder, Central Otago, New Zealand


Sylvia E. Nichol

National Institute of Water and Atmospheric Research, Kilbirnie, Wellington, New Zealand


Abstract

Solar ultraviolet irradiance has been monitored in Antarctica for almost two decades by a network of spectroradiometers established by the National Science Foundation. Data have been used for investigating increases in ultraviolet radiation in response to ozone depletion, validation of satellite observations, and the establishment of ultraviolet radiation climatologies and trends. To assess the quality of data collected, measurements of the monitoring spectroradiometer installed at Arrival Heights (78°S, 167°E) were compared with an independently calibrated, state-of-the art instrument, which was installed next to the monitoring system for a three-month campaign. Measurements of the two instruments differed by 5–7% on average. The discrepancy is quantitatively explained by the different irradiance scales used by the two systems, a bias in determining the reference plane of fore-optics, drifts of calibration standards, some temperature-dependence in the transmission of the entrance optics, and nonlinearity of one of the systems. The wavelength accuracy of data from both instruments was also tested with two commonly used correlation methods. Wavelength shifts determined with the two methods agreed to within 0.003–0.006 nm. Results of the campaign suggest that data collected by the monitoring instrument are of adequate quality for submission to the Network for the Detection of Atmospheric Composition Change.

Received 10 October 2007; accepted 14 March 2008; published 26 July 2008.

Keywords: Solar ultraviolet radiation; Antarctica; intercomparison.

Index Terms: 0394 Atmospheric Composition and Structure: Instruments and techniques; 9310 Geographic Location: Antarctica (4207); 0360 Atmospheric Composition and Structure: Radiation: transmission and scattering.

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Citation: Bernhard, G., R. L. McKenzie, M. Kotkamp, S. Wood, C. R. Booth, J. C. Ehramjian, P. Johnston, and S. E. Nichol (2008), Comparison of ultraviolet spectroradiometers in Antarctica, J. Geophys. Res., 113, D14310, doi:10.1029/2007JD009489.