Monitoring the solar UV-B radiation in the North of Munich: A comparison of two sites

Since 2008, measurements of the downwelling solar spectral irradiance from 290 to 400 nm were compared at two field sites at Neuherberg, north of Munich, Germany, 11.6 E, 48.22 N, 490 m above sea level: (1) Research Unit Environmental Simulation (EUS) at the Helmholtz Zentrum Munchen (former GSF National Reasearch Center for Environment and Health), (2) Federal Office for Radiation Protection (BfS). The spectral measurements of two double monochromator systems (TDM300, Bentham, Reading, UK) at 11:00 GMT were analyzed every day. Spectral comparison showed no misalignment of the wavelength calibration. The mean deviation of 1090 measurements at three different wavelengths in the UV-B range (280 – 315 nm) showed coefficients of determination better than 0.94 and a 10% higher value of spectral irradiance of the EUS system, mainly due to different entrance optics and spectral resolution.