Continous downwelling irradiances were measured at the surface (above-water) on deck of the research vessel Sonne avoiding shading by ship. Measurements were taken for 13. to 20 October 2010 with a hyper-spectral radiometer (RAMSES ACC-VIS, TriOS GmbH, Germany). The instrument covers a wavelength range of 320 nm to 950 nm with an optical resolution of 3.3 nm and a spectral accuracy of 0.3 nm. The sensor's raw data were converted to calibrated values using the standrad TRIOS software msda-xe.Automatically calibrated - may contain errors - not checked for shadowing effects etc.