The NSF-supported research icebreaker Nathaniel B. Palmer operates year-round in support of the U.S. Antarctic Program, carrying out global change studies in biological, chemical, physical, and oceanographic disciplines. This data set consists of underway data from leg NBP0806 on the R/V Nathaniel B. Palmer. This leg started at Punta Arenas, Chile and ended at Punta Arenas, Chile.
Data were obtained using a Macam, portable, double grating spectroradiometer that was routinely calibrated against deuterium and tungsten lamps. These lamps are calibrated to international standards (National Physics Laboratory). The spectral irradiance for downwelling solar radiation was measured at 5 min intervals between 280 and 400 nm wavelength. The irradiance at each nanometer was ... multiplied by the transmittance of UV-attenuating screens used to simulate increasing watercolumn depth in studies of the impact of UV radiation on marine microbes. This data were then multiplied by theerythemal weight at each wavelength and the results integrated over the UV spectrum, erythemal irradiance averaged over 10 mins and the cumulative erythemal irradiance calculated. Secondary calibration was then performed against simultaneous measurements of 10 min integrated erythemal irradiance obtained by ARPANSA at Davis during the experiment. Some deterioration of sensor function was experienced during the experiment. Inaccuracy resulting from this deterioration has been compensated for by the secondary calibration against ARPANSA data.