Doses were calculated from continuous in situ irradiance observations made with an Ocean Optics Jaz spectrophotometer (ILX-511B detector; Ocean Optics Inc., Dunedin, FL, USA). Incident irradiances were recorded at 0.3 nm bandwidth using an upward-facing plane irradiance cosine corrector (180° field of view) and 10 m fiber optic cable. The instrument was factory calibrated prior to deployment for absolute irradiance measurements from 210-850 nm. Irradiances were recorded at 1 min. intervals. These in situ daily doses may be compared to incident daily UV doses recorded as part of the U.S. National Oceanic and Atmospheric Administration's (NOAA) Antarctic UV Monitoring Network; the NOAA dosage data are available at https://www.esrl.noaa.gov/gmd/grad/antuv/