Solar radiation over and under sea ice during the ALERT2018 campaign (MAP Last Ice) in May 2018

Measurements of solar radiation over and under sea ice have been performed on First-Year-Ice (FYI) and Multi-Year-Ice (MYI) during the ALERT2018 campaign (Multidisciplinary Arctic Program (MAP) - Last Ice) off Alert, Nunavut, Canada in the Lincoln Sea between 07 May and 23 May 2018. All radiation measurements have been performed with Ramses spectral radiometers (TriOS, Rastede, Germany). All data are given in full spectral resolution interpolated to 1.0 nm, and integrated over the entire wavelength range (broadband, total: 320 to 950 nm). Two sensors were mounted on a Remotely Operated Vehicle (ROV) and one radiometer was installed on the sea ice for surface reference measurements (solar irradiance). On the ROV, one irradiance sensor (cos-collector) for energy budget calculations and one radiance sensor (9° opening angle) to obtain high resolution spatial variability were installed. Along with the radiation measurements, ROV positions were obtained from acoustic LBL (Long Baseline)-positioning and all parameters of vehicle depth, distance to the ice and attitude recorded. All times are given in UTC.