Incident and transmitted spectral irradiance from transects on ponded first year ice during the ICE12 expedition with RV Lance in 2012. Under ice irradiance was measured approximately every 1m along three different transects, incident surface irradiance was measured concurrently at a fixed location near the start of the transect. After irradiance measurements, ice thickness, freeboard and pond depth was measured every 1m along the transect.

This data set contains profiles of total attenuation and absorption measured with a Wetlabs AC-9 instrument during N-ICE2015. Scattering tube corrections of absorption data was done by subtracting the absorption values at 715nm, or in some cases 650nm. The value at 650nm was used when absorption here was lower than the absorption at 715nm. Corrections for temperature and salinity was done using coefficients from Röttgers et al (2014), with a calibration temperature of 21.9 °C, and in situ temperature from CTD casts. Some automated spike removal is performed by calculating the mean and standard deviation of a moving window along the profile, and removing values that are more than two standard deviations away from the mean. Only downcasts are used. After despiking, the 6Hz data is binned in 1m vertical bins, and averaged. Röttgers, Rüdiger, David McKee, and Christian Utschig. 2014. “Temperature and Salinity Correction Coefficients for Light Absorption by Water in the Visible to Infrared Spectral Region.” _Optics Express_ 22 (21): 25093. https://doi.org/10.1364/OE.22.025093