This data set contains spectral shortwave radiation data (incident, reflected and transmitted) from two different sites: time-series from a fixed site on Floe 3 and 4, so called "supersite", and from point measurements from a "refrozen lead" during drift of Floe 3.

#### Supersite

Downwelling and upwelling spectral SW radiation above and below ice, spectral SW albedo and transmittance, at one location on Floe 3 and 4. Measured with Ramses ACC-VIS radiometers (350-900 nm) and processed to 15 min averages.

Dataset contains one file for Floe 3 (incident, reflected and transmitted (right below ice)) and one for Floe 4 (incident, reflected, transmitted (right below ice) and transmitted at 10 m depth in the water) in Netcdf format. In both cases installed at a location with thick snow and ice, for respective Floe. To keep the sites undisturbed for the period of measurement no information on snow or ice thickness exist beyond the time of deployment.

Initial conditions.

Floe 3: snow depth 40 cm, ice thickness 130 cm.

Floe 4: snow depth 15-20 cm, ice thickness 120 cm.

#### Refrozen lead

Incident and transmitted spectral irradiance from transects on a refrozen lead.

Sensors: Trios RAMSES ACC-VIS

Wavelength range: 320-900nm

NOTE! Do not fully trust data for wavelengths below 350nm, the sensors are less accurate here.

Dataset has one file for measurements conducted with snow cover intact, and for some dates measurements were also made after snow had been removed (bareice).

- RefrozenLead_bareice_Trios-1.6.nc

- RefrozenLead_Trios-1.6.nc

#### Groups

The transect consisted of five repeated locations across a refrozen lead next

to R/V Lance. The groups in the files are called p1 through p5, where p1 is the location

closest to Lance, and p5 is farthest away from Lance. The transect was repeated 11 times between 12 May and 3 June 2015.(See [Kauko et al. 2017]( https://doi.org/10.1002/2016JG003626))

Variables

- wl: Wavelength [nm]

- inc: Incident irradiance [W m^(-2) nm^(-1)]

- trans: Transmitted irradiance [W m^(-2) nm^(-1)]

- time: Time in UTC (N x 6 matrix, columns are year, month, day, hour, minute, second)

- lat, lon: Position of Lance (i.e. not exact position of measurement)

- expday: Julian day of 2015 when transect was sampled

Processing

Spectra where the tilt of the under-ice sensor was >5 degrees along either x- or y-axes

have been discarded.