Sea ice, snow and melt pond example data from MOSAiC transect observations

This data set contains in-situ observation of sea ice, snow and melt pond properties from two days in winter (January 23, 2020) and summer (July 7, 2020) during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. It originates from two sensors:

1. Broad-band electromagnetic induction sensor (Geophex GEM-2) measuring the combined thickness of the sea ice and snow layers
2. A GPS snow depth probe (Snow-Hydro MagnaProbe) measuring the thickness of the snow layer and melt ponds depth during summer

Both sensors were operated coincidently along transect loops while different loops were used in both days. This data set is a subset of similar weekly activities between October 2019 and September 2020. This publication intends to provide a preview of the data properties and approximate changes between the winter and summer periods. It also has to be noted, that the final data of the EM induction sensor might differ from this release, which is based on a quick-look processing directly after data acquisition.

GEM-2 data files

The file format of GEM-2 data is a text file with comma-separated values. Notable parameters are:

• ‘time’: UTC time
• ‘longitude’: Longitude in degrees east (fill value: 0.0)
• ‘latitude’: Latitude in degrees north (fill value: 0.0)
• ‘`f{frequency}Hz_hcp_{i:Inphase|q:Quadrature}`: total (ice + snow) thickness of the sea ice and snow layers in meter for different channels*

*The channels correspond to the real (Inphase) or imaginary (Quadrature) part of the EM signal at a given frequency. The variable name in the csv file is to be read as `f{frequency}Hz_hcp_{i:Inphase|q:Quadrature}`. It is recommended to use the Inphase component of the 18.325 kHz frequency (variable `f18325Hz_hcp_i`) for analysis.

MagnaProbe data files

The file format of MagnaProbe data is a text file with comma-separated values. Notable parameters are:

• `timestamp`: Timestamp
• `longitude_a`: longitude degree in degrees east
• `longitude_b`: longitude minute
• `latitude_a`: latitude degree in degrees north
• `latitude_b`: latitude minute
• `depthCm`: Snow thickness or melt ponds depth in cm
• `flag`: flag value indicating the type or measurement*

Flag values are:

• -1 : melt pond
• 1 : snow or surface scattering layer depth,
• 2 : mixed surface type when pond water pools at the base of a melting

The filenames follow the naming convention of <sensor>-mosaic-transect-<date>-<device-operations-id>.csv with the device operation id as a unique identifier of the sensor raw data within the MOSAiC project.