de.pangaea.dataset996869 und dataset PANGAEA
info@pangaea.de
https://www.pangaea.de/ information pointOfContact 2026-09-02T09:14:55Z https://doi.pangaea.de/10.1594/PANGAEA.996869 <gco:CharacterString>GEM-2 raw electromagnetic measurements of the ice floe transects during the PS149 CONTRASTS expedition (July-August 2025)</gco:CharacterString> 2026-09-02T09:11:47 publication Ringel, Maximilian Harald
mringel@uni-bremen.de
https://orcid.org/0000-0002-0600-135X information author Spreen, Gunnar
gunnar.spreen@uni-bremen.de
https://orcid.org/0000-0003-0165-8448 information author Krumpen, Thomas
Thomas.Krumpen@awi.de
https://orcid.org/0000-0001-6234-8756 information author Neudert, Mara
mneudert@awi.de
author PANGAEA
info@pangaea.de
https://www.pangaea.de/ information publisher tableDigital This dataset contains the raw electromagnetic induction (EM) measurements from repeated walks with the GEM instruments on a sledge across ice floes (called long transects) conducted during the PS149 CONTRASTS expedition. All measurements were acquired using the Geophex Ltd. GEM-2-730 broadband EM sensor. During each ice station (i.e., floe visit), a long transect was traversed across the ice floe to obtain statistically representative distributions of snow/pond depth and ice thickness. Each transect was marked with flags at its corner points to ensure that a similar track was measured during repeated visits to each ice floe. This dataset provides only the raw GEM measurements acquired along these transects, including in-phase and quadrature responses, as well as electrical conductivity and magnetic susceptibility of sea ice and snow / melt ponds. These raw data enable users to apply various processing methods to, e.g., derive sea ice thickness. For reference, processed sea ice thickness derived from these measurements (using the gem2-seaice-toolbox, https://gitlab.awi.de/sitem/gem2-seaice-toolbox), along with co-located MagnaProbe snow and pond depth measurements, are available in the Level 2 dataset (doi:10.1594/PANGAEA.996908). completed Arctic CONTRASTS expedition electromagnetic induction GEM-2 Geophex ocean PS149 RV Polarstern Sea ice Sea ice thickness Transects theme <gco:CharacterString>PANGAEA Keyword List</gco:CharacterString> 1995-01-01 creation PANGAEA
info@pangaea.de
https://www.pangaea.de/ information pointOfContact AC3 Arctic Amplification theme <gco:CharacterString>PANGAEA Project List</gco:CharacterString> 1995-01-01 creation PANGAEA
info@pangaea.de
https://www.pangaea.de/ information pointOfContact copyright copyright CC-BY-4.0: Creative Commons Attribution 4.0 International textTable und geoscientificInformation -17.94507333 33.99214267 0.0 84.98494 2025-07-10T13:45:10 2025-08-27T16:43:15 The GEM instrument transmits and receives at multiple frequencies simultaneously that can be freely defined in the software. For the measurements presented here, we used the same frequency set as in the MOSAiC campaign (https://doi.pangaea.de/10.1594/PANGAEA.943666): 1.525 kHz, 5.325 kHz, 18.325 kHz, 63.025 kHz, and 93.075 kHz. The same sensor calibration method was also applied: the GEM was positioned at 8 known height levels using the steps of a wooden ladder standing on a flat area of the sea ice floe, where sea ice thickness was measured at five locations below the instrument. Based on these calibration measurements at different heights, an exponential function is derived and applied to the transect data to estimate total ice thickness (i.e., the distance from the sensor to the ice–ocean interface). For all calibrations, the conductivity of the sea ice plus snow layer was assumed to be 0.05 S m⁻¹, and the conductivity of seawater was set to 2.55 S m⁻¹. Since all calibrations were performed on unponded sea ice, the conductivity of melt pond water was not directly accounted for. If, for some reason, no successful calibration was done during the ice station the temporally closest calibration from another ice station is used for processing. For the transects the GEM instrument was mounted within a Pulka sledge leading to a height offset of about 0.11 m relative to the ground. In addition to the actual GEM measurements we provide metadata as YAML files which can be found under Additional metadata for each individual dataset. These YAML files were used to process the raw data into the total ice thickness estimates provided in the Level 2 dataset (https://doi.pangaea.de/10.1594/PANGAEA.996908). They are included here in the Level 0 datasets, as they contain valuable metadata, including comments on the transects and calibration procedures, as well as assumptions regarding sea ice dielectric properties. Under Further details all metadata of the calibration procedure - if available for the respective ice station - can be found. Next to the calibration measurements (...Calibration_data-table.tsv) two YAML files and one PDF are provided. The YAML file with the suffix "_Calibration.yaml" contains general information about the calibration measurements (e.g., ladder step heights). The file with the suffix "_Calibration_empex_fit.yaml" provides the coefficients of the derived exponential fit functions for each frequency, which can be used to calculate ice thickness from the raw measurements. The accompanying "_Calibration_empex_fit.pdf" displays these fit functions graphically. For further instructions on how to adapt and use these YAML files for processing, please refer to the following tutorial: https://gitlab.awi.de/sitem/gem2-processing-tutorial. Important note: For the transect on ice station PS149_47-1 (floe visit 3d) the Geophex Ltd. GEM-2-556 instrument was used due to malfunctioning of the GEM-2-730. The data output of the GEM-2-556 instrument differs from the GEM-2-730 which requires different data processing. The previously mentioned method of the gem2-seaice-toolbox does not work for the GEM-2-556 data of ice station PS149_47-1. Therefore, the YAML files - which are needed by this toolbox for the processing - can't be used to derive the ice thickness. Nevertheless, they are provided for the auxiliary information (ladder step heights during calibration etc., see below). The description of the Level 2 dataset (mentioned above) explains which method we used to derive ice thickness from the GEM-2-556 measurements of station PS149_47-1. application/zip unknown https://doi.pangaea.de/10.1594/PANGAEA.996869?format=zip download dataset The data set was checked for completeness, correctness, and consistency of metainformation. Validity of used methods was checked and - if applicable - precision and range of data. Related to <gco:CharacterString>The Expedition PS149 of the Research Vessel POLARSTERN to the Arctic Ocean in 2025</gco:CharacterString> 2026-01-01 publication https://doi.org/10.57738/BZPM_0808_2026 Nicolaus, Marcel
marcel.nicolaus@awi.de
https://orcid.org/0000-0003-0903-1746 information author documentDigital Berichte zur Polar- und Meeresforschung = Reports on Polar and Marine Research 808 382 pp Related to <gco:CharacterString>GEM-2 total ice thickness estimates and MagnaProbe snow and melt pond depth measurements of the ice floe transect during station PS149_25-1 during the PS149 CONTRASTS expedition (July-August 2025)</gco:CharacterString> 2026-01-01 publication https://doi.pangaea.de/10.1594/PANGAEA.996907 Ringel, Maximilian Harald
mringel@uni-bremen.de
https://orcid.org/0000-0002-0600-135X information author Spreen, Gunnar
gunnar.spreen@uni-bremen.de
https://orcid.org/0000-0003-0165-8448 information author Krumpen, Thomas
Thomas.Krumpen@awi.de
https://orcid.org/0000-0001-6234-8756 information author Neudert, Mara
mneudert@awi.de
author documentDigital Related to <gco:CharacterString>GEM-2 total ice thickness estimates co-located with MagnaProbe snow and melt pond depth measurements of the ice floe transects during the PS149 CONTRASTS expedition (July-August 2025)</gco:CharacterString> 2026-01-01 publication https://doi.pangaea.de/10.1594/PANGAEA.996908 Ringel, Maximilian Harald
mringel@uni-bremen.de
https://orcid.org/0000-0002-0600-135X information author Spreen, Gunnar
gunnar.spreen@uni-bremen.de
https://orcid.org/0000-0003-0165-8448 information author Krumpen, Thomas
Thomas.Krumpen@awi.de
https://orcid.org/0000-0001-6234-8756 information author Neudert, Mara
mneudert@awi.de
author documentDigital