Airborne sea ice classification during expedition ARTofMELT, Arctic Ocean, 2023

Henrik Stapel, Falk Pätzold, Evelyn Jäkel, Magnus Asmussen, Valtteri Hyöky, Lutz Bretschneider, Andreas Schlerf, Sven Bollmann, Astrid Lampert

The ARTofMELT expedition was carried out in the Fram Strait pack ice during the spring transition (May to June) of 2023, with the Swedish icebreaker Oden serving as research platform.

The helicopter-towed sensor system HELIPOD was deployed 12 times over the course of one month within a 20 NM radius around the ship. A downward facing RGB camera with a fisheye lens onboard the HELIPOD took images with a 0.5 Hz rate.

By setting the RGB limits, the surface classes were determined from these images pixelwise as open water, snow-covered ice, young ice, old ice or melt ponds. Surface type fractions were calculated per image, accounting for lens distortion. Two variants of the data are provided: (i) with unweighted area fractions and (ii) with cosine weighting according to the viewing zenith angle.

This dataset provides data for 11 flights, carried out between 2023-05-09 and 2023-06-09.

MarineObservationsArcticArctic OceanSea ice typeSea ice fractionOcean-Atmosphere interfaceFram StraitARTofMELTARTofMELT 2023 expeditionIcebreaker Oden

Name

Version

Citation

References

Jäkel E, Stapf J, Wendisch M, Nicolaus M, Dorn W, Rinke A (2019) Validation of the sea ice surface albedo scheme of the regional climate model HIRHAM–NAOSIM using aircraft measurements during the ACLOUD/PASCAL campaigns. The Cryosphere 13:1695–1708. https://doi.org/10.5194/tc-13-1695-2019

Pätzold F, Bretschneider L, Nowak S, Brandt B, Schlerf A, Asmussen MO, Bollmann S, Bärfuss K, Harm-Altstädter B, Hecker P, Wehner B, van der Wall BG, Sachs T, Huntrieser H, Roiger A, Lampert A (2023) HELiPOD—Revolution and evolution of a helicopter-borne measurement system for multidisciplinary research in demanding environments. Elem Sci Anth 11. https://doi.org/10.1525/elementa.2023.00031

Pätzold F, Bretschneider L, Schlerf A, Asmussen MO, Hyöky V, Welker J, Harm-Altstädter B, Pilz C, Düsing S, Stapel H, Jäkel E, Juranyi Z, Roiger A, Lampert A (2026) In-flight atmospheric and surface measurements using the HELiPOD helicopter-towed probe during ARTofMELT, Arctic Ocean, 2023. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/oden-artofmelt-2023-helipod-main-1

Sperzel TR, Jäkel E, Pätzold F, Lampert A, Niehaus H, Spreen G, Rosenburg S, Birnbaum G, Neckel N, Wendisch M (2023) Surface albedo measurements and surface type classification from helicopter-based observations during MOSAiC. Scientific Data 10. https://doi.org/10.1038/s41597-023-02492-6

Data description

• Number of files: 73
• Total data size: 11.9 GB
• File formats:
  • NetCDF (nc)
  • matlab struct (mat)
  • matlab table (mat)
  • text (txt)
  • image/jpeg (jpg)
  • image/png (png)
  • portable document format (pdf)

The dataset is provided in 12 folders, of which one contains data relevant for all flights and the other 11 contain data for one flight each.

1. All flights data folder

ARTofMELT_HELiPOD_allFlights_SurfaceClassification_v1/

The folder contains a visualization of the dataset content, the exclusion mask, sample images and numerical results.

Visualization of the dataset content

• ARTofMELT_Helipod-Surface-Classification_WorkflowAndFiles_v1.pdf

Description including the workflow to clarify the output.

Exclusion mask

• ARTofMELT_EOSdownward_skids_and_70deg_mask.mat
• ARTofMELT_EOSdownward_skids_and_70deg_mask.nc

NetCDF4 and MAT file containing the exclusion mask because of the Helipod skids and the field of view limited to 70 deg.

Folder with sample images for flight 7

ARTofMELT_F07_2023-05-24_3samples_filesPerImage_v1/

Contains 3 samples with the same image numbers of all 5 output files per image (corrected time in file name: UNIX milliseconds):

• JPG_3samples/
  • Sub-folder with jpg images postprocessed from raw image files: downsampled to 901 x 901 pixel and 8 bit, lens corrected.
• MAT_3samples/
• NC_3samples/
• TXT_3samples/
  • Sub-folders with numerical results of the classification as mat, nc, and txt files.
• PNG_3samples/
  • Sub-folder with visual result of the classification as png files.

2⁠ – ⁠12. Individual flights data folders

ARTofMELT_HELiPOD-F01_2023-05-09_SurfaceClassification_v1/
ARTofMELT_HELiPOD-F02_2023-05-15_SurfaceClassification_v1/
ARTofMELT_HELiPOD-F03_2023-05-16_SurfaceClassification_v1/
ARTofMELT_HELiPOD-F04_2023-05-19_SurfaceClassification_v1/
ARTofMELT_HELiPOD-F06_2023-05-22_SurfaceClassification_v1/
ARTofMELT_HELiPOD-F07_2023-05-24_SurfaceClassification_v1/
ARTofMELT_HELiPOD-F08_2023-05-27_SurfaceClassification_v1/
ARTofMELT_HELiPOD-F09_2023-05-28_SurfaceClassification_v1/
ARTofMELT_HELiPOD-F10_2023-06-01_SurfaceClassification_v1/
ARTofMELT_HELiPOD-F11_2023-06-06_SurfaceClassification_v1/
ARTofMELT_HELiPOD-F12_2023-06-09_SurfaceClassification_v1/

Data for each flight, identified by flight number and date in the folder name.

Each folder contains five files. File names include flight number and date. The file names given below are valid for flight 1, as an example.

Data as NetCDF4, MAT struct, and MAT table

• ARTofMELT_F01_2023-05-09_EOSdownward_surface_classification_v1.nc
• ARTofMELT_F01_2023-05-09_EOSdownward_surface_classification_struct_v1.mat
• ARTofMELT_F01_2023-05-09_EOSdownward_surface_classification_table_v1.mat

File content:

• Number of each included image (IMG_xxxxx) and the following related data:
• Time in different formats (UNIX, ISO8601, SoD, DoY)
• Position Lat [deg], Lon [deg], Alt [m] in WGS84 reference frame
• Radar altitude [m]
• Online derived lidar altitude [m]
• Fractions unweighted and cosine weighted within the not masked area differed into open water (blue), melt pond (red), bare ice (light green), young ice (dark green), snow-covered ice (yellow) and unclassified (gray) for each image

Two movies per flight

Based on the JPG images and classified PNG graphics (see example images for flight 7) including most of the above described data:

• ARTofMELT_F01_2023-05-09_SurfaceClassification_v1_noaudio.mp4
• ARTofMELT_F01_2023-05-09_SurfaceVIS_v1_noaudio.mp4

Comments

Methods

The helicopter-towed sensor system HELIPOD is described by Pätzold et al. (2023).

Surface type fractions were calculated per image, accounting for lens distortion as described by Jäkel et al. (2019).

The cosine weighting according to the viewing zenith angle is described by Sperzel et al. (2023).

Full dataset

Full image files sets, including raw CR3 and online-JPG can be obtained on request to the corresponding author.

AI declaration

All data were derived using heuristic methods and non-AI software. AI was used to create code solutions for data handling and shaping visual output.

Related dataset

In-flight atmospheric and surface measurements using the HELiPOD helicopter-towed probe during ARTofMELT, Arctic Ocean, 2023 (Pätzold et al. 2026).

The expedition

Data were collected during the ARTofMELT 2023 expedition on board the Swedish icebreaker Oden, which was organized by the Swedish Polar Research Secretariat from 8 May through 14 June, 2023.

Project

The preparation and participation of the HELIPOD in the ARTofMELT campaign was funded by the German Research Foundation DFG (LA2907/21-1) under project number 510976112.

Publisher

Bolin Centre Database

License

Creative Commons Attribution 4.0 International License (CC BY 4.0)

First name

Falk

Last name or organisation

Pätzold

Email address

f.paetzold@tu-braunschweig.de

Address

Technische Universität Braunschweig; Institute of Flight Guidance

Postal code

38108

City

Braunschweig

Country

Germany

GCMD science keyword

Earth science services > Data analysis and visualization

GCMD location

Ocean > Arctic Ocean

Dataset language

English

Begin date

2023-05-09

End date

2023-06-09

DOI

Time