/* DATA DESCRIPTION: Citation: Wong, Carmen Hau Man; Heuzé, Céline (2025): Daily Arctic polynya masks 1978-2024 from two satellite sea ice products (SMMR, SSM/I & SSMIS and SMOS & SMOS-SMAP) [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.987383 Abstract: This dataset provides four daily Arctic polynya masks derived from two satellite sea ice products. The products used are (1) the daily sea ice concentration (SIC) dataset from the National Snow and Ice Data Center (DiGirolamo et al., 2022; for years 1978–2024) and (2) the daily thin ice thickness (SIT) dataset from the University of Bremen Sea Ice Remote Sensing Group (SMOS and SMOS/SMAP Thin Ice Thickness, Huntemann et al., 2014 and Paţilea et al., 2019; for years 2012–2024). The study region covers the Arctic Ocean 65° - 90°N. Two wintertime study periods are included, corresponding to two research articles (Wong, C H M et al., 2026; Heuzé, C & Wong, C H M, in 2025). Polynya thresholds are defined as 50% for SIC and 20 cm for SIT. Details of the full polynya detection method are provided in Wong, C H M et al. (2026). Keyword(s): Arctic sea ice; Polynya; sea ice-atmosphere interactions Supplement to: Heuzé, Céline; Wong, Carmen Hau Man (2025): Automatic detection of Arctic polynyas using hybrid supervised-unsupervised deep learning. The Cryosphere, 19(11), 6043-6058, https://doi.org/10.5194/tc-19-6043-2025 Related to: Wong, Carmen Hau Man; Heuzé, Céline; Ickes, Luisa; Zhou, Lu (2026): The Spatiotemporal Variability, Trends, and Drivers of Winter Arctic Polynyas. Journal of Climate, 39(6), 1433-1455, https://doi.org/10.1175/JCLI-D-25-0312.1 Source: DiGirolamo, Nicolo; Parkinson, Claire; Cavalieri, Donald J; Gloersen, Per; Zwally, H (2022): Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data, Version 2 [dataset]. NASA National Snow and Ice Data Center Distributed Active Archive Center, https://doi.org/10.5067/MPYG15WAA4WX Huntemann, Marcus; Heygster, Georg; Kaleschke, Lars; Krumpen, Thomas; Mäkynen, M; Drusch, Matthias (2014): Empirical sea ice thickness retrieval during the freeze-up period from SMOS high incident angle observations. The Cryosphere, 8(2), 439-451, https://doi.org/10.5194/tc-8-439-2014 Paţilea, Cătălin; Heygster, Georg; Huntemann, Marcus; Spreen, Gunnar (2019): Combined SMAP–SMOS thin sea ice thickness retrieval. The Cryosphere, 13(2), 675-691, https://doi.org/10.5194/tc-13-675-2019 Funding: Swedish National Space Agency (SNSA), grant/award no. 2022-00149: Mapping Arctic polynyas from space (MAPS) Swedish Research Council (VR), grant/award no. 2022-06725_VR: National Academic Infrastructure for Supercomputing in Sweden (NAISS) (URI: https://www.vr.se/english/swecris.html#/project/2022-06725_VR) Coverage: LATITUDE: 90.000000 * LONGITUDE: 0.000000 DATE/TIME START: 1978-11-01T00:00:00 * DATE/TIME END: 2024-04-30T00:00:00 Event(s): Arctic_65-90N * LATITUDE START: 65.000000 * LONGITUDE START: -180.000000 * LATITUDE END: 90.000000 * LONGITUDE END: 180.000000 * LOCATION: Arctic * METHOD/DEVICE: Satellite remote sensing (SAT) Parameter(s): Identification (ID) * PI: Wong, Carmen Hau Man (https://orcid.org/0000-0002-4880-496X, hau.man.wong@gu.se) DATE/TIME (Date/Time) * GEOCODE * PI: Wong, Carmen Hau Man (https://orcid.org/0000-0002-4880-496X, hau.man.wong@gu.se) * COMMENT: start DATE/TIME (Date/Time) * GEOCODE * PI: Wong, Carmen Hau Man (https://orcid.org/0000-0002-4880-496X, hau.man.wong@gu.se) * COMMENT: end LATITUDE (Latitude) * GEOCODE * PI: Wong, Carmen Hau Man (https://orcid.org/0000-0002-4880-496X, hau.man.wong@gu.se) LONGITUDE (Longitude) * GEOCODE * PI: Wong, Carmen Hau Man (https://orcid.org/0000-0002-4880-496X, hau.man.wong@gu.se) netCDF file (netCDF) * PI: Wong, Carmen Hau Man (https://orcid.org/0000-0002-4880-496X, hau.man.wong@gu.se) netCDF file (File Size) [Bytes] (netCDF (Size)) * PI: Wong, Carmen Hau Man (https://orcid.org/0000-0002-4880-496X, hau.man.wong@gu.se) File content (Content) * PI: Wong, Carmen Hau Man (https://orcid.org/0000-0002-4880-496X, hau.man.wong@gu.se) License: Creative Commons Attribution 4.0 International (CC-BY-4.0) (URI: https://creativecommons.org/licenses/by/4.0/) Status: Curation Level: Enhanced curation (URI: https://wiki.pangaea.de/wiki/Curation_levels) Size: 12 data points Files: All files referred to in data matrix can be downloaded in one go as ZIP or TAR (PANGAEA user account required). To download single files, use the filename from data matrix appended to "https://download.pangaea.de/dataset/987383/files/". */ ID Date/Time (start) Date/Time (end) Latitude Longitude netCDF netCDF (Size) [Bytes] Content D1_1203_POL_SMMR_2024_1978 1978-12-01T00:00 2024-03-31T00:00 90.00 0.00 daily_location_SMMR_Dec_Mar.nc 2.8 GBytes Daily Arctic polynya mask retrieved from SIC dataset SMMR, SSM/I & SSMIS with a wintertime period from December to March D2_1104_POL_SMMR_2024_1978 1978-11-01T00:00 2024-04-30T00:00 90.00 0.00 daily_location_SMMR_Nov_Apr.nc 4.2 GBytes Daily Arctic polynya mask retrieved from SIC dataset SMMR, SSM/I & SSMIS with a wintertime period from November to April D1_1203_POL_SMOS_2024_2012 2012-12-01T00:00 2024-03-31T00:00 90.00 0.00 daily_location_SMOS_Dec_Mar.nc 3 GBytes Daily Arctic polynya mask retrieved from SIT dataset SMOS & SMOS/SMAP with a wintertime period from December to March D2_1103_POL_SMOS_2024_2012 2012-11-01T00:00 2024-04-30T00:00 90.00 0.00 daily_location_SMOS_Nov_Apr.nc 4.4 GBytes Daily Arctic polynya mask retrieved from SIT dataset SMOS & SMOS/SMAP with a wintertime period from November to April