• Cross-platform application of a sea ice classification method considering incident angle dependency of backscatter intensity and its use in separating level and deformed ice 

      Guo, Wenkai; Itkin, Polona; Lohse, Johannes; Johansson, Malin; Doulgeris, Anthony Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2021)
      Wide-swath C-band synthetic aperture radar (SAR) has been used for sea ice classification and estimates of sea ice drift and deformation since it first became widely available in the 1990s. Here, we examine the potential to distinguish surface features created by sea ice deformation using ice type classification of SAR data. To perform this task with extended spatial and temporal coverage, we ...
    • Different mechanisms of Arctic first-year sea-ice ridge consolidation observed during the MOSAiC expedition 

      Salganik, Evgenii; Lange, Benjamin; Itkin, Polona; Divine, Dmitry; Katlein, Christian; Nicolaus, Marcel; Hoppmann, Mario; Neckel, Niklas; Ricker, Robert; Høyland, Knut Vilhelm; Granskog, Mats (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-22)
      Sea-ice ridges constitute a large fraction of the ice volume in the Arctic Ocean, yet we know little about the evolution of these ice masses. Here we examine the thermal and morphological evolution of an Arctic firstyear sea-ice ridge, from its formation to advanced melt. Initially the mean keel depth was 5.6 m and mean sail height was 0.7 m. The initial rubble macroporosity (fraction of seawater ...
    • Does your lab use social media? Sharing three years of experience in science communication 

      Pavlov, Alexey K.; Meyer, Amelie; Rösel, Anja; Cohen, Lana; King, Jennifer; Itkin, Polona; Negrel, Jean; Gerland, Sebastian; Hudson, Stephen R.; Dodd, Paul A.; de Steur, Laura; Mathisen, Stig; Cobbing, Nick; Granskog, Mats A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-27)
      Effective science communication is essential to share knowledge and recruit the next generation of researchers. Science communication to the general public can, however, be hampered by limited resources and a lack of incentives in the academic environment. Various social media platforms have recently emerged, providing free and simple science communication tools to reach the public and young people ...
    • A Lagrangian Snow Evolution System for Sea Ice Applications (SnowModel‐LG): Part II - Analyses 

      Stroeve, Julienne C.; Liston, Glen E.; Buzzard, Samantha; Zhou, Lu; Mallett, Robbie; Barrett, Andrew; Tschudi, Mark; Tsamados, Michel; Itkin, Polona; Stewart, Scott (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-02)
      Sea ice thickness is a critical variable, both as a climate indicator and for forecasting sea ice conditions on seasonal and longer time scales. The lack of snow depth and density information is a major source of uncertainty in current thickness retrievals from laser and radar altimetry. In response to this data gap, a new Lagrangian snow evolution model (SnowModel‐LG) was developed to simulate snow ...
    • A Lagrangian Snow‐Evolution System for Sea‐Ice Applications (SnowModel‐LG): Part I – Model Description 

      Liston, Glen E.; Itkin, Polona; Stroeve, Julienne C.; Tschudi, Mark; Stewart, J. Scott; Pedersen, Stine Højlund; Reinking, A.K.; Elder, Kelly (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-06)
      A Lagrangian snow-evolution model (SnowModel-LG) was used to produce daily, pan-Arctic, snow-on-sea-ice, snow property distributions on a 25 × 25-km grid, from 1 August 1980 through 31 July 2018 (38 years). The model was forced with NASA's Modern Era Retrospective-Analysis for Research and Applications-Version 2 (MERRA-2) and European Centre for Medium-Range Weather Forecasts (ECMWF) ReAnalysis-5th ...
    • Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ic 

      Assmy, Philipp; Fernández-Méndez, Mar; Duarte, Pedro; Meyer, Amelie; Randelhoff, Achim; Mundy, Christopher John; Olsen, Lasse; Kauko, Hanna M.; Bailey, Allison; Chierici, Melissa; Cohen, Lana; Doulgeris, Anthony Paul; Ehn, Jens K.; Fransson, Agneta; Gerland, Sebastian; Hop, Haakon; Hudson, Stephen R.; Hughes, Nick; Itkin, Polona; Johnsen, Geir; King, Jennifer A.; Koch, Boris P.; Koenig, Zoe; Kwasniewski, Slawomir; Laney, Samuel R.; Nikolaus, Marcel; Pavlov, Alexey K.; Polashenski, Christopher M.; Provost, Christine; Rösel, Anja; Sandbu, Marthe; Spreen, Gunnar; Smedsrud, Lars H.; Sundfjord, Arild; Taskjelle, Torbjørn; Tatarek, Agnieszka; Wiktor, Josef; Wagner, Penelope Mae; Wold, Anette; Steen, Harald; Granskog, Mats A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-19)
      The Arctic icescape is rapidly transforming from a thicker multiyear ice cover to a thinner and largely seasonal first-year ice cover with significant consequences for Arctic primary production. One critical challenge is to understand how productivity will change within the next decades. Recent studies have reported extensive phytoplankton blooms beneath ponded sea ice during summer, indicating ...
    • Platelet ice under Arctic pack ice in winter 

      Katlein, Christian; Mohrholz, Volker; Sheikin, Igor; Itkin, Polona; Divine, Dmitry; Stroeve, Julienne C.; Jutila, Arttu; Krampe, Daniela; Shimanchuk, Egor; Raphael, Ian; Rabe, Benjamin; Kuznetsov, Ivan; Mallet, Maria; Liu, Hailong; Hoppmann, Mario; Fang, Ying‐Chih; Dumitrascu, Adela; Arndt, Stefanie; Anhaus, Philipp; Nicolaus, Marcel; Matero, Ilkka; Oggier, Marc; Eicken, Hajo; Haas, Christian (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-17)
      The formation of platelet ice is well known to occur under Antarctic sea ice, where subice platelet layers form from supercooled ice shelf water. In the Arctic, however, platelet ice formation has not been extensively observed, and its formation and morphology currently remain enigmatic. Here, we present the first comprehensive, long‐term in situ observations of a decimeter thick subice platelet ...
    • Preconditioning of Summer Melt Ponds From Winter Sea Ice Surface Temperature 

      Thielke, Linda; Fuchs, Niels; Spreen, Gunnar; Tremblay, Bruno; Birnbaum, Gerit; Huntemann, Marcus; Hutter, Nils; Itkin, Polona; Jutila, Arttu; Webster, Melinda A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-22)
      Comparing helicopter-borne surface temperature maps in winter and optical orthomosaics in summer from the year-long Multidisciplinary drifting Observatory for the Study of Arctic Climate expedition, we find a strong geometric correlation between warm anomalies in winter and melt pond location the following summer. Warm anomalies are associated with thinner snow and ice, that is, surface depression ...
    • Retrieval of Snow Depth on Arctic Sea Ice From Surface-Based, Polarimetric, Dual-Frequency Radar Altimetry 

      Willatt, Rosemary; Stroeve, Julienne; Nandan, Vishnu; Newman, Thomas; Mallett, Robbie; Hendricks, Stefan; Ricker, Robert; Mead, James; Itkin, Polona; Tonboe, Rasmus; Wagner, David N.; Spreen, Gunnar; Liston, Glen; Schneebeli, Martin; Krampe, Daniela; Tsamados, Michel; Demir, Oguz; Wilkinson, Jeremy; Jaggi, Matthias; Zhou, Lu; Huntemann, Marcus; Raphael, Ian A.; Jutila, Arttu; Oggier, Marc (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-18)
      Snow depth on sea ice is an Essential Climate Variable and a major source of uncertainty in satellite altimetry-derived sea ice thickness. During winter of the MOSAiC Expedition, the “KuKa” dual-frequency, fully polarized Ku- and Ka-band radar was deployed in “stare” nadir-looking mode to investigate the possibility of combining these two frequencies to retrieve snow depth. Three approaches ...
    • Sea ice and snow characteristics from year-long transects at the MOSAiC Central Observatory 

      Itkin, Polona; Hendricks, Stefan; Webster, Melinda A.; Albedyll, Luisa von; Arndt, Stefanie; Divine, Dmitry; Jaggi, Matthias; Oggier, Marc; Raphael, Ian A.; Ricker, Robert; Rohde, Jan; Schneebeli, Martin; Liston, Glen E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-16)
      Repeated transects have become the backbone of spatially distributed ice and snow thickness measurements crucial for understanding of ice mass balance. Here we detail the transects at the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) 2019–2020, which represent the first such measurements collected across an entire season. Compared with similar historical transects, ...
    • Sea ice classification of TerraSAR-X ScanSAR images for the MOSAiC expedition incorporating per-class incidence angle dependency of image texture 

      Guo, Wenkai; Itkin, Polona; Singha, Suman; Doulgeris, Anthony Paul; Johansson, Malin; Spreen, Gunnar (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-16)
      We provide sea ice classification maps of a subweekly time series of single (horizontal–horizontal, HH) polarization X-band TerraSAR-X scanning synthetic aperture radar (TSX SC) images from November 2019 to March 2020, covering the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. This classified time series benefits from the wide spatial coverage ...
    • Sea ice thermohaline dynamics and biogeochemistry in the Arctic Ocean: Empirical and model results 

      Duarte, Pedro; Meyer, Amelie; Olsen, Lasse Mork; Kauko, Hanna Maria; Assmy, Philipp; Rösel, Anja; Itkin, Polona; Hudson, Stephen R.; Granskog, Mats A.; Gerland, Sebastian; Sundfjord, Arild; Steen, Harald; Hop, Haakon; Cohen, Lana; Peterson, Algot Kristoffer; Jeffery, Nicole; Elliott, Scott M.; Hunke, Elizabeth Clare; Turner, Adrian K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-11)
      Large changes in the sea ice regime of the Arctic Ocean have occurred over the last decades justifying the development of models to forecast sea ice physics and biogeochemistry. The main goal of this study is to evaluate the performance of the Los Alamos Sea Ice Model (CICE) to simulate physical and biogeochemical properties at time scales of a few weeks and to use the model to analyze ice algal ...
    • The seeding of ice algal blooms in Arctic pack ice: The multiyear ice seed repository hypothesis 

      Olsen, Lasse Mork; Laney, Samuel R.; Duarte, Pedro; Kauko, Hanna M.; Fernández-Méndez, Mar; Mundy, Christopher John; Rösel, Anja; Meyer, Amelie; Itkin, Polona; Cohen, Lana; Peeken, Ilka; Tatarek, Agnieszka; Róźańska-Pluta, Magdalena; Wiktor, Josef; Taskjelle, Torbjørn; Pavlov, Alexey; Hudson, Stephen R.; Granskog, Mats A.; Hop, Haakon; Assmy, Philipp (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-03)
      During the Norwegian young sea ICE expedition (N-ICE2015) from January to June 2015 the pack ice in the Arctic Ocean north of Svalbard was studied during four drifts between 83° and 80°N. This pack ice consisted of a mix of second year, fi rst year, and young ice. The physical properties and ice algal community composition was investigated in the three different ice types during the ...
    • Snow and Ice Thickness Retrievals Using GNSS-R: Preliminary Results of the MOSAiC Experiment 

      Munoz-Martin, Joan Francesc; Perez, Adrian; Camps, Adriano; Ribó, Serni; Cardellach, Estel; Stroeve, Julienne; Nandan, Vishnu; Itkin, Polona; Tonboe, Rasmus; Hendricks, Stefan; Huntemann, Marcus; Spreen, Gunnar; Pastena, Massimiliano (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-10)
      The FSSCat mission was the 2017 ESA Sentinel Small Satellite (S⌃3) Challenge winner and the Copernicus Masters competition overall winner. It was successfully launched on 3 September 2020 onboard the VEGA SSMS PoC (VV16). FSSCat aims to provide coarse and downscaled soil moisture data and over polar regions, sea ice cover, and coarse resolution ice thickness using a combined L-band microwave radiometer ...
    • Snowfall and snow accumulation during the MOSAiC winter and spring seasons 

      Wagner, David N.; Shupe, Matthew D.; Cox, Christopher; Persson, Ola G.; Uttal, Taneil; Frey, Markus M.; Kirchgaessner, Amélie; Schneebeli, Martin; Jaggi, Matthias; MacFarlane, Amy R.; Itkin, Polona; Arndt, Stefanie; Hendricks, Stefan; Krampe, Daniela; Nicolaus, Marcel; Ricker, Robert; Regnery, Julia; Kolabutin, Nikolai; Shimanshuck, Egor; Oggier, Marc; Raphael, Ian; Stroeve, Julienne; Lehning, Michael (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-17)
      Data from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition allowed us to investigate the temporal dynamics of snowfall, snow accumulation and erosion in great detail for almost the whole accumulation season (November 2019 to May 2020). We computed cumulative snow water equivalent (SWE) over the sea ice based on snow depth and density retrievals from a ...
    • Sub-kilometre scale distribution of snow depth on Arctic sea ice from Soviet drifting stations 

      Mallett, Robbie; Stroeve, Julienne C.; Tsamados, Michel; Willatt, Rosemary; Newman, Thomas; Nandan, Vishnu; Landy, Jack Christopher; Itkin, Polona; Oggier, Marc; Jaggi, Matthias; Perovich, Don (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-04)
      The sub-kilometre scale distribution of snow depth on Arctic sea ice impacts atmosphere-ice fluxes of energy and mass, and is of importance for satellite estimates of sea-ice thickness from both radar and lidar altimeters. While information about the mean of this distribution is increasingly available from modelling and remote sensing, the full distribution cannot yet be resolved. We analyse 33 539 ...
    • Surface-based Ku-and Ka-band polarimetric radar for sea ice studies 

      Stroeve, Julienne C.; Nandan, Vishnu; Willatt, Rosemary; Tonboe, Rasmus; Hendricks, Stefan; Ricker, Robert; Mead, James; Mallett, Robbie; Huntemann, Marcus; Itkin, Polona; Schneebeli, Martin; Krampe, Daniela; Spreen, Gunnar; Wilkinson, Jeremy; Matero, Ilkka; Hoppmann, Mario; Tsamados, Michel (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-04)
      To improve our understanding of how snow properties influence sea ice thickness retrievals from presently operational and upcoming satellite radar altimeter missions, as well as to investigate the potential for combining dual frequencies to simultaneously map snow depth and sea ice thickness, a new, surface-based, fully polarimetric Ku- and Ka-band radar (KuKa radar) was built and deployed ...
    • Thermodynamic and dynamic contributions to seasonal Arctic sea ice thickness distributions from airborne observations 

      von Albeldyll, Luisa; Hendricks, Stefan; Grodofzig, Raphael; Krumpen, Thomas; Arndt, Stefanie; Belter, H. Jakob; Birnbaum, Gerit; Cheng, Bin; Hoppmann, Mario; Hutchings, Jennifer; Itkin, Polona; Lei, Ruibo; Nicolaus, Marcel; Ricker, Robert; Rohde, Jan; Suhrhoff, Mira; Timofeeva, Anna; Watkins, Daniel; Webster, Melinda; Haas, Christian (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-18)
      Sea ice thickness is a key parameter in the polar climate and ecosystem. Thermodynamic and dynamic processes alter the sea ice thickness.The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition provided a unique opportunity to study seasonal sea ice thickness changes of the same sea ice. We analyzed 11 large-scale (*50 km) airborne electromagnetic sea thickness ...
    • Winter storms accelerate the demise of sea ice in the Atlantic sector of the Arctic Ocean 

      Graham, Robert M.; Itkin, Polona; Meyer, Amelie; Sundfjord, Arild; Spreen, Gunnar; Smedsrud, Lars H.; Liston, Glen E.; Cheng, Bin; Cohen, Lana; Divine, Dmitry; Fer, Ilker; Fransson, Agneta; Gerland, Sebastian; Haapala, Jari; Hudson, Stephen R.; Johansson, Malin; King, Jennifer A.; Merkouriadi, Ioanna; Peterson, Algot Kristoffer; Provost, Christine; Randelhoff, Achim; Rinke, Annette; Rösel, Anja; Sennechael, Nathalie; Walden, Von P.; Duarte, Pedro; Assmy, Philipp; Steen, Harald; Granskog, Mats A. (Journal article; Peer reviewed, 2019-06-25)
      A large retreat of sea-ice in the ‘stormy’ Atlantic Sector of the Arctic Ocean has become evident through a series of record minima for the winter maximum sea-ice extent since 2015. Results from the Norwegian young sea ICE (N-ICE2015) expedition, a five-month-long (Jan-Jun) drifting ice station in first and second year pack-ice north of Svalbard, showcase how sea-ice in this region is frequently ...