Hypothesis:

Under Arctic amplification, oceanic kinetic energy increases, and hence ocean-sea ice-atmosphere heat fluxes in the Arctic intensify.

Specifically, we will address the questions:

• What is the basin-scale distribution of ocean heat fluxes coupling the ocean mixed layer, sea ice, and atmosphere?
• Do we already observe changes in the energy fluxes between ice, mixed layer, and warm Atlantic Water, and are they related to changes in the subsurface circulation of Atlantic Water?
• What is the quantitative role of upper-ocean processes in Arctic amplification?

Our anticipated results will contribute to the (AC)³ strategic questions SQ1 by clarifying the upper oceans’ role for sea ice loss and atmospheric convection, and SQ3 by identifying and quantifying regional varying sensitivities of the ocean-ice-atmosphere heat fluxes from observations, and their representation in model simulations.

Achievements phase II

• We obtained samples for the transient tracers SF6 and CFC-12, the noble gas isotopes 3He, 4He 20Ne and 22Ne, as well as tritium (3H) during the MOSAiC expedition and the Maria S. Merian expedition MSM93 to Fram Strait. These data sets were measured in the home lab, quality controlled and recently finalized. In parallel, historical data sets of transient tracers were compiled to set up a framework that revealed the changing flow paths of Atlantic Water on multiannual to decadal time scales in response to changing environmental conditions as ice cover and atmospheric forcing.
• A complex high-resolution hydrographic data set of the evolution of a frontal system in the marginal ice zone in an atlantified regime was obtained during MSM93. Subsequently analysis for the vertical and horizontal exchange processes revealed a complex structure with moving surface and subsurface fronts between Surface Water, Polar Water and Atlantic Water. Both the surface and subsurface fronts are affected by the mesoscale meandering and large scale motion of the ice edge as well as a complete absence of a mixed layer.
• Based on the hydrographic and mixing data sets collected during MOSAiC in the central Arctic, the development of the mixed layer during the winter period of the drift was described, attributing the observed heat and salt fluxes to horizontal and vertical sources and processes. The surprising result is, that horizontal advection of salt in the mixed layer represents a major sink of salt, thus counteracting the rejection of brine from sea ice formation. Upward salt fluxes from across the halocline into the mixed layer are significantly enhanced during storm events.

Role within (AC)³

Project Posters

Phase III Evaluation poster 2023	Phase II Evaluation poster 2019

Project Members

Publications

2026

2025

Reifenberg, S. F., Fer, I., Kanzow, T., Von Appen, W., Hoppmann, M., Krumpen, T., Neudert, M., Preusser, A., and Haas, C. , April 2025: Turbulence observations below drifting sea ice: TKE production and dissipation in the meltwater-influenced boundary layer. J. Phys. Oceanogr., 55(4):451–470, doi:10.1175/JPO-D-24-0102.1

2024

Hofmann, Z., Von Appen, W., Kanzow, T., Becker, H., Hagemann, J., Hufnagel, L., and Iversen, M. H. , May 2024: Stepwise Subduction Observed at a Front in the Marginal Ice Zone in Fram Strait. J. Geophys. Res. Oceans, 129(5):e2023JC020641, doi:10.1029/2023JC020641

Bracamontes-Ramírez, J., Walter, M., and Losch, M. , May 2024: Near-Inertial Wave Propagation in the Deep Canadian Basin: Turning Depths and the Homogeneous Deep Layer. J. Geophys. Res. Oceans, 129(5):e2023JC020228, doi:10.1029/2023JC020228

2023

Heuzé, C., Huhn, O., Walter, M., Sukhikh, N., Karam, S., Körtke, W., Vredenborg, M., Bulsiewicz, K., Sültenfuß, J., Fang, Y., Mertens, C., Rabe, B., Tippenhauer, S., Allerholt, J., He, H., Kuhlmey, D., Kuznetsov, I., and Mallet, M. , December 2023: A Year of Transient Tracers (Chlorofluorocarbon 12 and Sulfur Hexafluoride), Noble Gases (Helium and Neon), and Tritium in the Arctic Ocean from the MOSAiC Expedition (2019–2020). Earth Syst. Sci. Data, 15(12):5517–5534, doi:10.5194/essd-15-5517-2023

McPherson, R. A., Wekerle, C., and Kanzow, T. , October 2023: Shifts of the Recirculation Pathways in Central Fram Strait Drive Atlantic Intermediate Water Variability on Northeast Greenland Shelf. J. Geophys. Res. Oceans, 128(10):e2023JC019915, doi:10.1029/2023JC019915

Heukamp, F. O., Kanzow, T., Wang, Q., Wekerle, C., and Gerdes, R. , March 2023: Impact of Cyclonic Wind Anomalies Caused by Massive Winter Sea Ice Retreat in the Barents Sea on Atlantic Water Transport Toward the Arctic: A Model Study. J. Geophys. Res. Oceans, 128(3):e2022JC019045, doi:10.1029/2022JC019045

Ruiz-Castillo, E., Janout, M., Hölemann, J., Kanzow, T., Schulz, K., and Ivanov, V. , January 2023: Structure and Seasonal Variability of the Arctic Boundary Current North of Severnaya Zemlya. J. Geophys. Res. Oceans, 128(1):e2022JC018677, doi:10.1029/2022JC018677

Doglioni, F., Ricker, R., Rabe, B., Barth, A., Troupin, C., and Kanzow, T. , January 2023: Sea Surface Height Anomaly and Geostrophic Current Velocity from Altimetry Measurements over the Arctic Ocean (2011–2020). Earth Syst. Sci. Data, 15(1):225–263, doi:10.5194/essd-15-225-2023

2022

Rabe, B., Heuzé, C., Regnery, J., Aksenov, Y., Allerholt, J., Athanase, M., Bai, Y., Basque, C., Bauch, D., Baumann, T. M., Chen, D., Cole, S. T., Craw, L., Davies, A., Damm, E., Dethloff, K., Divine, D. V., Doglioni, F., Ebert, F., Fang, Y., Fer, I., Fong, A. A., Gradinger, R., Granskog, M. A., Graupner, R., Haas, C., He, H., He, Y., Hoppmann, M., Janout, M., Kadko, D., Kanzow, T., Karam, S., Kawaguchi, Y., Koenig, Z., Kong, B., Krishfield, R. A., Krumpen, T., Kuhlmey, D., Kuznetsov, I., Lan, M., Laukert, G., Lei, R., Li, T., Torres-Valdés, S., Lin, L., Lin, L., Liu, H., Liu, N., Loose, B., Ma, X., McKay, R., Mallet, M., Mallett, R. D. C., Maslowski, W., Mertens, C., Mohrholz, V., Muilwijk, M., Nicolaus, M., O'Brien, J. K., Perovich, D., Ren, J., Rex, M., Ribeiro, N., Rinke, A., Schaffer, J., Schuffenhauer, I., Schulz, K., Shupe, M. D., Shaw, W., Sokolov, V., Sommerfeld, A., Spreen, G., Stanton, T., Stephens, M., Su, J., Sukhikh, N., Sundfjord, A., Thomisch, K., Tippenhauer, S., Toole, J. M., Vredenborg, M., Walter, M., Wang, H., Wang, L., Wang, Y., Wendisch, M., Zhao, J., Zhou, M., and Zhu, J. , February 2022: Overview of the MOSAiC Expedition: Physical Oceanography. Elem Sci Anth, 10(1):00062, doi:10.1525/elementa.2021.00062

2021

Hofmann, Z., von Appen, W., and Wekerle, C. , July 2021: Seasonal and Mesoscale Variability of the Two Atlantic Water Recirculation Pathways in Fram Strait. J. Geophys. Res. Oceans, 126(7):e2020JC017057, doi:10.1029/2020JC017057

2020

2019

2018

2017

2016