SFB/TRR 172 "Arctic Amplification (AC)3"
Arctic Amplification: Climate Relevant Atmospheric and Surface Processes, and Feedback Mechanisms (AC)3
Project C04: Coupling between atmosphere, mixed layer and pycnocline under Arctic amplification: the role of sea ice related processes
Period: 2020 - 2023
- This project is part of the TRR 172 “Arctic Amplification (AC)3” and aims to understand the role of physical vertical and horizontal processes within the Arctic Ocean mixed layer. These processes are critical for the vertical heat flux between atmosphere and Atlantic layer, and thus for the change in Arctic sea ice and Arctic amplification.
- The inflow of warm and saline Atlantic water could reduce the upper ocean vertical stratification so that convective wintertime deepening of the mixed layer may cause an upward heat flux from the subsurface Atlantic layer toward the sea surface. This shift to conditions similar to those in the subpolar North Atlantic is called “Atlantification” of the Arctic Ocean and it may further reduce the sea ice cover. The feedback between fluxes across the halocline and base of the mixed layer and the sea ice for events like opening leads, passing storms, ice melt, passing oceanic eddies, or the decay of fronts in the upper ocean are not well understood.
- This study will provide vertical heat fluxes by combining integral estimates from dedicated helium and neon isotopes, tritium, CFC, and SF6 measurements with observations of turbulence, currents, stratification, and meteorological data. To contrast the situation in the ice-covered Arctic Ocean with a scenario of Atlantification, data from the overwintering MOSAiC expedition will be combined with observation from the current ice edge in Fram Strait, where AW and halocline waters form large horizontal gradients. These results will be combined with statistics for the occurrence of the studied events to assess the impact of Arctic amplification on the feedback between atmosphere, ocean, and sea ice.