Presenter: Feras Habbal (Applied Research Laboratories, University of Texas at Austin)

Description:
Unique to high latitude ocean environments, ice-ocean interactions produce freshwater flux sources at depth that modify the hydrography and impact large-scale circulation. For the Greenland Ice Sheet margins, freshwater runoff (formed from surface melt) crosses the grounding line subglacially and enters the Ocean at depth to form a buoyant plume. Such turbulent plumes modify the local hydrography by entraining and mixing with warmer, saltier background water masses, and rise to a neutrally buoyant position, potentially below the surface. In addition to modifying the local sound speed environment, these water masses are subsequently transported through the Greenland Sea (as observed by Argo floats) to produce freshwater lenses that may create or disrupt existing acoustic propagation paths. In this work, we explore using a high-resolution regional ocean model (MITgcm) coupled to an ice-ocean plume package, which is forced by subglacial freshwater flux. We use this modified ocean state to generate sound speed profiles that are used in acoustic transmission loss simulations. Using these results, we present the impact of including ice-ocean physics (missing from standard global Ocean circulation models) on the local hydrography and characterize the subsequent impact on acoustic propagation paths at mid-frequencies.