Interannual summer mixing processes in the Ilulissat Icefjord, Greenland

Enhanced oceanic mixing at the deep sill of Ilulissat Icefjord, Greenland, promotes upward heat and salt transport from subsurface layers to the surface mixed layer. This process, quantified using Thorpe scale analysis of density inversions from summer research cruises (2009–2017), revealed diapycnal diffusivity reaching up to 1×10⁻³.⁵ m²/s⁻¹—significantly higher than global ocean averages. The strongest mixing occurred in 2013, while the weakest was observed in 2016, correlating with glacier melting conditions and ice melange dynamics. Low melange concentrations increased ventilation, facilitating intrusions of Polar and Irminger waters that disrupted water column stability, reducing diffusive convection. These findings suggest that water intrusions from Disko Bay may influence the stability of Jakobshavn Isbræ Glacier, offering critical insights into fjord-glacier interactions.

Mojica, J. F., Djoumna, G., Holland, D. M., & Holland, D. (2021). Interannual summer mixing processes in the Ilulissat Icefjord, Greenland. Journal of Marine Systems, 214, 103476. https://doi.org/10.1016/j.jmarsys.2020.103476