Noble Gases Reveal Ocean-Glacier Interaction in Shallow and Deep-Silled Greenland Fjords

We present observations of water mass distribution and transformation in two glacier-fjord systems in Greenland: the deep-silled Sermilik-Helhiem system in east Greenland; and the shallow-silled Eqip-Kangilerngata system in west Greenland. By using noble gases as conservative tracers we unambiguously quantify distributions of submarine meltwater, subglacial discharge, and oceanic water masses in each proglacial fjord. The two systems have substantially different sill and glacier terminus depths -- parameters that have been shown to impact fjord circulation and ice-ocean interactions. Water mass distributions provided by the tracer observations provide an integrated view of fjord circulation and ice-ocean interaction and enable us to explore differences between the two systems, which are at opposite ends of the dynamical parameter space of Greenland proglacial fjords.