Controls on fjord temperature throughout Greenland in a reduced‐physics model

Greenland's fjords modulate exchanges between its outlet glaciers and the open ocean. Subglacial discharge and iceberg melt redistribute heat and salt in the fjord, modifying waters at glacier fronts and impacting glacier melt. Considering observations are sparse and general circulation models are computationally expensive, we use a reduced-physics model to simulate vertical profiles of temperature and salinity for 37 fjords around Greenland. For each fjord, we conduct large model ensembles to explore the effects of subglacial discharge, iceberg melt, and fjord-shelf exchange on water properties. We show that our model successfully captures water mass changes inside fjords: iceberg melt cools the surface, while subglacial discharge plumes and fjord-shelf exchange tend to decrease and increase temperature stratification, respectively. By comparing our ensemble to observations, we highlight that despite high interannual and fjord-to-fjord variability in ocean and meltwater forcings, a reduced-physics model can elucidate how fjords modulate ice-sheet-ocean exchanges at Greenland-wide scales.