A Box Model of Estuarine Amplification Within a Glacial Fjord

Glacial fjords are deep estuaries that link the margins of the Greenland Ice Sheet to the ocean. The circulation within glacial fjords is complex and plays an important role in regulating how much ocean heat reaches the ice sheet as well as diluting the fresh meltwater. We have developed a simplified box model to constrain the interaction of two parts of glacial fjord systems: buoyant subglacial discharge plumes and two-layer estuarine circulation. We constrain the parameters of the box model using the results of high resolution MITgcm simulations of fjords with idealized geometries. With these simulations we explore the parameter space of fjord and plume geometry over a range subglacial discharge volumes. The bounds of this parameter space are motivated by observations of fjords. We aim to use these simulations together with the box model to understand the up-fjord transport of heat and down-fjord dilution of ice sheet meltwater. This work is meant to be a first step in parameterizing the modification of heat and freshwater within fjords to provide a parameterization for coupling of an ice-sheet and ocean models.