Abstract

Models are reported to overestimate basal melting under “warm water” ice shelves. Hence, ice-ocean heat exchange and its parameterisation are investigated using an ice-ocean boundary current model (IOBCM). Using the simplified case of a horizontal ice-ocean interface (IOI), we demonstrate how common parameterizations in z-coordinate ocean models can significantly overestimate melt rates in stably stratified boundary layers with slow far-field ocean currents.

We also conceptualise a hybrid approach for the simple case of density driven currents under ice shelves. The hybrid model is a combination of the classic plume model for unstable regimes and the parameterized version of the IOBCM for stable regimes. In the hybrid model, for stable regimes, the melt rate as well as its response to warming are significantly reduced when compared to the regime independent treatment in the plume model.

Our findings highlight the importance of careful consideration of the ocean stratification and flow conditions when parameterizing ice-ocean interactions, especially in regions with slow-moving currents and stable stratification.