Influence of Melt Season Characteristics on Meltwater Partitioning and Delivery Into a Perennial Firn Aquifer

Perennial firn aquifers in the Greenland ice sheet are known to form and persist in regions of sufficiently high melt rates and accumulation rates throughout the year. However, it is not clear how seasonal to sub‐seasonal variations in surface melt forcings affect the dynamics of melt recharge into a firn aquifer and the accompanying refreezing processes. Here, we use a hydrological model to probe how different styles of seasonal melting influence the recharge of a firn aquifer and the structural changes of the unsaturated firn column above. We find that a simple subsurface energy balance can provide a good estimation for melt partitioning, however our results suggest that the early dynamics of the melt season dictates the timing of recharge. Further, we show that an increased magnitude of melt in a single season leads to deeper refreezing, and that seasons with intermittent melt events can create ice lenses at depth.

N. J., A. M., and X. F. acknowledge the partial support from the Resnick Sustainability Institute at California Institute of Technology and from the National Science Foundation under Grant Number EAR-2243631. R. C. is supported in part by NASA Grants 80NSSC24K1445 and 80NSSC24K1037. M. B. is supported by Ocean Cryosphere Exchanges in ANtarctica: Impacts on Climate and the Earth system, OCEAN ICE, which is funded by the European Union, Horizon Europe Funding Programme for research and innovation under Grant agreement Nr. 101060452, 10.3030/101060452, OCEAN ICE contribution number 36.