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arXiv · 2507.10916

Fine-Scale Heterogeneity of Snow Cover in the Antarctic Marginal Ice Zone

Ippolita Tersigni·Filippo Nelli·Emiliano Cimoli·Marcello Vichi·Petra Heil·Luke G. Bennetts·Giulio Passerotti·Alberto Alberello·Alessandro Toffoli
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Abstract

Snow cover on Antarctic sea ice is highly heterogeneous, yet climate models have historically simplified it to a uniform layer in winter and bare ice in summer, introducing uncertainty in simulated surface energy fluxes. Here, using shipborne, high-resolution, close-range imagery of the sea ice surface, visual observations, and concurrent atmospheric data from five expeditions across the Antarctic marginal ice zone (2019-2024), we show that fine-scale (sub-grid) snow cover heterogeneity persists across all seasons, is largely independent of ice concentration, and is governed by ice morphology and regional accumulation history. When the heterogeneity is incorporated into flux calculations, it introduces systematic biases in surface energy fluxes relative to uniform-surface assumptions. These findings, based on observations from two Southern Ocean sectors, suggest that the inclusion of sub-grid snow distribution should be considered for simulating Antarctic sea ice evolution and its broader polar climate feedback.

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Ippolita Tersigni, Filippo Nelli, Emiliano Cimoli, Marcello Vichi, Petra Heil, Luke G. Bennetts, Giulio Passerotti, Alberto Alberello, Alessandro Toffoli. 2025-07-15. Fine-Scale Heterogeneity of Snow Cover in the Antarctic Marginal Ice Zone. https://arxiv.org/abs/2507.10916

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