High-resolution spatio-temporal variability of surface albedo on the glaciers of Hurd Peninsula, Livingston Island (2018–2025): controls by snow metamorphism, surface impurities and terrain roughness

Abstract. Surface albedo is a primary control on the energy balance of maritime Antarctic glaciers, yet its fine-scale spatial and temporal variability remains poorly constrained. Here we present a multi-campaign broadband albedo dataset acquired on Hurd Peninsula (Livingston Island, South Shetland Islands) during four austral summer field seasons (2018, 2019, 2024, 2025), using a portable albedometer mounted on a snowmobile traverse at 5 s sampling resolution. Under clear-sky conditions, surface albedo undergoes exponential decay described by α(t) = α₀e^−kt with k = 2.24 × 10⁻⁵ 5 s⁻¹ (R² = 0.98), driven by wet-snow metamorphism and confirmed independently by time-lapse microscopy and field spectroradiometry. A statistically significant positive interannual trend in surface albedo (+0.016 yr⁻¹, R² = 0.57) is documented over the study period, most pronounced at elevations below 200 m above sea level (a.s.l.), and attributed to increased summer snowfall frequency associated with the regional intensification of precipitation. Residuals between observed and modelled albedo reveal two distinct classes of spatial forcing: (i) biological and mineral impurities — Chlamydomonas nivalis blooms recurrently concentrated below 100 m a.s.l. and cryoconite deposits near 250 m a.s.l. — and (ii) terrain roughness and slope, whose correlation with albedo residuals reverses sign between years of contrasting snow cover. An integrated albedo–altitude profile (n = 4,219) identifies the 200–260 m a.s.l. band as the locus of maximum variability, coinciding closely with the mean equilibrium-line altitude (ELA) of Hurd Glacier (∼203 m a.s.l.). These results demonstrate that broadband albedo on maritime Antarctic glaciers cannot be adequately characterized by temporal decay models alone, and that impurity distribution, terrain geometry, and proximity to the ELA must be explicitly accounted for in energy balance and remote sensing applications.