Basal melting of ice shelves is a major source of mass loss from the Antarctic Ice Sheet. In situ measurements of ice shelf basal melt rates are sparse, while the more extensive estimates from satellite altimetry require precise information about firn density and characteristics of near‐surface layers. We describe a novel method for estimating multidecadal basal melt rates using airborne ice penetrating radar data acquired during a 3‐year survey of the Ross Ice Shelf. These data revealed an ice column with distinct upper and lower units whose thicknesses change as ice flows from the grounding line toward the ice front. We interpret the lower unit as continental meteoric ice that has flowed across the grounding line and the upper unit as ice formed from snowfall onto the relatively flat ice shelf. We used the ice thickness difference and strain‐induced thickness change of the lower unit between the survey lines, combined with ice velocities, to derive basal melt rates averaged over one to six decades. Our results are similar to satellite laser altimetry estimates for the period 2003–2009, suggesting that the Ross Ice Shelf melt rates have been fairly stable for several decades. We identify five sites of elevated basal melt rates, in the range 0.5–2 m a⁻¹, near the ice shelf front. These hot spots indicate pathways into the sub‐ice‐shelf ocean cavity for warm seawater, likely a combination of summer‐warmed Antarctic Surface Water and modified Circumpolar Deep Water, and are potential areas of ice shelf weakening if the ocean warms.

中文翻译：

---

南极罗斯冰架的十年年代基础融化速率和结构，使用机载冰穿透雷达

冰架的基础融化是南极冰盖质量损失的主要来源。冰架基础融化速率的现场测量稀疏，而卫星测高仪进行的更广泛的估算则需要有关点火密度和近地表层特征的精确信息。我们描述了一种使用罗斯冰架3年调查中获得的机载冰穿透雷达数据估算多年代际基础融化速率的新方法。这些数据揭示了一个冰柱，其上下单元明显不同，其厚度随着冰从接地线流向冰面而变化。我们将下部单元解释为流经接地线的大陆流冰，将上部单元解释为由降雪形成的相对平坦的冰架形成的冰。我们利用测量线之间下部冰层的厚度差异和应变引起的厚度变化，结合冰层速度，得出一到六十年内平均的基础融化速率。我们的结果与2003年至2009年期间卫星激光测高仪的估计相似，这表明罗斯冰架的融化速率已经稳定了几十年。我们确定了5个基础融化速率升高的位置，范围为0.5–2 ma^-1，靠近冰架前部。这些热点表明进入温暖海底冰的海底通道的路径，可能是夏季温暖的南极地表水和改良的极地深水的组合，并且如果海洋变暖，可能是冰架的潜在区域减弱。