Iceberg calving strongly controls glacier mass loss, but the fracture processes leading to iceberg formation are poorly understood due to the stochastic nature of calving. The size distributions of icebergs produced during the calving process can yield information on the processes driving calving and also affect the timing, magnitude, and spatial distribution of ocean fresh water fluxes near glaciers and ice sheets. In this study, we apply fragmentation theory to describe key calving behaviours, based on observational and modelling data from Greenland and Antarctica. In both regions, iceberg calving is dominated by elastic-brittle fracture processes, where distributions contain both exponential and power law components describing large-scale uncorrelated fracture and correlated branching fracture, respectively. Other size distributions can also be observed. For Antarctic icebergs, distributions change from elastic-brittle type during ‘stable’ calving to one dominated by grinding or crushing during ice shelf disintegration events. In Greenland, we find that iceberg fragment size distributions evolve from an initial elastic-brittle type distribution near the calving front, into a steeper grinding/crushing-type power law along-fjord. These results provide an entirely new framework for understanding controls on iceberg calving and how calving may react to climate forcing.

中文翻译：

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碎片化理论揭示了控制冰山大小分布的过程

冰山崩解强烈控制冰川质量损失，但由于崩解的随机性，导致冰山形成的断裂过程知之甚少。产犊过程中产生的冰山的大小分布可以提供有关驱动产犊的过程的信息，也可以影响冰川和冰盖附近海洋淡水通量的时间、幅度和空间分布。在这项研究中，我们根据格陵兰岛和南极洲的观测和建模数据，应用碎片化理论来描述关键的产犊行为。在这两个地区，冰山崩解以弹脆断裂过程为主，其中分布包含分别描述大规模不相关断裂和相关分支断裂的指数和幂律分量。也可以观察到其他尺寸分布。对于南极冰山，分布从“稳定”产犊期间的弹性脆性类型变为冰架解体事件期间以磨削或压碎为主的分布。在格陵兰，我们发现冰山碎片尺寸分布从产犊前缘附近的初始弹脆型分布演变为沿峡湾的更陡峭的研磨/破碎型幂律。这些结果提供了一个全新的框架来理解冰山崩塌的控制以及崩塌对气候强迫的反应。我们发现冰山碎片尺寸分布从产犊前缘附近的初始弹脆型分布演变为沿峡湾的更陡峭的研磨/破碎型幂律。这些结果提供了一个全新的框架来理解冰山崩塌的控制以及崩塌对气候强迫的反应。我们发现冰山碎片尺寸分布从产犊前缘附近的初始弹脆型分布演变为沿峡湾的更陡峭的研磨/破碎型幂律。这些结果提供了一个全新的框架来理解冰山崩塌的控制以及崩塌对气候强迫的反应。