The Young’s modulus of an Antarctic iceberg: The first estimate from a coupled fluid–elasticity model constrained by reconstructed in-situ data

Iceberg break-up, and calving size and frequency is poorly constrained which creates challenges in including icebergs accurately in climate models. Iceberg calving depends on the effective Young’s modulus of an iceberg, however, it is extremely difficult to determine leading to estimates ranging over four orders of magnitude. Icebergs have been shown to resonate at certain wave periods with flexural amplitudes that cannot be explained by simple bending. This suggests that spectral analysis of the modes of flexural vibration in conjunction with a coupled fluid-elasticity model (CFEM) of iceberg motion could be used to determine the Young’s modulus of an iceberg. Using surface strain data and a complex mathematical model, we show that there is strong evidence that the effective Young’s modulus of an Antarctic iceberg lies between 1–5.5 GPa , with a best estimate of around 2 GPa . This is the first time that the effective Young’s modulus of an iceberg has ever been determined, despite it being a requirement for iceberg-calving models. These results are expected to have broad implications for understanding the role of icebergs in climate change. • First estimate of Antarctic iceberg Young’s modulus using surface strain data. • Used a coupled fluid-elasticity model to support modulus estimation. • Found Young’s modulus to be 1–5.5 GPa, best estimate around 2 GPa. • Used two independent resonance-based methods for Young’s modulus determination. • Both methods gave consistent estimates of the iceberg’s Young’s modulus.