Measuring the Elastic Modulus of Snow

Abstract

The elastic modulus is the most fundamental mechanical property of snow. However, literature values scatter by orders of magnitude and hitherto no cross-validated measurements exists. To this end, we employ P wave propagation experiments under controlled laboratory conditions on decimeter-sized snow specimen, prepared from artificial snow and subjected to isothermal sintering, to cover a considerable range of densities (170–370 kg m−3). The P wave modulus was estimated from wave propagation speeds in transverse isotropic media and compared to microstructure-based finite element (FE) calculations from X-ray tomography images. Heterogeneities and size differences between acoustic and FE sample volumes were characterized by SnowMicroPen measurements, yielding an elastic modulus as a by-product. The moduli (10–340 MPa) from the acoustic and FE method are in very good agreement (R2=0.99) over the entire range of densities. A remaining bias (24 %) between both methods can be explained by layer heterogeneities which systematically reduce the estimates from the acoustic method.