Non-Destructive Quantification of Snowpack Properties

A temporal observation of the stratigraphy of seasonal snowpacks is only possible with non-invasive methods. Electromagnetic waves, specifically radar waves, proved to be the most appropriate technique to estimate internal snow parameters and media transitions non-destructively. Thereby, it is possible to estimate quantitatively snowpack stratigraphy and observe the snowpack evolution with time. Radar systems work as an active wave transmitter, which records reflection intensities with travel-time. Either the system modulates the signal on a defined frequency range as frequency modulated continuous wave systems (FMCW) or a short impulse is radiated at a center frequency and bandwidth. The stratigraphic resolution and the penetration depth of both systems depends on the system parameters. The frequency determines the penetration depth and sensitivity and the bandwidth determines the vertical resolution. In previous studies FMCW X- and Ku-band frequencies failed to penetrate a moist snowpack, but provided convincing results in resolving the snowpack stratigraphy. Pulsed 900 MHz antennas, as well as L- and C-band FMCW systems penetrated a wet snowpack up to one meter and measured adequate gradients in snow density. Current research in pulsed and modulated systems show that electromagnetic wave systems are convincing methods to quantitatively measure snow stratigraphy non-destructively.