Using field spectroscopy to determine the water content of snow
Water is a valuable natural resource and seasonal snow in the Australian Alpine region is an important source of water. However, data is often lacking on the water content and extent of the seasonal snow cover. Snow Water Equivalence (SWE), a critical factor for enhanced water management, is determined from point based measurements of snow samples (cores). An ad hoc sampling regime is used to determine areal SWE by measuring snow depth and sample core weight at a dozen or more points along several transects.
This paper describes a component of a larger research project that aims to develop techniques to determine snow depth and SWE using remote sensing. The overall project combines aerial photography, hyperspectral imaging, GPS surveying and field spectroscopy to create a 3D model of SWE in the Victorian Alps. This paper presents preliminary results of the remote sensing of physical characteristics of snow, in particular, grain size, condition and SWE.
During the 2006 snow season, extensive field sampling was undertaken in a Victorian Alpine Ski Resort. A stratified random sampling regime was applied. Samples were stratified by aspect, underlying vegetation type, snow type (made or natural) and snow preparation (groomed or ungroomed). At each sample site, snow reflectance was measured with an ASD field spectrometer (Fieldspec Pro JR, 300nm-2500nm). In addition, snow cores and GPS measurements were taken at each site. The snow core weight was used to calculate SWE and reference photographs were used to ascertain mean grain size. Preliminary results show significant differences in reflectance and core weights across the stratifications.