Snow water equivalent estimation in the Mallero basin using snow gauge data and MODIS images and fieldwork validation

摘要

Snow accumulation and ablation rule the temporal dynamics of water availability in mountain areas and cold regions. In these environments, the evaluation of the snow water amount is a key issue. The spatial distribution of snow water equivalent (SWE) over a mountain basin at the end of the snow accumulation season is estimated using a minimal statistical model (SWE-SEM). This uses systematic observations such as ground measurements collected at snow gauges and snow-covered area (SCA) data retrieved by remote sensors, here MODIS. Firstly, SWE-SEM calculates local SWE estimates at snow gauges, then the spatial distribution of SWE over a certain area using an interpolation method; linear regressions of the first two order moments of SWE with altitude. The interpolation has been made by both confining and unconfining the spatial domain by SCA. SWE-SEM is applied to the Mallero basin (northern Italy) for calculating the snow water equivalent at the end of the winter season for 6 years (2001-2007). For 2007, SWE-SEM estimates are validated through fieldwork measurements collected during an 'ad hoc' campaign on March 31, 2007. Snow-surveyed measurements are used to check SCA, snow density and SWE estimates.