REMOTE SENSING OF SNOW AS A TOOL TO FORECAST WATER SHORTAGE IN THE ARGENTINIAN DRY ANDES

摘要

In the Argentinian Dry Andes the annual snow melt is the main source of superficial water and aquifer recharge, essential for the population of the oases. Interannual variability in the snow cover in the Andes mountains causes variability in the water volumes available. In this study we analyze the errors of a water discharge forecast method based on the MODIS MOD10A2 snow cover product, with regards to the mass anomalies estimated by GRACE satellite at the scale of four watersheds.Because the high-water period (September-April) discharge is directly related to the snow extent at the beginning of the snowmelt period, i.e. in September and October, we use MOD10A2 images to forecast the average high water season discharge. Despite an average uncertainty of 15%, uncertainty peaks to about 50% in several years. Comparison with mass anomalies retrieved GRACE satellite data suggests that overestimation of our forecast method comes from snowbed thickness interannual variations.