A MICROCOMPUTER-BASED ALPINE SNOW-COVER ANALYSIS SYSTEM (ASCAS)

The paper describes the design of an Alpine Snow-Cover Analysis System (ASCAS) for monitoring snow-cover variations in mountainous regions. In addition to observation of snow-cover variations, the system permit s derivation of interrelationships between snow cover and regional cli mate variables. ASCAS integrates several software modules, including i mage processing, geographic information systems (GIS), snow volume and runoff calculations, scientific visualization, and creation of a data base. Problems involved with integrating the different modules into AS CAS and of transferring data from one module to another are discussed. Special attention is given to the necessary hardware because the inte grated system is run on microcomputers. In a second part of the paper, a case study for the hydrological year 1990 shows first results of si mulating snowmelt runoff using the Snowmelt Runoff Model (SRM) and of calculating snow-water equivalent for three basins in the Swiss Alps. In this study, the calculations show that the accumulated snow volume is less in the Inn/Martina basin than in the other two basins (Rhine/F elsberg and Ticino/Bellinzona) because it is drier as a result of it b eing a continentally influenced inner-alpine valley. Based on a temper ature-increase scenario of +2 degrees C in the Inn/Martina basin, the effects of climate change on ablation and runoff are estimated. Ablati on occurs two to three weeks earlier than under present conditions, an d runoff occurs about three weeks earlier, resulting in an earlier and higher snowmelt peak pow and a steeper recession pow in summer.