NEAR REALTIME SNOW COVERED AREA MAPPING WITH ENVISAT ASARWIDESWATH IN NORWEGIAN MOUNTAINEOUS AREAS

摘要

A near-real time GMES-relevant monitoring system forsemi-operational retrieval of snow covered area forhydrological and climatological applications has beendeveloped in the Envisnow EC EESD FP 5 project. Thesystem, using ENVISAT ASAR wide swath data fromESA AOE 785 and from the Kongsberg satellite station,geocodes and classifies Envisat ASAR dataautomatically, and produces SCA maps with confidenceflags. The snow covered area maps are used inhydrological models in Norway to improve run-offforecasting and flood warnings.We show that Envisat ASAR wide swath data can beused to produce snow cover maps with 100 m resolutionand 500 km by 500 km coverage. This allows semioperationaluse of SAR data for regional and maybeglobal snow mapping. The applied wet snow detectionalgorithm (Nagler and Rott, 2000) has beencomplimented with a dry snow algorithm, predicting drysnow above medium wet snow line. Results andaccuracy assessments from campaigns in southernNorway in 2003 and 2004 will be shown. Results from anear-real time multi-sensor demonstration of the systemin 2004 will also be shown.