The operational processing of NOAA-AVHRR data and the derivation of vegetation index (NDVI), leaf area index (LAI) and vegetation cover fraction for the European Alps is presented. The analysis was done for three elevation zones (<500m, 1000-1500m and >2500m) to show the dynamic characteristic of vegetation in the years 1995 to 1998. The vegetation cover fraction shows a high variability in lower elevations during winter caused by the not persistent snow cover. In elevations above 2500m the high variability could be detected during summer. The exponential approach to derive LAI using NDVI data is only valid for elevations above 2000m or for NDVI less than 0.5. Otherwise the LAI values are saturated because small changes in NDVI result in an increased range of LAI up to 1.5. This prevents an exact
derivation of leaf area index based on the normalized difference vegetation index.
Snow and ice play an important role in the earth`s radiation balance because of the high albedo in comparison to other natural surfaces. Furthermore ice and snow is the largest contributor to rivers and ground water over major parts of the middle and high altitudes. These are reasons why hydrological and climatological studies require estimates of snow covered areas. Most of such snow cover maps generated from satellite data include information of snow or not snow for each image pixel. In this study a linear spectral unmixing algorithm is used to calculate snow cover portions within each data cell. We examine the ability of this algorithm for operational and near-real time snow cover estimation at subpixel scale using medium spatial resolution satellite data from NOAA-AVHRR. The automated methodology is presented which produces snow cover fraction maps showing plausible distribution of snow in comparison to TERRA-ASTER data. The qualitative analysis of the results present how suitable the approach implemented in the preliminary processing chain is. Simplifying assumptions are made to the procedure which explains some variation between derived snow cover fraction map and reference data. Further work should include an accurate quantification of areal snow coverage comparison to traditional approaches.