Spatial and temporal analysis of the snow line in the alps : based on NOAA-AVHRR data

Abstract

A method to derive the snow line elevation using NOAA-AVHRR satellite data in combination with a digital elevation model is presented. The AVHRR sensor enables the frequent Observation of snow cover with a sufficiently high temporal resolution. The definition of the snow line and the impact of geocoding errors, as well as errors due to misclassification, are discussed. A comparison of the NOAA-AVHRR data with data from the higher resolution IRS-WiFS indicates that even at a spatial resolution of 1.1 km, a quantitative analysis of the snow line elevation is possible. The influence of different winter conditions in Switzerland on the elevation of the snow line is reflected in satellite data from 1990,1996 and 1999. The results of the investigation were, firstly the presentation of the spatial pattern of the average snow line elevation, secondly the derivation of snow line signatures for three regions. These were then compared with the Overall alpine snow line signature.