Webcam-based Snow Cover Retrieval: Potential and Applications

Abstract:

Terrestrial photography offers an enormous potential to study snow cover variability in mountainous regions at high spatio-temporal scales. The oblique view of a camera on the mountains enables detailed analyses of snow cover on steep slopes in mountainous regions. Moreover, such camera systems can provide snow cover information even under cloudy conditions since they are often located below the cloud cover. It’s application, however, is often restricted to small catchment scales due to a limited number of cameras used. In Switzerland, a network of several hundred of publicly available webcams enables us to gather snow cover information over a large area. Here, we present a semi-automatic framework to to derive snow cover maps with a minimum amount of manual user input. Key of our system is an image-to-DEM registration procedure that resolves required webcam parameters automatically (camera orientation and FOV) using a high resolution DEM and a manual estimate of the webcam’s position only. We evaluate our proposed framework and discuss the accuracy of the resulting snow cover mapping. In addition, we demonstrate the benefits of our system by estimating the regional snow line elevation in the Swiss Alps.