Die Paritätsforderung der schweizerischen Landwirtschaft (Eine Richtigstellung und Ergänzung)

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Towards an automated detection of avalanche deposits using their directional properties

Snow avalanches killed more people in the Swiss alpine area during the past decades than any other natural hazard. To further improve the avalanche prediction and the protection of people and infrastructure, information about the occurrence and the distribution of avalanche activity is crucial. Nevertheless this information is missing for large parts of the Alpine area. The surface roughness of avalanche deposits differs considerably from the adjacent undisturbed snow cover and is an important factor of the directional reflectance anisotropy. The undisturbed snow-cover exhibits a strong forward scattering, while the structure of an avalanche deposit causes shadow casting and tilt effects. Therefore, the observed reflectance of avalanche deposits and undisturbed snow cover is strongly dependent on the illumination- and viewing angles. This study demonstrates the potential of multiangular remote sensing data for detecting and mapping avalanche deposits. The results indicate, that air- or spaceborne multiangular sensors are suitable for rapid detection and mapping of avalanches in inaccessible and remote regions

Automated detection and mapping of avalanche deposits using airborne optical remote sensing data

Rapidly available and accurate information about the location and extent of avalanche events is important for avalanche forecasting, safety assessments for roads and ski resorts, verification of warning products, as well as for hazard mapping and avalanche model calibration/validation. Today, observations from individual experts in the field provide isolated information with very limited coverage. This study presents a methodology for an automated, systematic and wide-area detection and mapping of avalanche deposits using optical remote sensing data of high spatial and radiometric resolution. A processing chain, integrating directional, textural and spectral information, is developed using ADS40 airborne digital scanner data acquired over a test site near Davos, Switzerland. Though certain limitations exist, encouraging detection and mapping accuracies can be reported. The presented approach is a promising addition to existing field observation methods for remote regions, and can be applied in otherwise inaccessible areas