Proposta di nuova scheda per il censimento dei rock glaciers da fotografie aeree: applicazioni sull'Alta Val d'Ultimo (Gruppo Ortles-Cevedale)

Proposal for a new database for the census of rock glaciers by means of aerial photographs: application to the Upper Val d'Ultimo (Ortles-Cevedale Group)

Abstract

This research proposes a new database for the census and characterization of rock glaciers based on the analysis of aerial photographs. The methodology proposed combines the stereoscopic observation of aerial photographs with the use of a GIS for the mapping and identification of the main morphometric parameters of the deposits. Use of the GIS, in fact, allows the measurement of specific parameters (length, width, gradient, etc.). The GIS is also used for the management, organization and visualization of the data, by means of the creation of a database linked with the geographic elements on the map. On the basis of recent research carried out in many alpine areas, the information in the database integrate and update that already available in the literature and used for the Rock Glacier Inventory of the Italian Alps. In particular, the most recent definitions have been used regarding the state of activity of the rock glaciers (classified as active/inactive or relict according to specific characteristics), their geometry (lobe-shaped, tongue-shaped or equi-dimensional deposits) and general aspect (simple or composite deposits). Other fields of the database define the origin of the debris feeding the deposits, their location, their relation with glacial and nival forms, their relations with local vegetation boundaries and characteristics of their surface morphology. The new database was tested in the Upper Val d'Ultimo (Ortles-Cevedale Group), an alpine area of about 30 km² with a significant variety of landforms. The application of the database and methodology proposed enabled us to describe adequately an alpine area distinguished by a relevant diversity of landforms, giving us a precise and complete starting point for their monitoring.