Problematiche relative alla raccolta ed alla interpretazione dei dati per un nuovo catasto dei ghiacciai

Problems arising from collection and interpretation of data for a new glacier inventory

Abstract

1979 saw the beginning of collection, followed by recording, processing and interpretation, of data on the glaciers and glacierets in the central and eastern sections of the Alps and, in particular, of the whole Alto Adige (South Tyrol) area. In practice, the criteria adopted were those recommended by the Temporary Technical Secretariat on behalf of the World Glacier Inventory (head office in Zürich). The first phase of work organization entailed subdivision of the territory into minimal hydrographical units, whose area was determined essentially on glaciological considerations. Code numbers were assigned to all glaciers, for their easy and accurate identification. This was followed by analysis of the various factors which are decisive in the setting-up and execution of an operational plan for data collection, which can only be carried out in a relatively short period of time at the end of the summer. Suitable aerial photographs were therefore the most important source of information. Direct samplings taken at the terminus also proved useful, and allowed the gathering of various data, including those of tourist interest. The scale mostly used for mapping was that of the Istituto Geografico Militare 1: 25 000. Most mapping work consisted in the updating of glacial mass boundaries and the tracing of important parameters such as snow-line and firnline. In order to record the units in the inventory, it was necessary to introduce some parameters such as the minimum area acceptable for inventory. Some essential features regarding glacierets were also detailed. Primary classification and various other morphological descriptions were listed following a greatly simplified system prepared by the T.T.S.. Some very important parameters such as snow-line, were studied with particular reference to their morphometric and physical significance, especially for the purpose of calculating the relationships between ablation areas and accumulation basins. Among the aims of the World Glacier Inventory, there is also that of a quantitative estimate of the water reserve stored in solid form, and the difficulty of estimating the depth of the glacial masses consequently takes on special importance. Calculation of this parameter was made on the basis of area, separately for glaciers and glacierets. Special cards, some of which follow the layout proposed by the World Glacier Inventory, were used as a preliminary means of recording all data.