Environmental changes induced by dump pollution analyzed through historical orthophotos and multi-spectral images

摘要

A series of analyses has been carried out in a landscape where for three decades a dump was located by using three orthophotos and a multispectral image from ASTER sensor. The orthophotos acquisition time spans from 1953 to 2002. The aim of the analyses is twofold. On one side the analysis detects some paleao structures that were visible in 1953 and that under the pressure of human activities have disappeared. The change detection analysis indicates two main phases of changes. The first main change from 1953 to 1973 interests mainly woodland and wild vegetation while the second one is driven by agricultural practices. On the other side, the analysis allows finding some useful indices that are able to reveal degraded areas. The combination of some spatial indices, such as Shannon's diversity index (SHDI) ad contiguity index, has been found suitable to distinguish the characteristic texture of a dump from that of other fields. Furthermore, by using thermal infrared bands from the ASTER image, a thermal anomaly is found in correspondence of the dump location.