Remote sensing investigation of the tunguska explosion Area.

摘要

A multidisciplinaiy investigation of the Tunguska site (Central Siberia) devastated in 1908 by the explosion of a cosmic body has been carried out in July 14-29, 1999 by the Tunguska99 expedition (see http://www-th.bo.info.it/tunguska/). In this framework, the remote sensing of a 300-km~2 territory has been performed in collaboration with the Russian "State Research Institute of Aviation Systems" (GosNIIAS). An aerophotosurvey and a line scanner survey in 6 spectral bands, from optical to thermal infrared, have been made simultaneously. The 1999 surveys are used to re-examine the 1938 aerophotographic material in order to check details of the 1908 explosion and to verify some recent hypothesis on the event. The 1938 photographic material has beenanalyzed with the help of the "Tomsk Creative Collective" to obtain new information on the fallen tree distribution. The comparison between the two aerophotosurveys will make it possible to map more accurately the areas with trees surviving the 1908 catastrophe and those with flora variation due to the impact. From this comparison we shall obtain new data on the effects of a cosmic body impact on the forestland coverage, on the spectra reflected from the flora cover, on the Leaf Area Index and other vegetation indices.