Influence of biophysical, meteorological and topographic factors on multidate ERS tandem data acquired over forested terrain

Interferometry with ERS 1/2 SAR appears as a new promising tool for forest observations. With four ERS tandem pairs acquired during one year, this paper investigates the influence of biophysical, meteorological and topographic factors on such data. It is shown that the degree of coherence has a potential for discrimination between forest types. It appears also that it is correlated with the NDVI, the stem volume and stand density. Moreover, the authors studied how seasonal and meteorological effects influence the degree of coherence, in particular it appears that it is very useful for snow cover detection. However, topography affects strongly the coherence and its estimation, pointing out the need for semi-empirical correction or rejection of strong slopes areas