Temporal Decorrelation for Forested Areas Observed in Spaceborne L-band SAR Interferometry

Interferometric coherence from nine image pairs acquired by the Japanese satellite ALOS over a forest area in northern Sweden have been analyzed. Coherence levels for sparse and dense forest are compared. The results are in line with previous studies for JERS-1 and confirm that in most cases the temporal decorrelation is a severe problem for L-band SAR with repeat cycles on the order of six weeks. However, frozen conditions can give relatively high coherence for sparse forest and thereby allow good separation between dense and sparse forest.