Title: Usable optical and SAR observations are irregularly spaced

Description: This figure shows the availability of usable remote sensing observations over time - optical (green) and SAR (blue). For SAR, both orbit directions (ascending/descending) are considered individually. Every point is an observation window of one year or six months. Areas in red denote observation windows with too few observations, which were discarded. The Landsat 5 TM sensor issue, which resulted in a lack of observations, is visible for all areas of interest between 2002 and 2003 (see gap in green plots).

Copyright: Zitzlsberger et al