Initial testing of ERS Tandem data quality for InSAR applications
Examples from Taiwan, Madagascar, Zaire, Ivory Coast, Mali and Greenland
RS/E Data Utilisation Section
di Milano, Dipartimanto di Elettronica e Informazione, Under contract to
ESA/ESRIN RS/P ERS Section
preliminary investigation has been performed in which interferometric products
were generated from selected ERS tandem data. The data covered a number
of areas throughout the world and represented a variety of land cover types
ranging from glaciers to tropical forests, savannah and deserts. A prototype
interferometric quick-look processor was used in an ad-hoc operation where
relatively large amounts of data were processed in a short time period
(over 50 standard frames of ERS data). In addition to demonstrating the
potential of quick-look InSAR processing we could draw the following preliminary
- Tandem InSAR coherence over dense rain-forest is low and results
in highly fragmented fringe-areas. This can be exploited in several applications
concerned with land use monitoring.
- Over mountain rainforest the fragmentation is even more pronounced
due to the effect of foreshortening and layover on SAR imagery. This can
partly be remedied by combining interferogrammes from ascending and descending
passes, but remains a serious obstacle for operational use of ERS InSAR
over mountainous terrain.
- Maximum NDVI, as derived from AVHRR over a two month period (to
eliminate cloud and haze signatures), can be an important tool for establishing
the expectancy of high coherence areas. This can help the user in identifying
the areas where a specific application has highest probability of success
and can be a major cost saver if e.g. large scale use of ERS InSAR in mapping
is going to be carried out.
- Tandem InSAR has high potential in arctic and Antarctic areas due
to the high coherence obtained over dry snow and ice and sparse vegetation.
Since there are large amounts of data acquired over these areas the user
applications should be assured in most instances.
The results presented here are available from ESRIN under the reference:
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,