ENVISAT Data Provision
Launched in April 2002, ENVISAT provides continuity of measurements provided by ERS while adding significant new capabilities.
Mission will support long term data sets which are essential for both operational applications of remote sensing systems and climatological and environmental research. ENVISAT will monitor:
- The Land
- Oceans
- Atmosphere
- Ice Caps
Infoterra run one of the Processing and Archiving Centres (PAC) on behalf of ESA.
ASAR
ENVISAT is the first permanent spaceborne radar to incorporate dual-polarisation capabilities – it can transmit and receive in either horizontal or vertical polarisation. This Alternating Polarisation (AP) mode can improve the capability of a SAR instrument to classify different types of terrain. The reflective properties of a material are dependent on the polarisation of the incoming radar signal.
- Various resolution / swath combinations
- Image mode, 100Km width, 30m resolution (example is from Brazil)
- Wide Swath mode, 400Km width, 150m resolution (example over the Netherlands)
- Global monitoring mode, 400Km width, 1Km res
- High resolution vingettes – 10m resolution in wave mode
ASAR enables more advanced:
- Land Classification – the cross polarisation combinations offer better discrimination between terrain types, such as vegetation and bare soil, or between forested and clear-cut regions
- Sea Ice Monitoring – The AP mode can help better identify the boundaries between sea ice and open water
- Oceanography – HH polarisation can better identify ocean wave phenomena such as internal waves or effects due to the proximity of the ocean floor. VV polarisation can be more effective at recording ocean features caused by localised differences in atmospheric condition
