Earth Observation & Aquifer

1. Role of Earth observation in Ground water management

By definition of the project and its context Earth observation (EO) data are the key ingredient or "raw material" for AQUIFER:

EO data enable continuous retrieval of different hydro-geological variables and biophysical parameters involved in the water cycle: e.g. water quantity, quality, and consumption, vegetation, erosion, river bed conditions, urbanisation, land use, land cover, topography, floods, evapotranspiration, etc
EO data provide neutral information for integrated management of Africa's trans-boundary surface and ground water systems allowing the generation of common databases, inter-country comparable information and shared water management information systems

but... satellite remote sensing is basically confined to the surface:

Optical EO: measure reflectance values of surface features
Radar and thermal sensor have max depth penetration of cm - few metres
EO works but indirectly (proxies) or has to rely on secondary effects

therefore...

Ground truth is mandatory for calibration, interpretation and validation
Data assimilation required - combination with ancillary data by means of GIS, models etc.

Conclusion

Earth Observation is not a stand alone tool
Earth Observation can just have a supporting role

2. Earth observation as data and information source within AQUIFER

The full spectrum of EO data is used, as required and as most appropriate for the generation of the AQUIFER products:

Multisensor: optical (e.g. Landsat, IRS, SPOT, NigeriaSat, Alsat) as well as radar data (ESA ERS and Envisat) are put to use
Results and hyperspectral AVIS data of the airborne AquiferEx campaign
High resolution - low temporal repeat rate data (e.g. SPOT) as well as mid and low resolution - high repeat rate data such as Meteosat or Envisat ASAR to assure high spatial detail as well as dense multitemporal coverage
Multiplatform: satellite data as well as airborne (AquiferEx)
Preprocessed EO mosaics or data sets like the SRTM DEM, SRTM water mask or the GEOCOVER LC product

3. Synopsis

A total of around 800 data sets for both basins SASS and SAI were identified and selected, ordered, processed and interpreted. The EO data sets are shared and distributed among all project partners, within the applicable copyright regulations of satellite operators and image data distributors.

4. Acknowledgements

EO data were acquired and procured through / from:

ESA TIGER Announcement of Opportunity / Eurimage: ERS and Envisat
ESA AquiferEx: airborne Radar and Hyperspectral data
CNTS: Alsat-1
NSDRA: Nigeriasat-1
euromap / ISRO: IRS-P6 AWIFS
SPOT Image: SPOT 5 data
Eurimage: Landsat
VISTA-EARS: Meteosat
MDA Federal Inc.: GeoCover LU/LC
NASA/USGS: SRTM DTM and water mask

Aquifer project has prepared steps to also make upcoming ALOS and TerraSar X data available to the project and its partners.