TIGER space hunt for Africa’s water

The launch of the ESA’s TIGER project in 2002 was in recognition of the importance of satellite data in managing Africa’s water resources, as expressed at the Johannesburg World Summit on Sustainable Development (WSSD). The aim of TIGER is: “assisting African countries to overcome problems faced in the collection, analysis and dissemination of water-related geo-information by exploiting the advantages of Earth Observation (EO) technology”.

At a five-day workshop on Earth Observation (EO) technology, which ran from 3-7 October, ESA’s director of EO programmes and head of the European Centre for Earth Observation (ESRIN), Volker Liebig said, “There are now 50 projects in progress, 70% of which are being headed by African organisations. A dedicated TIGER Office will also be opened in Africa.”

The workshop sessions, which took place at ESRIN in Frascati in Italy, involved 95 participants from 31 countries. The projects span the African continent as well as the various stages of the water cycle.

Presentations included the use of satellite data to chart soil moisture across southern Africa, monitoring flood plains and humid zones in the Sahel region of Senegal, combining radar and optical EO data to monitor the environmental state of the northwest coast of Madagascar and modeling the water balance of semi-arid rock watersheds using both satellite imagery and in-situ data.

The ESRIN event also saw the launch of a new web-based demonstration to remotely follow the flow of rivers and height of lakes across the African continent. The effort to develop the River and Lake product was led by Professor Philippa Berry of De Montfort University’s (DMU’s) Earth and Planetary Remote Sensing Laboratory in Leicester, England.

“Monitoring of water resources is vital over Africa, to enable best use of this precious commodity,” said Professor Berry. “Until now reliable information has been difficult to access because of the high cost in equipment, manpower and communications, and because it is difficult to obtain these precious hydrological data from many countries”

“Whilst data from a few selected large lakes has been available previously, the combination of DMU’s sophisticated processing scheme and the unique design of the Envisat altimeter have for the first time allowed near-real time measurements to be made over lakes and major rivers across Africa,” she continued. “The new system identified which part of each surface echo originated from inland water, enabling measurement of much smaller targets than has previously been possible. This, combined with the altimeter’s capability to return good data even in rough terrain, means that we can provide much more accurate and up-to-date water level information than has ever been possible before.”