REMOTE SENSING

Improving our distance vision

The space adventure has kick-started Earth observation, boosting our knowledge about our planet. Previously scattered around the continents, this knowledge has now been brought together into a global programme that will provide the multisectoral tools needed for sustainable development. One aim of satellite data is to help anticipate food crises which, according to the Food and Agriculture Organization of the United Nations (FAO), affect more than 40 countries, with 850 million people suffering from famine worldwide.

Patchwork of polders used for farming on the banks of the Scheldt (NL). Image from the PROBA satellite’s CHRIS sensor. © SSTL through ESA
Patchwork of polders used for farming on the banks of the Scheldt (NL). Image from the PROBA satellite’s CHRIS sensor.
© SSTL through ESA
Patchwork of polders used for farming on the banks of the Scheldt (NL). Image from the PROBA satellite’s CHRIS sensor. © KARI through ESA 2005
© KARI through ESA 2005
© SSTL through ESA
View of cereal farms in South Africa’s Free State, which supply 70 % of South Africa’s domestic market. Image from the PROBA satellite’s CHRIS (Compact High Resolution Imaging Spectrometer) sensor. © SSTL through ESA
© SSTL through ESA

The conquest of the skies led to the first-ever images of the Earth. In the mid-19th century photographs taken from a hot-air balloon unveiled land and sea, before space became our new vantage point. After the Cold War, space agencies switched their concerns to environmental safety. In 1972, Landsat 1 - the world's first remote sensing satellite - was placed in orbit. Radar and infrared optical sensors were used to keep an eye on the planet.

Before long, this data recorded from hundreds of kilometres above the Earth's surface was fed into instruments for analysing terrestrial, oceanic and atmospheric events. However, over time and with a lack of space agency funding, this technical infrastructure became eroded.

But the tide is turning and governments now understand the full importance of Earth observation. At the 2002 World Summit on Sustainable Development in Johannesburg, the international community recognised the urgent need for coordinated information on the state of the planet. A few years later, a 10-year plan emerged, which called for a Global Earth Observation System of Systems (GEOSS) to be set up in 2004 (see box on page 36).

A global network

The Earth, atmosphere and oceans are interdependent, forming part of a single planetary system. Exhaustive and interoperable data will be required in order to explain their natural dynamics and design cross-thematic tools to support decision-making and resource management. This data will include spatial and in situ geographical information (collected either by specialists or by systems of ground-, seaand air-based sensors). Obviously such data is useful only if it is integrated into interconnected systems based on an open standard.

In Europe, this work towards data collection and interoperability has already begun at the European Space Agency (ESA). Since 1998, the Global Monitoring for Environment and Security (GMES) programme has been streamlining European observation activities by combining terrestrial data (from observation networks and land-use, biodiversity and socioeconomic surveys) with space data into a single system. While the space data comes from existing satellites, preparation for the next generation of Earth observation satellites has already introduced improvements. In 2012, GMES is expected to offer a number of services.

Contributions and prospects

The GMES initiative is Europe's main contribution to the implementation of GEOSS, with the European Commission as the key contributor. Other European programmes are also participating in GEOSS, including those in the area of information and communication technologies, which are developing cross-cutting applications, particularly for sensor networks. Sensor Web Enablement integrates the data from geosensors into web-based interactive information services or into virtual globes (1).

Although not all the 72 countries and 46 international organisations in the GEOSS own satellites, the data are pooled and made accessible to all GEOSS members, in particular developing countries, with which special partnerships are sometimes established.

AEGOS

Africa is at the heart of a large-scale GEOSS associated project - the African-European Georesources Observation System (AEGOS) initiative (2). As explained by Marc Urvois, from the French Geological Survey (Bureau de Recherches Géologiques et Minières, BRGM) and coordinator of the AEGOS support action of the EU's Seventh Framework Programme for Research and Technological Development, "AEGOS will make it possible to exploit African georesources sustainably, not only its mining resources, but also groundwater, building materials and energy (geothermal deposits at an exploitable depth)."

This will take the form of two initiatives. "We shall start by setting up pan-African infrastructure to assemble all the maps held by African countries and by European countries with a colonial history. This data will then be supplied to national and international mapping agencies, mainly for the use of decisionmakers (to help them to structure sustainable development policies) and the geoscience community (to give them an idea of how the processes work)," reports Marc Urvois.

Benefits of cross-linking

This data, scattered around 45 African and 20 European countries, will be combined into a single system without actually being centralised. "The scientific community has extensive knowledge of the entire African continent's geological and mineral resources. There are more than 5 000 maps describing its soils and subsoils, as well as 40 000 characterised deposits and showings," adds Marc Urvois, "so now the challenge is to make this information visible in order to facilitate exchanges and to create derivative products and services. 24 partners will be promoting a distributed architecture, using international standards for Internet mapping and interoperability."

AEGOS is only one example among the hundred or so regional and sectoral programmes that will supply GEOSS with data. GEOSS will cross-reference all this data collected from different observation sites using tools with specific or more general objectives, such as checking compliance with the obligations of environment treaties like the Kyoto Protocol. Sustainable development is at the core of a broad-based 10-year global effort (2005-14) that is subdivided into nine beneficiary areas: disasters, health, energy, climate, water, weather, ecosystems, agriculture and biodiversity.

Securing livelihoods

Obviously agriculture is one of the most important beneficiary areas. According to Michael Rast, head of GEOSS farming applications, "A key aspect of stability is to optimise agricultural production management because of the short- and long-term threats, including a growing number of natural disasters. Disasters cause significant damage, especially for farms in developing countries."

Strategically, remote sensing satellites have always kept farming in their sights. "The United States has been using Landsat 1 data to monitor the Soviet Union's wheat and corn harvests since the 1970s," says Michael Rast. Since then, scientific advances have sharpened the precision of the on-board spectrometers that examine images of the Earth and analyse them with reference to a library of spectral signatures. Every plant emits its own specific wavelength, which changes according to its state of growth and health, as well as its environmental conditions and constraints.

"Satellites assist farmers in a wide range of tasks," adds Michael Rast, "including precision farming, crop rotation, partition of land and improved weather forecasting. In addition, satellite data allow us to predict the yield of an upcoming harvest with a fair degree of accuracy, or to identify the causes of food shortages and to quantify losses," he explains. "By locating and quantifying the various crops, remote sensing makes it possible to evaluate each country's ratio for biofuel production. The European institutions also use satellites to monitor compliance with Common Agricultural Policy (CAP) declarations" (see box).

Already up and running

Planned for completion in 2015, GEOSS has already notched up several achievements. After scanning the Earth using the MEdium Resolution Imaging Spectrometer Instrument (MERIS) sensor aboard the ENVISAT satellite, with 260-metre x 300-metre full spatial resolution, the ESA has now developed a new global land cover map, called GlobCOVER, which is compatible with the United Nations Land Cover Classification System. Although the preliminary version of the land cover map presented in February 2008 will not be distributed owing to a number of artefacts, the second version of GlobCOVER has been in service since July 2008.

This mapping phase represents a giant stride forward in efforts to improve production management, predict food shortages and develop a famine alert system. Twenty-five national and international organisations representing agriculture sector stakeholders have set three priorities for defining ways to improve agricultural management and for implementing these improvements in collaboration with other GEOSS stakeholders.

Risks and balance

There is an increasing risk of disruption to food supplies. The Earth is being subjected to mounting pressure from climate change, energy demand and population growth. However, strategic investment in the next 10 years could improve matters by revolutionising agricultural resource management and alleviating malnutrition. This would involve creating a Global Agricultural Monitoring System.

Michael Rast endorses the concept: "The system will enable us to make a better assessment and quantitative representation of the situation, which we badly need. We can do this by interconnecting information systems, as GEOSS is doing, while at the same time learning how to improve the way in which we manage the environmental impacts of farming activities."

At the very heart of farming is this relationship of interdependence binding humans to their environment in a fragile balance. To maximise productivity and guarantee long-term food security we must safeguard ecosystems and all their constituents.

Delphine d’Hoop

  1. See the European projects SANY www.sany-ip.eu and OSIRIS www.osiris-fp6.eu


  2. www.brgm.fr/brgm/aegos

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Monitoring the CAP

The Monitoring Agriculture Remote Sensing (MARS) programme is the Common Agricultural Policy (CAP) compliance tool. Researchers use raw data to identify crop types and their stage of maturation. MARS started up in 1988 and lasted 10 years. As research developed, different MARS strands emerged, including MARS-STAT for area statistics and yield monitoring, and MARS-PAC (now renamed the GeoCAP Action) for monitoring implementation of the CAP. All have proven the economic benefit of the approach and have also led to the development of tools for monitoring deforestation, soil degradation, desertification, drought and famine.


www.marsop.info


GEOSS race

The international community has launched a race for geological knowledge to bridge current gaps in our information about the planet. The race has developed on a scale commensurate with the threats posed by water, natural disasters, energy, mineral resources and climate change. In the space of a few years, the GEOSS initiative has sketched out an initial response. In 2002, the Johannesburg summit instigated a uniform information system. The next stages followed in quick succession: in 2003, the G-8 summit in Evian (FR) made it a priority project. One month later, the first Earth Observation Summit in Washington finally paved the way forward: 33 countries set up an ad hoc Group on Earth Observation (GEO) chaired by the European Commission, the USA, China and South Africa, which will prepare a 10-year implementation plan.


www.earthobservations.org



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