Volker Liebig at environmentalresearchweb

Volker Liebig, Director of Earth Observation at the European Space Agency (ESA), speaks to environmentalresearchweb about ESA’s vigorous Earth observation programmes, which include launching 17 satellites over the next seven years.

Why is demand for Earth observation data increasing?
There is no easy answer to this question – the increase is a result of many factors. On the one hand, many Earth observation systems – that is instruments, observation methods and data processing lines – have matured over the last few years and their use is now more common and widespread. Observations from space are increasingly operational, delivering data on a daily basis. The first operational field of Earth observation was meteorology, meanwhile others have followed and the trend will continue. Another factor is that we have more and increasingly diverse missions and systems in space. Also, public awareness is increasing, not least thanks to the climate change debate, but also because of the demonstration of Earth observation capabilities in many aspects of managing life on Earth, such as post-disaster management.

What type of data is most commonly needed and is the type of data changing?
The type of data requested depends heavily on the envisaged use; it is difficult to generalise. Scientists dealing with climate change monitoring need parameters like sea surface temperature, sea surface height, polar ice sheet thickness, atmospheric composition data and many others. For monitoring agricultural and other types of land use, optical medium resolution data are most commonly used. ESA recently presented the first freely available portrait of the Earth at 300 m resolution. This map has a resolution 10 times sharper than any of its predecessors.

What plans does ESA have for launching satellites in the future?
Our plans include the family of Earth Explorers that will measure key Earth system processes to understand their role in climate change, and the Sentinels that will provide operational information services for global monitoring of the environment and security.

Our Earth Explorer missions are high-end technology missions that address specific scientific issues. With the Explorers we want to remain at the forefront of Earth observation technology and provide scientists with new data for answering some of the most pressing questions about the Earth system. The first Earth Explorer to be launched will be the gravity field and steady-state ocean circulation explorer (GOCE) in autumn this year, followed by the soil moisture and ocean salinity mission (SMOS) in spring 2009. We will also continue to send the next meteorology missions into space. These are the newest Meteosat Second Generation (MSG) and Metop satellites. As of 2011/2012 we will start to bring the ESA Sentinel Missions into space, missions specifically designed to meet user demands within the EU-ESA initiative Global Monitoring for Environment and Security (GMES).

What is ESA’s Initiative on Climate Change?
The new ESA Initiative on Climate Change will serve to systematically generate, preserve and give access to long-term data sets of so-called essential climate variables (ECVs). These climate variables will be produced and fed using the wealth of information ESA possesses already, considering 30 years of archived data. The generation of such ECVs will meet the needs of the UNFCCC and IPCC. It’s important to understand that Earth observation from space plays a vital role in understanding the fundamentals of climate change, and ESA through a global partnership in the Committee on Earth Observing Satellites (CEOS) has committed to delivering global observations of ECVs and associated products. With this initiative, we will quantify the state of the climate system to advance our knowledge of climate change. ECVs are needed as soon as possible to support climate science and policy.

What technology will ESA’s new satellites be using and what can they do that couldn’t be done before?
It’s impossible to list all the technologies that will be used on future missions. Let me highlight some examples: the next mission to be launched is the GOCE. This low-orbiting spacecraft is the first mission to employ the concept of gradiometry – the measurement of acceleration differences over short distances between an ensemble of proof masses inside the satellite. GOCE is equipped with three pairs of ultra-sensitive accelerometers arranged in three dimensions that respond to small variations in the gravitational tug of the Earth. Although the gradiometer forms the heart of the satellite, to measure gravity there can be no interference from moving parts so the entire spacecraft is actually one extremely sensitive measuring device.

Other missions, like Sentinel-1, will continue, in a refined way, the success of ESA Synthetic Aperture Radar (SAR) missions; SAR has already been used on our first Earth observation satellite, ERS-1, launched in 1991, and ESA has certainly built up an important competence in radar observations and related applications, such as interferometry. Many of the cutting-edge technologies now embarked on for the Earth Explorers, such as a wind LIDAR onboard the Atmospheric Dynamics Mission (ADM-Aeolus), could – once proven working – become operational in future missions.
About the author

Nadya Anscombe is a contributing editor to environmentalresearchweb

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