A roadmap for calibration and validation( The volume of data acquired by more ...)

The volume of data acquired by more than 50 Earth Observation satellites is increasing at an exponential rate and is providing unprecedented synoptic views of our planet. Because these satellites often use different methodologies, using data for trend analysis and environmental monitoring can be difficult, making it essential to establish globally recognised guidelines for Calibration and Validation processes.

More than 50 experts from space agencies and organisations around the world met earlier this month at the GEO/CEOS Workshop on Calibration and Validation Processes in Geneva, Switzerland, to identify and scope key elements needed to develop and implement a data quality strategy.

Calibration is the process of quantitatively defining the system responses to known, controlled signal inputs. Validation is the process of assessing, by independent means, the quality of the data products derived from the system outputs.

The workshop, hosted by the Group on Earth Observations (GEO) and ESA from 2 to 4 October, was structured around four main sessions:

• Cal/Val site characterisation & classification

• Satellite and in situ Cal/Val data access

• Methodology and guidelines for Cal/Val

• Harmonisation of quality information

At the beginning of each session, the chair presented a summary of the relevant key issues and then opened the floor for discussion.

The dialogue and recommendations will be used to achieve the ultimate goal of the Global Earth Observation System of Systems (GEOSS) for data inter-operability and inter-comparison. Prof. Jose Achache, Director, GEO Secretariat, stressed that in order for GEOSS to be fully successful, there must be calibration, validation and intercalibration between all instruments.

The Committee on Earth Observation Satellites (CEOS), the space contribution to GEOSS, identified the need to take a more a
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