Select Committee on Science and Technology Written Evidence

Memorandum 49

Submission from the National Physical Laboratory


  0.1  The UK has the key elements of infrastructure and expertise necessary to take full advantage of the emerging opportunities from Earth Observation. However, the lack of data quality and inflexibility of funding mechanisms within the UK are a major barrier to the development of a flourishing EO-based industrial sector, and to the provision of reliable data to inform and monitor policy decisions.

  0.2  Opportunities exist and are emerging for the UK to take a lead role in a number of key aspects effecting data quality. These opportunities need to be nurtured and targeted as priority issues for the UK in order to maximise the benefit of Earth Observation to the UK and for it to remain at the forefront of public imagination inspiring the next generation of scientists.


  1.1  This submission is made on behalf of the National Physical Laboratory, the UK's national standards laboratory, which underpins the National Measurement System (NMS), ensuring consistency through traceable calibration of all measurements throughout the UK, and that UK measurements are similarly compatible with our international trading partners.

  1.2  Our role is to deliver world-class measurement science, to provide measurement infrastructure for the UK and to maximise the impact that this science and infrastructure has on the UK economy and quality of life—including key issues such as climate change and the maintenance and development of a sustainable environment.

  1.3  This submission draws on our expertise in measurement science and our knowledge of the international space sector derived in part from our leadership role in a variety of Earth Observation calibration and validation activities.

  1.4  In addition to the development and provision of measurement and instrumentation services to the space and in particular Earth Observation community, NPL represents the UK, and in some cases the international metrology community as a whole, on a number of key committees. These include Committee on Earth Observation Satellites Working group on Calibration and Validation (CEOS WGCV), Network for Detection of Stratospheric Change (NDSC) and World Meteorological Organisation (WMO). It also supports UK government funded research within the research councils and government policy (in this context) through Defra, DTI and associated agencies. NPL is recognised as the European lead national metrology institute (NMI) in this sector and is providing strategic support to the European Space Agency (ESA).

  1.5  NPL and metrology play a major role in many other space activities, eg:

    —  Time standards necessary for satellite-based global positioning systems.

    —  Communications between satellites and to ground.

    —  Microwave antennas.

    —  Ion thrust drives.

  However, this submission focuses on an area in which metrology is most critical—Earth Observation (EO) data, ie data collection at satellite sensor through to highly processed data (data product) as received by the "end user" or customer. At present, the end users are predominantly public funded bodies, where EO data is increasingly providing the critical evidence for the development and monitoring of the impact of government policy.


  2.1  It has long been recognised that measurements used for trade and regulation must be based upon an agreed international system of units. Such a system was formalised through the Convention of the Metre in 1875, which set up the System International for measurement units, which is used around the World today.

  2.2  However, the Convention only defines the base units, and in the intervening 130 years formalised arrangements have been established, eg quality procedure covered by ISO 17025, to ensure the validity of measurements made against the SI units. These have ensured that items for trade can be reliably specified across national borders, for example precision pieces of an automobile engine can be manufactured in more than one European State and assembled in another. They also ensure that regulators and policy makers can carry out their work with confidence, for example emission levels from vehicle engines can be evaluated by the manufacturer and then the vehicles traded around the World subject to national emission control regulation.

  These examples demonstrate one of the essential requirements for a market, confidence in the commonality and reliability of measurement data on the products or services traded.

  2.3  Clearly this requirement has not gone unnoticed by those designing and operating Earth Observation data collecting instrumentation. They all make their measurements using the same SI units. However, there is no formalised arrangement in Europe to ensure the general validity of such data. Indeed, there is strong evidence that data collected by different EO instruments often have significant discrepancies. For example this is a factor in the international controversy over the issue of climate change. The discrepancies and biases do not arise from any lack of care in the design and calibration of EO instrumentation, but from the extremely challenging requirements for accuracy that are made on such instruments, if the data they collect are to meet the requirements of policy makers and regulators, and of the challenges of operating in the hostile space environment.

  2.4  Until recently most EO satellite missions, with the exception of meteorological satellites, have been initiated and operated to meet clear science driven objectives. However, as their success is promoted to a wider user community, new applications become apparent. These applications, like the weather services, often require data products to be produced in a more operational mode—focusing more on reliability and consistency than the flexibility often seen as a necessity accompanying a science mission. To meet these emerging demands, many science missions have been modified to produce some products in an operational manner. It has also triggered initiatives such as GMES (Global Monitoring for Environment and Security), which seeks to build the necessary infrastructure to enable true operational services to be developed and exploited to the benefit of European industry and its citizens. Such services draw on data derived from all components of the EO sector: space, in-situ, airborne and in most cases the synergistic combination of them.

  EO operational services are unlikely to successfully develop for monitoring the environment and security without establishing formalised arrangements for validating the data collected by EO instruments, both terrestrial and space borne.

  2.5  The establishment of the joint EU, ESA GMES initiative is a measure of the importance governments and the Commission have given to issues that EO data can help to address. This has been further reinforced through the establishment of the global initiative, GEOSS (Global Earth Observation System of Systems), which seeks to establish coordinated efforts between largely existing activities to address a set of key societal themes.

  2.6  Examples of applications for EO data include:

    —  Understanding the drivers for climate change:

      —  To inform European policy on necessary steps to protect the living conditions of citizens, whilst not putting at risk European competitiveness with ineffective or unnecessary emission controls.

      —  To remove any equivocation over the affects of human activity on the Earth's climate, to strengthen the European negotiation position with countries which are not yet convinced of the urgency to reduce industrial and transport emissions.

    —  Monitoring the effects of climate change:

      —  Monitoring European costal zone to manage the effects of sea level rise.

      —  Monitoring biodiversity.

    —  Monitoring of food production, pests and disease across Europe.

      —  For the security of food production.

      —  To measure the impact and police subsidies provided by the EU to food producers.

      —  To measure the impact of the release of GMO on biodiversity.

    —  Monitoring air and water quality for the health of citizens.

    —  Monitoring and policing pollution so that those responsible for major pollution events can be challenged for compensation.

    —  Management of major calamities, eg cyclones, floods and storms.

  These issues affect decisions on investments and regulations that will have significant economic impact in Europe and require data that is unequivocal, from which international protocols that tackle issues at a global level can be agreed, and ultimately will require data that is robust enough to be challenged in court.



  3.1  The UK is internationally recognised as being strong in many aspects of Earth Observation. It has a well-coordinated academic research community funded through the research councils. This community is involved in all aspects of Earth Observation including: instrument design, build, calibration, validation and operation. It exploits and develops expertise in modelling and data manipulation as well as the more engineering-based activities.

  3.2  The UK also has an efficient and expanding "added value" commercial sector, which develop application specific data products. The strength of this sector stems from government policies of the 1980s, which emphasised that funding for Earth Observation should be focused on applications with commercial or Government policy objectives. The industrial sector is also engaged in some hardware manufacturing, which includes instrumentation and platforms etc. It is worth noting that it has become particularly strong in the small satellite business, with Surrey Satellite Technology Ltd being a particularly good example.

  3.3  Finally the UK has a potentially large, relatively astute and innovative user community. Public funded bodies already use remote sensing for a wide range of operational activities including land/forest management, pollution and air quality monitoring, mapping etc. Climate change studies, monitoring and adaptation to its impact are arguably the most demanding (in terms of accuracy) of current applications. However, whilst there is some coordination between government agencies and departments this is very weak and leads to inefficiency and fragmentation. It leads to duplication of effort in studies and expertise, but more seriously it prevents the development of critical mass to allow coordinated funding for larger scale projects, which would allow the UK to take on greater international leadership roles. Sufficient critical mass might stimulate and justify UK led missions with more operational objectives, controlled by user needs.

  The UK has a strong infrastructure in all aspects of Earth Observation and is well placed to play a major role in exploitation.


  3.4  Although the UK EO sector has many strengths, it regularly fails to achieve its "juste retour" from its ESA contribution. This failing is because the necessary full complement of key skills and prototype technologies are not available to make credible bids. The success of nations such as Germany and France can often be attributed to the underpinning support of strong national programmes, which allow critical mass and expertise to be developed and maintained in the interim periods between the larger ESA missions. It also allows strong links to be established between academia and the commercial sector with the ready supply of data to further research aims. National programmes also encourage the establishment of clear national objectives for both science and policy and make possible the development of low cost missions to meet defined priorities. These in turn help to steer the direction of the multi-national bodies such as ESA and EUMETSAT and act as catalysts for wider international collaborations with agencies from Japan, USA etc.

  3.5  The British National Space Centre (BNSC) whilst being the de facto focus for space activities in the UK, has few mechanisms or resources to influence or steer UK and international efforts. Despite this the UK still manages to play a significant role in international affairs, through the efforts of individuals and targeted funding from BNSC. BNSCs influence was weakened when most of the UK space budget was transferred to the research councils. The government aim was to simplify funding by bringing together all discretionary research funding. Whilst this has advantages, it limits flexibility and innovation particularly for more application-focused research objectives because of eligibility criteria attached to the funding mechanisms of the research councils. In particular, Public Sector Research Establishments (PSREs) such as NPL cannot be directly funded by research councils for EO research. Not only is this a barrier to innovation, in some cases it can lead to inefficiency and duplication of capabilities. There are many examples of university departments obtaining research grants to establish capabilities for "one-off" experiments or calibrations when facilities already exist in a developed or semi-developed form within a PSRE. Similarly, it is difficult for PSREs to take part in "Announcement of Opportunity" (AO) calls from ESA, since they often require as a prerequisite, national funding. This is particularly true for calibration and validation activities within ESA, which are nearly always by AO calls, and as a consequence are limited in participation to academic institutions.

  3.6  This inflexibility and restriction on participation is particularly damaging for the future of the EO sector. The evolution of EO from largely science driven objectives into user driven services requires robust, operationally delivered data products targeted at user needs. The operational production and delivery of these services will be through commercial organisations. Such services, both as delivered and during development, will require a more rigorous, transparent level of Quality Assurance (QA) and hence calibration and validation than is currently provided. Although still largely science based, this same level of QA is increasingly demanded of climate change studies in order to allow governments to take informed evidence based policy decisions. It is hard to see how the QA necessary to meet these demands can be achieved without significant change to calibration and validation practices.


  3.7  As the market for quality assured EO data develops it presents a significant opportunity for the UK to provide the necessary infrastructure to underpin this "certification" activity. The British Government is well versed at championing and implementing appropriate regulatory frameworks to satisfy all stakeholder interests. Politically it continues to provide international leadership for environmental issues, a position and activity acclaimed by all political parties. The already strong added value space sector is well placed to exploit new "certified" data products.

  However, this opportunity may be missed by the UK because of the fragmented nature of funding from government departments and the limited access to the only major UK source of space research funding through the research councils.


  The following example illustrates an innovative opportunity for the UK to establish a unique position as the international benchmark reference for all optical-based Earth Observation measurements made from space. In addition, it provides the necessary accuracy to reduce uncertainty in measurements underpinning climate change, and consequently removing the opportunity for sceptics to debate its cause and consequences.

  The Earths biosphere and climate is driven by the input energy from the Sun. This energy is largely concentrated in the optical region of the spectrum from the UV to NIR (200 to 2,500 nm). All surfaces, vegetation, soils etc exhibit unique spectral signatures in their reflectance characteristics, in the case of vegetation this varies not only with species but also life cycle. Similarly pollutants, on land and water, aerosols in the atmosphere can all be characterised, qualitatively and quantitatively by their spectral signature. For some simple diagnostics, spatial maps, land cover etc, absolute accuracy is of limited importance. However, as soon as temporal information is required, such as is necessary for climate change, or that the data needs to be combined with another sensor, then accuracy becomes critical.

  The calibration of every optical sensor launched into orbit has changed from ground to orbit, and continues to degrade with time. The size of this change varies between sensor type and even between nominally identical sensors. This make it difficult to establish a baseline from which to reference climate change and also to compare and combine data products from different missions, since each sensor will be seen to have an unknown bias with respect to the truth.

  The solution to this problem, bias and drift, in principle is simple and only needs to reflect the processes employed in the terrestrial environment ie regular recalibration against SI standards traceable to a national standards laboratory. However, the inability to retrieve space sensors makes this difficult to achieve in practise. As an alternative, in-flight calibration systems have been devised, but all fail in varying degrees with respect to the necessary accuracy and demonstration of traceability, as the transfer artefacts used, also drift with time.

  Recognising the issue the international community is starting to consider the establishment of a dedicated space-based reference satellite, which could serve to provide a set of "benchmark calibrations" of the Sun, Moon, Earth deserts, which all other in-flight sensors could view allowing the removal of bias through normalisation. If the reference satellite were sufficiently accurate this would also improve the accuracy of the other sensors in addition to simply removing bias.

  Although the call for such a mission concept is only now being discussed internationally, the UK already has a designed solution. In 2003, NPL led an international team in a proposal for a mission called TRUTHS (Traceable Radiometry Underpinning Terrestrial- and Helio- Studies). The proposal was in response to an ESA call for Earth Explorer missions and although at the time was unsuccessful stimulated significant interest for its innovative concept.

  TRUTHS proposed the flight of a small satellite with a suite of instruments to measure incoming solar radiation and spectrally resolved reflected radiation from the Earth or Moon. The instrumentation was designed to have accuracies 10x better than any previous mission. This accuracy was guaranteed by the use of a novel calibration system, which incorporated a "primary standard" and the establishment in space of calibration chain analogous to that carried out on the ground. In essence, the satellite could be considered as a "standards laboratory" in space and is widely acknowledged as the only technically viable solution to achieve the accuracies necessary for such a benchmark mission.

  The TRUTHS satellite would provide traceability to all other optical sensors by transferring its high accuracy to commonly viewable reference targets such as the Sun, Moon and Earth deserts.

  Whilst acknowledged as a breakthrough concept, it is surprisingly difficult to develop and exploit the idea further, even to the stage of a full study. Although all technologies required for implementation are available within the UK there is no funding mechanism for its development, as the idea originated within a PSRE. A further barrier to funding is the wide range of applications it would address, underpinning, measurements of the Oceans, Land and atmosphere for Earth Observation and measurements of the Sun. Each of these applications is considered separately when evaluating a project for funding. All four academic communities are supportive of the aims of the project but find it difficult to pool resources for a shared mission, which they perceive has a large "operational" component, and insufficient focus on each of their own individual objectives.

  EO does not as yet have sufficient priority within any one government department for data quality to be seen as a driver, or for which the additional international kudos that would be generated, to be considered important.

  However, with the international community starting to request a mission for which TRUTHS is the only currently proposed response, it will not be long before the ideas are exploited elsewhere. This will result in a lost opportunity for the UK to lead a project that provides the foundation of data quality for Earth Observation measurements in the future, which will underpin policy decisions that affect the future of the whole planet.

October 2006

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