How GEOmon improves knowledge on Climate Change ?
GEOmon is helping to improve CO2 and CH4 monitoring using measurements
a) on the ground (in situ) at many stations around Europe and globally;
b) from aircraft to study the air in the free troposphere; and
c) by using upward-looking remote sensing techniques to measure the total amount of carbon gases in a column from the ground to the top of the atmosphere.
1. In situ monitoring
In situ monitoring is direct measurement of carbon dioxide and methane by instruments on the ground. Most measurement is currently done by the USA but there is a need for other nations to contribute more significantly to these efforts particularly in proportion to their emissions. Europe has several observation stations monitoring greenhouse gases, but they are not sufficiently well interlinked. France and Germany, as well as nations like Finland and Holland, have strong national efforts. France also monitors the Indian Ocean and the Atlantic. However there are major problems. The UK has no national programme at all, and the European methane network was closed in 2005.
GEOmon will improve measurement considerably. Cooperating with other EU programmes such as IMECC and Carbo-Europe, GEOmon will help with the intercomparison of measurements. This is essential if a seamless dataset is to be created for modelling. For example, if air arriving at London is measured as 1820 ppb methane, and then blows to Paris, arriving with 1830 ppb, a model might assume that 10 ppb have been added over the channel and intervening land. But if the intercomparison shows that Paris measurements are say 5 ppb higher than those in London, then the addition is only half: 5 ppb. Careful intercomparison is therefore very important in working out emissions.
GEOmon will also speed up reporting. Several stations will produce 'near real-time', reporting data. In the not-too-distant future it may be possible to model emissions as they occur.
Outside Europe, most greenhouse gas monitoring is done by the US, Australia, New Zealand, Canada etc. France's Indian Ocean programme contributes important information, but there is very little measurement in Africa or South Asia. Most global models use US data mainly. GEOmon will improve the EU contribution by commencing greenhouse gas measurement in Cyprus and adding to the French overseas work with monitoring in southern Africa in areas of extensive biomass burning.
2. Measurements from aircraft: Caribic 
The troposphere is the lowest portion of the Earth's atmosphere. It contains approximately 75 percent of the atmosphere's mass and 99 percent of its water vapor and aerosols. Most of the phenomena we associate with day-to-day weather occur in the troposphere and therefore it is one of the most important parts of the atmosphere for research purposes. The planetary boundary layer is the lowest part of the troposphere, where friction with the Earth's surface influences air flow. Above this layer, in the ‘free troposphere’, air moves more freely and it is in this zone that aircraft fly.
For several years, commercial aeroplanes have been carrying instruments which conduct measurements in the free troposphere. One of the most extensive projects is Caribic which uses Lufthansa flights. This programme is costly and requires ongoing funding.
GEOmon provides considerable support for Caribic, in measurements of both greenhouse gases and other important components of the air. The Caribic flights measure greenhouse gases in the free troposphere from Frankfurt to Latin America, Asia and Africa. The work will be particularly important in the tropics, where there is very little information available.
Caribic results will be vital for computer modelling of greenhouse gas budgets – the tropical data in particular mean that global models of greenhouse gases will be much improved.
3. Remote sensing: FTIR measurements
Atmospheric greenhouse gases can be measured using a technique called FTIR (Fourier Transform Infrared measurement). Greenhouse gases absorb and re-emit the Earth's outward radiation so that a smaller proportion passes through the atmosphere and escapes into space. The Earth receives energy as visible sunlight, but radiates it outwards as infrared light. In order for the Earth’s temperature to remain constant, the inward and outward radiation must balance. If more energy comes in than goes out, the planet heats up (which is happening at the moment).
Infrared radiation is heat radiation (you can feel it if you put your hand above a hot plate of a kitchen cooker). Carbon dioxide and methane block this, and the blocking can be measured directly by examining either sunlight coming down, or outward radiation upwards (detected by satellite).
Several satellites use these meaurements to map carbon gases around the planet. The European Union's ENVISAT includes an instrument package known as Sciamachy, which oversees the sunlit Earth and maps upward infra-red radiation. Soon the USA will launch a satellite to look especially at greenhouse gases. This is called OCO (named after CO2, which is really O-C-O).
But satellite measurements are complex, difficult to interpret and need careful 'ground-truthing' (validation from in situ controls) Many factors, such as clouds or poor calibration can contribute to misleading results from satellite instruments.
GEOmon will provide important 'ground-truthing' for satellites with upward-looking FTIR measurements. GEOmon will finance several FTIR instruments measuring the total amount of greenhouse gases in the column of air above the instrument. This counterbalances the downward satellite measurements and so the two sets of data can be used to check each other. GEOmon will also have data from its other in situ measurements so the data-sets can be used to further validate the satellite studies.
Currently FTIR work is much less accurate that in situ work. We hope GEOmon will help improve that. The two techniques are both needed – at night and in the Arctic winter there is no sunlight, so in situ work is essential, but in the tropics where there are very few measurements, FTIR work will be very helpful.
The contribution by GEOMON and IMECC to global monitoring of carbon gases
Currently,the bulk of the burden of global monitoring of carbon gases is undertaken by US programmes. To date, Europe has contributed very little to this essential work , partly because major nations such as the UK have not participated, and partly because pan-European programmes monitoring methane and CO2 have either been cancelled? or weakly supported...
GEOmon and its sister programme IMECC will go some way to improving this situation. If the Kyoto process is to succeed, it is vital that greenhouse gases be monitored properly. By supporting monitoring in Europe, Africa and the Indian Ocean, Europe will begin to contribute more to this vital common global task which will in turn aid understanding and policy-making.
