MSG - More than just the weather
ESA INFO 5-2002. Some 36,000 kilometres above the coast of West Africa, a new satellite will soon take up a geo-stationary orbit, and train its powerful imager on the continents below. This is Meteosat Second Generation (MSG), the new wave of Meteosat weather satellites.
MSG has been developed through the close cooperation between the European Space Agency (ESA) and EUMETSAT, the European Organisation for the Exploitation of Meteorological Satellites.
The combination of ESA's space technology development skills and EUMETSAT's meteorological expertise and long-term operational perspective has resulted in this new satellite system set to provide an essential service for at least the next 12 years.
MSG is not just a satellite but encompasses a series of three spacecraft and a completely new ground processing and satellite control system developed by EUMETSAT. The MSG satellites will be operated from the EUMETSAT control centre in Darmstadt, Germany where the data from space will be processed then beamed to thousands of direct users in Europe, Africa and neighbouring countries.
The central facility in Darmstadt will be fully supported by specialist processing centres throughout Europe responsible for production of information on ozone, ocean and sea ice, climate monitoring, numerical weather prediction, land surface conditions, nowcasting and very short range forecasting in addition to specialised processing to derive meteorological information from navigation satellite signals.
All over Europe MSG data will lead to better weather forecasts especially when it comes to predicting "freak" conditions such as sudden thunderstorms or blankets of fog. This will be an important evolution of the forecasts we have grown used to over the past 25 years. But directly beneath MSG, across the African continent, the impact of its data will be revolutionary. Not only will MSG provide information on the weather for over 40 African nations, it will also provide data that can improve food security, predict the paths of killer diseases like malaria and meningitis and keep a watchful eye on slumbering volcanoes.
Technically, MSG is a direct successor to the seven Meteosat satellites that have carried out their weather watching function for the past quarter century. It shares many of the qualities of these satellites. "MSG is not an experiment, it's a robust, operational satellite that builds on the experience of the past". That's how Dr. Eva Oriol-Pibernat, European Space Agency mission manager for the project describes the new satellite. "The first objective will be to continue the mission of the original Meteosat family. The second will be to improve it".
The crucial difference is the technical proficiency of the imager on board MSG. It will send back much more information, far more often. The big improvement is the number of channels that can take in information. There were three on Meteosat - there are 12, in the visible and infrared, on MSG. Also the scanning rate is much improved, an image every 15 minutes instead of every half hour.
This will mean that weather satellite image sequences seen on European TV will be smoother and more realistic because they will have more data in them. And it's good news also for professional forecasters because they will have extra information from different channels, for example, how the instability of the atmosphere is behaving, and this is very important in predicting rapidly developing weather events.
For citizens across Europe this will mean that short-range forecasts of extreme weather such as thunderstorms, torrential rain or snow will improve markedly. This will impact transport, agriculture and many commercial activities. As well as the benefits for Europeans, improved forecasts of drought and severe weather will bring real benefits to African citizens too.
PUMA springs to life
Through a project known as Preparation for Use of MSG in Africa (PUMA) initiated by EUMETSAT together with its African user community in 1996, MSG will bring significant benefits to the meteorological services of 41 African nations and 4 Indian Ocean countries. Thanks to funding from the European Commission through the European Development Fund, each of these countries will benefit from integrated receiving stations that will give them more accurate and more frequent data than ever before.
Through the PUMA project, funds are being made available for the purchase of the hardware and the training of meteorologists in using the system. According to Dr. Tillmann Mohr, Director-General of EUMETSAT, it was recognised early in the MSG Programme that a coordinated approach to the provision of the new data streams would be essential for Africa. "In close cooperation with the European Commission and representatives of African meteorological services plus other related agencies, we are striving to ensure that the superior facilities offered by MSG will be utilised on a widespread and sustainable basis throughout the continent".
According to Dr. Etienne Bartholome of the Joint Research Centre of the European Commission, the key issue is to make this technology transfer work. "Firstly we have to ensure that the hardware is up and running. Secondly we have to get the data from MSG into the users current applications. That will be a real benefit".
The project according to Dr. Bartholome is breaking new ground in many ways. "All the African partners have come together and chosen to spend their aid resources on this. This level of co-operation shows the true importance of MSG to this community of users". The EU is putting 11 million Euro into the project and Bartholome is convinced it will have a really large impact. "This will make a difference for up to 20 years, once we have the infrastructure in place we can develop new applications and new ideas for a generation".
Dr Tillmann Mohr agrees. "Many of these countries didn't have the Meteosat information, now they are all getting equipped with receiving stations for MSG data and this is going to make a real impact on weather forecasting, and also in many other areas".
According to European Commission spokesman Fabio Fabbi, moving on from simply dealing with the weather is an important part of the project. "The PUMA initiative is now taking on a new dimension - this follow-up phase is called AMES-D (African Monitoring for the Environment and Sustainable Development). We are expanding the range of applications that MSG data can be used in, so it may be used in environment monitoring, agriculture, hydrology and global change".
One of those areas is in tracking the desert and by extension improving food security, a task that in many parts of Africa is still a question of life or death. MSG puts new tools at the disposal of scientists like Dr. Michael Rasmussen from the Institute of Geography at the University of Copenhagen. With his colleagues he's been using Meteosat data for a number of years to track the progress of the desert in Senegal. MSG, he says, will make that job much easier.
"We're using a very common parameter called the Normalised Difference Vegetative Index (NDVI). We compare reflected sunlight from the red part of the spectrum, where the vegetation is absorbing energy for photosynthesis. We are also measuring reflected energy in the near infrared - and this part of the spectrum cannot be used for photosynthesis, the actual difference between the two levels tells us whether photosynthesis is taking place or not - Its a simple difference but very effective".
"If you use this measure during the growing season, you getting a good indication of the productivity of the vegetation, because it indicates how much photosynthesis is taking place during the season. You can use ground measurements to calibrate the model. In Senegal we usually have between 30 and 40 ground control points and we can estimate the entire biomass of Senegal".
"For us the big advantage of MSG will be the new data, we can really identify changes in vegetation, and quickly. MSG will give us data every 15 minutes, and this will help with cloud cover, which can distort the picture in a longer time frame. You can also follow the changes in reflected light during the day and the amplitude of changes in surface temperature will be a good indicator of how dry the soil really is".
"We really expect that MSG will help us a lot in improving our models. And this will be important for the people on the ground".
"If you go to Senegal and you ask farmers what their problems are they will give you a long list - they will say declining yields, there is salt in the soil, there is reduced tree cover. What we are doing with the satellites and will continue to do with MSG is to compare between years and identify the areas that have really experienced a decline and equally find the areas that have improved productivity. MSG data is fundamental to this process".
Dr. Michel Legrand from the Université des Sciences et Technologies de Lille agrees. He has studied the impact of dust in the atmosphere over Africa. "This is a new satellite, a new generation that will give us the opportunity to be really efficient, to make a difference. One of the difficulties so far has been the need to do a correction to allow for the atmospheric contribution to our readings. With the fact that MSG has more channels, the atmospheric correction can be more accurate, and it will give us a true picture of the crops - so if there's a crop failure, it might be possible to spot it".
Tracking the killer diseases
Farmers across Africa will obviously benefit from better forecasts and a better understanding of desertification. But MSG will also have wider applications in tracking the progress and predicting the paths of two mass killers, malaria and meningitis.
Dr. David Rogers from the University of Oxford has been working with Meteosat to track conditions favourable for mosquitoes which spread the disease from infected to healthy people. With good data he says he can develop a sound model that will be an effective early warning system for a disease that kills two million people each year.
Rogers says that in areas of seasonal malaria outbreaks, his warning system could be very useful. "The plan is to anticipate the extent of malaria in seasonal areas, now that's often the function of the amount of rainfall which you can detect by satellite. You'd have a warning time of about a month or so. That would allow you to warn the health authorities so they can deliver the drugs that people need. I understand from people who are familiar with treatment in Africa that a couple of weeks to a month's warning would make a great deal of difference".
"Now it's much more difficult to make predictions in areas where malaria is present all the time. But malaria is a cyclical disease, we think there's a three year natural cycle of malaria - and that three year cycle is also affected by climate - so if climate is very favourable to malaria at a time when malaria is increasing anyway, you'll get more malaria than you'd expect. So climate signal from satellite is very important. You can still make a forward prediction of a few months and that's good enough for healthcare services".
Dr. Rogers says that moving onto data from MSG will really help his work. "We'll have a greater number of satellite channels to play with, and they'll have greater spectral stability than the current generation. We should be able to capture more precisely the areas in which malaria is being transmitted. And we should be able to use the satellite to monitor changes over time in the environment, that might favour malaria".
"MSG will make a real difference and give us a real advantage - because of the breadth of its data gathering and the frequency of its images - it will give us a fantastic advantage in the battle against malaria".
From dust to disease
As well as malaria, one of the most frightening and rapid diseases to stalk the African continent is meningitis. According to Dr. Madeline Thomson of Columbia University in the United States, the scale of meningitis in Africa is frightening. "In Europe we think of an epidemic when maybe 20 people contract the disease. But in Africa an epidemic can affect hundreds of thousands of people. And it's been getting worse in recent years". In 2002 it's estimated that the disease threatens over 8 million people in Ethiopia alone.
In an effort to try and understand the nature of these epidemics scientists have been looking at the environmental connection to meningitis. They believe that there is a connection to the desertification that's been happening in the past 40 years. The disease doesn't occur in the forested areas of central Africa, but is endemic in the dry region stretching from Senegal to Ethiopia.
"The epidemics all occur in the dry season - when the rain starts, the disease generally stops", says Dr. Thomson. To try and come up with a meaningful model that could predict outbreaks, Dr. Thomson and her colleagues collected all the information on epidemics going back 150 years. They have mapped these outbreaks and found they were closely related to absolute humidity and the type of land cover. "We wanted to see if the distribution of the epidemics has changed. And it has, they've been moving south into areas that were once wetter".
If the link between climate conditions and outbreaks of the disease was strong, then accurate data about climatic conditions was essential to any model that might work in predicting high-risk areas. "If you want to do real time monitoring then you need to use satellite data, there's little choice" says Dr. Thomson. "We've been using Meteosat and other data, and our preliminary work has suggested there is a relationship in the inter-annual variability of meningitis epidemics with the satellite data we have, the situation is still not clear enough, to give us a model we can really work with, a model we can depend on".
But there are some hopeful signs. She spoke of how earlier this year she presented an outline of the model to health professionals in Niger. "To illustrate what we were talking about, we tried to forecast the areas most likely to suffer outbreaks this year. The surveillance people on the ground said that actually we'd picked out the right places, because from their recordings on the ground these places had passed the epidemic thresholds already". Dr. Thomson stresses that this is a very preliminary system that needs further refining. When they tried to use it in Burkina Fasso the predictions of the model simply didn't match the experiences on the ground.
Will MSG improve this work? The key thing according to Dr. Thomson is the ability to record the levels of aerosols in the upper atmosphere and relate that to dustiness on the ground. Michel Legrand form Lille University says that MSG will meet that need. "MSG will have a better ability to detect dust over Africa. The main reason is that MSG has 4 channels in thermal infrared window regions while Meteosat has only one that is useful for the detection and tracking of dust. This will improve our ability to see and characterise dust".
Even if MSG can provide the data, Dr. Thomson says it will still take between five and ten years to put an accurate model in place. However she believes that the approach is sound. "I wouldn't say we've got a forecasting system that works - but we do have the methodology that works".
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