New era begins for European weather satellite system
EUMETSAT NEWS RELEASE
Posted: February 1, 2004

With commissioning activities finished, the Meteosat Second Generation (MSG-1) begins delivering nine new and three improved products at higher speeds. In keeping with tradition, MSG-1 will be renamed Meteosat-8.

The very first satellite in a new series of meteorological satellites has become operational, offering improved and faster images and data to European forecasters on a daily basis.

These data will undoubtedly help weather services give more accurate predictions of extreme weather, thereby saving property and lives. They will also help researchers gain a deeper understanding of physical processes important to weather and climate.

The first of the Meteosat Second Generation (MSG-1) satellites was launched in August 2002 and completed commissioning activities in December 2003, allowing the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) to declare the satellite operational at the end of January.

The satellite was commissioned by EUMETSAT to the European Space Agency (ESA), and manufactured by a consortium led by ALCATEL. The satellite and ground segment are owned and operated by EUMETSAT. Three additional MSG satellites will be built and launched, extending the MSG programme until 2018, allowing a smooth transition into the planned third generation of Meteosats.

The newly designed satellites are spin-stabilised in the geostationary orbit and will perform full-disc scans of the Earth like their predecessors. But, with MSG's 12 spectral channels, or "eyes," and a repeat cycle of only 15 minutes (instead of 30 minutes before), MSG can provide 20 times the information of the previous Meteosat system.

"For the first time ever, we can look at the Earth with 12 different 'eyes' every 15 minutes - a major breakthrough in monitoring cloud development," said Johannes Schmetz, the Head of EUMETSAT's Meteorological Division.

Each of the 12 channels offers a different perspective of the Earth and different combinations of channels can be used for novel meteorological products.

Improvements
MSG not only offers images of the full 'earth-disc' faster than other satellites, these images are greatly improved. Certain images of weather phenomena are available in colour after they are processed in the ground segment. This colour coding of weather activity helps meteorologists monitor sweeping weather patterns.

MSG satellite information helps scientists find out when clouds begin to ice and hence helps them examine the cloud structure more deeply than before. By tracking the displacement of clouds in different channels, meteorologists can infer wind speed and direction.

With MSG's improved imaging capabilities, meteorologists can produce 'false colour' pictures that make their work easier. For example, ice clouds can show up as blue and dust clouds over the Sahara desert can be coloured yellow - making these weather phenomena easy to distinguish. Colours can be used to denote information that comes from a combination of different channels, allowing a more comprehensive view of weather phenomena.

Meteorologists at airports will also benefit as short-term predictions become more accurate. The MSG scans allow forecasters to track if a cloud transforms from water to ice or, even more dangerous to aircrafts, when a cloud consists of supercooled water.

Because of its position in geostationary orbit, MSG supplies unprecedented coverage of weather events across Africa. These data are of interest to those studying changes in the climate, and they will help mitigate the effects of natural disasters in Africa. Together with the European Union, EUMETSAT is equipping and training African meteorologists on the MSG system.

Finally, MSG will boost the effectiveness of Numerical Weather Prediction (NWP) models by improving the initial data for a model forecast.

"When a model starts to run, it needs very accurate data on the initial conditions that prevail in the atmosphere. This is where MSG comes in - it can have a very positive impact on NWP models," Schmetz said.

Instruments
The MSG satellites carry a main instrument called the Spinning Enhanced Visible and Infrared Imager (SEVIRI). SEVIRI generates a vastly improved stream of data and images in 12 channels with twice the speed of first-generation Meteosats, as well as greatly improved resolutions:

"With MSG, it is as if we were taking simultaneously eleven images every 15 minutes using a 14-megapixel camera instead of taking two simultaneous pictures using a 6-megapixel camera every 30 minutes, with the MTP. For the high resolution visible channel, the comparison would be 64 megapixels for MSG compared with 25 megapixels for MTP," said Denis Fayard, EUMETSAT's MSG Commissioning Coordinator.

A second instrument on board is the so-called GERB, or Geostationary Earth Radiation Budget instrument. GERB measures the Earth's radiation balance as it views the top of the atmosphere. GERB gathers information critical for Earth sciences, in particular the analysis of the climate critical interactions between clouds and radiation.

Finally, MSG satellites are also equipped with a search and rescue transponder that can be used to relay distress messages to emergency centres.

Ground-segment innovations are also a crucial part of the MSG programme. EUMETSAT operates a Primary Ground Station north of Frankfurt and a specially built system in the Mission Control Centre (MCC). Raw data are processed in the MCC and retransmitted to users via EUMETCast, EUMETSAT's Multicast Distribution System developed as alternative dissemination mechanism to deliver MSG-1 data to users.

Finally, seven Satellite Application Facilities (SAFs), a network of processing centres, play an important part in exploiting MSG data.

"Now that MSG has been declared operational, it is the end of a complex programme but the beginning of an exciting phase - actually using the data. In this sense, the end is also a beginning," said Schmetz.

Commissioning Activities
As EUMETSAT Director General Dr. Tillmann Mohr declared MSG operational, the popping of corks and the clinking of glasses could be heard in the background. It was a big day for the people of EUMETSAT.

Quite some time has passed since the MSG programme was defined by ESA in 1984 and initiated by EUMETSAT in 1990. And, of course, those years have been accompanied by ups and downs.

One of the highest highs was the actual launch on 29 August 2002 of MSG-1 from French Guyana. One of the lowest lows was the failure of the solid state power amplifier (SSPA) in October 2002. However, the failure of the amplifier was a blessing in disguise. It caused EUMETSAT engineers to find a better way to disseminate MSG data - through the EUMETCast system. Another great moment in the history of MSG-1 was the display of the first image on 28 November 2002.

The first image was displayed during the event commemorating the 25th anniversary of METEOSAT in the Darmstadt headquarters.

"People kept saying it wouldn't work on time. We managed it just in time - everyone was waiting for it," said Fayard.

EUMETSAT conducted and was responsible for commissioning, which was performed in two phases - Phase A and Phase B. Phase A focused on the satellite in-orbit testing and a first version of the ground segment (relying on a temporary solution for image processing). Considerable progress was made during Phase A, despite sometimes difficult circumstances. One example is the rapid development of the EUMETCast system used to mitigate the effects of the power amplifier failure on-board the spacecraft.

Phase B focused on tests of the operational ground segment, especially imaging and meteorological product extraction. Phase B was conducted from June 30 to the end of December. The final review was passed successfully on 18 December 2003.

The commissioning process included in-depth tests and tuning of the MSG satellite and ground segment, and tests showed excellent performance. Many EUMETSAT scientists therefore believe that the quality of the products, after seasonal adjustment and fine-tuning, will exceed expectations.

Transmission Improvements
In addition to the improvements already mentioned, data transmission capabilities from the MSG satellite have been improved greatly to handle the significant increase of information gathered by the satellite.

Low Rate and High Rate transmission services replace the High Resolution Image (HRI) dissemination service and the WEFAX services of the Meteosat Transition Programme (MTP). MTP services will continue largely unchanged throughout the period of parallel MTP/MSG Operations until the end of 2005.

The dissemination via EUMETCast of the new services allows European users to use a widely available and low cost commercial solution to receive MSG data.

Additionally, an MSG Internet Service provides, among other things, some of the services formerly available from the WEFAX broadcast.

The 12 SEVIRI Imaging Channels
Here is a brief overview of the 12 channels of the MSG-1 satellite. A meteorological product is taken from one or several channels, which represent the measurements at particular wavelengths. Channels are operational day and night, except solar channels which are available only during daylight.

The VIS 0.6 and VIS 0.8 Channels are essential for cloud detection, cloud tracking, scene identification and the monitoring of land surfaces and aerosols. They can be used in combination to generate information on vegetation, an important element of climate change studies. These channels are solar channels and are useful only during daylight hours. Compared to first-generation satellites, MSG delivers these services with much finer detail.

The third channel, NIR 1.6, also a solar channel, measures reflected sunlight and helps to discriminate between snow and water clouds. It provides aerosol information as well. This channel is important for aviation, because of its ice-cloud detection abilities. Compared to previous satellites, the NIR 1.6 can distinguish snow on the surface of the Earth from water clouds. This was practically impossible with the first generation of Meteosats. NIR 1.6 is also essential for scene identification.

The IR 3.9 is primarily for the detection of low clouds and fog at night. But it is also useful for the measurement of land and sea temperatures at night and the detection of forest fires. Compared to previous satellites, this channel offers a completely new service - the identification of low clouds and fog at both day and night.

The WV 6.2 continues the Meteosat water vapour channel to measure upper-troposphere water vapour. In addition, the WV 7.3 provides information on the humidity conditions in the mid-troposphere. The humidity information from both channels is used for tracking water vapour features and thus provides the local wind field in even cloud-free conditions. These channels also support scene identification and height assignment for semi-transparent clouds. The WV channel data are used to infer possible local atmospheric instability which might lead to convection and severe storms.

The seventh channel, IR 8.7 is used primarily to provide quantitative information on thin cirrus clouds and to support the discrimination between ice and water clouds. It is also necessary for scene identification and the atmospheric instability product.

IR 9.7 is a channel focused on ozone. It measures ozone concentration in the lower stratosphere. It is used to monitor total ozone and height of the tropopause. It has the potential for tracking ozone patterns as an indicator of wind fields at that level. Elaborate algorithms and the data of other MSG channels, however, are necessary to actually infer the ozone field from the IR 9.7 measurements.

The IR 10.8 and IR 12.0 channels are known as IR window channels, as their view on the Earth's surface and cloud tops is only little affected by gaseous absorption within the atmosphere. Each responds to the temperature of clouds and the surface. In combination, the two channels measure the small atmospheric effects of low-level atmospheric moisture, and therefore the two channels are usually referred to as "split-window" channels. These channels are also used for scene identification, cloud tracking, cloud heights, surface and sea surface temperatures, atmospheric winds and for estimates of atmospheric instability. The IR 10.8 channel is a follow-on of the previous Meteosat IR channel.

The IR 13.4  channel is in the CO2 absorption band and is used for scene identification and the estimation of atmospheric instability. The most important application of the IR 13.4 is to infer the height of semi-transparent clouds.

Finally, the HRV channel, a solar channel dubbed the broadband visible channel, is the current Meteosat visible (VIS) channel with an improved sampling interval of just 1 kilometre compared to the Meteosat's 2.5 kilometres. The high resolution visible channel combines information from channels one and two for fine detail on land surfaces and small clouds. This channel is completely new at MSG's higher resolution.

"Because of MSG's multitude of channels, EUMETSAT is now able to offer a completely new product in the field of "nowcasting" - or short-range weather forecasting. A combination of the IR and WV channels is used to infer atmospheric instability which will help meteorologist predict thunderstorms and lightning, for example," said Marianne Koenig, a scientist in the Meteorological Division of EUMETSAT.

Weather forecasters will be better able to plan for fog, snowfall, hazardous winds and volcanic activity. Ships and aircraft in distress will be able to send distress messages via MSG satellites to emergency centres, where rescue missions will be coordinated.

Finally, African nations will benefit from the technology via a programme - known as the PUMA project - coordinated by the European Union. The EU will help countries become equipped with MSG reception and processing stations that will track tropical cyclones and help predict severe weather and droughts.

EUMETSAT
EUMETSAT is an intergovernmental organisation that establishes and maintains operational meteorological satellites for 18 European States (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, Turkey and the United Kingdom). EUMETSAT also has six Cooperating States (Croatia, Hungary, Poland, The Slovak Republic, Slovenia and Romania). Additionally, an agreement has been signed with Serbia and Montenegro, and upon ratification by its government, Serbia and Montenegro will become the latest Cooperating State.

The images and the data from Meteosat make a significant contribution to weather forecasting and to the monitoring of the global climate.