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ECMWF operational weather forecasts now use IASI and ASCAT data

(PresseBox) (Darmstadt, ) IASI radiance and ASCAT surface wind data, both derived from instruments on board of Metop-A, are operationally used in the European Centre for Medium-Range Weather Forecasts (ECMWF) forecasting system - just over 12 weeks after the first data were disseminated to Numerical Weather Prediction centres and only 8 months after the launch of the Metop-A satellite on 19 October 2006.
The assimilation follows a number of previous experiments to assess the impact of the Infrared Atmospheric Sounding Interferometer (IASI) radiances upon quality of the ECMWF analyses and forecasts. IASI provides measurements in the thermal infrared at 8461 spectral samples at a spectral resolution from 0.35 - 0.5 cm-1 resolving the absorption spectrum of the atmosphere in fine details. The extremely fine spectral sampling allows the assessment of detailed atmospheric structures of temperature and composition.

The accuracy of these measurements is unprecedented as there currently are no instruments on existing operational weather satellites to provide similar results.
From a low-altitude, over a swath width of 2200 kilometres sun-synchronous orbit, IASI is cross track scanning and collects 120 soundings per 8 seconds. The Earth’s atmosphere is covered twice a day due to the sun-synchronous orbit of Metop-A. IASI includes an integrated imager which samples the area of IASI sounder in the infrared window region. The integrated imager is used for the co-registration with the AVHRR instrument on Metop-A. The purpose of the co-registration is the Earth location of the soundings and the cloud detection therein.

The ASCAT (Advanced Scatterometer) provides triplets of radar backscatter which are used to estimate surface vector winds over global oceans. Data from ASCAT have been monitored at ECMWF since the start of trial dissemination on 31 January 2007 and a high-quality, stable wind product has already been developed. The accuracy of the wind direction measurements is excellent. Assimilation experiments of ASCAT surface vector wind in the ECMWF analysis and forecast system showed a positive effect on forecast skill over the Southern Hemisphere. As with IASI, surface winds from ASCAT were included in the ECMWF operational forecast system on the 12th June 2007.

About ECMWF: world leader in numerical weather prediction

The European Centre for Medium-Range Weather Forecasts (ECMWF) is an independent international organisation supported by 18 European Member States and 10 Co-operating States. At its headquarters situated in Reading, England, a supercomputer complex is linked by highspeed telecommunication lines to the computer systems of the national weather services of its supporting States. The Centre's computer system contains the world's largest archive of numerical weather prediction data, and runs the world's most sophisticated medium-range prediction model of the global atmosphere and oceans.

Established in 1975, ECMWF is renowned worldwide as providing the most accurate medium-range global weather forecasts to ten days and seasonal forecasts to six months. Its products are provided to the European National Weather Services, as a complement to the national short-range and climatological activities.

About CNES

CNES (Centre National d’Etudes Spatiales) is the French space agency, a state-owned organization founded in 1961. It is responsible for shaping and implementing France’s space policy. Approximately 2,400 employees with highly specialised know-how work on CNES sites. Nearly 1,800 are engineers or managers and 35 % of them are women.
To accomplish its assigned missions, CNES calls on the expertise of these employees in four complementary centres.
IASI is a joint CNES/EUMETSAT initiative. CNES has overall technical responsibility for the instruments through to in-orbit checkout. It is also in charge of deve¬loping the data-processing software and setting up and running a technical expertise centre. EUMETSAT operates the IASI instrument, processes, archives and distributes data to national weather services and other research institutions in Europe.


The European Organisation for the Exploitation of Meteorological Satellites is an intergovernmental organisation with currently 20 European Member States (Austria, Belgium, Croatia, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland, Turkey and the United Kingdom) and 10 Cooperating States (Bulgaria, Estonia, Hungary, Iceland, Latvia, Lithuania, Poland, Romania, Slovenia and the Czech Republic).

EUMETSAT is operating Meteosat-8 and -9 over Europe and Africa, and Meteosat-6 and -7 over the Indian Ocean.
Metop-A was launched in October 2006 and is delivering operational data since 15 May 2007. The data, products and services from EUMETSAT’s satellites make a significant contribution to weather forecasting and to the monitoring of the global climate.


Die europäische Organisation für die Nutzung meteorologischer Satelliten ist eine zwischenstaatliche Organisation mit Sitz in Darmstadt, Deutschland, mit derzeit 21 europäischen Mitgliedsstaaten (Belgien, Dänemark, Deutschland, Finnland, Frankreich, Griechenland, Irland, Italien, Kroatien, Luxemburg, die Niederlande, Norwegen, Österreich, Portugal, Schweden, Schweiz, Slowakei, Slowenien, Spanien, Türkei und das Vereinigte Königreich) und 9 Kooperationsstaaten (Bulgarien, Estland, Island, Lettland, Litauen, Polen, Rumänien, Tschechische Republik und Ungarn).

EUMETSAT betreibt gegenwärtig die geostationären Satelliten Meteosat-8 und -9 über Europa und Afrika sowie Meteosat-6 und -7 über dem Indischen Ozean. Metop-A, Europas erster polarumlaufender Wettersatellit, wurde im Oktober 2006 gestartet und liefert seit dem 15. Mai 2007 operationelle Daten. Nach seinem Start, der für Mitte Juni 2008 geplant ist, wird der Jason-2-Meeresbeobachtungssatellit die bisherigen Missionen von EUMETSAT um Daten zur Meeresoberflächentopographie erweitern. Die Daten, Produkte und Dienste von den Satelliten von EUMETSAT leisten einen bedeutenden Beitrag für die Wettervorhersage und für die Überwachung des globalen Klimas.