OVERVIEW ON THE PROGRAM

1 - IMPORTANT OCEANIC FEATURES AND REQUIREMENTS FOR SATELLITE DATA
2 - OSI SAF BRIEF HISTORY
3 - A CONSTANT ADAPTATION TO THE USERS REQUIREMENTS

For complementing its Central Facilities capability in Darmstadt and taking more benefit from specialized expertise in Member States, EUMETSAT created Satellite Application Facilities (SAFs), based on co-operation between several institutes and hosted by a National Meteorological Service.

1 - IMPORTANT OCEANIC FEATURES AND REQUIREMENTS FOR SATELLITE DATA

     The research in oceanography, the monitoring of climate and coastal environment, the operational marine meteorology, the Navy operations and the off-shore activities have a common need to observe, describe, analyse and forecast the state of the oceans and its variations. In this respect, the measurement of oceanic physical parameters (temperature, salinity and currents), as well as momentum, energy and fresh water exchanges at the ocean/atmosphere interface which drive their evolution, is of extreme importance.

Because of its physical nature, the ocean is much more difficult to observe than the atmosphere : most of the significant phenomena have a characteristic size which is one order of magnitude smaller than their equivalent in the atmosphere, and most of the signals are weaker. Moreover, the environmental conditions at sea make the in-situ measurements more difficult and more expensive than over land. As an example, the oceanic meso-scale eddies, which dominate the oceanic signal in most basins, have a typical size between 10 and 300 km, while the atmospheric synoptic perturbations have a typical size of 1000 km. The temporal spectrum of significant oceanic signals is also very wide, between a few hours (surface waves, internal waves, tides...) and a few months or years (eddies, equatorial waves, subtropical gyres and associated currents).

All these reasons make the earth observation satellites an unique opportunity to observe the oceans with the necessary coverage, sampling and availability in operational conditions, which an in-situ measurement network would never fulfil alone. Nevertheless, the ocean is opaque for electromagnetic radiation, which implies that only surface signals can be observed from space. As a consequence, the knowledge of the three-dimensional structure of the oceans requires the combined use of satellite observations, in-situ observations and ocean numerical models through assimilation techniques.

Momentum exchange between the atmosphere and the ocean determines wave spectra, storm surges, ocean circulation. The measurement of near-surface wind by scatterometer is of utmost importance.

In addition to the Sea Surface Temperature (SST), two important components of the heat budget at the ocean surface, which drives its evolution, can be inferred from satellite visible and infrared radiometers : the radiative short wave (SSI) and long wave (DLI) fluxes. No direct routine measurements of the radiative fluxes are available from ships or buoys, as the maintenance of pyranometers or pyrgeometers at sea is very difficult, and requires in addition a frequent cleaning of the instruments. Moreover, the estimates of these fluxes, provided by the NWP outputs suffer from a lot of systematic errors due to the weaknesses of models radiation and cloud parameterisations, to the lack of upper-air observations over the oceans, and model spin-up problems.

Accurate information on sea ice is also crucial for a range of applications from operational NWP and numerical ocean models to climate research. Combining data from different satellites and sensors in a multi-sensor approach ensures an optimal use of available real-time satellite data.

2 - PROJECT PHASES and CONSORTIUM

• 1997 - 2002 : Development phase.
• July 2002 - February 2007 : Initial Operational Phase (IOP).
• March 2007 - February 2012 : Continuous Development and Operations Phase (CDOP).

3 - A CONTINUOUS ADAPTATION TO THE USERS REQUIREMENTS

     Initially, i.e. for the development phase (1997-2002) the OSI SAF was conceived as an answer to implicit requirements from the meteorological and oceanographic communities of EUMETSAT Member States and Co-operating States for a comprehensive information derived from meteorological satellites at the ocean-atmosphere interface. In particular, the expected target applications of OSI SAF products were :

• Operational weather forecasting, for direct use and/or assimilation into Numerical Weather Prediction systems,
• Operational marine meteorology (including operational Sea Ice monitoring and prediction), for direct use in marine forecast activities or related service activities (storm surge prediction, oil drift prediction, ship routing etc...),
• Operational oceanography, for use and/or assimilation into Numerical Ocean Prediction systems,
• Polar research, to monitor sea surface conditions in polar regions,
• Research in meteorology and oceanography,
• Climate monitoring, for direct use and/or assimilation into coupled ocean/atmosphere numerical models,
• Environment monitoring.

• their increasing needs for global coverage, in particular for global modelling and climate monitoring,
• theirs needs for higher horizontal and temporal resolution,
• their needs for a flexible access to full resolution products, allowing on demand geographical extraction, re-mapping, format change etc...

• at International level : the Global Ocean Data Assimilation Experiment (GODAE), and its High Resolution Sea Surface Temperature Pilot Project (GHRSST-PP), and the Global Climate Observing System (GCOS),
• at European level : the Global Monitoring for Environment and Security (GMES) initiative, and its Large Integrated Project MERSEA (Marine EnviRonment and Security for the European Area) (2002-2008), which resulted into the implementation MyOcean in 2009.