SATMOS and meteorological satellites
An important part of AERIS’ meteorological activities is the provision of data and products from satellite observation.
One of the AERIS Data and Service Centres, SATMOS (Service d’Archivage et de Traitement Météorologique des Observations Satellitaires), has been specialised since 1985 in the collection of meteorological satellite data and their availability to the scientific community.
Implemented by the Centre de Météorologie Spatiale of Météo-France, SATMOS currently concentrates the basic data from imaging radiometer of five complementary geostationary* meteorological satellites to ensure global coverage of the Earth and makes them available in a common format through the ICARE CDS. SATMOS and ICARE also provide access to enhanced products in the areas covered by these five satellites: cloud masks and classifications, cloud top height and pressure, cloud microphysics.
Data from multiple polar-orbiting meteorological satellites (notably the European METOP and American NOAA satellites) acquired at the Lannion site and archived by the Centre de Météorologie Spatiale are also made available to scientists by SATMOS.
Megha-Tropiques: a scientific mission at the service of the weather
Megha-Tropiques is a space mission developed and operated jointly by the French and Indian space agencies (CNES and ISRO). This mission is designed to study the convective systems of the atmosphere and more particularly the analysis of the water cycle through the transport and distribution of water vapour, the life cycle of convective systems and energy exchanges in the equatorial belt. This satellite has a very specific orbit: it only flies over the intertropical zone, where the planet’s most intense weather phenomena occur. Three to five times a day, it observes water vapour density in the atmosphere with a resolution of 10 km.
Although primarily a scientific mission, Megha-Tropiques provides valuable information for weather forecasting and tropical storm monitoring: the data from the SAPHIR instrument are assimilated into the operational models of Météo France and several other national meteorological agencies (NOAA, JMA, KMA, UK Met Office…).
The ICARE Data and Services Centre is the scientific ground segment of the Megha-Tropiques mission. It collects level 1 data from the three instruments, MADRAS (stopped since January 2013), SAPHIR and ScaRaB from ISRO and processes level 2 and higher science products. These products cover precipitation, water vapour, radiation and cloud classification. They are made available to users in standard formats: HDF4, HDF5, or NetCDF, depending on the product specifications.
Combining geostationary information with data from low orbit satellites
Through SATMOS and ISRO, ICARE therefore hosts the level 1 data of geostationary satellites and those of Megha-Tropiques. The combination of these data allows the realization of innovative level 4 products that are useful for tropical meteorology and hydrology as well as for the characterisation of the life cycle of convective clouds.
Geostationary satellites provide high temporal resolution and are particularly useful for detecting and tracking convective cloud systems. Low orbit microwave instruments, including the SAPHIR sounder radiometer, present on-board Megha-Tropiques, provide the measurement of the vertical profile of humidity in the atmosphere (with several daily passages in the tropical zone thanks to its highly inclined orbit).
For example, the TAPEER (Tropical Amount of Precipitation with Estimation of Errors) processing chain, operated by ICARE and based on an algorithm developed by the Laboratoire de Météorologie Dynamique (LMD/IPSL), provides daily rainfall accumulation products in the intertropical zone on a 1° grid.
* Geostationary satellite: a satellite which, placed in a circular orbit at an altitude of 36,000 km, rotates at the same speed as the Earth and therefore appears fixed to an observer on ground.